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Family Salmonidæ.
Prototroctes oxyrhynchus, Günther. Upokororo—The Grayling
D. 12; P. 15; V. 6; A. 15; 0. 17; Br. 5; Vert. 70; Lat. 1. 100.
The occurrence of this fish in the Mataura River is of considerable interest, as it is by no means common in Otago waters. This specimen was found dead on the Mataura river-bank at Gore, and was sent up to the editor of the Otago Witnsss for identification, and subsequently came into my hands on the 29th April, 1884. Gore is about thirty-five miles from the sea.
The body was long and cylindrical, total length seven times that of the head, or six times greatest depth, and covered with large cycloid scales, adherent. Lateral line barely visible, straight. Eye in diameter equal to one-sixth the length of head, and placed one-third from the snout, pupil black, iris yellow. Maxillary terminates in narrow rounded point posterior to centre of orbit; mandible shorter than maxillary and toothless. Teeth fine and comb-like even row (cardiform) along maxillary, a few on vomer and some on palatines and tongue. Operculum and sub-operculum fine transparent bones with rounded margins and much larger than pre- and inter-opercles. Fins fine, ventrals in advance of dorsal, anal in advance of adipose; caudal deeply forked. In colour slaty-brown along back passing into slate-blue on sides and silvery-white on belly, which had patches of azure, no spots. Fins orange colour tipped with dark slate and white; cheeks with slight golden tinge, also the belly. When fresh, it had a herring-like smell on boiling, and ate nearly as well as a herring; flesh white and delicate.
| Inches. | |
|---|---|
| Total length | 10.40 |
| Depth | 1.80 |
| Least depth of tail | 0.65 |
| Girth | 4.50 |
| Head | 1.50 |
| Diameter of eye | 0.25 |
| Eye from snout | 0.50 |
| Dorsal " | 5.10 |
| Adipose " | 7.80 |
| Ventral " | 4.75 |
| Anal " | 7.25 |
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Abdominal cavity was black, the viscera had almost disappeared from decay, one long silvery lobe only being recognizable, probably the air bladder. Vent situated immediately in advance of anal fin.
In form this specimen corresponded almost exactly with figure at p. 136, vol. iii., Trans. N.Z. Inst., which is an excellent drawing of the species. According to the Catalogue of New Zealand Fishes, the upokororo had not been found in the sea, but only in the rivers and lakes of both islands. Mr. Rutland's account however (vol. x., Trans. N.Z. Inst.) is, I think, conclusive circumstantially that during a portion of the year it is resident in salt water, as it is never seen in the Maitai and other neigbouring rivers of Nelson excepting during autumn and winter when spawning or getting into spawning quarters, but disappears entirely for the rest of the year. Recently, on 29th September, Mr. A. K. Smith informed me of a fish he had been keeping for me which was taken in the sea at Otago Heads off the North Spit but which I did not get—evidently a grayling. He described it as found by him among some mullet to which it had a general likeness, but on closer inspection he found the first dorsal fin was softer and had more rays than the mullets, while the second dorsal had no rays. The head was small and salmon-like, pectoral fin-origin lower than in mullet, body rounder, silvery and spotless. I have found Mr. Smith very correct and reliable in his observations on fish, so that I believe in this case also he is not mistaken, although it is not impossible that the fish may have been a spotless trout or young salmon-trout.
References.—Cat. N.Z. Fishes, 1872, p. 123; Trans. N.Z. Inst., vol. iii. p. 136, and vol. x., p. 250. Specimens are in Otago Museum.
Note.—The order of classification I have followed is that of Dr. Günther in his “Study of Fishes,” 1880, as regards families.