36 EFFECT OF TRAWLING ON INVERTEBRATES. 



the same conclusion. Again, the deeper water is the home of 

 the post-larval frog-fish, even the pelagic eggs being rather 

 uncommon near shore. The adolescent and adults, on the 

 other hand, are frequent in shallow sandy bays like St Andrews. 

 It is apparent, from certain remarks in the preceding 

 paragraph, that it is a mistake to say that the trawl alone can 

 capture flat fishes. If the bait be suitable, the lines are toler- 

 ably effective in regard to plaice, lemon-dabs, dabs, and 

 flounders. Again, halibut-fishing (by hook) is the most pro- 

 ductive method off the coasts of Iceland, Faroe, and elsewhere, 

 and even the turbot and the sole are occasionally caught by the 

 liners. 



a. Effect of Trawling on the Invertebrate Fauna of the Sea- 

 bottom (forming Fishfood), and Collateral Relations with 

 Pelagic Life. 



The value of the bottom-fauna, in regard to the sustenance 

 of the food-fishes, has been fully recognised by all zoologists. 

 In the Trawling Report for 1884 it was stated \ 'There 

 cannot be a doubt about the importance of maintaining the 

 invertebrate fauna of these parts (Forth) in a flourishing condi- 

 tion, since upon this many of the food-fishes depend for much 

 of their nourishment; indeed, both adult and young fishes 

 could hardly exist without such, notwithstanding the abundance 

 of herring and other pelagic food at some seasons ^Z 



In considering the effect of the trawl on the sea-bottom, it 

 must be borne in mind that while many sponges, zoophytes, 

 star-fishes, crabs, and shell-fishes are, in their adult state, 

 inhabitants of the bottom, their larvae and young are pelagic, 

 that is, free-swimming, and quite beyond the reach of injury, 

 so that were the majority of their parents killed and the sea- 

 bottom rendered barren^ (of which, apparently, there is an 



1 "A Brief Sketch of the Scottish Fisheries," 1882—1892, p. 6. 



2 Op. cit., p. 370. 



3 Vide an interesting Essay on this subject by Mr Anderson Smith, Trans. 

 Highland and Agricultural Society, 1890, p. 45. 



