CONSIDERATION OF INDIVIDUAL FISH 8i 



no one knows what proportion of fish eggs and larvse are destroyed 

 in a state of nature. 



In defence of fish hatching " the risks of non-fertilisation " in a 

 state of nature are touched upon. Here again there are no definite 

 statements as to the percentage, if any, of non-fertilised pelagic 

 fish eggs in the sea. In fact, authentic records of linfertilised eggs 

 are either non-existent or of the greatest rarity. 



Although there is a great mortality in a state of nature somewhere 

 in the life history of the plaice, we have no logical reason for believing 

 that the period of maximum mortality is tided over in the 

 hatchery. 



It may be taken for granted that there is a considerable mortality 

 in the sea. There is no evidence to show that this occurs before 

 hatching, it possibly or even probably occurs after hatching, i.e. 

 subsequent to the stage at which the larvse are set free from the 

 hatchery. No supporter of fish hatching, however enthusiastic he 

 may be, can conscientiously say that the thread-like larvae at 

 present liberated are at all capable of protectiag themselves. 



Another theoretical objection urged against the artificial pro- 

 pagation of sea fish for economic reasons is based upon consideration 

 of the vast area of the sea as compared with lakes and rivers, and 

 upon the enormous fecundity of most sea fish, especially those, 

 which like the plaice, produce pelagic eggs. But as Fulton,^ in an 

 able and impartial paper on the subject, has pointed out, although 

 the extent of the sea is vast, the parts frequented by edible fish — 

 the fishing grounds on which the fish are caught — are relatively 

 small, usually confined to the neighbourhood of coasts or to banks in 

 close propinquity to them. Of recent years much information has 

 been obtained with regard to the migrations of several valuable 

 species, and we now know that, with regard to plaice, at any rate, 

 the extent of wandering is, especially in the early years, very small. 

 In the case of marked plaice liberated by Fulton in the Firth of 

 Forth and St. Andrew's Bay, and by Meek on the Northumberland 

 coast, nearly 90 per cent of those recaptured were taken within a 

 few miles of the place of liberation, sometimes after an interval of 

 two years or more. The fact that the natural range of certain species 

 may on the whole be quite restricted, materially modifies the 

 application of the argument based on the vastness of the sea. 



In combating the argument against artificial hatching of sea fish 

 based on the enormous fecundity of most edible marine species, 

 Fulton to some extent supports our contention as to the fact that 

 " there is not sufficient information to enable one to apportion with 



* " The Loch Fyne Experiments with Plaice," by Dr. T. Wemyss Fulton, 26th 

 Annual Rept. Scots. Fish. Bd., Part III, Glasgow, 1909. Cd. 4454. 



G 



