14 



Part III. — Thirteenth Annual Report 



The Capture of immature fish by hooks. 



Experiments have been carried on, the results of which are given 

 in the present Eeport, with the view of determining the proportion 

 of immature fish caught by hooks, the proportion that would be 

 likely to survive if returned to the sea, and the possibility of 

 diminishing their capture by a modification of the size of hook 

 used. The experiments serve to show that while the smaller hooks 

 catch larger numbers of small fish, no precise relation subsists 

 between the size of hook used and the size of the fish captured ; 

 and that the capture of immature fish by this mode of fishing 

 could not be dealt with by varying the size of the hook. 



The Life-Histories and Development of the Food Fishes. 



In the present Eeport will be found an important paper by 

 Professor M'Intosh (p. 220), giving the results of his continued 

 investigations on the eggs, young, and development of several of 

 the food fishes, the work having been carried on, as in previous years, 

 at St. Andrews Marine Laboratory. The principal investigations 

 relates to the development of the turbot, which has now for the first 

 time been elucidated, fertilised eggs having been procured from 

 the hatchery. The ripe egg of the turbot has an average diameter 

 of 1*0287 mm., and is perfectly buoyant, floating at the surface of 

 still water or suspended midway, and it possesses a prominent oil- 

 globule. The embryonic fish, which is of a reddish colour, emerges 

 from the egg about the sixth or seventh day, so that the period is 

 short before hatching occurs. The larvse in a few days become 

 active and dart rapidly through the water, and they are hardy ; 

 the yolk-sac becomes absorbed about the seventh day, and there- 

 after they feed for themselves, being extremely quick in noticing 

 the movements of the minute crustaceous and other forms in the 

 water around them. Professor M'Intosh states that no form 

 hitherto observed at St. Andrews appeared to be more hardy, or to 

 undergo the vicissitudes of temperature and manipulation with 

 greater impunity than the young turbot ; there are grounds, there- 

 fore, for expressing the hope that they may yet be reared in great 

 numbers from the post-larval to the adolescent and adult condition 

 in suitable enclosures. The various stages in the development of 

 this valuable form are described and figured. Another species 

 whose development is described is the long rough dab, the pelagic 

 eggs of which are found in considerable abundance in March and 

 April. 



Mr H. Charles Williamson, M.A., B.Sc, also contributes an 

 elaborate paper on the reproduction of the common eel, which has 

 been, and still is, in many respects, involved in considerable 

 obscurity. He gives a very full account of the reproductive organs, 

 both as described by other naturalists, and as observed by himself 

 in a number of specimens examined at St Andrews ; and the paper 

 includes a description of the migrations of the eel, and all that has 

 been ascertained about its spawning. It is a remarkable fact that 

 the ripe egg of the eel has never yet been discovered. 



