THE director's REPORT. 113 



of the free-swimming fry of the herring-, some of them very recently 

 hatched and with the yolk-sac not yet absorbed, in the sui'face net. 



In March I was present at the explosion of some submarine mines 

 in the mouth of the St. Germans river and obtained a number of 

 young herrings which were killed by the explosion. Some of these 

 were very small and apparently belonged to the January brood of 

 the year, but the majority were larger and must have been hatched 

 out in the early months of 1888. 



During the early part of February the weather was very rough 

 and we were for some time prevented from carrying on dredging 

 outside the breakwater. On the 12th of the month, being favoured 

 with a fine northerly breeze, we chartered a trawler and succeeded 

 in making a large haul of plaice, flounders, and other fish. Nearly 

 all the plaice and flounders were ripe, and Mr. Cunningham fertilized 

 and brought back a large number of these species, which were 

 hatched out in the aquarium, and the larvae lived, as those of the 

 herring had done, until they had absorbed the yolk-sac, after which 

 the same difliculty was found in feeding them and they all perished. 

 At the same time Mr. Cunningham obtained the ova of the sprat and 

 the dragonet [Gallionymus lyra) and was able to verify some of his 

 previous observations on these species. 



The difliculty of feeding the young fry constitutes a serious 

 difliculty to the cultivation of sea-fish. Similar difficulties have been 

 experienced by the American Commissioners of Fisheries, who have 

 had recourse to turning out the larvas into the sea at the time of the 

 absorption of the yolk-sac. Captain Dannevig, of Arendal in Nor- 

 way, has been more successful and has hatched out and kept for 

 three years herring, cod, and other valuable fishes. He keeps 

 his fry in a large basin or tidal tank into which the sea is admitted 

 directly by means of sluice gates. In this tank Captain Dannevig 

 is able to grow seaweeds and to mimic the natural conditions of the 

 sea very nearly to perfection. For some reasons which we cannot 

 yet satisfactorily explain we are unable to keep seaweeds in the 

 sheltered tanks of our aquarium, and in consequence we cannot 

 supply that profusion of minute life on which the existence of the 

 young fry depends. Success in rearing fish is probably to be 

 obtained only by the use of tidal ponds into which the newly hatched 

 fry can be turned loose. 



In January the surface-net contained little else than Copopods 

 of different species, and when it was attempted to feed the fry of 

 fish with the material collected in the surface-net we found that 

 these Copepods, instead of aiiording food for the young fishes, were 

 themselves the aggressors, and attacked and destroyed the larvge. 

 The more delicate pelagic organisms which are so abundant in the 

 VOL. U, NO. II. 8 



