CH. IV] 



LIFE IN THE SEA 



95 



Previously many of these plants have formed resting spores, and 

 are lying dormant. Genera like Biddidphia, Goscinodiscus and 

 Chaetoceros appear about the end of February, at times in great 

 profusion, so that the tow-nets may occasionally contain little else 

 than these organisms. The fishes begin to spawn, and the copepods 

 too increase in numbers. But the changes which characterise the 

 months of February and March are (1) the increase in the diatoms, 

 and (2) the appearance of fish eggs and larvae. The outburst in 

 diatoms is due to meteorological changes principally, and it effects 

 a part of the plankton which is already present in the sea as such, 

 but the fish eggs and larvae result from the multiplication of 

 animals which are nektic in their habits. The diagram below has 

 been constructed from observations of the appearance of fish eggs 

 in Cardigan Bay for the years 1905-6 ^ It shews that even at the 

 end of the year plaice begin to spawn. Then follow the rockling 



J any. Feby 



Plaice . . 



Rockling ? 

 Dab .... 



Flounder 



Haddock 



Bib .... 



Coalfish 

 Common 

 dragonet 

 AVhiting 

 Cod .... 



Brill .... 



Solenette 



Sprat 



Spotted 

 dragonet 

 Ling .... 



Turbot.. - 



Anchovy 



Mackerel 



Weever 



Top-knot 



Fig. 22. The succession of fish ova in the plankton of 

 Cardigan Bay, 1905 and 1906. 



(Motella, probably more than one species), flat-fishes like the 

 flounder and dab, gadoid fishes like the haddock, bib and coalfish, 

 and the common dragonet. Cod and whiting begin to spawn in 

 March and the brill, solenette, sprat and spotted dragonet complete 



1 Scott, Annual Reports Lancashire Sea-Fisheries Laboratory, 1905 and 1906. 



