Animal Communities of the Sea-bottom in Auckland and Manukau Harbours
[Read before Auckland Institute, August 11, 1936; received by the Editor, August 18, 1936; issued separately, March, 1937.]
Method of Collecting the Samples.
Origin of Auckland and Manukau Habbours.
List of Stations.
The Animal Communities.
The Echinocardium formation.
The Maoricolpus formation.
The Tawera+Glycymeris formation.
The Arachnoides formation.
The Baryspira community.
Succession in the animal communities of Auckland Harbour.
Range of certain benthic animals in respect to animal communities.
Benthic animal communities in relation to food of snapper (Pagrosomus auratus).
Effect of harbour works upon benthic communities and fishing grounds.
Recent ecology and its bearing upon paleoecology.
The following report is an attempt to define and classify the benthic animal communities of the Auckland and Manukau Harbours and to correlate them with the bottom materials. The littoral animals of this area have been dealt with to some extent by Oliver (1923) in his excellent paper on Marine Littoral Plant and Animal Communities in New Zealand. In Oliver's paper most of the communities are based upon algae, but in the benthic communities which form the subject of the present paper fresh algae do not play an important part except for the support of a few gasteropod molluscs, such as Trochus tiaratus in the Tawera+Glycymeris formation. As detritus, however, algae are one of the main factors governing the Echinocardium and other mud-bottom communities.
A paper by Hounsell (1935) entitled Hydrographical Observations in Auckland Harbour is intended as an introduction to subsequent reports on the ecology of this area. Accounts of tides, rain-
fall, humidity, barometric pressure, prevailing winds and their velocity, hours of sunshine, air and sea temperatures, effects of sewage, salinity, and hydrogen-ion concentration of the sea-water are all given, and need not be repeated in the present paper. Apart from the bottom communities dealt with herein, other reports dealing with littoral communities and special reports by other members of the committee are in preparation.
The present investigation was made possible by the allocation to an Auckland Institute committee of two research grants, one in 1925 from the New Zealand Institute and the other in 1932 from the Hutton Fund, also administered by the New Zealand Institute, now the Royal Society of New Zealand. The writer's thanks are due also to Professor W. B. Benham for numerous polychaete determinations and to Mr. E. W. Bennett for assistance with the crustacea. Also, the writer gratefully acknowledges the assistance rendered by the following launch owners: Mr. Saunders (1926–27), Mr. J. Low (1927–31) and Dr. H. A. Cooper (1932–35). The bulk of the work was done from Dr. Cooper's launch, the “Frances C,” which was used on frequent occasions during four successive years. During 1936 the writer's launch “Tawera” has been used.
Method of Collecting the Samples
The bottom-samples were dredged with either a small naturalist's dredge with wide-angled deep-cutting jaws, curved outwards in the middle, or else a small conical dredge. The naturalist's dredge has the cutting edges 20 inches wide, and the conical dredge a diameter of 12 inches. Each has an impervious heavy canvas bag attached so that the sample comes up intact, without any appreciable loss of the finer silts by the passage of the dredge through the water. As a further precaution, the measured sample for obtaining the texture by mechanical grading (described later) is taken from the middle of the mass of material as soon as it is emptied from the dredge. The widely-tilted jaws of both the naturalist's dredge and the conical dredge ensure a substantial haul soon after the dredge strikes bottom, and it is seldom necessary to drag the dredge for more than a few yards, due partly also to the soft or loose nature of most of the bottom over the areas investigated. Although not as efficient as the “Petersen Bottom Sampler” or “grab,” which makes possible accurate quantative data of animal density per square metre, each dredge-sample from the present survey may be considered to represent an approximately equal area of sea bottom. Certainly the wide-angled jaws in causing the dredge to dig in and fill quickly minimise the selective action usually credited to the naturalist's dredge. The small size of the dredges used is an undesirable feature, since the chances of getting a thoroughly representative fauna in any one haul are somewhat reduced. However, standard sized dredges were impracticable, as all the hauling had to be done by hand from a motor-launch. In consequence, the number of dredge-stations made per day was not great, the average being five.
The total number of dredging-stations established is 148, and a list of them follows. In many cases one dredging-station may represent several casts, additional ones being necessary for plotting the boundaries of communities, but in all cases the records of texture and fauna are recorded from one cast only.
Origin of Auckland and Manukau Harbours.
Both the Auckland and Manukau Harbours have originated in comparatively Recent times, owing to the submergence of an extensive area of low relief. Professor J. A. Bartrum (1917) and Mr. C. W. Firth (1930) have explained that these harbours are typical drowned valley-systems that have been widened and cliffed by wave-action, the rocks for the most part being soft. The debris derived from these eroded rocks has gradually silted up many of the bays and formed extensive tidal mudflats. Following this negative movement of the land the only other recognizable movement has been described (Turner and Bartrum 1929) as an uplift of from 5 feet to 8 feet, that occurred within Recent times. This uplift has prevented further large-scale erosion of the soft cliffs of Waitemata sandstone (Up. Oligocene-Miocene), many of which now have in front of them protective mud-flats or raised beaches.
Both harbours are mainly shallow, with extensive intertidal flats, the main channels varying in depth from 5 to 12 fathoms in Auckland Harbour and from 5 to 20 fathoms in Manukau Harbour. No large amount of fresh water discharges into either harbour, so that both may be regarded as typical tidal estuaries, the only marked difference being that the Manukau is a bar-harbour, and has a deep-water basin within the entrance, the bottom of which is formed of fine iron-sand that washes in from the West Coast. Over the greater part of the area in both harbours and in Hauraki Gulf the substratum is composed of soft mud, hard ground being confined to the main channels, beaches and shell-gravel ramps surrounding outlying islands. These are referred to again under the heading of “Succession in the Animal Communities.” For the purposes of the present survey the Auckland Harbour and adjacent areas of investigation were divided into areas, defined in the next section.
The Upper Harbour. All that area westward of a line between Kauri Point and Point Chevalier Reef. It is composed largely of intertidal mud-flats, and the main channels are shallow with hard shelly bottom only in the vicinity of Kauri Point. The salinity is lower than for either the Inner Harbour or the Hauraki Gulf, and the animal life is sparse and lacking in variety.
The Inner Harbour. This includes the commercial port of Auckland. It starts immediately eastward of the Upper Harbour boundary and extends to a line from North Head to Bean Rock and thence to Bastion Point. This area is largely soft mud-bottom but with a moderately wide strip of hardy shelly sub-
stratum in the main channel. The salinity ascends to normal at the outer or eastern boundary of the area. Tidal scour causes the hardy shelly bottom and decides its position.
The Motukorea and Motuihi Channels including the Tamaki Estuary. The western boundary of this area is Bean Rock to Rangitoto Island, and the eastern boundary, Motuihi Island to Eastern Beach, Tamaki. This area is practically all soft mud except for the Motuihi Channel, which has a hard shelly substratum, also caused by tidal scour.
The Tamaki Strait westward of Awaroa Bay and the Channel between Waiheke and Motuihi Island. This area is similar to the last, mostly soft mud, but shelly where there is tidal scour in the Channel.
The Rangitoto Channel. This is mostly soft mud, muddy sand and fine clean sand with a shelly strip in the main channel, which is caused by tidal scour.
Northern shore of Waiheke Island in vicinity of Oneroa (Haroto Bay). Soft mud off-shore but with shell-gravel ramps accumulated off the rocky shores, and a fine sand belt off the beach. Both the shell-gravel and the fine sand owe their origin to wave-action in collecting and comminuting the dead shells.
Off the northern shores of Rangitoto and Motutapu Islands and the passage between the latter and Rakino Island. The bottom is soft mud except for the accumulation of shell-gravel in the passage between Motutapu and Rakino.
The “Noises” Group of Islands. (Motuhurakia, David Rocks, etc.). The bottom off-shore is soft mud, but shell-gravel ramps occur close inshore off all the islands. These are formed by wave action.
Whangaparaoa Passage, Kawau and Omaha Bay. Several kinds of bottom are represented, sandy mud, shelly and clean sand. The results from this area are useful for comparison with the harbour stations.
Eastern end of Waiheke Island and Tamaki Strait to the eastward of Awaroa Bay. The bottom is mostly soft mud except for small shelly areas in the tidal channels.
A series of nine Manukan Harbour stations. For contrast with the Auckland Harbour.
Off Mount Maunganui, Bay of Plenty. This is a coastal type of bottom and it is included for comparison with station I.6.
|Station.||Date.||Depth in Fath.||Bottom.*||Average Grade.||Locality.||Animal Community.|
|A.1||16-11-1933||7||m.+sh.||5.902||Off Greenhithe wharf.||1a2|
|A.2||16-11-1933||6||m.+sh.||5.409||Between Hobsonville and Birkdale wharves.||1a2|
|A.3||16-11-1933||4½||m.+sh.||6.611||Between Birkdale and Island Bay wharves.||1a2|
|A.4||16-11-1983||4½||m.+sh.||7.029||Off Island Bay wharf (mid-channel).||1a2|
|A.5||16-11-1933||8||m.||5.764||[ unclear: ] way from Onetaunga wharf to Boat Rock.||1a2|
|A.6||16-11-1933||9||sh.||2.928||Off Shark Bay (mid-channel).||2|
|A.9||27-2-1926||10||sh.||—||Off Kauri Pt. (mid-channel).||2|
|A.10||30-5-1930||10||sh.||—||Off Kauri Pt. (mid-channel).||2|
|A.11||30-5-1930||4||m.||—||Off Island Bay.||1a1|
|A.12||14-4-1932||5–6||sm.||6.575||S.W. from Pt. Chevalier Reef.||N.S.|
|B.12||8-12-1930||8||sh.||—||Off Stokes Point, Northcote (mid-channel).||2|
|B.13||8-12-1930||8||sh.||—||Off Stanley Point. (mid. channel).||2|
|B.14||8-12-1930||8||sh.||—||Off Devonport (mid-channel)||2|
|B.16||14-4-1932||7||shm.||4.310||Off Birkenhead (channel).||2|
|B.17||14-4-1932||10||m.||—||Off Bean Rock.||1a|
|B.18||5-5-1932||4||m.||7.073||Off Hobson Point.||1|
|B.20||16-5-1932||4||m.||—||Off Hobson Point (two dredges).||1a1|
|B.21||16-5-1932||4||m.||—||Off Hobson Point (two dredges).||1a|
|B.22||23-5-1932||4||m.||—||Off Hobson Bay.||1a|
|B.23||23-5-1932||4||m.||—||Off Orakei Bay.||1a1|
|B.24||23-5-1932||7||sm.||—||Off North Head.||2a|
|B.25||30-5-1932||4||m.||—||Off Hobson Point.||1a|
|B.26||30-5-1932||2½||m.||—||Off Hobson Point.||1a1|
|B.27||23-5-1932||2||rb.||—||Off Hobson Point.||N.S.|
|B.28||12-3-1930||9–14||m.||—||Between North Head and Bean Rock.||2c|
|B.29||16-11-1933||7||m.||7.021||Off Birkenhead wharf.||1a1|
|B.30||16-11-1933||7||shm.||5.521||Off Birkenhead (mid-chanl.).||2c|
|B.31||1-5-1934||2¼||m.||7.809||Off Hobson Bay towards steamer anchorage.||1a1|
|B.32||1-5-1934||5||m.||7.938||Off Hobson Bay at steamer anchorage.||1a1|
|B.33||1-5-1934||8||sh.||3.037||Between Hobson Bay and Devenport (channel).||2|
|B.34||1-5-1934||5||sm.||7.239||Level with Sandspit Beacon, Devonport.||1|
|B.35||1-5-1934||½||sm.||7.257||Inside Sandspit Beacon, Devonport.||N.S.|
|B.36||7-3-1935||1 ¾||shm.||7.681||Abreast of Stokes Point, Northcote.||2c|
|B.37||7-3-1935||11||m.||4.801||Off Stokes Point, Northcote.||2c|
|B.38||7-3-1935||2½||m.||—||Stanley Bay, between point and wharf.||2c|
|B.39||7-3-1935||1½||m.||7.427||Stanley Bay, between point and wharf (further in).||1a1|
|B.40||7-3-1935||4||m.||—||Steamer anchorage off Hobson Bay.||1a1|
|B.41||7-3-1935||4||m.||5.844||Inside steamer anchorage off Hobson Bay.||2c|
|B.42||5-4-1935||6||shm.||7.153||Off Dolphin, off Point Resolution.||2c|
[Footnote] *fs. = fine sand, fs. + m. = fine sand + mud. m. = mud. m. + sh. = mud + shell, sh = shell, shm. = shelly + mud, sm. = sandy mud, st. = stony, rb. = rock bottom.
|B.43||5-4-1935||6½||sh.||4.825||Off Dolphin, off Point Resolution.||2|
|B.44||13-12-1935||8||sh.||—||Off Devonport (mid-channel).||2a|
|B.45||13-12-1935||8||sh.||—||Off Stanley Point (mid-channel).||2|
|C.5||28-3-1930||8–10||sh.||—||Motuihi Channel, between Emu Pt. and Home Bay.||3|
|C.7||8-12-1930||10||shm.||—||Off N.E. coast of Motuihi Id.||1|
|C.8||19-2-1931||8–10||sh.||2.408||Motuihi Channel, between Emu Pt. and Motuihi.||3|
|C.9||19-2-1931||10||m.||3.639||Between Brown's Id. and Motuihi Id.||3c|
|C.11||20-4-1931||3||m.||—||Motukoreho Channel (⅓ mile off Rangitoto wharf).||N.S.|
|C.12||23-3-1931||10||sh.||—||Motuihi Channel (off buoy).||3|
|C.13||23-4-1931||9||sh.||—||Off N. coast of Motuihi Id. midway between Motuihi Channel and Waiheke Id.||N.S.|
|C.14||4-5-1931||6||m.||—||Between Islington Bay and Brown's Id.||1|
|C.15||9-6-1931||3–4||s.||7.024||Tamaki Estuary, N. of Buckland's Beach.||5|
|C.16||16-5-1932||8||m.||—||Between Brown's Id. and Motuihi Id. (mid-way).||1a|
|C.17||16-5-1932||6||m.||—||Between Brown's Id. and Motuihi Id. (⅓ distance from Motuihi).||1a|
|C.18||30-5-1932||3||sm.||—||Entrance to Islington Bay.||N.S.|
|C.20||24-3-1933||8–10||sh.||2.601||Motuihi Channel, off Emu Point.||3|
|C.22||5-5-1932||2½||m.||—||Off Karaka Bay, towards Brown's Id.||1a|
|C.24||7-3-1935||2½||shm.||5.529||Close inshore off N.E. side of Brown's Id.||1|
|C.25||7-3-1935||4 ¾||m.||7.807||¼ way from Brown's Id. to Motuihi Id.||1|
|C.26||7-3-1935||8||shm.||4.841||½ way between Brown's Id. and Motuihi Id.||1|
|C.27||7-3-1935||4||shm.||7.746||Close inshore off W. coast of Motuihi Id.||1|
|C.29||23-5-1936||4||sh.||—||Off Buckland's wharf Tamaki Estuary.||2a|
|C.30||23-5-1936||4½||sh.||—||Off Buckland's wharf, Tamaki Estuary.||2a|
|C.31||11-12-1935||3½||m.||—||Entrance to Islington Bay.||1|
|D 3||20-4-1931||6–8||sh.||2.307||Between Crusoe Id. and Motuihi Id.||3|
|D.4||20-4-1931||4–5||sh.||3.521||Between Crusoe Id and Waiheke Id.||3|
|D.5||23-4-1931||6–8||sh.||1.463||Between Crusoe Id. and Waiheke Id. (mid-chanl.).3|
|D.6||23-4-1931||3–4||sh.||—||On ridge off N. end of Crusoe Id.||3|
|D.7||4-5-1931||12–13||sh.||2.687||Between Matiatia and Crusoe Id.||3|
|D.8||4-5-1931||6||sh.||—||About ¼-way from Crusoe to Squadron Bay.||3|
|D.9||4-5-1931||6||sh.||—||Midway between Crusoe Id. and Squadron Bay.||3|
|D.10||4-5-1931||5||sh.||—||About ¼-way from Squadron Bay to Crusoe Id.||3|
|D.11||9-6-1931||8||sh.||—||A little S. of channel between Crusoe Id. and Motuihi.||3|
|D.12||9-6-1931||6||m.||—||Midway along S.E. coast of Motuihi Id.||1|
|D.13||9-6-1931||5||m.||7.335||Channel along S.E. coast of Motuihi Id.||1a|
|D.14||28-3-1933||2||shm.||5.865||Te Hurui Bay, Waiheke Id.||N.S.|
|D.15||28-3-1933||3||shm.||5.985||Te Hurui Bay, Waiheke Id.||1a|
|D.16||28-3-1933||8||sh.||2.519||Tamaki Strait, channel off Te Hurui Bay.||3|
|D.17||28-3-1933||4½||m.||7.057||Tamaki Strait, towards Clark Pt.||1|
|D.18||3-12-1933||3||m.||7.248||Middle of Matiatia Bay, Waiheke Id.||1a|
|D.19||3-12-1933||2||m.||7.211||Line between wharf and old hulk, Matiatia.||1|
|D.20||23-5-1936||4½||m.||—||Off Eastern Beach, Tamaki Strait.||1|
|E.3||12-3-1930||7||sh.||—||¼ mile S.W. from Rangitoto beacon.||3|
|E.5||28-3-1930||2||s.||—||Off Cheltenham Beach.||5|
|5.7||23-12-1930||8||sh.||—||N.W. of Rangitoto beacon.||3|
|E.8||23-12-1930||4||ms.||6.836||Takapuna Beach (close inshore).||1|
|E.9||23-12-1930||7||ms.||6.078||Midway between Takapuna and Rangitoto.||1|
|E.10||18-12-1931||8||sh.||—¾ mile N. of Rangitoto beacon.||2a|
|E.12||23-5-1932||5||shm.||5.117||Off rocky coast, S. of Takapuna Beach.||1|
|E.13||16-12-1933||1 ¾||s.||6.999||Off Cheltenham Beach.||5|
|E.14||16-12-1933||4½||s.||6.112||Off Takapuna Head.||5|
|E.15||16-12-1933||7||—||Edge of Rangitoto Channel, off Takapuna.||N.S.|
|E.16||1-5-1934||4½||sm.||7.299||250 yards S. of Rangitoto beacon.||N.S.|
|E.18||1-5-1934||6||sh.||2.965||Between mid-channel and Rough Rocks beacon.||2a|
|E.19||1-5-1934||9||m.||7.715||Between North Head and Bean Rock.||1a1|
|E.21||16-5-1936||5 ½||sh.||—||Rangitoto Channel.||3|
|F.2||23-4-1931||6||sh.||—||Oneroa (Haroto Bay), Waiheke Id. (W. side near cape).||3a|
|F.3||23-4-1931||3–4||fs.||—||Oneroa (Haroto Bay) (close in W. end of beach).||5|
|F.4||14-4-1935||6||sh.||4.803||Oneroa (Haroto Bay) (W. side near cape).||3a|
|F.5||14-4-1935||6||sh.||4.008||Oneroa (Haroto Bay) (W. side near cape).||3a|
|F.6||14-4-1935||5||sh.||5.126||Off Little Oneroa, Haroto Bay.||3a|
|F.7||14-4-1935||7||m.||6.976||Oneroa (Haroto B.), middle.||1|
|G.1||23-12-1930||10||m.||7.222||Off N.W. coast of Motutapu Id.||1|
|G.2||23-12-1930||5||m.||7.414||Off Station Bay, N.E. coast of Motutapu Id.||1|
|G.3||23-5-1932||11||m.||—||Off bay between Motutapu & Rangitoto (outside coast).||1|
|G.4||16-12-1933||2||fs.||6.595||Off bay on S.W. side of Rakino Id.||N.S.|
|G.6||16-12-1933||9||sh.||1.662||Off N.E. coast of Motutapu Id.||3c|
|H.1||31-8-1931||8||sh.||—||Off E. side of (main island) of “Noises,” Otatou Id.||3|
|H.2||31-8-1931||11||sh.||—||Off E. side of (main island) of “Noises.”||3a|
|H.3||30-5-1932||15||m.||7.686||Outside David Rocks, “Noises.”||1|
|H.4||30-5-1932||10||sh.||—||Between David Rocks and (main island) “Noises.”||3a|
|H.5||30-5-1932||11||m.||7.686||Between Rakino Id. and David Rocks.||1|
|H.6||6-12-1932||5||s.||2.664||Close inshore (main island) of “Noises.”||3|
|H.7||6-12-1932||3–4||s.+st.||5.098||Between Motuhurakia Id. and (main Island) “Noises.”||3|
|H.8||6-12-1932||12||m.||6.938||Between “Noises” and Rakino Id.||1|
|H.9||24-3-1933||15||sh.||3.423||About 150 yds. W. of main island of David Rocks.||3a|
|H.10||24-3-1933||3||st.||1.545||Close inshore off N. coast of Maria Id., “Noises.”||3|
|H.11||3-3-1934||5||sh.||3.801||Off N.E. corner of Motuhurakla Id., “Noises.”||3a|
|I.2||5-4-1933||7||shm.||—||½ mile N.W. of Tiri Tiri-wharf.||3c|
|I.3||5-4-1933||4½||sm.||6.993||Off point E. of Manly. Whangaparaoa Pen.||1|
|I.4||5-4-1933||4½||sm.||7.042||Off Manly Bay, Whangaparaoa Pen.||1|
|I.5||6-4-1933||10||sh.||5.920||Off west side of Challenger Islet, Kawau.||3c1|
|I.6||6-4-1933||9||s. + sh.||5.660||Omaha Bay, near entrance to Whangateau.||3b|
|I.7||1-3-1934||13||shm.||—||Off Bostaquet Bay, Kawau Island.|
|J.1||12-11-1927||4||sh.||—||Passage between Ponui Id. and Rotoroa Id.||3|
|J.2||6-12-1933||5–3||m.–shm.||—||Hooks Bay nr. Thumb Pt., Waiheke.||1|
|J.3||6-12-1933||8||m.||7.540||From Single Rock towards Cowes Bay, Waiheke.||1|
|J.5||7-12-1933||20||m.||6.943||N.N.W. off Tarakihi Id. (Shag Rock).||1|
|J.7||7-12-1933||9||sh.||3.548||Channel between Orapiu and Sunday Rock, Tamaki Strait.||3a|
|J.8||13-11-1927||4||m.||—||Off Mataku Bay (McLeod Bay), Waiheke Id.||1|
|J.9||13-11-1927||4||m.||—||Off Mataku Bay (McLeod Bay), Waiheke Id.||1|
|M.4||19-9-1930||4||fs.||6.968||Off Huia Bank, Manukau Harbour.||4|
|M.5||19-9-1930||4½||fs. + m.||6.790||Midway between Cornwallis wharf and Big Muddy Creek, Manukau Harbour.|
|M.6||19-9-1930||6||sh.||3.589||Off Titirangi Beach, Manukau Harbour.||2b|
|M.7||19-9-1930||4||sh.||3.513||Off Cape Horn, Waikowhai, Manukau Harbour.||2b|
|M.8||11-11-1932||11||s.||5.992||Off Swatchway, Papakura Channel, Manukau.||2b|
|M 9||11-11-1932||16||s.||6.329||Off Te Hana Point, Manukau Harbour.||4|
|M.10||11-11-1932||17||fs.||6.992||Off Wattle Bay, near entrance Manukau Harbour.||4|
|M.11||11-11-1932||17||fs.||6.987||Off Puponga Point, Manukau Harbour.||4|
|M.12||11-11-1932||2½||sh. 3.442||Between Cape Horn and Puketutu Id., Manukau.||2b|
|T.8||26-3-1932||18–20||s.+sh.||—||Four miles out from Mount Maunganui Beach, Bay of Plenty.||3b|
The mechanical grading method selected for the bottom-deposits is that used by E. J. Allen in his fine paper “On the Fauna and Bottom-Deposits near the Thirty-fathom Line from the Eddystone Grounds to Start Point” (Journal of the Marine Biological Association, Plymouth, vol. 5, pp. 365–542, 1899). As already described, the material was secured by means of either a naturalist's dredge or a conical dredge designed so that there was no appreciable loss of the finer silts on the way to the surface. A half-gallon jar from each dredging was set aside and was subjected to the sieving process while still in a wet state. The sieves, six in number, were especially made, and each had a diameter of 15 cm. The sizes of the circular perforations were 15 mm., 5 mm., 2.5 mm., 1.5 mm., 1 mm., and 0.5 mm. The material that passed through the 0.5 mm. sieve was further subdivided into two parts, one of which was considered as fine sand and the other as silt. The separation of the fine sand from the silt was made by taking the material that passed the 0.5 mm. sieve and stirring it up with a quantity of fresh water;* then at the end of one minute the material that had settled was considered to be fine sand and that still in suspension was regarded as silt. In this way eight grades of material were obtained from each dredging, and following for the most part Allen's original classification, they may be given the following nomenclature, which becomes a very satisfactory method of supplying a precise meaning to such common terms as gravel, sand, and silt.
The eight grades with their descriptive equivalents are as follows:
Material left on 15 mm. sieve = stones (if inorganic) or large shell-fragments.
Material left on 5 mm. sieve = coarse gravel or coarse shell-gravel.
Material left on 2.5 mm. sieve = medium gravel, etc.
Material left on 1.5 mm. sieve = fine gravel, etc.
Material left on 1 mm. sieve = coarse sand or coarse shell-sand.
Material left on 0.5 mm. sieve = medium sand, etc.
Material that passes 0.5 mm. sieve and settles in one minute = fine sand, etc.
Material that passes 0.5 mm. sieve and does not settle in one minute = silt.
The samples from the various grades were first thoroughly dried at a low temperature and then weighed, the results being expressed as percentages of the total dry weight. Allen (loc. cit.) has devised an ingenious method of reducing the entire eight grades of each dredging to a grade-number which indicates the general nature of the material, and can be used not only in comparing samples, but also indicating the range in substratum favoured by a particular organism. I quote Allen's method, which is as follows:—“The method adopted is founded on the determination of the average grade of the whole sample. The figures I, II, III, etc., are purely conventional, but may be conveniently adopted for the purpose of shortly stating the average grade of any sample. The actual method followed
[Footnote] * Salt water was used by Allen, but as most of the present work was done at a distance from the sea a day or so after the material was collected, the use of fresh water was far more convenient.
was to multiply each percentage in the table by the conventional number attached to its grade, add together the figures so obtained, and divide by 100; the result has been described as the ‘average grade’ of each sample, and affords a ready means of comparing the texture of any two deposits.”
An instance of this method of determination of the “average grade” is here given for dredging D.3:—
|1.||Material left on 15 mm. sieve||36.78×1 = 36.78|
|2.||" " 5mm. "||31.03 × 2 = 62.06|
|3.||" " 2.5 mm. "||13.70 × 3 = 41.10|
|4.||" " 1.5 mm. "||8.57 × 4 = 34.28|
|5.||" " 1 mm. "||5.73 × 5 = 28.65|
|6.||" " 0.5 mm. "||1.70 × 6 = 10.20|
|7.||" settled in 1 minute||2.29 × 7 = 16.03|
|8.||" not settled in 1 minute||0.20 × 8 = 1.60|
|230.70 / 100 = 2.307|
|2.307 the “average grade” of D.3.|
Hard-bottom grades vary between 1.5 and 3.5 and have the fine sand and silt grades constantly very low. Soft-bottom grades are between 5.4 and 7.9 and always the fine sand and silt grades make up the bulk of the sample.
Each of the main animal communities of the sea-bottom in the Auckland Harbour and vicinity is found in association with a distinctive bottom grading. Of course other physical conditions such as salinity, depth, and p.H. have a definite bearing on the distribution of organisms; but since the range in these factors is not great over most of the area, it follows that the grade of the substratum and the animal community suited to that grade coincide very well. It is only when considering the truly estuarine part of the harbour, where there is a fairly marked decline in the salinity, that the normal animal community associated with a similar mud from an area of normal salinity is found to be wanting. This means that with the physical conditions of the sea-water more or less uniform and no very great variation in depth there is a definite correlation between animal community and substratum.
The graph shown below gives the average curves for four distinct animal formations, three of them occurring in the Auckland Harbour and the fourth in the Manukau. So far as we know, this latter one is not represented in the Auckland area under investigation. Notice the characteristics of each curve. In (1) the Echinocardium formation, the heart-urchin and its associates can live only in a substratum that averages 293.81% mixture of fine sand and silt; and in (2), the Arachnoides formation, 94.79% of the sample is fine sand, there being practically no silt. No. (3), the Tawera-Glycymeris formation, has high percentages of the coarse grades, but diminishes rapidly over the remaining grades until there is a very small amount of fine sand and silt, while (4), the Maoricolpus formation, although similar to Tawera-Glycymeris in the coarse grades, has a comparatively large amount of fine sand and silt, the intermediate grades being least.
Diagram I. Showing Distinctive Texture-curve for Each of the Four Main Animal Communities of the Auckland and Manukau Harbours.
(a) Horizontal figures 1–8 = Texture-grades of Substratum.
1 = Material left on sieve with round holes of 15 mm. diameter.
2 = " " 5 mm. " "
3 = " " 2.5mm. " "
4 = " " 1.5mm. " "
5 = " " 1 mm. " "
6 = " " 0.5mm. " "
7 = Material that passes sieve 6 and settles in one minute = (fine sand).
8 = " " does not settle in one minute = (silt).
(b) Vertical figures 0–100 indicate percentages (i.e., percentage of each grade to the whole sample).
(c) Numbers enclosed in circles indicate the Animal Community (see below) of the particular Substratum-curve it appears against.
1 = Echinocardium formation.
2 = Maoricolpus formation.
3 = Tawera+Glycymeris formation.
4 = Arachnoides formation.
In Diagram III particulars of respective animal communities are arranged vertically above the community indicator numbers (enclosed in circles) on the base-line. The thin vertical line represents the maximum number of species at any one station in the community, and the thick line the average number of species for all stations of that community. Lateral extensions on the base line indicate rough quantitative estimates of the animals present in the community. The extension to the left represents the macrofauna, and the number beside the arrow is the total of the larger animals taken from the whole dredging. The extension to the left represents the microfauna, and the numbers quoted are not for the entire sample, but for a
Diagram III. Showing the relationship between the substratum-textures and the frequency of animals (both in species and in relative abundance) for the four main animal communities of the Auckland and Manukau Harbours.
(1) Echinocardium formation.
(2) Maoricolpus formation.
(3) Tawera+Glyoymeris formation.
(4) Arachnoides formation.
small quantity weighing about six ounces. The transverse lines are texture-curves for each of the eight grades. Dotted lines 1–6 are the coarser grades (representing finer grades in descending order), and continuous lines 7 and 8 are the fine-sand and silt grades respectively. The vertically arranged numbers at the sides may be applied numerically or as percentages. The graph illustrates how the maximum fauna both in species and quantitatively is associated with coarse textured bottom, and conversely that the minimum fauna is found in the fine textured bottom. The critical grades are thus shown to be fine sand (7), and silt (8). The substratum most unfavourable to animal life appears to be that which is almost entirely fine sand. The reason for the poor fauna of this type of bottom is probably the extreme mobility of the surface, for it does not bind, and in consequence no great accumulation of food material in the form of organic detritus is possible.
The Animal Communities.
The majority of the dredgings taken in these two harbours can be classified in one or another of four extensive formations. In the preceding account of the substratum I have shown that each of these formations can be correlated with a definite type of bottom. It will be noticed that the critical grades of the bottom-samples are both fine sand and silt. The Echinocardium formation was shown to favour a soft bottom that averaged 93.81% fine sand and silt; the Arachnoides formation was found only in the outer basin of Manukau Harbour, where the influx of West Coast iron-sand produced a fine-sand bottom which averaged 94.79% without the silt. Both the Maoricolpus formation and the Tawera+Glycymeris formation are restricted to hard bottom and have the coarse grades similarly high; but here again the distinction comes in the fine-sand and silt grades, it averaging 20.49% for the Maoricolpus formation and only 2.81% for Tawera+Glycymeris.
|F. sand and silt grade||93.81%|
1. Echinocardium formation (Echinocardium+Dosinia lambata + Amphiura rosea).
1a. Echinocardium association (one or two of the typical organisms present).
1a1. Polychaete+Zenatia associes.
1a2. Polychaete associes.
|F. sand and silt grade||24.01||15.21%||39.47%|
2. Maoricolpus formation.
Maoricolpus (manukauensis)+Nucula association.
|F. sand and silt grade||2.81%|
3. Tawera-Glycymeris formation.
|F. sand (only) grade||94.79%|
4. Arachnoides formation.
5. Baryspira community.
Formations and Associations Found in Each Harbour.
Maoricolpus + Dosinula association.
Paphirus + Dosinula + Maoricolpus association.
Maoricolpus (manukauensis)+Nucula association.
(Note: It is likely that 1a1, 1a2, 3c, 3cl, and 5 may occur.)
It is remarkable that the two harbours are so very different in their animal communities, no one formation or association being found common to both. The nearest approach to a correlation is between the Maoricolpus formation of the Auckland Harbour and the Maoricolpus+Nucula association of the Manukau. Both have a similar bottom-grade and occur under distinctly estuarine conditions, but apart from the Maoricolpus the faunas of the Auckland formation and the Manukau association respectively are distinct. Even the dominant organism Maoriocolpus is not quite identical for both areas, the Manukau shell being a local variant narrower than the typical shell, and which I have previously named as a subspecies M. rosea manukauensis (Powell 1931). The huge development of Nucula and a distinctive microfauna are characteristic of the Manukau Maoricolpus+Nucula association. The other extensive Manukau community, the Arachnoides formation, has not been found in Auckland Harbour, but it occurs, or perhaps more correctly an association of it occurs, at Pilot Bay, Tauranga. Here the species associated with the Arachnoides is Baryspira australis.
The Manukau Survey is based upon a very small series of dredgings, but nevertheless I do not think that many of the thirteen formations and associations recorded for Auckland Harbour will be
found in the Manukau, for many of the dominant species of these animal communities do not seem to occur there. I have no records from the Manukau of dominants of Auckland communities such as Echinocardium australe, Tawera spissa, Glycymeris laticostata, Venericardia purpurata and Maoricolpus rosea (typical).
Faunal lists for the various animal communities follow. It will be noticed that the faunas for the soft and hard-bottom stations respectively are almost completely different. It is at once evident that the hard bottom supports the richer fauna both in respect to variety and to quantity. The average number of species and specimens for the soft-bottom series is very low and the microfauna is hardly represented at all, Nozeba emarginata being one of the few small molluses represented. By microfauna I refer to small organisms, mostly molluses, that are larger than the Protozoa. Now the average of species and specimens for the hard-bottom series is many times more than for the soft-bottom series, and small molluses in the microfauna are particularly abundant.
It appears that lower salinity in the Upper and Inner Harbours is the main factor which confines the Maoricolpus formation to these areas, and that with the soft-bottom communities this very same factor is responsible for the exclusion of the Echinocardium formation from the Upper Harbour, and from most of the Inner Harbour.
The nature of the microfauna is of interest also. A new species of Notosetia is abundant in and characteristic of the Maoricolpus formation, but not of the Tawera+Glycymeris formation; and conversely Argalista and Condylocardia usually represented in the latter formation are always entirely absent from the former. On the other hand, Estea impressa is common to both communities. Again, the Maoricolpus+Nucula association of the Manukau has a microfauna which is entirely different from that of the typical Maoricolpus formation; neither Notosetia n.sp nor Estea impressa occur, but they are replaced by Turbonilla n.sp. and a tiny n.sp. of the Liotiidae. There is also what may prove to be a further Maoricolpus association in the Manukau, in which the Nucula is entirely absent; but more likely this is just a benthic phase of the association, as Nucula hartvigiana is never found except in quite shallow water. Insufficient dredgings were taken to determine definitely the cause of the omission of Nucula from stations M.6 and M.8. The bottom-texture in M.8 shows a very large amount of fine sand which may be too gritty for Nucula, but on the other hand M.6 is very similar in character to M.7a. Depth therefore seems to be the only apparent difference between these two stations.
1. The Echinocardium Formation.
This is the most extensive animal community in Auckland Harbour, Hauraki Gulf, for it covers the greater part of that area; yet it appears to be entirely absent from Manukau Harbour. The
typical Echinocardium formation has as its dominant animals the following three organisms:—(1) The common heart-urchin, Echinocardium australe, (2) the bivalve shellfish, Dosinia lambata, and (3) the rose-coloured brittle starfish, Amphiura rosea.
A predominance of the fine-sand grade over the silt which takes place in certain of the soft-bottom dredgings is the most favourable to Echinocardium, and on this type of bottom, I.3 and I.4 for instance, the more sandy nature of the mud is responsible for the elimination of the bivalve Dosinia lambata. The Dosinia is also affected bathymetrically, for it is shown to be absent from dredgings taken in less than two fathoms as well as from those exceeding eleven fathoms. The salinity factor is shown to operate also, and is evidently the cause of the omission of Echinocardium, and the two other dominant animals, from the muds of the Upper Harbour and from most of the Inner Harbour. Bottom-textures from the Upper and Inner Harbours are practically identical with those from outside areas where the Echinocardium formation occurs, so the inference is that salinity is definitely the limiting factor to the spread of the Echinocardium formation into estuarine waters. The Echinocardium formation therefore is shown to occur on a soft bottom with an average grade of 7.215 (the complete range noted being from 5.117 to 7.938), very little comminuted shell, the combined fine-sand and silt grades averaging 93.81% dry weight of the total sample, and a salinity that does not fall below 34%°. The range in salinity for the Upper Harbour where this formation is absent was found to be 29.63%°–32.80%°.
Economically the Echinocardium formation is of importance as its dominant animals provide a considerable proportion of the diet of our main food fish, the snapper. Examine the table on page 395, which shows records of the stomach contents of some 957 Auckland-Hauraki Gulf snapper, and you will notice that the animals of the soft-bottom Echinocardium formation account for almost one-third of the varied diet of this food fish. With the exception of an occasional carnivore, all the animals found in the Echinocardium formation and its association are either deposit or suspension-feeders, probably the former. Deposit-feeders obtain their nourishment from the surface film of the mud, which is usually composed of fine organic detritus.
Soft mud-bottom is never rich in species, for the physical factors are very severe. Owing to the fineness of its particles mud is easily disturbed by wave-action and currents, and as in suspension it tends to clog the respiratory organs, there are few epifaunal animals, and even the infaunal animals are not abundant, mud being usually badly aerated below the surface.
|*1. Echinocardium australe Gray.||Ech.||B.18, B.34, C.7, C.14, D.12, D.17, D.19, E.8, E.9, E.12, G.1, G.2, G.3, H.3, H.5, H.8, I.3, I.4, J.2, J.3, J.5.|
|*2. Dosinia lambata (Gould).||Mol.||B.17, B.21, B.22, B.25, B.34, C.10, C.14, C.16, C.17, C.22, D.12, D.13, D.15, D.17, D.18, E.8, G.1, G.3, H.5, J.2, J.3.|
|*3. Amphiura rosea Farquhar.||Ech.||B.18, B.22, C.7, C.14, C.16, D.13, D.15, D.17, D.18, G.1, G.3, H.3, H.5, H.8, I.3, I.4, J.2, J.3, J.5.|
|*4. Onuphus aucklandensis Augener.||Ann.||C.7, C.10, C.22, D.12, E.9, G.1.|
|*5. Glycera americana Leidy.||Ann.||C.7, C.14, D.13, E.9.|
|*6. Lumbriconereis brevicirra Schmarda.||Ann.||C.10, C.14, D.12, G.1.|
|7. Pectinaria (Lagis) australis Ehl.||Ann.||B.25, C.22, E.8, I.3, I.4, J.2.|
|8. Cominella (Acominia) adspersa (Brug.).||Mol.||B.25, D.19, E.8, E.12. I.3.|
|*9. Venericardia lutea Hutton.||Mol.||D.17, E.8, H.8.|
|*10. Baryspira mucronata (Sowb.).||Mol.||C.17, D.19, E.12, J.2.|
|*11. Neilo australis Q. and G.||Mol.||B.20, H.5, H.8, J.3.|
|12. Amphipoda.||Crust.||B.18, B.21, B.34, C.10, C.17, D.19, E.8, I.4.|
|13. Isopoda (large).||Crust.||B.18, B.21, B.25, C.22, I.4, J.5.|
|14. Angulus edgari (Iredale).||Mol.||B.18, B.21, B.25, C.17, D.18, I.4.|
|15. Zenatica acinaces (Q. and G.).||Mol.||B.18, B.21, B.22, B.25, C.16, E.8.|
|(c) Secondary Species.|
|16. Tawera spissa (Desh.).||Mol.||B.22, C.7, E.9.|
|17. Nucula nitidula A. Adams.||Mol.||B.18, E.8.|
|18. Praxillella insecta Ehlers.||Ann.||C.7, C.22, E.9.|
|19. Nephthys dibranchis Gr.||Ann.||C.22, E.8, E.9.|
|20. Lepidonotus polychromus Schmarda.||Ann.||E.8, E.9.|
|*21. Hyalinoecia tubicola Muller.||Ann.||G.1.|
|22. Owenia fusiformis d.Ch.||Ann.||C.7.|
|23. Amphicteis philippinarum Gr.||Ann.||E.9.|
|24. Euchone pallida Ehl.||Ann.||E.9.|
|25. Lumbriconereis sphaerocephala Schm.||Ann.||C.10, C.22, E.9.|
|26 Dasychone curta Ehl.||Ann.||E.9.|
|27. Nephthys macroura Schmarda.||Ann.||C.7.|
|*28. Polychaetes (not identified).||Ann.||B.17, B.18, B.21, B.22, B.25, C.17, D.13, D.15, D.17, D.18, D.19, E.12, G.3, H.3, H.5, H.8, I.3, I.4, J.2, J.3.|
|*29. Trochodota (a holothurian).||Ech.||C.7, C.14.|
|*30. Hemiplax hirtipes (Jacq. & Lucas).||Crust.||B.18, B.21, B.25, C.14.|
|31. Dosinia greyi Zittel.||Mol.||B.18, B.21.|
|32. Mactra ovata Gray.||Mol.||B.18.|
|33. Leptomya retiaria Hutton.||Mol.||B.18, B.21.|
|34. Pecten (Notovola) medius Lamk.||Mol.||E.8.|
|35. Atrina zelandica Gray.||Mol.||E.8.|
|36. Chione stutchburyi Gray.||Mol.||D.18, D.19.|
|37. Nucula castanea A. Ad.||Mol.||H.8.|
|38. Glaphyrina vulpicolor (Sowb.).||Mol.||I.3.|
|39. Pervicacia tristis (Desh.).||Mol.||E.8.|
|40. Notocorbula zelandica (Q. and G.).||Mol.||I.3.|
|41. Alipta n.sp.||Mol.||I.3.|
|42. Paramithrax minor Filhol.||Crust.||D.13. I.4.|
|43. Pinnotheres novaezelandiae Filhol.||Crust.||H.8.|
|44. Petrolisthes elongatus M. Ed.||Crust.||B.22.|
|45. Baryspira novaezelandiae (Sowb.).||Mol.||B.21.|
|46. Pelicaria vermis (Martyn).||Mol.||B.17, C.10.|
|47. Philine sp.||Mol.||C.17.|
|48. Macomona liliana (Iredale).||Mol.||D.18.|
|49. Guraleus sinclairi (Smith).||Mol.||B.21.|
|50. Edwardsia tricolor Stuckey.||Coel.||B.21.|
|51. Amphiura pilosa (Lyman).||Ech.||B.22.|
|52. Terebellides stroemi M. Sars.||Ann.||B.22, C.22.|
|53. Caudina coriacea.||Ech.||D.13.|
|54. Nemertine sp.||Nem.||B.22, C.22.|
|Microfauna (no dominants).|
|55. Nozeba emarginata (Hutton)||Mol.||E.8, E.9.|
|56. Chemnitzia cf. powelli Bucknill.||Mol.||C.7, E.9.|
|57. Odostomia n.sp.||Mol.||E.8.|
|*58. Cadulus delicatulus Suter.||Mol.||J.3.|
|59. Melliteryx parva (Desh.).||Mol.||J.5.|
|Note.–Ann. = Annelida, Polychaeta; Coel. = Coelenterata; Crust. = Crustacea; Nem. = Nemertinea; Mol. = Mollusca; Ech. = Echinodermata.|
Of the 59 species listed as occurring in this formation and its association 1a the maximum number found in any one station is 15 and the average number for all the stations is 7.3. The stations of the typical formation have a total of 13 species. The microfauna is only barely represented.
1a. Echinocardium Association.
The separation of the association from the typical formation is based upon the absence of the characteristic species, Echinocardium australe, but the presence of one or both of the other dominants of the typical formation. As Echinocardium is shown to accommodate itself to a big range in bottom-textures, salinity and depth, its absence from a community requires an explanation which so far is not always apparent. There is always a chance of course that the dredge has missed the species where they occur sparsely, or failed to locate them by not digging in deeply enough, but Dosinia lambata and Amphiura alba are both infaunal animals, so that when these are present the latter explanation is not at all likely.
1a1. Polychaete+Zenatia associes.
The Echinocardium formation, typical, breaks down just within the entrance to the Inner Harbour and is absent from the remainder of that area and the Upper Harbour. It is strongly indicated (see salinity table) that lower salinity is the factor which accounts for the absence of the Echinocardium formation dominants from the estuarine areas of the harbour. The farthest recorded penetration of Echinocardium into the Inner Harbour is off Hobson Bay (B.18) and near Devonport wharf (B.34). The associes 1a1 covers a fauna composed of some of the more hardy subdominant and secondary species of the typical formation, but without any of its dominants.
There is a marked increase in polychaetes, the substratum frequently being one mass of slender polychaete tubes (B.20 and B.26). The fauna of this associes is listed below.
|1. Polychaetes (not identified).*||Ann.||B.20, B.23, B.26, B.29.|
|2. Zenatica acinaces Q. & G.||Mol.||A.11, B.20, B.23, B.26|
|3. Pectinaria (Lagis) australis Ehl.||Ann.||B.20, B.23, B.26.|
|4. Hemiplax hirtipes (Jacq. & Luc.).||Crust.||B.20, B.23, B.26.|
|5. Amphipods.||Crust.||A.11, B.20, B.26, B.29.|
|6. Isopoda (large).||Crust.||B.20, B.23, B.26.|
|7. Cominella (Acominia) adspersa (Brug.).||Mol.||B.20, B.26.|
|8. Leptomya retiaria (Hutt.).||Mol.||B.20, B.26.|
|9. Angulus edgari (Ired.)||Mol.||B.20, B.26.|
|10. Nucula nitidula A. Ad.||Mol.||B.20, B.26.|
|(c) Secondary Species.|
|11. Owenia fusiformis d.Ch.||Ann.||A.11.|
|12. Terebellides stroemi M. Sars.||Ann.||A.11.|
|13 Amphicteis philippinarum Grube.||Ann.||A.11.|
|14. Lumbriconereis brevicirra Schm.||Ann.||A.11.|
|15. Pelicaria vermis (Mart.).||Mol.||B.20, B.29.|
|16. Neilo australis||Q. & G.||Mol.||B.20.|
|17. Dosinia greyi Zitt.||Mol.||B.26.|
|18. Tawera spissa (Desh.).||Mol.||B.23.|
|19. Paramithrax minor Filhol.||Crust.||A.11, B.29.|
|20. Amphiura sp.||Ech.||A.11.|
|21. Soletellina siliqua (Rve.).||Mol.||B.26.|
Summary: Of the 21 species listed for this associes the maximum number found in any one station is 12 and the average for the four stations 9.25. Although the range in species is small and the maximum number found in any one station less than in the typical formation, the average is considerably higher. The microfauna is entirely absent.
1a2. Polychaete associes.
This is an Upper Harbour estuarine soft-bottom community having a still further restricted fauna. Species are few and individuals sparsely represented, polychaetes being dominant. With them is an association of odd species in no apparent order of frequency when the several stations are considered. The texture of the substratum for this and the associes 1a1 comes within the range favoured by the typical formation, and so another cause, presumably salinity, is indicated as the limiting factor.
The following table shows the drop in salinity, proceeding from Outer Harbour waters (Echinocardium formation area) through the Inner Harbour and up the estuarine waters of the Upper Harbour. Hydrogen-Ion concentration is given also, although no definite bearing on the issue is indicated. The determinations quoted below were made especially for this report by Mr. W. K. Hounsell, and some of them together with a description of the methods employed were published by him in his paper, “Hydrographical observations in Auckland,” Trans. Royal Soc. N.Z., vol. 64, p. 269, 1935.
[Footnote] * Polychaete determinations have been obtained only for Station A.11, hence species 11–14 may not be correctly placed as secondary species when the determinations from the other stations are available.
|7/4/33||19.75||35.00||8.32||Rosaria Channel, Kawau||9.15 a.m.|
|7/4/33||20.25||35.09||8.37||Off west coast of Moturoa Id.||11.40 a.m.|
|14/12/32||19.00||35.12||8.33||Between Tiri Tiri and Rangitoto.||10.45 a.m.|
|7/4/33||20.25||34.95||8.33||Between Tiri Tiri and Rangitoto.||4.5 p.m.|
|6/12/32||17.10||35.22||8.30||Between Motutapu and Waiheke.||10.30 a.m.|
|6/12/32||16.50||35.25||8.24||David Rocks, Noises Islands.||11.20 a.m.|
|6/12/32||17.20||34.90||8.20||Between Rangitoto wharf and Tamaki.||9.40 a.m.|
|6/12/32||17.40||35.00||8.25||Off Orakei wharf.||9.20 a.m.|
|14/12/32||18.50||35.00||8.29||North Head.||9.50 a.m.|
|14/12/32||18.00||34.52||8.26||Queen's wharf (Inner Harbour).||8.30 a.m.|
|16/11/33||17.00||33.67||8.47||Off Western Tide-deflector (Inner Harbour).||9.15 a.m.|
|16/11/33||18.00||32.80||8.45||Off Kauri Point (Upper Harbour).||9.40 a.m.|
|16/11/33||18.00||31.52||8.43||Off Island Bay (Upper Harbour).||9.55 a.m.|
|16/11/33||18.50||30.94||8.36||Off Birkdale (Upper Harbour).||10.10 a.m.|
|16/11/33||18.50||29.63||8.23||Off Greenhithe wharf (Upper Harbour).||10.40 a.m.|
Table showing Salinity and Hydrogen-Ion Concentration of Sea-water for Outer, Inner and Upper Harbour Areas.
The fauna of the 1a2 Polychaete is given in the following list:—
|1. Polychaetes (not identified).||Ann.||A.1, A.2, A.3, A.4, A.5.|
|2. Amphipoda.||Crust.||A.2, A.3, A.4.|
|3. Pectinaria (Lagis) australis Ehl.|
|(c) Secondary Species.|
|4. Helice crassa Dana.||Crust.||A.1, A.2.|
|5. Amphiura sp.||Ech.||A.1, A.2.|
|6. Mytilus canaliculus Martyn.||Mol.||A.4.|
|9. Notoplax mariae (Webster).||Mol.||A.2.|
|10. Terenochiton inquinatus (Rve.).||Mol.||A.2.|
|11. Nucula hartvigiana Pfr.||Mol.||A.2.|
|12. Tawera spissa (Desh.).||Mol.||A.5.|
Summary: Of the 12 species listed for this associes the maximum number found in any one station is 7 and the average number for the five stations 3.8. The microfauna is entirely absent.
2. The Maoricolpus Formation.
This formation occurs typically only in the main channel of the inner and upper sections of the Auckland Harbour. Its dominant organism is the gasteropod Maoricolpus rosea, which is so superabundant (Pl. 30) that the dredge-contents at a glance appear to be made up of this and very little else. The microfauna of this formation is interesting, as there are two species so extremely abundant that if it were not for their microscopic size they would be considered as dominants.*
The Maoricolpus formation occurs on a hard bottom that is made up of an accumulation of coarse shell-debris that has been dragged down from higher levels by the tidal stream and is by this same agency kept moderately free from silts. The average grade is 3.425 (the coarse shell grades are proportionately large, medium grades small, and with a moderate admixture of fine sand and silt about 24.01% dry weight of the total sample). The salinity is mostly below 34.5%.
2a. Maoricolpus+Dosinula association.
This association borders the Tawera+Glycymeris formation of the Rangitoto Channel, Auckland, being situated between it and the inshore Echinocardium formation or nondescript mud zone as the case may be. This Maoricolpus+Dosinula association extends also to within the entrance to the Inner Harbour, where it forms a connecting community between the typical Maoricolpus formation of the Inner Harbour channel and Tawera+Glycymeris of the Rangitoto Channel. Its dominant organisms are six in number, Maoricolpus, the dominant of the typical formation, being far less abundant and supplemented by Dosinula, Paphirus, Notocorbula, Trochus and Cominella quoyana. The only notable change in the microfauna is the complete absence of Notosetia n.sp., one of the dominants of the microfauna of the typical formation.
The substratum belongs to the hard-bottom series and is similar to that of the typical formation except that the percentage of fine sand and silt is less, only about 15.21% dry weight of the total sample. The average grade is 2.862.
2b. Maoricolpus (manukauensis)+Nucula association.
This association is peculiar to the estuarine section of the Manukau Harbour. It differs from the typical formation of the Auckland Harbour in having a much smaller fauna, a maximum of 30 species compared with 62 for the typical formation. The main faunal differences are that the Manukau Maoricolpus is a subspecies distinct from the Auckland dominant, and that in the shallower water Manukau stations Nucula hartvigiana becomes a second dominant, while in the microfauna Estea impressa and Notosetia n.sp., superabundant in the typical formation of the Auckland Harbour, are entirely absent from the Manukau association.
[Footnote] * Actual numbers do not decide the dominance of a species; size and its effect on the other members of the community, such as top on the food supply, have to be taken into account.
The average grade for the Maoricolpus (manukauensis)+Nucula association is 4.134 as compared with 3.425 for the typical formation. No doubt the greater percentage of sand and silt in the Manukau substratum, 39.47% dry weight of the total sample, is one of the main causes of the comparatively small fauna and its differences in composition from that of the typical formation. Unfortunately salinity records were not taken for the Manukau.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|1. Maoricolpus rosea (Q. & G.).||Mol.||A.6, A.10, B.12, B.13, B.14, B.16, B.33.|
|2. Notocorbula zelandica (Q. & G.).||Mol.||A.10, B.12, B.13, B.14, B.16, B.33.|
|3. Tawera spissa (Desh.).||Mol.||A.6, B.12, B.13, B.14, B.16.|
|4. Zegalerus tenuis (Gray).||Mol.||A.10, B.12, B.13, B.14, B.33.|
|5. Nucula nitidula (A. Adams).||Mol.||A.6, A.10, B.12, B.13, B.16.|
|6. Petrolisthes elongatus M. Ed.||Crust.||A.10, B.12, B.13, B.14.|
|7. Terenochiton inquinatus (Reeve).||Mol.||A.6, A.10, B.13, B.16, B.33.|
|8. Sigapatella novaezelandiae (Lesson)||Mol.||A.10, B.12, B.13, B.33|
|9. Buccinulum multilineum Powell.||Mol.||A.10, B.12, B.13, B.14, B.33|
|10. Mytilus canaliculus Martyn.||Mol.||B.12, B.13, B.14.|
|11. Cominella adspersa (Brug.).||Mol.||B.12, B.13, B.14.|
|12. Venericardia purpurata (Desh.).||Mol.||A.6, B.13, B.16.|
|13. Amphipoda.||Crust.||A.10, B.12, B.13, B.33.|
|14. Trochus tiaratus Q. & G.||Mol.||A.10, B.13, B.14.|
|15. Paramithrax minor Filhol.||Crust.||A.10, B.13, B.14.|
|16. Pilumnus novaezelandiae Fil.||Crust.||A.10, B.12, B.13.|
|17. Nucula hartvigiana Pfr.||Mol.||A.6, A.10, B.13.|
|18. Chlamys zelandiae (Gray).||Mol.||A.10, B.12, B.14.|
|19. Lepidonotus polychromus (Sch.).||Ann.||A.10, B.12, B.16, B.33.|
|(c) Secondary Species.|
|20. Murexsul octogonus (Q. & G.).||Mol.||A.10, B.13.|
|21. Sertularia.||Coel.||A.10, B.13, B.14.|
|22. Amphiura alba Mortensen.||Ech.||A.10.|
|23. Zemysia zelandica (Gray).||Mol.||A.6, A.10, B.12.|
|24. Zelithophaga truncata (Gray).||Mol.||B.13, B.14.|
|*25. Leptomya retiaria (Hutton).||Mol.||B.13, B.14, B.33.|
|26. Proxiuber australis (Hutton).||Mol.||A.10, B.12.|
|*27. Paphirus largillierti (Phil.).||Mol.||B.14, B.16.|
|*28. Dosinula zelandica (Gray).||Mol.||B.13, B.14.|
|29. Maurea pellucida (Val.).||Mol.||A.10, B.33|
|30. Austrosipho adusta (Phil.).||Mol.||B.13.|
|31. Cominella quoyana (A. Ad.).||Mol.||A.10.|
|32. Maoricrypta monoxyla (Less.).||Mol.||A.10.|
|33. Proxichilidium obliquum (Thomp.).||Arth.||A.10.|
|34. Porifera.||Por.||A.10, B.13.|
|36. Anomia walteri Hector.||Mol.||B.13.|
|37. Notoplax mariae (Webster).||Mol.||B.33.|
|38. Halicarcinus planatus Fabr.||Crust.||B.33.|
|39. Nectocarcinus antarcticus (Jacq. & Lucas).||Crust.||B.12.|
|40. Thelepus spectabilis Verrill.||Ann||B.14.|
|41. Psammolyce antipoda (Schm.).||Ann.||B.14.|
|42. Trypanosyllis gigantea McInt.||Ann.||B.12.|
|43. Coscinasterias calamaria (Gray).||Ech.||B.14.|
|44. Terebratella inconspicua (Sowb.).||Brach.||A.10.|
[Footnote] (*Occasional stragglers from Maoricolpus + Dosinula association.)
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|47. Lyroseita chathamensis (Suter).||Mol.||A.10, B.33.|
|48. Xymene plebjus (Hutt.).||Mol.||B.13.|
|49. Zemitrella choava (Reeve).||Mol.||A.10, B.33.|
|50. Notosetia n.sp.||Mol.||A.6, A.10, B.12, B.13, B.14, B.16, B.33.|
|51. Estea impressa (Hutton).||Mol.||A.6, A.10, B.12, B.13, B.14, B.16, B.33.|
|52. Chemnitzia n.sp.||Mol.||A.6, A.10, B.12, B.13, B.14, B.16, B.33.|
|53. Melliteryx parva (Desh.).||Mol.||A.6, B.10, B.12, B.13, B.14, B.16.|
|54. Orbitestella toreuma Powell.||Mol.||A.10, B.12, B.13, B.14, B.33.|
|55. Odostomia n.sp.||Mol.||A.10, B.12, B.13, B.14.|
|56. Awanuia dilatata Powell.||Mol.||A.6, A.10, B.16.|
|57. Scrobs rugulosa Powell.||Mol.||A.10, B.12, B.13, B.16.|
|58. Scrobs ovata Powell.||Mol.||A.10, B.16.|
|59. New genus aff. Lodderia.||Mol.||A.10, B.12, B.13.|
|(c) Secondary Species.|
|60. Rochefortula reniformis (Suter).||Mol.||A.10.|
|61. Pyrgulina rugata (Hutt.).||Mol.||B.13.|
|62. Arthritica bifurca (Webster).||Mol.||B.33|
Of the 62 species listed as occurring in this formation the maximum number found in any one station is 41 and the average number for all the stations is 25.57. Compared with the Echinocardium formation species are more numerous, they occur in far greater numbers, the constituents of the community are more stable and the microfauna is richly represented. Not one species of the typical Maoricolpus formation is found in the typical Echinocardium formation; but six molluscs, one crab, and one polychaete are common to typical Maoricolpus formation and Echinocardium association 1a.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|1. Maoricolpus rosea (Q. & G.)||Mol.||B.24, E.10, E.17, E.18.|
|2. Dosinula zelandica (Gray).||Mol.||B.24, E.10, E.18.|
|3. Paphirus largillierti||(Phil.).||B.24, E.10, E.18.|
|4. Notocorbula zelandica (Q. & G.)||Mol.||B.24, E.10, E.17, E.18.|
|5. Trochus tiaratus Q. & G.||Mol.||B.24, E.10, E.17, E.18.|
|6. Cominella quoyana A. Ad.||Mol.||B.24, E.10, E.17, E.18.|
|7. Terenochiton inquinatus (Reeve).||Mol.||B.24, E.10, E.17, E.18.|
|8. Petrolisthes elongatus M. Ed.||Crust.||B.24, E.10, E.17, E.18.|
|9. Tunicates.||Tun.||B.24, E.10, E.17, E.18.|
|10. Paramithrax minor Filhol.||Crust.||B.24, E.10, E.18.|
|11. Tawera spissa (Desh.).||Mol.||E.17, E.18.|
|12. Cominella adspersa (Brug.).||Mol.||B.24, E.10.|
|13. Amphipoda.||Crust.||B.24, E.10, E.18.|
|14. Sigapatella novaezelandiae (Less.).||Mol.||E.10, E.17, E.18.|
|15. Zegalerus tenuis (Gray).||Mol.||B.24, E.10, E.18.|
|(c) Secondary Species.|
|16. Venericardia purpurata (Desh.).||Mol.||E.17, E.18.|
|17. Rhyssoplax stangeri (Reeve).||Mol.||E.17, E.18.|
|18. Polychaetes (not identified).||Ann.||B.24, E.10, E.17.|
|19. Cirsotrema zelebori (Dunk.).||Mol.||E.17, E.18.|
|20. Lyroseila chathamensis (Suter).||Mol.||E.17, E.18.|
|21. Bryozoa.||Poly.||E.10, E.17.|
|22. Buccinulum multilineum Powell.||Mol.||E.17.|
|23. Murersul octogonus (Q. & G.).||Mol||E.10.|
|24. Baryspira novaezelandiae (Sowb.).||Mol.||B.24, E.10.|
|25. Cancer novaezelandia (Jacq. & Luc.)||Crust.||E.10.|
|26. Nectocarcinus antarcticus (J. & L.)||Crust.||E.10.|
|27. Halicarcinus planatus Fabr.||Crust.||E.10, E.17.|
|28. Hemiplax, hirtipes (Jacq. & Luc.)||Crust.||B.24, E.10.|
|29. Pilumnus novaezelandiae Fil.||Crust.||E.18.|
|30. Pelicaria vermis (Martyn).||Mol.||E.18.|
|31. Buccinulum heteromorphum (Powell).||Mol.||E.18.|
|32. Zelithophaga truncata (Gray).||Mol.||E.18.|
|33. Zemysia zelandica (Gray).||Mol.||E.18.|
|34. Chlamys zelandiae (Gray).||Mol.||E.18.|
|35. Maoricrypta monoxyla (Lesson).||Mol.||E.18.|
|36. Austrosipho adusto (Philippi).||Mol.||E.18.|
|37. Zeacolpus fulminatus (Hutton).||Mol.||B.24, E.10.|
|38. Proxiuber australis (Hutton).||Mol.||E.17.|
|39. Leptomya retiaria (Hutton).||Mol.||E.17.|
|40. Epitonium philippinarum Sowb.||Mol.||E.10, E.17.|
|41. Epitonium jukesianum Forbes.||Mol.||E.10.|
|42. Modiolaria impacta (Herm.).||Mol.||E.17.|
|43. Asterina regularis Verril.||Ech.||B.24, E.10.|
|44. Ischnochiton maorianus Iredale.||Mol.||E.17.|
|45. Zemitrella choava (Reeve).||Mol.||E.17.|
|47. Cryptomella albula (Hutt.).||Mol.||B.24, E.10.|
|48. Taron dubius (Hutton).||Mol.||E.10.|
|49. Monia zelandica (Gray).||Mol.||E.10.|
|50. Mytilus canaliculus Martyn.||Mol.||E.10.|
|51. Kellya suborbicularis (Mont.).||Mol.||E.10.|
|52. Nucula castanea A. Ad.||Mol.||E.10.|
|53. Proxichilidium obliquum (Thomp.).||Arth.||E.10.|
|54. Lepidonotus polychromus (Sch.).||Ann.||B.24, E.10.|
|55. Terebratella inconspicua (Sowb.).||Brach.||E.10.|
|56. Isocladus armatus (M. Ed.)||Crust.||E.10.|
|62. Rochefortula reniformis (Sut.).||Mol.||B.24.|
|63. Austromitra rubiradix Finl.||Mol.||B.24.|
|64. Estea impressa (Hutton).||Mol.||E.10, E.17, E.18.|
|65. Estea zosterophila (Webster).||Mol.||E.17, E.18.|
|66. Chemnitzia n.sp.||Mol.||E.10, E.17, E.18.|
|67. Mellite [ unclear: ] yx parva (Desh.).||Mol.||E.10.|
|68. Notosetia micans (Webster).||Mol.||E.17, E.18.|
|69. Odostomia n.sp.||Mol.||E.17, E.18.|
|(c) Secondary Species.|
|70. Awanuia dilatata Powell.||Mol.||E.17.|
|71. Eulima n.sp.||Mol.||E.17.|
|72. Scrobs ovata Powell.||Mol.||E.17.|
|73. Orbitestella toreuma Powell.||Mol.||E.17.|
|74. Pyrgulina rugata (Hutton).||Mol.||E.10, E.17.|
|75. Dardanula roseola (Iredale).||Mol.||E.17.|
|76. Odostomia incidata Suter.||Mol.||E.10.|
|77. Nozeba emarginata (Hutt.).||Mol.||E.10.|
Of the 77 species listed as occurring in this association the maximum number found in any one station is 47, and the average number for all the stations is 35. There is a greater number of species represented and very few of the typical formation that are not present, the only notable omission being Notosetia n.sp., one of the dominants of the microfauna in the typical formation. This association occurs through a greater range in salinity than does the Maoricolpus typical formation, and this probably accounts for the greater number of species.
|1. Maoricolpus rosea manukauensis Powell.||Mol.||M.6, M.7, M.8, M.12.|
|2. Nucula hartvigiana Pfr.||Mol.||M.7, M.12.|
|3. Zegalerus tenuis (Gray).||Mol.||M.6, M.7, M.8, M.12.|
|4. Cominella adspersa Brug.||Mol.||M.6, M.12.|
|5. Pecten (Notovola) medius Lamk.||Mol.||M.6, M.8.|
|6. Terenochiton inquinatus (Reeve).||Mol.||M.6, M.12.|
|7. Polychaetes (not identified).||Ann.||M.8, M.12.|
|(c) Secondary Species.|
|8. Buccinulum multilineum Powell.||Mol.||M.12.|
|9. Xymene plebejus (Hutton).||Mol.||M.12.|
|10. Lepidonotus polychromus (Sch.).||Ann.||M.12.|
|11. Acanthochiton zelandicus hookeri Gray.||Mol.||M.12.|
|12. Rhyssoplax stangeri (Reeve).||Mol.||M.12.|
|13. Sigapatella novaezelandiae (Less.).||Mol.||M.8.|
|14. Lamellaria ophione Gray.||Mol.||M.8.|
|15. Notocorbula zelandica (Q. & G.).||Mol.||M.8.|
|16. Baryspira australis (Sowb.).||Mol.||M.8.|
|17. Halicarcinus planatus (Fabr.).||Crust.||M.12.|
|18. Paramithrax minor Filhol.||Crust.||M.8.|
|19. Austrosipho adusta (Philippi).||Mol.||M.6.|
|20. Notoplax mariae (Webster).||Mol.||M.6.|
|21. Guraleus sinclairi (Smith).||Mol.||M.7.|
|23. Chemnitzia n.sp.||Mol.||M.6, M.7, M.8, M.12.|
|24. Melliteryx parva (Desh.).||Mol.||M.6, M.7, M.8, M.12.|
|25. Estea zosterophila (Webster).||Mol.||M.6, M.7.|
|26. New genus aff. Lodderia.||Mol.||M.6, M.8, M.12.|
|(c) Secondary Species.|
|27. Dardanula limbata (Hutton).||Mol.||M.12.|
|28. Odostomia cf. incidata Suter.||Mol.||M.8.|
|29. Arthritica bifurca (Webster).||Mol.||M.6, M.12.|
|30. Retusa oruaensis (Webster).||Mol.||M.8.|
Of the 30 species listed as occurring in this association the maximum found in any one station is 17 and the average number for all stations is 13.5. Compared with the typical Maoricolpus formation this association has less than half the number of species, different dominants and ten species that do not occur in the typical formation.
2c. Paphirus+Dosinula+Maoricolpus association.
This association borders the typical Maoricolpus formation of the Inner Harbour and extends out into areas C and E where it borders 2a, the Maoricolpus+Dosinula association. The substratum is mud with a strong admixture of shell, chiefly whole and comminuted shells of Chione stuchburyi, Paphirus largillierti, Tawera spissa, Maoricolpus rosea and Dosinula zelandica. This association 2c forms in the Inner Harbour a zone intermediate between the shallower water “nondescript” soft-bottom, inshore communities and the comparatively hard tide-swept Maoricolpus formation of the main channel. Its dominant animals are Paphirus largillierti and Dosinula zelandica with a few Maoricolpus rosea.
The fauna of this association is listed below.
|1. Paphirus largillierti (Phil.).||Mol||B.28, B.37, B.38, B.4.|
|2. Dosinula zelandica (Gray).||Mol.||B.38, B.41.|
|3. Maoricolpus rosea (Q. & G.).||Mol.||B.37, B.41.|
|4. Amphipoda.||Crust.||B.28, B.41.|
|(c) Secondary Species.|
|5. Baryspira mucronata (Sowb.).||Mol.||B.28.|
|7. Euchone pallida Ehlers.||Ann.||B.2.8.|
|8. Amphicteis philippinarum Gr.||Ann.||B.28.|
|9. Owenia fusiformis d.Ch.||Ann.||B.28.|
|10. Venericardia purpurata (Desh.).||Mol.||B.37.|
|11. Petrolisthes elongatus M. Ed.||Crust.||B.36.|
|12. Pleuromeris zelandica (Desh.).||Mol.||B.36.|
|13. Melliteryx parva (Desh.).||Mol.||B.37, B.41|
3. The Tawera+Glycymeris Formation.
This formation occurs on a hard clean substratum in the middle of the main channels of the Outer Harbour, and does not extend into the Inner Harbour, where its place is taken by the Maoricolpus formation. Lower salinity and a greater percentage of silt for the Inner and Upper Harbour channel are evidently the factors which exclude the Tawera+Glycymeris formation from that area, and, conversely, although Maoricolpus does occur in the Glycymeris+Tawera formation, it is always as a secondary species, which indicates that the physical conditions best suited for this Glycymeris+Tawera formation are adverse to those requiste to the development of the Maoricolpus formation. Apart from the main channels of the Outer Harbour, the Glycymeris+Tawera formation also occurs close inshore around small islands in exposed situations, where wave-action causes the accumulation of a ramp of shell-gravel. The Tawera+Glycymeris formation occurs on hard bottom with an average grade of 2.668, the substratum being composed mostly of worn whole bivalve-shells and comminuted shell, with a very small amount of fine sand and silt, only 2.81% of the dry weight of the total sample.
The dominant animals of the formation are: (1) The bivalve shellfish Tawera spissa, (2) the bivalve Glycymeris laticostata, (3) the herbivorous gasteropod Trochus tiaratus, (4) the half-crab Petrolisthes elongatus, (5) the crab Paramithrax minor, (6) the common mussel Mytilus canaliculus and (7) the carnivorous gasteropod Cominella quoyana. The Tawera+Glycymeris formation is rich in species and in individuals. Tidal currents in the narrow channels where this formation occurs (or wave-action in the case of the off-shore islets) circulate an abundance of food in the form of plankton; the almost complete absence of silt is favourable to the majority of marine animals, and the dead shells of the dominants, Tawera and Glycymeris provide shelter for the smaller and the more delicate organisms, as well as serving as a base for epiphytic animals and seaweeds, the latter providing food for a certain number of herbivorous gasteropods.
|1. Tawera spissa (Desh.).||Mol.||C.5, D.6, C.8, C.20, D.3–11, H.1, H.7.|
|2. Glycymeris laticostata Q. & G.||Mol.||C.5, C.8, C.20, D.3–11, E.3, H.1, H.6, H.7, H.10.|
|3. Trochus tiaratus Q. & G.||Mol.||C.5, C.6, C.8, C.12, C.20, D.3–11, E.3, H.6, H.7, H.10.|
|4. Petrolisthes elongatus M. Ed.||Crust.||C.5, C.6, C.8, C.12, C.20, D.3–11, E.3, H.6, H.10.|
|5. Paramithrax minor Filhol.||Crust.||C.5, C.6, C.8, C.12, C.20, D.3–11, E.3, H.7, H.10.|
|6. Mytilus canaliculus Mart.||Mol.||C.5, C.8, D.3, D.4, D.6, D.9, D.10.|
|7. Cominella quoyana A. Ad.||Mol.||C.5, C.6, C.8, C.12, C.20, D.3, D.4, D.5, D.6, D.7, D.8, D.10, D.11, E.3, H.1, H.6, H.10.|
|8. Murexsul octogonus (Q. and G.).||Mol.||C.5, C.6, C.8, C.12, C.20, D.3, D.4, D.5, D.7–10, H.7, H.10.|
|9. Baryspira novaezelandiae (Sowb.).||Mol.||C.5, C.6, C.8, C.20, D.3, D.4, D.7, D.9, D.10, D.11, H.7.|
|10. Taron dubius Hutt.||Mol.||C.5, C.6, C.8, C.20, D.3, D.4, D.5, D.7–10, E.3, H.10.|
|11. Asterina regularis Verril.||Ech.||C.5, C.8, C.20, D.3, D.4, D.5, D.7–11.|
|12. Zegalerna tenuis (Gray)||Mol.||C.5, C.6, C.8, C.20, D.4–7, D.10, D.11.|
|13. Sigapatella novaezelandiae (Less.).||Mol.||C.5, C.6, C.8, D.3, D.5, D.6, D.7, D.8, H.1, H.10.|
|14. Maurea pellucida (Val.).||Mol.||C.5, C.6, C.20, D.3, D.4, D.7, D.9, D.10.|
|15. Trachelochismus pinnulatus Forster.||Vert. (Pisc.)||C.6, C.20, D.4, D.5, D.8, D.9, D.10, H.10.|
|16. Austrosipho adusta (Phil.).||Mol.||C.6, C.8, C.12, D.4, D.5, D.7, D.8, D.10, E.3.|
|17. Leander sp.||Crust.||C.5, C.12, C.20, D.4–11, E.3, H.1, H.7, H.10.|
|18. Pilumnus novaezelandiae Fil.||Crust.||C.5, C.6, C.8, C.20, D.3, D.4, D.5, D.10, E.3.|
|19. Coscinasterias calamaria (Gray).||Crust.||C.5, C.6, C.8, C.12, D.3, D.4, D.5, E.3.|
|20. Notocorbula zelandica (Q. & G.).||Mol.||C.5, C.6, C.8, C.20, D.4, D.5, D.7, D.8, D.10, D.11, D.3, H.7, H.10.|
|21. Tunicata.||Tun.||C.5, C.6, C.8, C.20, D.3, D.4, D.5, D.3, H.10.|
|22. Bryozoa.||Poly.||C.5, C.6, D.3, D.4, D.8, D.3.|
|23. Sertularia.||Coel.||C.5, C.8, C.12, D.3, D.7, D.8, D.11, D.3.|
|24. Terenochiton inquinatus (Rve.).||Mol.||C.5, C.6, C.8, C.12, C.20, D.4, D.5, D.6, D.11, E.3, H.1, H.10.|
|25. Buccinulum multinineum Powell.||Mol.||C.5, C.6, C.8, C.12, C.20, D.9, D.3, H.6, H.10.|
|26. Isocladus armatus (M. Ed.).||Crust.||C.5, C.6, C.8, C.12, C.20, D.3, D.4, D.5, D.9, D.10, D.11, E.3, H.1, H.10.|
|(c) Secondary Species.|
|27. Zemysia zelandica (Gray).||Mol.||C.5, C.8, D.3–6, D.9–11.|
|28. Terebratella inconspicua (Sowb.).||Brach.||C.5, C.6, D.3–7, D.10, E.3, H.10.|
|29. Amphiura alba Mortensen.||Ech.||C.5, C.6, C.20, D.3, D.6, D.11, D.3, H.10.|
|30. Nucula nitidula A. Ad.||Mol.||C.5, C.6, C.8, C.12, D.4, D.7, H.10.|
|31. Proxichilidium obliquum (Thomp.).||Arth.||C.5, C.6, C.8, C.20, D.4, D.8.|
|32. Venericardia purpurata (Desh.).||Mol.||C.5, C.6, C.20, D.4, D.6, H.1.|
|33. Glycymeris modesta Angas.||Mol.||C.12, D.4, D.7, H 6, H.7, H.10.|
|34. Lyroseila chathamensis (Suter).||Mol.||C.5, C.6, C.8, C.20, D.3, D.4, D.5, D.7, E.3, H.10.|
|35. Halicarcinus planatus Fabr.||Crust.||C.12, D.3, D.5, D.7.|
|36. Cominella adspersa (Brug.).||Mol.||C.6, C.8, D.4, D.10, H.1.|
|37. Xymenella pusilla (Suter).||Mol.||C.6, D.5, D.7, D.9, D.11, E.3.|
|38. Chlamys radiatus (Hutt.).||Mol.||C.5, C.8, D.5, D.6, E.3, H.1.|
|39. Leptomya retiaria (Hutt.).||Mol.||C.5, C.6, C.8, D.6, D.7, D.10, D.11.|
|40. Porifera.||Por.||C.5, C.8, D.6, D.9.|
|41. Cirsotrema zelebori (Dunk.).||Mol.||C.5, C.6, C.8, C.20, D.3, D.7, E.3, H.7.|
|42. Chlamys zeelandonus (Hertlein).||Mol.||C.5, C.6, C.8, D.3, D.7, H.1, H.10.|
|43. Vermicularia sipho Lamk.||Mol.||C.8, D.4, D.9.|
|44. Austromitra rubiradix Finl.||Mol.||C.8, D.4, D.6, E.3, H.10.|
|45. Actinaria.||Coel.||C.6, D.4, D.5, D.7, E.3.|
|46. Nectocarcinus antarcticus (J. & L.).||Crust.||C.5, D.4, D.6, E.3, H.10.|
|47. Buccinulum heteromorphum Powell.||Mol.||C.8, D.8, D.9, H.10.|
|48. Marginella maoriana Powell.||Mol.||C.5, C.6, D.8, D.11, E.3.|
|49. Lepidonotus polychromus (Sch.).||Ann.||C.6, C.20, D.10, E.3.|
|50. Gari stangeri (Gray).||Mol.||C.5, C.6, C.8.|
|51. Maoricolpus rosea (Q. & G.).||Mol.||C.5, C.6, C.12, D.7, E.3.|
|52. Micrelenchus rufozonus (A. Ad.).||Mol.||C.5, C.8, D.7.|
|53. Cancer novaezelandiae (Sowb.).||Crust.||D.5, D.9.|
|54. Owenia fusiformis d.Ch.||Ann.||D.4, D.7, E.3.|
|55. Nereis mortenseni Aug.||Ann.||D.4, D.6.|
|56. Nereis australis Sch.||Ann.||D.4, D.8.|
|57. Amphipoda.||Crust.||C.8, D.4, H.10.|
|58. Odontosyllis polycera Sch.||Ann.||C.6, D.7.|
|59. Amphicteis philippinarum Gr.||Ann.||D.7, D.11, D.3.|
|60. Trichosirius inornatus (Hutt.).||Mol.||D.5, D.7.|
|61. Melatoma buchanani maorum (Smith).||Mol.||C.6, D.7.|
|62. Zemitrella pseudomarginata (Suter).||Mol.||D.8, D.9, D.10, E.3.|
|63. Daphnella cancellata Hutt.||Mol.||C.5, C.8.|
|64. Proxiuber australis (Hutt.).||Mol.||C.6, C.8.|
|65. Notoplax mariae (Webster).||Mol.||C.6, D.5.|
|66. Paphirus largillierti (Phil.).||Mol.||C.5, D.3, E.3.|
|67. Alcyonaria.||Coel.||C.12, D.3.|
|68. Pecten (Notovola) medius Lamk.||Mol.||C.5.|
|69. Kellya suborbicularis (Mont.).||Mol.||C.5.|
|70. Thelepus plagiostoma Sch.||Ann.||C.12, E.3.|
|71. Lepidametria comma Thom.||Ann.||C.12, E.3.|
|72. Psammolyce antipoda Sch.||Ann.||C.12.|
|73. Liocaroinus corrugatus (Penn.).||Crust.||C.20, E.3.|
|74. Rochefortula reniformis (Suter).||Mol.||C.12, D.7.|
|75. Amphitrite vigintipes Gr.||Ann.||D.9.|
|76. Maoriicrypta costata (Sowb.).||Mol.||D.5.|
|77. Maoricrypta monoxyla (Less.).||Mol.||D.10.|
|78. Nemertina.||Nem.||D.7, E.3, H.1.|
|79. Marginella oairoma Brookes.||Mol.||C.5, D.7.|
|80. Anomia walteri Hector.||Mol.||D.6.|
|81. Trochus viridis Gmel.||Mol.||D.9, H.6, H.10.|
|82. Cryptomella albula (Hutt.).||Mol.||D.7, H.7.|
|83. Pinnotheres novaezelandiae Filhol.||Crust.||C.5.|
|84. Lingimactra elongata (Q. & G.).||Mol.||C.5.|
|85. Limatula maoria Finlay.||Mol.||D.11.|
|86. Rhyssoplax stangeri (Reeve).||Mol.||C.6, H.1, H.6, H.10.|
|87. Zelithophaga truncata (Gray).||Mol.||C.12, E.3.|
|88. Acanthochiton zelandicus hookeri (Gray).||Mol.||D.3. H.10.|
|89. Craspedochiton rubiginosus (Hutton).||Mol.||D.4.|
|90. Epitonium jukesianum (Forbes).||Mol.||D.4, H.10.|
|91. Marginella pygmaea Sowb.||Mol.||D.4, H.6, H.7, H.10.|
|92. Thoristella oppressa (Hutt.).||Mol.||D.4.|
|93. Zemitrella stephanophora (Suter).||Mol.||D.4.|
|94. Cookia sulcata (Martyn).||Mol.||H.6.|
|95. Zeacolpus fulminatus (Hutt.).||Mol.||H.1, H.7.|
|96. Pervicacia tristis (Desh.).||Mol.||H.7.|
|97. Myodora striata (Q. & G.)||Mol.||H.7.|
|98. Onithochiton neglectus (Roch.).||Mol.||H.10.|
|99. Holothuria sp.||Ech.||H.10.|
|100. Dosinula zelandica (Gray).||Mol.||H.10.|
|101. Mitra hedleyi Murdoch.||Mol.||H.1, H.10.|
|102. Musculus impactus (Hermann).||Mol.||E.3.|
|104. Harmothoe sp.||Ann.||E.3.|
|105. Nicolea chilensis Sch.||Ann.||E.3.|
|106. Lumbriconereis sphaerocephala Sch.||Ann.||E.3.|
|107. Podarke angustfrons Grube.||Ann.||E.3.|
|108. Sphaerosyllis sp.||Ann.||E.3.|
|109. Armandia maculata Webster.||Ann.||E.3.|
|110. Estea impressa (Hutton).||Mol.||C.5, C.6, C.8, C.12, C.20, D.3, D.4, D.7–11, E.3, H.1, H.10.|
|111. Argalista nana Finlay.||Mol.||C.5, C.8, C.12, C.20, D.3, D.6–11, H.10.|
|112. Condylocardia crassicosta Bern.||Mol.||C.5, C.8, C.20, D.4, D.6, D.7, D.9, D.10, D.11.|
|113. Scrobs ovata Powell.||Mol.||C.5, C.12, C.20, D.6, D.8, D.9, D.10, D.11, E.3, H.10.|
|114. Odostomia n.sp.||Mol.||C.5, C.8, C.12, D.3, D.6, D.8, D.9, D.10, E.3, H.10.|
|115. Orbitestella toreuma Powell.||Mol.||C.5, C.6, C.8, C.12, C.20, D.3, D.6, D.7, D.9, D.10, D.11, E.3, H.1, H.10.|
|116. Awanuia dilatata Powell.||Mol.||C.8, C.12, C.20, D.3, D.4, D.6, D.7, D.10, D.11. E.3.|
|117. Eulima n.sp.||Mol.||C.5, C.6, C.8, C.12, C.20, D3, D.4, D.7, D.9, D.10, D.11, E.3, H.10.|
|118. Chemnitzia n.sp.||Mol.||C.6, C.8, C.12, C.20, D.7, D.8, D.10, D.11, E.3.|
|119. Melliteryx parva (Desh.).||Mol.||C.8, C.12, C.20, D.4, D.6, D.7, D.9.|
|120. Notosetia micans (Webster).||Mol.||C.12, D.4, D.6, D.11, H.1, H.10.|
|(c) Secondary Species.|
|121. Pyrgulina rugata (Hutt.).||Mol.||C.12, D.3, D.6, D.9, D.11, E.3. H.1.|
|122. Scrobs rugulosa Powell.||Mol.||C.5, C.8, D.7, E.3, H.1.|
|123. Scorbs hedieyi angulata Powell.||Mol.||C.5, C.8, C.12, D.7, D.10.|
|124. Zemitrella websteri Suter.||Mol.||C.5, C.8, D.9, D.10, H.10.|
|125. Dardanula limbata (Hutt.).||Mol.||C.8, D.10, H.1, H.10.|
|126. Dardanula roseola (Ired.).||Mol.||C.12, D.10.|
|127. New genus aff. Lodderia.||Mol.||E.3, H.1, H.10.|
|128. Elachorbis subtatei (Suter).||Mol.||H.1, H.10.|
|129. Estea subfusca (Hutton).||Mol.||D.10.|
|130. Estea zosterophila (Webster).||Mol.||H.10.|
|131. Scrobs hedleyi (Suter).||Mol.||D.4.|
|132. Scrobs semen (Odhner).||Mol.||H.10.|
|133. Notosetia n.sp.||Mol.||H.10.|
|134. Notosetia n.sp.||Mol.||H.1.|
|135. Gumina dolichostoma (Suter).||Mol.||C.12, D.4.|
|136. Pellax huttoni (Pilsbry).||Mol.||H.7.|
|137. Notoacmea subtilis (Suter).||Mol.||H.10.|
|138. Zelaxitas n.sp.||Mol.||H.10.|
|139. Notolepton sanguineum (Hutt.).||Mol.||H.10.|
|140. Odostomia georgiana Suter.||Mol.||C.12.|
|141. Graphis blanda (Finlay).||Mol.||C.12.|
Of the 142 species listed as occurring in this formation the maximum number found in any one station is 61, and the average number for all the stations is 39. Compared with the other formations Tawera+Glycymeris has a far greater number of species, they occur in greater quantity and the microfauna is equally rich and more varied than in any other Auckland-Manukau formation.
3a. The Tawera+Venericardia association.
In this association Tawera spissa and Venericardia purpurata are the dominants, Glycymeris laticostata being entirely absent. The substratum differs from that of the typical formation in having the fine-sand and silt grades a little greater and the coarse grades comparatively small, the bulk of the material being in grades 3, 4 and 5. On account of the lack of the large dead Glycymeris shells there are fewer parasitic animals, and the slight increase in the fine-sand and silt grades accounts for the reduction in species.
The association takes the place of the typical formation in localities where there is no great tidal current. It is found therefore in open exposed bays such as Oneroa, Waiheke Island, and also on the outside and below the Glycymeris+Tawera belt in the case of exposed islets such as the Noises.
|1. Tawera spissa (Desh.).||Mol.||F.2, H.2, H.4, H.9, H.11, J.4.|
|2. Venericardia purpurata (Desh.).||Mol.||F.2, H.2, H.4, H.9, H.11, J.4.|
|3. Cominella quoyana A. Ad.||Mol.||F.2, H.2, H.4, H.11, J.4.|
|4. Notocorbula zelandica (Q. & G.).||Mol.||F.2, H.2, H.4, H.9, H.11.|
|5. Glycymeris modesta A. Ad.||Mol.||F.2, H.2, H.11.|
|6. Zeacolpus fulminatus (Hutt.).||Mol.||F.2, H.2, H.4.|
|7. Cominella adspersa Brug.||Mol.||F.2, H.4, H.11, J.4.|
|8. Baryspira novaezelandiae (Sowb.).||Mol.||F.2, H.4, H.9.|
|(c) Secondary Species.|
|9. Nectocaroinus antaroticus (J. & L.).||Crust.||F.2, H.11, J.4.|
|10. Nucula nitidula A. Ad.||Mol.||F.2, H.2.|
|11. Pervicacia tristis (Desh.).||Mol.||F.2, H.2.|
|12. Pleuromeris zelandica (Desh.).||Mol.||F.2, H.2, H.4.|
|13. Austrosipho adusta (Phil.).||Mol.||F.2, H.11.|
|14. Murexsul octogonus (Q. & G.).||Mol. H.2, H.9.|
|15. Trochus tiaratus Q. & G.||Mol.||H.11, J.4.|
|16. Zegalerus tenuis (Gray.).||Mol.||H.4, H.11, J.4.|
|17. Petrolisthes elongatus M. Ed.||Crust.||H.11, J.4.|
|18. Leptomya retiaria (Hutton).||Mol.||F.2, H.2.|
|19. Owenia fusiformis d.Ch.||Ann.||F.2, H.4.|
|20. Cirsotrema zelebori (Dunk.).||Mol.||H.2, J.4.|
|21. Proxiuber australis Butt.||Mol.||H.2, J.4.|
|22. Amphipoda.||Crust.||H.2, H.4, H.9.|
|23. Pelicaria vermis (Martyn).||Mol.||H.2.|
|24. Struthiolaria papulosa Martyn.||Mol.||H.11.|
|25. Poirireria zelandica (Q. & G.).||Mol.||H.9.|
|26. Mytilus canaliculus Mart.||Mol.||F.2.|
|27. Rhyssoplax stangeri (Rve.).||Mol.||J.4.|
|28. Zemysia zelandica (Gray).||Mol.||J.4.|
|29. Baryspira mucronata (Sowb.).||Mol.||F.2.|
|30. Baryspira depressa (Sowb.).||Mol.||F.2.|
|31. Emarginula striatula Q. & G.||Mol.||H.9.|
|32. Terebratella inconspicua (Sowb.).||Brach.||H.9.|
|33. Antisolarium egenum (Gould).||Mol.||F.2.|
|34. Isocladus armatus M. Ed.||Crust.||F.2, H.9.|
|35. Epitonium jukesianum Forbes.||Mol.||J.4.|
|36. Holothuria (small, pink).||Ech.||J.4.|
|37. Trachelochismus pinnulatus Forster.||Vert. (Pisc.)||J.4.|
|38. Myadora striata Q. & G.||Mol.||H.2.|
|39. Cryptomella albula (Hutt.).||Mol.||H.4.|
|41. Scalpomactra scalpellum (Rve.).||Mol.||H.2.|
|42. Terenochiton inquinatus (Reeve).||Mol.||J.4.|
|43. Marginella pygmaea Sowb.||Mol.||J.4.|
|44. Condylocardia concentrica Bern.||Mol.||J.4.|
|45. Condylocardia crassicosta Bern.||Mol.||J.4.|
|46. Notosetia micans (Webster).||Mol.||J.4.|
|47. Estea minor (Suter).||Mol.||J.4.|
|48. Notoacmea subtilis (Suter).||Mol.||J.4.|
|49. Dosinia subrosea (juveniles).||Mol.||F.2.|
|51. Arthritica bifurca (Webster).||Mol.||H.2.|
|52. Myllitella vivens Finlay.||Mol.||H.2.|
|53. Chemnitzia n.sp.||Mol.||F.2.|
|54. Zemitrella choava (Hutt.).||Mol.||J.4.|
|55. Melliteryx parva (Desh.).||Mol.||H.9.|
Of the 55 species listed the maximum number occurring in any one station is 24, and the average number for all the stations is 16.16. Compared with the typical formation this association has fewer species and the microfauna is represented by few species per station and no obvious dominants.
In H.2, Tawera is replaced in dominance by Zeacolpus fulminatus. The substratum differs in the comminuted shell-grades being greatest and the whole dead shells of Tawera least. However, Venericardia purpurata is present, and pending further investigation the station may be classified as above. It may represent an associes of the Tawera+Venericardia association.
3b. The Tawera+Astropecten association.
This is an open-sea and coastal community known to occur at depths between 9 and 20 fathoms, but it probably has a greater range. The substratum is characterised by having about 90% grade seven, fine silica-sand. There is practically no silt, the remaining coarse grades being made up of a moderate amount of whole and comminuted Tawera valves. The dominant animals are (1) the bivalve shellfish Tawera and several carnivores, the most important being (2) the starfish Astropecten polyacanthus (= edwardsi) and (3) the gasteropod shellfish Cominella adspersa.
More stations are required to indicate the normal fauna of this association, the following list being based on two dredgings only, one from 9 fathoms off Whangateau, Big Omaha Bay, and a comparative one from 18–20 fathoms 4 miles out from Mount Beach, Tauranga.
|1. Tawera spissa (Desh.).||Mol.||I.6, T.8.|
|2. Astropecten polyacanthus M. & T.||Ech.||I.6, T.8.|
|3. Cominella adspersa (Brug.).||Mol.||I.6.|
|4. Baryspira novaczelandiae (Sowb.).||Mol.||I.6, T.8.|
|5. Cryptomella albula (Hutt.).||Mol.||I.6.|
|6. Antisolarium egenum (Gould).||Mol.||I.6, T.8.|
|7. Pervicacia tristis (Desh.).||Mol.||I.6.|
|8. Cominella quoyana A. Ad.||Mol.||I.6.|
|9. Zegalerus tenuis (Gray).||Mol.||I.6.|
|(c) Secondary Species.|
|10. Venericardia purpurata (Desh.).||Mol.||I.6.|
|11. Pleuromeris zelandica (Desh.).||Mol.||I.6.|
|12. Cirsotrema zelebori (Dunk.).||Mol.||I.6.|
|13. Paradione multistriata (Sowb.).||Mol.||I.6.|
|14. Myadora boltoni Smith.||Mol.||I.6.|
|15. Proxiuber australis (Hutt.).||Mol.||I.6.|
|16. Pupa alba (Hutton).||Mol.||T.8.|
|17. Austrofusus glans (Bolten).||Mol.||I.6, T.8.|
|18. Micrelenchus rufozonus (A. Ad.).||Mol.||I.6.|
|19. Notoplax cuneata (Suter).||Mol.||I.6.|
|20. Melatoma buchanani maorum (Smith).||Mol.||I.6.|
|21. Zeacolpus fulminatus (Hutt.).||Mol.||I.6, T.8.|
|22. Notoacmea subtilis (Suter).||Mol.||I.6.|
|23. Chemnitzia n.sp.||Mol.||I.6.|
|25. Condylocardia concentrica Bern.||Mol.||I.6.|
|26. Odostomia n.sp.||Mol.||I.6.|
|27. Teretianax pagoda Powell.||Mol.||I.6.|
|28. Myllitella vivens Finlay.||Mol.||I.6.|
Of the 28 species listed as occurring in this formation 27 are found in I.6 and only 7 in T.8. The microfauna is very poorly represented in the former station and entirely absent in the latter. The abundance of the silica-sand in grade 7 seems to be the limiting factor to the animals of this formation. Although this association does not occur in Auckland Harbour it is included in this report on account of its comparative value in indicating how an open coastal community penetrates into the Hauraki Gulf but has not been found so far in as the harbour or immediate vieinity. From casual observation the Tawera+Astropecten association would appear to be widespread in North Auckland East Coast districts and in the Bay of Plenty, wherever there is an abundance of fine silica-sand. Where this association changes to a related estuarine one as in Tauranga Harbour the little-known chiton, Notoplax cuneata, becomes quite abundant.
3c. The Flabellum+Notocorbula association.
In this association neither Tawera nor Glycymeris laticostata is found living, but dead shells of the former make up most of the substratum. The substratum differs from that of both the typical formation and the association 3a in being composed almost entirely of coarse shell with very little comminuted material, fine sand or silt. It seems to represent a wash of dead shells from a nearby Tawera+Glycymeris or Tawera+Venericardia area, that has not been subjected to sufficient wave-action to reduce much of its bulk to the finer grades. It occurs in moderately wide or open channels in the Outer Harbour and Hauraki Gulf. The dominant organisms are the fan-coral Flabellum rugulosum and the mollusc Notocorbula zelandica. The microfauna is very poorly represented.
The fauna of this association is listed below
|1. Flabellum rugulosum Ten. W.||Coel.||C.9, G.5, G.6, I.2.|
|2. Notocorbula zelandica (Q. & G.).||Mol.||G.5, G.6, I.2.|
|3. Cominella quoyana A. Ad.||Mol.||C.9, G.5, G.6, I.2.|
|4. Baryspira novaezelandiae (Sowb.).||Mol.||C.9, G.5, G.6, I.2.|
|5. Amphiura alba Mortensen.||Ech.||C.9, G.5, G.6, I.2.|
|6. Holothuria (small, pink).||Ech.||G.6, I.2.|
|7. Asterina regularis Verril.||Ech.||C.9, G.5.|
|8. Amphipoda.||Crust.||C.9, G.6, I.2.|
|9. Tunicata.||Tun.||C.9, G.6.|
|(c) Secondary Species.|
|10. Coscinasterias calamaria (Gray).||Ech.||G.5.|
|11. Baryspira mucronata (Sowb.).||Mol.||G.5, I.2.|
|12. Paramithrax minor Filhol.||Crust.||C.9, G.6.|
|13. Trochus tiaratus Q. & G.||Mol.||G.6.|
|14. Venericardia purpurata (Desh.).||Mol.||G.6.|
|15. Terebratella inconspicua (Sowb.).||Brach.||G.5, G.6, I.2.|
|16. Nectocarcinus antarcticus (J. & L.).||Crust.||G.6, I.2.|
|17. Lepidonotus polychromus (Sch.).||Ann.||G.6, I.2.|
|18. Petrolisthes elongatus M. Ed.||Crust.||G.6, I.2.|
|19. Terenochiton inquinatus (Rve.).||Mol.||C.9, G.6, I.2.|
|20. Pelicaria vermis (Martyn).||Mol.||I.2.|
|21. Sigapatella novaezelandiae (Less.).||Mol.||I.2.|
|22. Pecten (Notovola) medius Lamarck.||Mol.||I.2.|
|23. Chlamys radiatus (Hutton).||Mol.||I.2.|
|24. Siphunculus sp.||Geph.||I.2.|
|25–27. Polychaetes (3 species).||Ann.||I.2.|
|28. Murexsul octogonus Q. & G.||Mol.||I.2.|
|29. Maurea pellucida (Val.).||Mol.||I.2.|
|30. Pleuromeris zelandica (Desh.).||Mol.||I.2, G.6.|
|31. Lyroseila chathamensis (Suter).||Mol.||C.9, I.2.|
|32. Cominella adspersa (Brug.).||Mol.||C.9.|
|33. Zeacolpus fulminatus (Hutt.).||Mol.||G.6.|
|34. Zelithophaga truncata (Gray).||Mol.||C.9.|
|35. Chlamys zeelandonus Hert.||Mol.||C.9.|
|36. Bryozoa.||Poly.||C.9, I.2.|
|37. Halicarcinus planatus Fabr.||Crust.||C.9.|
|38. Alcithoe graoilis (Swain.).||Mol.||I.2.|
|39. Maoricolpus rosea (Q. & G.).||Mol.||I.2.|
|40. Austromitra sp.||Mol.||I.2.|
|41. Aeneator (juvenile).||Mol.||I.2.|
|42. Steggoa brevvicornis Ehl.||Ann.||C.9.|
|43. Kellya suborbicularis Mont.||Mol.||I.2.|
|44. Melliteryx parva (Desh.).||Mol.||G.5, G.6, I.2.|
|45. Nozeba emarginata (Hutt.).||Mol.||C.9.|
|46. Chemnitzia n.sp.||Mol.||I.2.|
Summary: Of the 46 species listed as occurring in this association the maximum number found in any one station is 31, and the average number for all the stations is 18.95. Compared with the typical formation the fauna of this association is poor in both species and numbers and the microfauna is barely represented.
3c1. The Notocorbula+Pleuromeris associes.
This associes is related to the Tawera+Venericardia association, but neither of the dominants of that association occur. The substratum is composed of clean comminuted shell, mostly Tawera valves from an adjacent Tawera+Venericardia area. It is a later development of the Flabellum+Corbula associes suited to a substratum in which the comminution of the Tawera valves is further advanced.
The dominant species are Notocorbula zelandica and Pleuromeris zelandica. Nemocardium pulchellum, Micrelenchus rufozonus and Monia furcata appear as secondary species new to the area. This associes has been noticed in the sheltered coastal waters off the Bay of Plenty and North Auckland East Coast.
The fauna given below is from one station only, I.5, but it probably occurs as a bordering zone elsewhere in the outer Hauraki Gulf wherever Flabellum+Corbula occurs.
|1. Notocorbula zelandica (Q. & G.)|
|2. Pleuromeris zelandica (Desh.).|
|3. Nuoula nitidula A. Ad.|
|4. Zegalerus tenuis (Gray).|
|5. Cominella quoyana A. Ad.|
|6. Emarginula striatula Q. & G.|
|7. Chlamys radiatus (Hutton).|
|(c) Secondary Species.|
|8. Nemocardium pulchellum (Gray).|
|9. Glaphyrina vulpicolor (Sowerby).|
|10. Micrelenchus rufozonus (A. Ad.).|
|11. Monia furcata (Suter).|
|12. Zemyllita stowei Hutton.|
|13. Melliteryx parva (Desh.).|
|14. Odostomia sp.|
4. The Arachnoides Formation.
This formation occurs in the outer basin of Manukau Harbour, but has not been located either in Auckland Harbour or in the Hauraki Gulf. It occurs in a substratum that averages 95% grade 7, fine iron-sand, practically no silt, and just a trace of comminuted shell. The dominant animal is the cake-urchin Arachnoides placenta, and the subdominant the gasteropod Zethalia zelandica. The fauna is very sparse both in species and in numbers. The formation seems to be governed by the combination of the factors of iron-sand substratum, which has been washed in from the West Coast, and the semi-estuarine conditions of the outer basin of the Manukau Harbour. The range in depth noted was 4 to 17 fathoms.
|1. Arachnoides placenta Linn.||Ech.||M.4, M.9, M.10, M.11.|
|2. Zethalia zelandica (A. Ad.).||Mol.||M.4, M.11.|
|(c) Secondary Species.|
|3. Cirsotrema zelebori (Dunk.).||Mol.||M.9.|
|4. Maoricolpus rosea manukauensis Powell.||Mol.||M.9.|
|5. Notocorbula zelandica (Q. & G.).||Mol.||M.9.|
|6. Polychaetes.||Ann.||M.9. M.11.|
|7. Soletellina siliqua Reeve.||Mol.||M.11.|
|8. Myadora boltoni Smith.||Mol.||M.10.|
|9. Eupagurus sp.||Crust.||M.10.|
|10. Ohemnitzia n.sp.||Mol.||M.4.|
|11. Melliteryx parva (Desh.).||Mol.||M.4.|
|12. Retusa oruaensis (Webster).||Mol.||M.4.|
|13. Notosetia n.sp.||Mol.||M.4.|
Of the 13 species listed as occurring in this formation the maximum number for any one station is 6 and the average for four stations is 4.5. The maximum number of specimens for any one station is 48, of which 44 are the Arachnoides. The microfauna is very poorly represented, with a maximum of 4 species, none of which occur commonly.
5. Baryspira Community.
This community favours a substratum of fine clean sand and occurs in shallow water below low spring-tide level in from 2 to 4 fathoms, off Outer Harbour beaches and sheltered coastal beaches.
Insufficient stations have been taken to indicate either the relationship of this community to the classification proposed in this paper or to give a comprehensive list of its fauna. It is evidently a benthic phase of a littoral community that favours a clean fine-sand substratum. The classification of these inshore to low-tidal communities may be dealt with later in a paper on the littoral animal communities of the Auckland Harbour and vicinity.
|1. Baryspira australis (Sowb.).||Mol.||C.15, E.5, E.13, E.14, F.3.|
|2. Pervicacia tristis (Desh.).||Mol.||F.3.|
|3. Cominella (Acominia) adspersa (Brug.).||Mol.||C.15, E.13, F.3.|
|4. Baryspira depressa (Sowb.).||Mol.||F.3.|
|5. Nucula nitidula A. Ad.||Mol.||C.15, F.3.|
|6. Amphiura alba Mort.||Ech.||C.15, F.3.|
|(c) Secondary Species.|
|7. Owenia fusiformis d.Ch.||Ann.||C.15.|
|8. Polychaetes (not identified).||Ann.||E.14.|
|9. Notocorbula zelandica (Q. & G.).||Mol.||E.14.|
|10. Asterina regularis Verril.||Ech.||C.15, E.14.|
|11. Myadora boltoni Smith.||Mol.||F.3.|
Under this heading is grouped the few stations that do not conform to any of the formations, associations or associes here outlined. They are just odd stations taken at random, and more intensive work in the same areas will be necessary in order to determine their classification.
These nondescript stations are: A.12, B.27, B.35, C.11, C.13, C.18, D.14, E.15, and E.16.
The polar Year was magnetically a quiet period, and Mr Skey wishes to continue the working of the Quick-Run Magnetographs in the hope of recording some intense magnetic storms. It is probably that numbers of other observatories will also keep their instruments in operation for a further period.
The programme of extra meteorological observations at Wellington and Christchurch has been completed.
The authorities concerned consider that the Polar Year scheme has been very successfully carried out. An immense amount of valuable data has been collected, and the International Commission is proceeding vigorously with the publication and discussion. Numbers of researches are already under way, but the President anticipates that these matters will keep the Commission fully occupied for another five years.
Statement of Receipts and Expenditure for Year ending 31st March, 1934.
|To Balance in Post Office Savings Bank||148||9||6||By Balance forward||152||14||10|
|Interest in 1932–33 Financial Year||3||19||7|
Interest to the amount of £4 11s 2d has accrued during the year ending 31st March, 1934.
Edward Kidson, Hon. Secretary.
G. Shirtcliffe, Chairman.
Audited and found correct.
E. J. Archibald, Accountant.
Wellington, 30th April, 1934.
Note added: Since the end of the financial year, expenditure to the amount of £109 7s 11d has been incurred. It is anticipated that the remaining funds will be absorbed during the current year.
Dr Kidson, Secretary of the Polar Year Committee, moved the adoption of his report, which was seconded by Dr Marsden and carried.
National Art Gallery and Dominion Museum.
Reported by Vice-president.
During the year ending 31st March, 1934, five meetings of the Board of Truestees have been held, and these were attended by your representatives, the President's deputy (Professor Kirk or by Dr Marshall) and the Vice-president; also by Mr Oliver, a member of this Council.
A Matter for congratulation is that the Hon. the Minister of Internal Affairs (Mr Young) was able to attend and preside over most of the meetings.
Building.—The main work of the year took place in connection with the erection of the main building, which had been decided upon last year. The building operations have gone steadily forward according to schedule; Putaruru vitric tuff is the only stone being used in the construction, and it has continued to give the same satisfaction as it has done in the completed Carillon building. At the end of the business year, 31st March, 1934, the erection of the building was well advanced, and the arrangements for the laying of the foundation stone had been completed. It is now possible to see from the lay-out the Museum galleries.
Committee of Control.—Messrs Fraser, Aston, and Oliver were appointed a sub-committee to look into the matter of an appointment of a committee to control the Museum as provided by the Act, and to report later to the Board, but so far no meeting of this committee has been held.
herbivorous feeders both have a greater range, but show their optimum development in one particular texture of substratum. Carnivores have no particular preference in substratum, as usually they are predatory on a number of animals and are not directly concerned with the substratum in which their food lives.
The dominants of three of the animal communities defined herein are deposit-feeders, those of the fourth being suspension-feeders. Carnivores are usually of secondary importance in a community.
|Average fine sand + silt. %||93.81||24.01||15.21||39.47||48.18||2.81||5.97||65.64||2.40||94.79|
|Neilo australis (Suspension-feeders)||B|
|Epifaunal Animals—(Carnivorous feeders)|
|Baryspira novaezelandiae (Herbivorous feeders)||C||C||B||B||B||B|
|Maurea pellucida (Deposit-feeders)||C||B||C|
|Maoricolpus rosea (manukauensis in 2b.)||C||C|
Inter-Community Range of Animals correlated with the Substratum.
A indicates dominance of species, B subdominance, C secondary occurrence only, and X abundant dead in substratum but none living. 1 Echinocardium formation. 2 Maoricolpus formation. 2a Maoricolpus+Dosinula association. 2b Maoricolpus (manukauensis)+Nucula association. 2c Paphirus+Dosinula+Maoricolpus association. 3 Tawera+Glycymeris formation. 3a Tawera+Venericardia association. 3b Tawera+Astropecten association. 3al Flabellum+Corbula association. 4 Arachnoides formation.
(c) Benthic Animal Communities in Relation to Food of Snapper
In the New Zealand Marine Department's Reports on Fisheries for the years 1928, 1929 and 1932 respectively, results of investigations into the schooling of snapper in the Hauraki Gulf are given. It is shown that in the early summer there is a great concentration of schooling snapper in an area just to the eastward of Tiri Tiri Island and extending up to Kawau. The pelagic eggs have been taken in quantity by numerous tow-nettings and the approximate boundaries of the schooling ground determined by this method. This migration to the schooling ground is clearly indicated by the accompanying graph illustrating the monthly analysis of snapper stomach-contents. It will be noticed that during the spawning time the snapper takes a greatly increased proportion of pelagic food consisting of small fishes and salps: otherwise this fish shows a marked preference for benthic organisms.
An investigation made at Auckland by the Fisheries Department for each month during 1928–1931 gave the following results based upon 3515 fish:—(1) Crustacea 35.7%, (2) Mollusca 17.9%, (3) Echinoderms 17.5%, (4) Fishes 15.0%. Although the exact determination of many organisms is not given in the table of snapper stomach-contents prepared by the Fisheries Department, it is nevertheless clearly evident that the benthic communities 1. Echinocardium formation and 3. Tawera+Glycymeris formation make up a considerable proportion of the snapper's diet throughout the year. These important food-organisms and their source may be summarised as follows. Percentages are given only where the identity of the organism is certain.
|1. Echinocardium formation.|
|3. Tawera + Glycymeris formation.|
|Crabs (mostly Petrolisthes elongatus)||25.05%|
Records of the stomach-contents of two catches of snapper recorded below serve to show the diversity of the snapper's diet. An interesting point is the marked preference for Anomia walteri. In April, 1936. a similar preference for Anomia was shown by a catch of some thirty snapper from the same locality.
A. Stomach-contents of three specimens of snapper from off the North coast of Motuihi in six fathoms. Line caught by A. W. B. P., 15/4/1935.
|1. Cominella adspersa (size of operculum indicates shell 45 mm. in height.)||2 sp. (foot with operculum only).|
|Cominella quoyana||8 sp. (crunched).|
|Eupagurus sp.||4 sp. (small).|
|Trochus tiaratus||several (crunched).|
|Proxiuber australis||1 sp.|
|Rhyssoplax stangeri||1 sp.|
|Sigapatella novaezelandiae||2 sp.|
|(A quantity of shell-debris swallowed with food).|
|2. Zenatia acinaces||1 sp. (small).|
|Baryspira mucronata (size of operculum indicates shell 30 mm. in height)||1 sp. (foot with operculum).|
|Struthiolaria papulosa (size of operculum indicates shell 75 mm. in height)||1 sp. (foot with operculum).|
|3. Eupagurus sp.||several (large).|
Note.—There was no trace of the shells of Struthiolaria, Cominella or Baryspira. Apparently the snapper simply mutilates the exposed parts of these larger shellfish.
Stomach-contents of eight specimens of snapper from off Motutapu. Line caught by Mr. W. M. Young, 26/6/1935.
|1. Anomia walteri||47 sp. (up to lin.).|
|Tawera spissa||1 fragment.|
|2. Anomia walteri||15 sp. (up to lin.).|
|Tawera spissa||1 fragment.|
|Gari stangeri||1 fragment.|
|3. Anomia walteri||69 sp. (up to lin.).|
|4. Anomia walteri||98 sp. (up to lin.).|
|Small fish||1 sp.|
|Tawera spissa||1 fragment.|
|Notocorbula zelandica||1 fragment.|
|5. Anomia walteri||35 sp. (up to lin.).|
|6. Coscinasterias calamaria||1 juvenile.|
|Elminius sp.||1 sp.|
|Petrolisthes elongatus||1 large.|
|7. Anomia walteri||22 sp. (up to lin.).|
|Pelicaria vermis||1 sp. (foot with operculum).|
|8. Anomia walteri||87 sp. (up to lin.).|
|Cominella quoyana||1 fragment.|
A survey of the sea-bottom over a wider area, including the outer Hauraki Gulf and coastal waters, correlated with further work on the stomach-contents should give a fairly accurate idea of the location month by month of the most suitable fishing-grounds.
|Pelagic Food||Benthic Food|
|Station||Date.||Fish Salpes Cephalopoda (Squids)||Crabs||Crustacea||Heart Urchin (Echinocardium)||Brittle Star Amphiura||Worms (Polychactes)||Shellfish (Gasteropoda)||Slipper Limpet (Crepidula)||Shellfish (Pelecypoda)||Tawera spissa||Dosinia lambata||Common Mussel Mytilus canaliculus||Horse Mussel Atrina zelandica||Shellfish Amphineura Chitons||Sea Squirts Tunicates||No. of fish examined||No. of empty stomachs|
|A* 1||9 7 1929||– – –||–||–||–||–||25||–||–||–||–||–||–||–||–||–||25||–|
|G* 1||4 10 1928||17 – –||22||–||–||–||–||–||–||7||–||–||3||2||–||–||41||1|
|G* 2||10 1 1929||1 – –||10||1||8||–||2||–||–||–||–||10||–||2||–||–||25||3|
|C* 1||9 10 1928||3 – –||14||–||3||–||1||–||–||5||–||–||–||2||–||–||23||4|
|F* 1||10 10 1928||27 – –||3||–||–||–||–||–||–||–||–||–||–||25||–||–||60||5|
|H* 1||– 4 1929||12 – –||10||1||2||–||11||1||–||2||–||–||–||–||–||1||50||11|
|H* 2||2 7 1931||3 – –||18||–||7||–||15||1||–||2||–||–||–||–||–||–||50||6|
|H* 3||30 7 1931||1 – –||25||–||8||3||6||1||–||2||–||–||–||1||–||–||50||4|
|H* 4||25 6 1931||8 1 –||16||–||4||–||8||–||–||4||–||–||–||–||–||–||50||9|
|I* 1||25 5 1931||– – –||44||–||–||1||–||–||1||–||–||–||4||–||–||–||51||1|
|I* 2||10 4 1931||3 2 1||13||1||15||–||4||–||1||5||–||–||–||1||–||–||50||10|
|I* 3||26 10 1928||11 37 –||4||–||3||–||–||–||–||–||–||–||–||3||–||–||60||4|
|I*4||26 10 1928||8 43 –||–||–||3||–||5||–||–||–||–||–||–||5||–||–||60||4|
|I*5||25 5 1931||– – –||10||5||6||1||1||–||–||5||–||–||–||14||–||–||50||8|
|I*6||25 5 1931||5 5 –||10||3||4||–||–||1||–||1||–||–||–||16||–||–||50||5|
|I*7||8 2 1929||9 4 –||13||–||21||–||5||–||–||–||–||–||–||–||–||–||50||–|
|I*8||26 10 1929||4 22 –||–||3||1||–||1||–||–||–||–||–||–||–||–||–||30||2|
|I*9||17 1 1929||– 57 –||–||–||1||–||–||–||–||–||–||–||–||–||–||–||58||–|
|I*10||16 7 1931||6 – –||1||13||6||1||10||–||1||4||–||–||–||–||–||–||50||10|
|J*1||12 9 1928||– – –||20||–||–||–||–||1||1||–||3||–||1||1||–||–||30||3|
|J*2||12 9 1928||2 – –||19||–||–||1||1||–||1||–||–||–||3||–||–||–||30||3|
|J*3||10 12 1928||– – –||2||5||–||–||–||–||–||–||7||–||1||–||1||–||14||1|
|120 171 1||254||22||92||7||95||5||5||37||10||10||12||72||1||1||957||94|
|Stomachs containing pelagic food:||292||Benthic f od : 623|
Note.—One stomach may contain more than one type of food—e.g., fish, crab, heart-urchin. this would be recorded as three items, and accounts for the total of stomachs containing pelagic food, those containing benthic food and those empty, exceeding the total of fish examined.
Diagram VI.—Comparison Between Benthic and Pelagic Elements in Monthly Stomach Contents of Snapper
Fish from Hauraki Gulf and Bay of Plenty, 1928–31.
Note.—One stomach may contain more than one kind of food—e.g., fish, crustacean, mollusc. This is recorded under separate headings, and accounts for the monthly totals in several cases exceeding 100%.
Based upon statistics kindly made available by Mr. A. E. Hefford, Fisheries Department, Wellington.
List of Stations for Snapper Stomach-contents Table.
A*1. Upper reaches, Auckland Harbour. 9/7/1929. “Selma.”
G*1. Off Rakino Island. 4/10/1928. “Anzac.”
G*2. Off eastern side of Rakino Island. 10/1/1929. “Anzac.”
C*1. Off Home Bay, Motutapu Island. 9/10/1928. “Anzac.”
F*1. Off D'Urville Rocks. 10/10/1928. “Fox.”
H*1. Close in, outside Noises. –/4/1929. “Orion.”
H*2. Off Noises. 2/7/1931. “Orion.”
H*3. Off Noises. 30/7/1931. “Cleopatra.”
H*4. Between Tiri Tiri and Noises. “Orion.”
I*1. Western shore, inside Whangaparoa. “Maori.”
I*2. Western shore, Whangaparoa. “Rialto.”
I*3. Off Tiri Tiri. 26/10/1928.
I*4. Off N.W. end of Tiri Tiri. 26/10/1928. “Thomas Currell.”
I*5. Outside Flat Rock. 25/5/1931. “Tiri.”
I*6. Outside Flat Rock. 25/5/1931. “Serfib”.
I*7. Close to Tiri Tiri. 8/2/1929. “Humphrey.”
I*8. Off N.W. end of Tiri Tiri. 26/10/1929. “Thomas Currell.”
I*9. 4 miles N.N.E. Tiri Tiri. 17/1/1929. “Anzac.”
I*10. Off Omaha Bay. 16/7/1931. “Fox II.”
J*1. Close in to Ponui Island. 12/9/1928. “Wanderer.”
J*2. Close in to Ponui Island. 12/9/1928. “Wanderer.”
J*3. Man-o'-war Bay, Waiheke Island. 10/12/1928. “Anzac.”
(d). Effect of Harbour Works Upon Benthic Communities and Fishing-Grounds.
Since the construction of the waterfront road across Hobson Bay in the Auckland Harbour it seems that the two narrow openings in this structure, which are spanned by bridges, have caused a concentration of the tidal-current resulting in a marked effect upon the benthic communities within range. It seems that whereas formerly algal detritus was distributed over a wide area from this shallow bay, it is now discharged through one or the other of these narrow outlets and in their paths there are now two restricted more densely populated patches of animals of communities 1, 1a and 1a1. These two locations (about half a mile out from each bridge) are now recognised by amateur line fishermen as being good snapper grounds.
Unfortunately there is no prior account of the bottom-conditions in the harbour, but the fact that these fishing-grounds have been located since the building of the waterfront road may be taken as an indication of the probable truth of the surmise that this structure is responsible for the present conditions. Other changes are going on within the bay as the direct result of the roadway; channels of hard shell have been formed and areas of soft mud are becoming increasingly shelly, and the Zostera (sea-grass), once abundant in the bay, has now almost entirely disappeared.
Tide-deflectors and reclamation works elsewhere in the harbour have considerably reduced the areas of Zostera. Undoubtedly this factor has a bearing on the animal communities, as decaying Zostera along with other algae plays, as detritus, an important part in the nourishment of benthic animals. Muds formerly rich in detrital content may become comparatively sterile, no longer supporting a rich benthic fauna. Apart from all other reasons this deterioration of the food-content of the benthic muds has a marked effect upon
the frequency of carnivorous fishes such as the snapper, and in respect to depletion of the harbour fishing-grounds generally, may be a more important factor than either over fishing or assumed harbour pollution.
(e) Recent Ecology and Its Bearing upon Paleoecology.
One has only to note the many references by palaeontologists to the detailed work of Petersen and his colleagues in the Baltic to realise the value of this work in the interpretation of conditions and the recognition of animal communities of the past. Local work of this nature provides data that can be used far more effectively than general conclusions based upon a boreal fauna. To cite instances, many faunal changes consistent with oscillation in depth are indicated by animal communities identical with Recent ones that occur in the upper Pliocene of Wanganui. A sandy bed was noted with mud-stone both above and below it. The sandy bed was a typical shallow-water Arachnoides community and the mud-stone a deep-water mud-bottom community dominated by Chlamys radiatus.* Also both the Tawera+Glycymeris and the Echinocardium formations were noted, as well as others not dealt with in this paper.
Auckland and Manukau Harbours are both typical tidal estuaries formed within Recent times by the drowning of valley-systems.
Succession in the bottom communities in Auckland Harbour and vicinity is dependent upon the gradual accumulation of shells. It seems likely that the whole area was originally soft mud and that the small areas of hard bottom are due to the accumulation of shells and debris formed under the influence of tides and wave-action.
As the result of mechanical grading of the sea-bottom it has been found that with the physical conditions of the sea-water and depth fairly constant there is a definite correlation between animal communities and texture of the substratum.
Four main animal communities (formations) have been defined. Each formation has a very distinctive bottom-texture (illustrated by a graph).
Animal communities of Auckland and Manukau Harbours dissimilar.
Average number of species and specimens low, and microfauna barely represented in soft-bottom communities. Average number of species and specimens extensive, and microfauna rich in hard-bottom communities.
Animals restricted to one type of sea-bottom are mostly infaunal deposit-feeders.
[Footnote] *This same community was dredged by the writer at depths between 13 and 15 fathoms in Paterson Inlet, Stewart Island. The dominants were Echinocardium qustrale, Chlamys radiatus, Diplodonta globus, Terebratella sanguinea and Neothyris Ienticularis.
Harbour works such as tide-deflectors, embankments and reclamations cause depletion of Zostera beds, which results in less vegetable detritus, and affects the distribution and frequency of animals taking this kind of food, as well as the abundance of fish feeding upon such organisms.
Animals of the Echinocardium and Tawera+Glycymeris formations provide a considerable proportion of the diet of our main food-fish, the snapper (Pagrosomus auratus).
The snapper is mainly a benthic feeder, but has a preference for pelagic food during the schooling period of from October to February.
Work on the Recent ecology of the sea-bottom may be applied in the interpretation of similar fossil faunules.
Allen, E. J., 1899. On the Fauna and Bottom-Deposits near the Thirty-fathom Line from the Eddystone Grounds to Start Point, Journ. Marine Biol. Ass. Plymouth, 5, pp. 365–542.
Augener, H., 1923 and 1924. Polychaeten von Neuseeland, Papers Dr. Th. Mort. Pac. Expd. 1914–16, 14, pp. 1–115; 18, pp. 241–441.
Bartrum, J. A., 1917. Concretions in the Recent Sediments of the Auckland Harbour, Trans. N.Z. Inst., vol. 49, pp. 425–428.
Blegvad, H., 1915. Food and Conditions of Nourishment among the Communities of Invertebrate Animals found on or in the Sea Bottom in Danish Waters, Rep. Dan. Biol. Stat. Copenhagen (1914), pp. 41–78.
——1922. Animal Communities in the Southern North Sea, Proc. Zool. Soc., pp. 27–32.
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