Tuatara: Volume 2, Issue 1, March 1949
The New Zealand Grayling—A Vanishing Species
The New Zealand Grayling—A Vanishing Species
In a land where there were no native mammals, fish were a very important source of food to the Maori before the coming of the white man, and the Maori became very skilled in their capture, both in the sea and in the fresh-water lakes and rivers. Although some fish, particularly the larger species, were caught with hooks and lines, the Maori depended to a large extent on the use of nets and traps of which he developed many ingenious forms. Among the fish, then abundant, which he caught in the rivers in this way was one generally called the Upokororo, although like most animals known to the Maori it had a number of other names, either peculiar to certain tribes or denoting particular phases in its life history. This fish entered the rivers at certain seasons of the year in large shoals, and was found in many parts of the country. One of the most usual ways of taking it was by setting basket-work traps in the rapids with their mouths upstream and with two walls of boulders arranged in a V to divert the current and any fish moving downstream into the trap which was fixed at the apex of the V. When the trap was set it was sometimes left overnight, so that fish moving out on to the rapids from the pools to feed were swept into it and caught. On other occasions the fish were driven out of the pools upstream by men armed with long poles, and, fleeing downstream with the current, were carried headlong into the trap. That other and possibly more original methods were sometimes used is suggested by an early writer on New Zealand who says of the grayling: “It bites at the hairs of the legs and is thus caught by the natives going into the water.” Unfortunately, it is not quite clear whether the fish took firm hold and the natives then walked out towing the fish!
When the white man arrived he found the graylng both widespread and abundant, although it was some time before it attracted the notice of scientists. Apparently, however, it received the English name of “grayling” at an early date, presumably on account of its superficial resemblance to the European species of that name in its slender shape, silvery scales and the possession of an adipose fin, although it lacked the very large dorsal fin which is such a characteristic feature ot the true graylings. In 1869 some specimens were sent to Frank Buckland, who passed them on to Dr. Gunther at the British Museum. In the following year Gunther described them, naming the species Prototroctes oxyrhynchus, and referring it to the family Haplochitonidae; a family which is related to the northern trouts and whitefish but which has a southern hemisphere distribution.page 23
At this time the species was still abundant and Hector in 1871 says that it was “found in most of the streams of the colony,” and goes on to speak of the “immense shoals” ascending the Hutt River in January. Apparently, however, signs of decreasing numbers were evident soon afterwards, and in 1878 Rutland, who studied the species in the Nelson and Marlborough district, notes that in the Maitai River it has “become very scarce during the past three years.” This disappearance continued rapidly and by the 1920′s the species was known to exist only in some streams in the East Cape, Wairarapa and Otaki districts in the North Island, and on the West Coast of the South Island, and even in these areas it had so decreased in numbers that instead of being present in large and conspicuous shoals, the few specimens occasionally taken were considered so unusual as to be worthy of record. In the last twenty-five years there have been no further recorded occurrences which I have been able to trace, although I was told by a reliable observer in 1939 that he had seen them two or three years earlier in a river in South Westland.
New Zealand Grayling After Hector
Drawing by J. Buchanan
Thus it seems clear that this fish, which was apparently abundant throughout many parts of New Zealand when the Pakeha first arrived, and which remained abundant until at least 1870, declined rapidly in numbers, until fifty years later it was confined to a few isolated parts of the country, and has since continued to decline, so that no known stocks now remain. The accompanying map shows the districts from which it has been reliably recorded; the shaded areas being the approximate drainage basins of the rivers in which it is known to have occurred, while the black circles represent localities from which the species has been reported since 1920. The appearance of the map together with a number of less precise reports suggest that the distribution on the west coasts of both islands was probably much more continuous than is indicated, but it seems likely that it may have been relatively scarce on the eastern coasts. There appears to be a fairly close degree of correspondence between the known distribution of the grayling and the areas which were originally covered in forest.page 24 page 25
The causes of this disappearance form an interesting subject for speculation, but unfortunately at this late date it cannot be very much more. There seem to be three most likely causes to consider if we assume, as appears justifiable, that it has resulted from some activity of the white settlers. These are—that man has taken sufficient direct toll of the species to cause its disappearance: that he has, by some means such as the clearing of bush from the water-sheds, so altered the habitat that the fish can no longer survive: or that the introduction of the trout has somehow destroyed the grayling. Of these, the first seems most unlikely; there is little evidence of the grayling being subjected to fishing for the market except in a few cases, and with the coming of the trout few anglers would be interested in it, although earlier on it was fished for in some places. Also, it seems to have disappeared even from streams in sparsely settled districts where any intensive fishing would be most improbable. The widespread clearing of the bush and other agricultural practices have undoubtedly seriously affected many rivers, generally causing an increase in the extent of the shifting shingle of the beds and more violent floods and droughts. These factors are generally adverse to most species of fish and could conceivably have been particularly adverse to the grayling. However, the species seems to have disappeared not only from waters affected in this way but also from others, particularly in Westland, where the bush covering of the water-shed has not been touched.
It seems then that neither of the above possibilities is likely to have been the cause of the disappearance of the grayling, and serious consideration must be given to the third possibility—that the grayling has been unable to survive in the presence of trout. There is some evidence that supports this possibility. In one of the few cases where a date can be put to the decline of the grayling—the Maitai River in Nelson—we find that it began to be scarce about 1874, and trout were first introduced into this river in 1870 and were apparently successfully established. It is also noticeable that some of the waters in which grayling are known to have been present at a relatively late date, the Waiapu River near East Cape, the Turanganui near Featherston, and the Wahapo River in Westland, are all waters where trout are present only in small numbers. On the other hand, grayling are said to have disappeared from the Waikato about 1874 (the same year that saw the beginning of the decline in the Maitai) although trout were not established there until at least ten years later. There are also many waters in New Zealand which do not contain trout, and from all of these the grayling is now absent. This absence may of course be due to the unsuitability of these streams to grayling as well as trout, but if they were ever present the introduction of trout cannot have caused the disappearance.page 26
Thus none of the suggested explanations seems to cover the facts fully, and the true cause of the disappearance of the grayling must remain a mystery. The apparently simultaneous disappearance in waters as diverse as the Maitai and the Waikato tempts one to consider an epidemic as a possible cause, but there is no other evidence supporting this and on general grounds it seems most unlikely. The whole position is made still more obscure by the lack of reliable information regarding the life history of the fish. It apparently ascended the rivers in large shoals, composed of fish between 5 and 12 inches in length. These shoals after their ascent rested in the bottoms of the deep pools by day and were believed to come out on to the rapids, to feed upon filamentous algae and other growths encrusting the stones, at night. It is said that their presence could be detected by their teeth-marks on the stones when feeding in this way. After remaining in the rivers for some time they disappeared, although no definite downward migration seems to have been observed. The ascending fish were heavy with spawn, but no observation of their spawning habits has been recorded, nor has the presence of the young stages. It seems most likely that the ascending fish were coming up from the sea, but even this is not definitely established. There are some discrepancies between the various accounts as to the time of year in which it was in the rivers, but most of them seem to accord with the following outline. The movement into the rivers began about early or mid-summer, and from then until about March or later the fish were slowly moving upstream. In late autumn and early winter they were in the upper reaches of the rivers and if this was a spawning migration spawning probably actually took place at this time. In late winter and early spring they disappeared, perhaps returning to the sea. When first entering the rivers they were silvery in colour, slightly brown on the back, but appear to have gradually become darker, being finally rich brown on the back and yellow beneath.
The little that is known of its life history thus gives no clue to the causes of its disappearance, but there still remains the possibility that the study of a surviving stock, if one exists, would not only reveal the life history of this interesting species, but also explain why it vanished under the impact of European civilization. At present, however, we do not even know whether it is indeed extinct, or whether, like the now-famous takahe, it still survives in some unfrequented spots.
PHILLIPPS, W. J.—N.Z. Journ. Sci. & Tech., 1923, p. 115. “Life-history of the New Zealand Grayling, Prototroctes oxyrhynchus.”
RUTLAND, J.—Trans. & Proc. N.Z. Institute, 1877, p. 250. “On the habits of the New Zealand Grayling.”
BEST, ELSDON—Dominion Museum Bulletin No. 12, 1929. “Fishing methods and devices of the Maori.”
HECTOR, J.—Trans. & Proc. N.Z. Institute, 1871, p. 133. “On the Salmonidae of New Zealand.”
TE RANGI HIROA (P. J. BUCK).—Trans. & Proc. N.Z. Institute, 1926, p. 597.)“The Maori craft of netting.”
PHILLIPPS, W. J.—“The fishes of New Zealand,” Vol. 1, Wellington, 1940.
PHILLIPPS, W. J.—N.Z. Journ. Sci. & Tech., 1921, p. 114. “Notes on the edible fishes of New Zealand.”
GUNTHER, A.—Proc. Zool. Soc., 1870, p. 150. “Notes on Prototroctes, a fish from freshwaters of the Australian region.”
ARTHUR, W.—Trans. & Proc. N.Z. Institute, 1884, p. 160. “Notes on New Zealand fishes.”
DOWNES, T. W.—Trans. & Proc. N.Z. Institute, 1917, p. 296. “Notes on Eels and Eel-weirs (Tuna and Pa-tuna).”
K. R. ALLEN, Fisheries Laboratory, Wingfield Street, Wellington.
The native Grayling: as explained elsewhere in this issue the history and biology of this fish is somewhat mysterious, and it is not even known whether it still exists. Any records of its occurrence during the past twenty years, or specimens or notes of locality, number, size and season would be very welcome to Mr. Allen. The only fish with which it may be confused are the trout and salmon and the native “smelt” or “silvery.” It may be distinguished from the former by the generally smaller size (5-12′) and absence of spots, and from the latter by the larger size (the smelt is generally 2-5”), absence of a bluish stripe along the flanks and relatively forward position of the first dorsal fin which in the smelt is approximately above the vent. In no other fish is there a second dorsal fin reduced to a fatty protruberance.