MARINE BIOLOGICAL STATION AT PORT ERIN,- 107 



gunnellus) and the Conger eel are also usually to be" seen 

 in our tanks. 



Although most of these shore fishes lay their eggs in 

 spring under stones or in crevices or on old shells in the 

 sand, the majority of the fish we eat from the sea (with 

 the exception of the herring) produce in enormous quan- 

 tities eggs that are very minute and transparent, and 

 which float freely in the open sea. These are known as 

 " pelagic," and the eggs of Cod, Haddock, Whiting and 

 their relations, and of Sole, Plaice, Flounder and other 

 related flat fish are of this kind. It is these pelagic eggs 

 of our most important food fishes that can be obtained in 

 millions at the spawning season and hatched artificially 

 in sea-fish hatcheries, and so may be kept and protected 

 during the first few days or weeks of their existence when 

 they would otherwise be exposed to innumerable enemies 

 in the surface waters of the ocean. 



But it cannot be too emphatically stated, and widely 

 made known, that sea-fish hatcheries ought not to be 

 merely for the purpose of hatching young fish and then 

 setting them free in the sea. Hatching and Rearing of 

 fish is the end to have in view, and scientific men who 

 have charge of fish hatcheries will not be content till 

 they have succeeded in rearing into young fish, at a 

 reasonable cost, a large proportion of the fry which they 

 can now hatch from the eggs by the million. Professor 

 Gr. 0. Sars first showed how the eggs of an edible fish 

 (the Cod) could be hatched in small numbers as a labora- 

 tory experiment ; Dannevig in Norway and the U.S. Fish 

 Commission in America have devised the apparatus and 

 technique by which it has become possible with very slight 

 mortality to hatch out such eggs on an industrial scale 

 by hundreds of millions. The next advance must be in 

 rearing. At present practical difficulties block the way, 



