Art. X. — On a Species of Regalecus or Great Oar-fish, caught in Okain's Bay.
[Read before the Philosophical Institute of Canterbury, 4th June, 1891.]
On the morning of the 28th May I received a note from Mr. Warnes, the fishmonger, requesting me to inspect a curious fish caught in Okain's Bay, Banks Peninsula, on the 26th, and which he was bringing up to town that day. On its arrival in Christchurch in the afternoon I found the fish to be a species of Regalecus, or oar-fish, of unusually large proportions.
Regalecus is a genus of fishes belonging to the family Trachypteridæ or ribbon-fishes. According to Dr. Günther, of the British Museum, they “are true deep-sea fishes, met with in all parts of the ocean, generally found when floating dead on the surface or thrown ashore by the waves.”
The oar-fishes are among the largest of the deep-sea fishes known. They derive their name from the singular form of their ventral fins, which—reduced to one long, slender, and fragile filament, terminating in an oar-blade-like expansion, which projects from its sides for a distance, in our specimen, of nearly 3 ½ft.—are functionally useless.
The Regaleci, or oared ribbon-fishes, have been taken in the Mediterranean, in the North and South Atlantic, and in the Indian Ocean. In Australasian waters one has been taken off the coast of Victoria, and several on the shores of this colony. But they are very scarce, not more than twenty captures having been recorded from England in the space of a century and a half, and not more than thirteen from the coasts of Norway. The present specimen is the tenth caught in New Zealand. I take from a paper read before the Otago Institute by Professor Parker, F.R.S., who has compiled a list of these captures up to the date of his communication, which described the last species known to have been stranded on our coast, the following notes: Of these one was captured at Nelson in 1860; a second at Jackson's Bay in 1874; another (Regalecus pacificus, Haast), which is now in the Canterbury Museum, as well as a drawing of it by Dr. Powell, was caught at New Brighton in 1876; a fourth was cast ashore on Little Waimangaroa Beach, on the west coast of the South Island, in 1877; a fifth (R. banksii) at Cape Farewell in 1877; the sixth
was thrown on the shore near Moeraki about the year 1881, and near the same place; the seventh also (Regalecus argenteus, Parker) on the 14th June, 1883, whose skeleton is now in the British Museum, South Kensington; the eighth—a specimen of the same species — came ashore in Otago Harbour about ten miles north of Dunedin on the 3rd June, 1887; while the ninth was taken in Nelson Harbour on the 23rd September, 1890, and is now in the Otago Museum. Of the fewer than twenty specimens captured in England, eleven are referable, the same author observes, to a single species, Regalecus banksii, while one is assigned to Regalecus grillii. The specimen captured in May, 1878, between Victoria and Tasmania has been identified by Sir Fred. McCoy as Regalecus banksii. Taking as our guide, however, the key to the species of Regalecus given by Professor Parker in vol. xvi. of the Transactions of the New Zealand Institute, it ought, it would appear, to bear the name of R. grillii, on account of the number of its dorsal-fin rays. This specimen has been described and figured by Sir Frederick in the 15th decade of the Prodromus of the Zoology of Victoria. After a careful comparison of the descriptions and figures of the species of Regalecus known to me, I have come to the conclusion that the species that has been exhibited during the past week in Christchurch is identical with that taken off the Australian coast—namely, the species described by Lindroth under the name of Regalecus grillii. In an addendum to his paper in volume xx. of the Transactions of the New Zealand Institute, Professor Parker, who, while writing his excellent monograph on R. argenteus, gave the literature of the subject his careful attention, writes, “Everything seems to lead to the conclusion that most of the supposed species of Regalecus are identical, and that the more recent specific names (including argenteus) will have to give way, probably in favour of Ascanius's original name ‘glesne.’” The synonymy of the species is rather involved and the works necessary to its elucidation are not within my attainment here. Professor Parker's opinion, however, is entitled to very great weight, and the observations on the present specimen tend to support it. This new specimen, therefore, ought strictly to be denominated R. glesne; but for the present I shall speak of it under the name R. grillii, to indicate that in my opinion it belongs to the same species as Lindroth described.
This fish had been exhibited in Lyttelton, I believe, before being brought to Christchurch, and had, unfortunately, in its various transports, and perhaps also in its capture—for it was still alive when caught—suffered to some extent. It had lost much of its brilliant colouring, and most of the singular rays of its crest, as well as received damage to the long rays of the
ventral fins. With these exceptions, however, the specimen was a particularly fine and complete one. The Regaleci, being deep-sea denizens, are generally found to have suffered on approaching the surface from the expansion of their internal gases consequent on the diminution of pressure; but the specimen under description showed no signs of any “loosening or tearing of its ligaments and tissues” by its ascent to the surface of the sea.
The following notes were drawn up under considerable disadvantage owing to the fish being under exhibition at the time, and that in a very badly lighted room. I had to write amidst a talkative crowd, while my observations were confined to the one side—naturally the best—exposed to the public. Imperfect as they may be, I lay them before the Institute as a contribution towards our better knowledge—still very imperfect—of this rare genus of fishes.
It is remarkable that all the New Zealand specimens have been found on the South Island; and, like all the other specimens, European or New Zealand—except the Nelson Harbour one, which was a male—whose sex has been determined, the present is a female, and it has occurred on our shores at the same period of the year (the spring and early winter) as they have invariably done on previous occasions.
In order to facilitate comparison with the observations recorded by Professor Parker in the Transactions of this Institute for 1887, I shall arrange my notes under the same heads, and in the order adopted by him.
Size, Proportions, and Number of Fin-rays.—It will be seen from the accompanying measurements (Appendix A) that the present is the largest species of Regalccus yet taken on the coast, its length being 18ft. 10in., with its protrusile mouth not extended. It is probable, however, that it does not exceed by much the length attained by Professor Parker's Otago Harbour specimen when complete. This specimen was broken across, and he conjectures that it was most likely about 17ft. in length. Its ribbon-like form is indicated by the proportion of its height to its length, which was one-fifteenth; the New Brighton specimen was one-eleventh; the Moeraki specimen, sent to London, one-tenth; while the Victorian specimen was still more band-like, its height being only one twenty-third of its total length. The Otago Harbour specimen is given as one-eleventh; but if this were corrected for the length that the fish is conjectured, as stated above, to have reached, the proportion of height to length would closely approximate that of the Okain's Bay example. In this specimen the nuchal crest is damaged, and a gap occurs in the dorsal fin, so that it is difficult with absolute accuracy to determine the number of the fin-rays. Taking 14, the number
given by Professor Parker in the crest of the Otago Harbour specimen, as the probable number here, these were succeeded by 221 rays anterior to the gap—in which 17 were made out, but there may have been one more—and succeeded by 170 more to the termination of the tail, giving in all 422, which comes very close both to the number recorded by Lindroth in R. grillii, and by Professor McCoy in the Victorian specimen, which is 423. The accompanying table (Appendix A), taken from Professor Parker's paper, with the addition of the Okain's Bay and Victorian specimens, will enable the eye to compare these measurements at a glance. The number of the pectoral, ventral, and branchiostegal rays corresponds with those in R. argenteus.
Tail.—In the present specimen the tail is almost perfect, a mere fraction only being possibly absent. It terminates in a point, and is curved upwards for its terminal few inches. The dorsal fin extended, I am convinced, to, but it did not pass, the extreme point. Its fin-rays have been broken off for the last few inches, but with a magnifying-glass it was possible to detect their broken extremities. There is therefore no caudal fin. There is no sign of any old fracture having at any time taken place, as the body graduates gently from head to tail. It would seem, therefore, that the supposition that the end of the tail “has been lost as a useless appendage at a much earlier period of the life of the fish,” which has arisen from the circumstance that these fishes are so often found in a truncated condition, is probably groundless, and their mutilation is merely the result of accident. Moreover, as the stomach has an extraordinary cæcal prolongation, which extends for many feet behind the anus, it is evident that a loss of any considerable length of its tail would probably be fatel to the fish.
Colour and Markings.—In general appearance the fish presented on its arrival in Christchurch numerous bright silvery patches, and indications that this colour had covered the whole general surface of the fish. These patches were eventually lost, and the fish assumed a light-greyish colour. Its crest, its dorsal, pectoral, and ventral fins, had faded to a dark salmon-red colour. In some lights it could be detected that dark spots and stripes had been dispersed over the anterior part of the body, but they had almost faded out at the date of examination. As to their number, form; and situation, I can therefore speak with no certainty. On the sides of the body there are five well-defined black bars (or ridges) running longitudinally. These bands, on examination, prove to be composed of raised tubercles, and they are distinctly separated by interspaces, which in the fresh fish would be bright silvery stripes, quite free of tubercles, as a sensitive
finger passed along them discovers only the very finest skin-granulations. Above the uppermost of these bars, and separated by a smooth interspace, a broader tuberculated band extends up to the base of the dorsal fin. The tubercles in this band are not so rough as on the lateral bars. Towards the tail, and at a few feet anterior to it, these bars become lost, and exchange their dark colour for a silvery-white. The second, which is the most prominent of all, runs furthest along the body, and is finally lost at 2ft. from the tail, when the tuberculations entirely cease, and the rest of the body is soft and glistening. The first true bar and the sub-dorsal-fin band pass forward, which is not the case with the others, and terminate on the front of the head above the anterior margin of the eye. The lateral line cuts the second, third, and fourth true bar (or ridge) a little posterior to the hind margin of the operculum, while the fifth follows the lateral line for a great part of its length. The ventral surface is very roughly tuberculated—rougher than any other part of the body, the tubercles presenting a suspicion of points. Behind the anus this surface is very dark-coloured, and was probably black in the living fish.
Mr. Warnes was good enough to give me the entrails, which, for the better preservation of the fish, he had removed from the body. These organs were not entirely complete, but they agree so closely with those figured by Hancock and Embleton in the “Annals and Magazine of Natural History” as to require no further description except in regard to the liver, which must arrest the attention of any one opening the body of Regalecus by its rich-pink colour. This organ was very tender and friable when it reached my hands. In form it differed considerably from the figure I have referred to. On its upper surface, partially dividing it into two unequal portions, lies a deep fissure, in which are the hepatic and other vessels. The right portion has its lower fourth separated into a distinct lobe; and on the left portion occurs, on its external margin, a small lobule. The anterior ends of the two main portions are pointed, but towards the posterior end the liver is thicker and bluntly rounded. From this organ, when placed in spirit, escaped a very large quantity of a deep-salmon-coloured oil. In the ovaria there were very minute ova; but, as in all the other specimens hitherto examined, these were unimpregnated, as the winter is evidently not their breeding-season.
The food in the stomach consisted of finely-comminuted matter, entirely structureless under the microscope. In the æsophagus a gelatinous glairy fluid was found, mingled with a quantity of very fine grey sand. It is probable, therefore, that Regalecus finds its food in the minute animal forms, or
débris, among the fine sand at the bottom of still deep waters. It has no teeth.
As was found in the gigantic skate recently thrown on the Summer coast, this Regalecus was infested to an extraordinary degree with intestinal worms, thousands extruding themselves from the liver as it lay on the table. They were found in the œsophagus also. Perhaps these fishes become infested during the winter season with these parasites, and in their desire to rid themselves it may be that they seek shallower water, and are thus thrown on our coasts by currents in a dying state.
Again following Professor Parker, I have given a table of measurements for easy comparison of R. argenteus with R. grillii, Lindroth (cf. Appendix B).
I have to record my thanks to Mr. Warnes and the syndicate exhibiting this fish for their extreme courtesy and goodnature in allowing myself and my assistant to intrude on their show whenever we desired in order to make the notes recorded above, and especially for their kindness in permitting us to remove the fish from its stand for the purpose of obtaining a photograph of it. I am indebted also to Mr. Sparks, the taxidermist of the Museum, for his help and care in taking the measurements.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|New Brighton.||Moeraki.||Otago Harbour.||Okain's Bay.||Victorian.|
|Ft. in.||Ft. in.||Ft. in.||Ft. in.||Ft. in.|
|Total length||12 5||12 6||[17 0]||18 10.||13 7|
|Greatest height of body||0 13.5||0 15.25||0 12.1||0 14.5||0 7.25|
|Length of head(jaws retracted)||0 7.75||0 9.0||0 9.5||0 8.125||0 7.5|
|Distance between snout and anus||4 11||5 6||4 9.5||5 4.125|
|Proportion of height to length||1:11||1:10||1:11||1:15.6||1:23|
|Proportion of length of head to total length||1:19||1:17||1:14||1:15.6||1:23|
|Proportion of pre-anal region (=head+trunk)to total length||1: 2.5||1: 2.27||1: 2.29||1: 3.36|
|Total number dorsal-fin rays||232[9+223]||205[14+191]||189 (?)[14+175]||422[14 + 221 17(?)* 170]||423[17+406]|
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Moeraki.||Otago.||New Brighton.||Okain's Bay.||Victorian.|
|Total length (jaws retracted)||12 6||11 0||12 5||18 10||13 7|
|Length of head (jaws retracted)||0 9||0 9.5||0 7.75||0 8.125||0 7.50|
|Length of head (jaws protruded)||0 11||0 11.75|
|Height of head through centre of eye||0 9||0 8.25|
|Height of body at post. ext.oper||0 11||0 10.5|
|Height of body 2ft. from head||1 2.5||1 1.5|
|Height of body 4ft. from head (greatest)||1 3.25||1 0||1 1.75||1 2.5||0 7.25|
|Height of body 5ft. 6in. from head (levelof anus)||1 2.5||1 1.25||1 1.625|
|Distance of anus from post. ext. oper.||4 8|
|Distance of anus from snout.||5 6.0||4 9.5||4 11||5 4.125|
|Height of body 4ft.from tail||0 11.25||0 5.75|
|Height of body 2ft.from tail||0 9||0 3.875|
|Thickness of body 3ft. 2in.from head||0 3.5||?0 3.0*|
|Thickness of body 5ft. 11in.from head||0 3.0||?0 2.0|
|Thickness of body 9ft. from head||0 2.0||?0 2.0|
|Diameter of iris||0 1.35||0 1.375|
|Diameter of pupil||0 0.5||0 0.562|
|Length 1st dorsal||1 5.5||0 1.375|
|Length 7th dorsal||1 5.5||0 1.125|
|Length 9th dorsal||1 3.5||0 1.75|
|Height of 2nd dorsal fin||0 2.25–3||0 2.0||.|
|Length of pectoral fin||0 3.0||0 1.75†|
|Base of pectoral fin||0 1.25||0 1.375|
|Length of ventral fin||3 1.0||3 5.25|
[Footnote] * Approximate.
[Footnote] † Broken.