PORTOBELLO MARINE FISH HATCHERY.

Otago Witness, Issue 2652, 11 January 1905, Page 59

PORTOBELLO MARINE FISH HATCHERY.

THE PROGRESS MADE.

SOME VALUABLE OBSERVATIONS

It is just about a year since the members of the Australasian Association for the Advancement of .Science visited the marine fish hatchery at Portobello on the occasion of the official opening of that establishment. A record of what has been done since then, and of the kind of work which has been undertaken, may prove of interest to our readers, and tv« are indebted to the chairman of the Hatchery Board for the following account: —

Though nominally opened last January, the station was very far from being in working order, in this respect resembling many of the great exhibitions which have^Tßeen held during the last half-century. The ponds had been roughly constructed, the large higli-level storage tank was finished, and the shell of the hatchery building was up. The caretaker's house was only in course of erection; so that those who only 6aw the station then have little idea of what has been done since in the way of flnlshing the buildings, making, asphalt walks and paths, and starting a small garden. In the first "place, the ponds were found to leak, and a great deal of concrete work in the shape of lining walls has had to be put in to make them tight. This has been successfully accomplished, as the present leakage of a few inches per tide is of no importance, the level of -water in the ponds being kept fairly uniform by the control valves, which are opened for about an hour and a-half ,at "high tides. This enables ,the water to be more or less renewed daily. By means, too, of- a powerful 'pump it is .possible to pour from 8000 to 10,000 gallons per .hour joi sea water into either of the ponds should -there be any necessity to do so. The work which has been undertaken up to the present at the hatchery has been entirely observational and experimental. Seeing that nothing whatever was known of the life "histories of any of the native fishes or other inhabitants of the sea, it was thought advisable, before any attempt was made to introduce new forms, to acquire some knowledge of those already in our waters, and to gain experience in handling fish and their ova. ~Lt -"was the end of July before any such work could be commenced, the curator's time up to that date being fully engaged in the work of construction.

The board is tinder obligation to Mr J. F. Sullivan for the valuable assistance he has all along given to its curator, Mr T. Anderton. The latter out with the trawler on various occasions. On July 24 preliminary observations we're made as to the spawning of the various fish, caught. Red cod were found to have the ova still immature, while from brill and soles numerous eggs . were obtained, but were unfertilised. From observations made on this and several subsequent trips, it would seem to be quite possible to obtain eggs from sexually-mature flat fishes (soles, brill, flounders, etc.) during the winter months, to fertilise them on board the trawler, and then hatch them out in the hatching-boxes at the station, should such work ever be thought desirable. As was anticipated, it was found that all these flat fishes produce minute floating eggs. On July 31 a number of live soles were obtained on the trawler -and brought into the hatchery ponds, but all were dead within 48 hours. The fish were all found to be badly bruised and crushed in the trawl net, wliioh was presumably the cause of_ their loss. But other causes may have militated against -the success of the experiment. Mr Anderfcon was single-handed after leaving the- trawler with his tubs of live fish, and had difficulty in transporting them across to Portobello, while trying also to keep them continually supplied with fresh sea water. Heavy rain, too, reduced the salinity of the water in the ponds, and this no doubt impaired the chance of recovery of the weakened fish. During August five trips were made on the trawler, and further supplies of soles were obtained and placed in the pond. Nearly every day, however, dead fish bad to be removed, and it was found in each case that they were bruised, especially over the ovarian region. Another factor which no doubt contributed to the non-recovery of the injured fish was that while the temperature of the ocean water where the fish were taken was uniformly about 9deg C, ihat of the ponds was only about 4de»- C. Sea fish appear to be somewhat sensitive to sharp changes of temperature. Though ova were obtained by pressure from the fish in ihe pond, none were found floating, though searched for daily with the tow-net, and none of those obtained wore fertilised. The soles were kept in the pond till late in November, but as they were not thriving — many of them developing sores over the ovarian region, perhaps from retention of Hip ova — it wv resolved to libcite the remainder, and they were s.ll set free in the harbour. The results of the experiment, though nsgative have yielded much information as to the habits, and especially the mode of feeding, of these fish.

. On the 11th of October 34- blue cod were caught off Cape Saunders and were brought alive to the uoudSj where they were tjjrned

out auc) have since thriven remarkably. They { ha^ c become extremely tame, and come up to the edge of the pond to be fed, opening their big mouths in anticipation, and takingcookies and other food from the hands of anyone who feed-5 them. They also take fingers, as several visitors have found to their dismay, for they bite very sharply. Several hundred floating ova have been obtained from these fish by means of the tow-net, and numbers of fry have been hatched out and reared for a certain length of time. But, so far. it las not been found possible to keep them alive for more than about 10 days. This is most probably due j to the excessive amount of lime in the water of the reserve tank which supplies the hatoiiing boxes and jars, a fault, which will come right in the course of a few months, and which all new hat-?hery stations suffer from. Besides these observations on soles and blue cod, *">va have been collected from some j other fishes. Those of the gurnard have been obtained, and when extruded from the fish the fry have been found to have the j eyes well developed and to be ready to swim about. Ova have also been collected of a species of Nototheni (?); these were found attached to the under sides of stones. Shortly after being "brought into the hatchery they hatched out, and the develop- ' ment of the fry was followed and observed for several days. Experiments have also been made "in hatching and rearing the zoere of shore crabs (Hteerograpsus) and porcelain orab3 • (Petrolisthes) . and in keeping bei'ried-prawns (Leander) in confinement ; the latter have not as yet liberated their fry. Tli9 development of the common whale-feed (GrimoI thea?) is being- followed out at present. All these experiments in— handling and observing local crustacea are of importance in view of the fact that negotiations are now in progress for the introduction of the European lobster, and the experience now gained will be most useful when these animals ar-e brought here. Most of the work specified has been carried out by Mr Anderton, the curator, acting in conjunction with Mr G. M. Thomson, chairman of the board. Professor Chilton, of Canterbury College, spent a fortnight at the hatohery recently, making observations chiefly on crustacea; and Professor Benham is shortly going down to do biological work. For students of biology the station offers excellent opportunities of research, and as it becomes better known these will no doubt be more widely taken advantage of. A collection of the vertebrate and invertebrate fauna of the adjaceut waters is being made by the curator. In this and much of the other work of the station most valuable and ready assistance has been given by Mr W. Dougall. of Quarantine Island. Since July, also, daily observations "have been taken of the temperature of the air, the ponds, and the open water of the harbour. It is hoped shortly to have the aquarium house fitted, and this will greatly add to the usefulness and attractiveness of what is already a most interesting establishment.