PORTOBELLO MARINE FISH HATCHERY.

Otago Witness, Issue 2686, 6 September 1905, Page 57

PORTOBELLO MARINE FISH HATCHERY.

INTERESTING EXPERIMENTS

Late wmier and spring are among the busiest seasons of the year at £sh hatcheries, and this is being verified at Pottobel'o just now. .Before any work of introduction of "new and desirable kincs oi fish from the Okl Country or from America can be undertaken local conditions have to be studied, and information has to be obtained as lo the food supply, effects of changes o£ temperature, and many other details, a knowledge of which is essential •before success can be de-served, muoh less achieved. The loss of che breeding stock of blue cod in the breeding ponds last June showed one of the dangers of imprisoning fish in shallow water. The experience was cheaply bought, though it involved the loss of all the fish. It will be necessary to be very careful not to attempt io keep large numbers of deep-sea fithes throughout the winter months. By keeping daily records of the temperature of the ponds and of the water of the bay outside, and by comparing Lhese with records of the ocean surface temperature, kepi by the engineer of the trawler Express, valuable information is being rained by Mr Andarlon at Portobello. It would seem that one effect of the low temperature of the ponds 13 to retard the soxual development of the flounders at present kept there. Though the water is examined daily for ova -by dragging a, light net backwards and forwards over the surface of the ponds, no eggs have yet been obtained from the large slock of fine healthy fish. Meanwhile, thanks to the courtesy of Mr F. J. Sullivan, who has done much to further the work of the hatchery, Mr Anderlon has been able to make several trips on the trawler, with the object of securing ova. The spawning season of the lemon sole is now more than half over, many of the fish taken being spent ; but on August 17 he was able to secure about. 80,000 ova, and by the 20fch he had 25.000 joung fry hatched out and developing in the boxe*. On that day he obtained another 60 000 o\a, and as opportunity offers he will continue this wo'-k throughout tho spawning season. Working single-handec, a a he docs, it is impossible to go in fo_the syvstematic roaring of largo numbers o". fish; "this wi!l be a work of time. _ All that is sought to be learned at first is t-a find out the iMndilions under which tie various kinds -ii fish spawn, the nature oi the eggs proluood (vrbethor floating or

ileniersal), the time taken to hatch out, md any other particulars which can he ascertained under the circumstances. The amount of information already acquired is Very considerable, and from this point of jriew alone the station is more than justify- . ing its existence.

' At ! present the young fry are being turned out into the bay soon after they are hatched; when more observation tanks have been erected it will be possible to -follow their development through its various phases. With information of this .nature available it will be possible, in the future, to proceed to experimental work in -the" direction of introducing new forms of fishes. . , *