of the Fishery Board for Scotland. 



369 



inshore waters abound with young fish. Small flat-fishes, such as plaice, 

 dabs, and turbot, exist in great numbers on sandy beaches and shallows, 

 and young round-fishes, as cod, saithe, and ling, frequent the more 

 rocky regions. It is therefore evident that these young post-larval 

 forms, which were spawned offshore, must be carried to the inshore 

 grounds principally by the movement of the water ; and by the use of 

 tow-nets their progress shorewards may be traced. For example, eggs 

 of plaice, ling, haddock, and cod, advanced in development, as well as 

 the larval fishes with the yolk-sac still attached, and the older post-larval 

 forms, may be found close inshore, as in the Firth of Forth and St 

 Andrews Bay. They are in process of being swept in by the currents ; 





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Fig. 4. — Diagram representing the carriage of pelagic eggs from offshore spawning 

 grounds, A, to inshore waters, C, by the surface current B. 



and it is largely in this way that the inshore grounds are recruited from 

 the spawning areas further out (Fig. 4). Young fishes are not, however, 

 limited to the grounds near the shore. Some kinds, such as the long 

 rough dab and the haddock, are more common at a distance from shore 

 in deeper water ; but our knowledge respecting the distant grounds is at 

 present very imperfect, owing to the fact that no vessel is available 

 capable of making the investigation. For the same reason we do not 

 know the limits or extent of the great spawning areas. All that can be 

 said is that such species as cod, haddock, ling, plaice, and turbot spawn 

 from five or six miles up to great distances from shore, and also on the 

 offshore banks and their neighbourhood, such as the Dogger Bank, the 

 Great Fisher Bank, Smith Bank, etc. During the greater part of the 

 year the adults are more or less scattered about the North Sea and 

 within territorial waters, searching for food, but towards the approach 

 of the spawning season they congregate in shoals in particular localities. 



The nature of the bottom does not appear to have any influence in 

 the determination of the spawning area of fishes producing pelagic eggs ; 

 it may be muddy, or sandy, or rocky. There is thus a great difference 

 from the case of fishes producing demersal eggs, such as the herring, 

 where the eggs are attached, as a rule, to objects in the bottom, and 

 where the presence of mud might prove extremely injurious. At the 

 same time it cannot be held that the selection of spawning places by 

 fishes producing pelagic eggs is fortuitous, for adults with ripening 

 reproductive organs move out from the inshore waters at the approach 

 of the spawning season, and may return to them after their spawn is 

 shed. As pointed out by the author some years ago,* the selection of areas 



* Eighth Annual Report for 1889, Part iii., "The Spawning and Spawning Place 

 of Marine Food-Fishes," p. 258. 



2 A 



