O INTRODUCTION. 



Floating or Pelagic Eggs. During the investigations con- 

 nected with the Royal Commission on Trawling ample oppor- 

 tunities were afforded for becoming acquainted with the pelagic 

 eggs of sea-fishes. They were found to frequent the surface, 

 mid-water and bottom, and their abundance in a given area 

 was generally diagnostic of the prevalence of the parent fishes. 

 The latter feature was boldly illustrated by contrasting in April 

 the area at Smith Bank, where the eggs were in enormous 

 numbers, with that off the Forth, where they were fewer. In 

 the former area the vast multitudes caused the sea to resemble 

 a great hatching-pond in which eggs and larval fishes occasion- 

 ally were driven by surface-currents into long lines marked at 

 a distance by numerous ducks and other sea-birds that greedily 

 fed on them. It often happens that when one region of the 

 sea is almost devoid of pelagic eggs, for example the surface, 

 they may be found in mid-water or near the bottom. Thus 

 the investigations with the trawl-like tow-net show that a vast 

 number of pelagic eggs, such as those of the cod, whiting, 

 rockling, sole, flounder, gurnard, sprat and other forms, are to 

 be found near the bottom, when the surface and mid-water 

 nets are devoid of them. The cause of this feature is not fully 

 known, but it may, as in the case of pelagic invertebrates, be 

 due either to temperature or to currents. The areas usually 

 called fishing-banks especially abound iu these pelagic eggs 

 during the spawning season, and thus in a sense the examination 

 of the tow-nets gives certain data in regard to the prevalence 

 of the food-fishes. Pelagic ova, however, may be borne long 

 distances before hatching takes place, and the larvte may 

 subsequently be still further carried from the spawning ground, 

 so that their distribution is amply provided for. Thus it 

 happens that the inshore grounds receive supplies of eggs from 

 the offshore, where many of the breeding fishes are, and on 

 the other hand the young and adolescent fishes leave the inshore 

 and seek the deeper waters beyond. 



To close the inshore grounds therefore (except to the liners) 

 and leave the offshore free to all may not have the result of 

 increasing the food-fishes of the area to a noteworthy extent, 

 since the spawning fishes which supply a constant increment 



