LEMON SOLES 145 



is due, not to a later spawning period, but to a longer pelagic ^ 

 life. The species is a deep-water form, and the main spawning 

 probably takes place well off shore.' It is evident that the fish 

 is ripe very much earlier in southern waters than farther to the 

 north. Cunningham found eggs floating at the surface at 

 Plymouth in March, April, and May ; Holt got them off the 

 west coast of Ireland in April, May, and June. Eipe fish are 

 to be had, according to Mcintosh, off the east coast of Scotland 

 from April to August ; and Ehrenbaum says that off HeHgoland 

 the spawning is at its height in the latter half of June and in 

 July .2 Meek summarizes the spawning grounds as occurring 

 west of Ireland and Scotland, and in the deeper parts of the 

 middle and northern North Sea, and the Skagerrak ; the main 

 grounds being in the north-east of the North Sea, and one off 

 the coast of Fife. 



The Eggs and Incubation 



The eggs, which measure about 0-05 ^ inch in diameter, are 

 smaller than those of the plaice. As with so many species, no 

 exact table has been worked out, or at any rate published in 

 English, to show how the rate of incubation varies with varia- 

 tions in the temperature of the water. This means that there is 

 plenty of work to be done on the life-history of the lemon sole. 

 All that is cef tain is that the hatching takes place more quickly 

 in warm water. Cunningham, for instance, fertilized eggs in 

 April at Plymouth which hatched on the seventh or eighth day. 

 Mcintosh's eggs at St. Andrews were fertilized at 8 p.m. on the 

 8th July, and hatched — some on the sixth, some on the seventh 

 day. It is hardly possible to lay too much stress on the very 

 urgent need for further experiment with fairly large numbers of 

 eggs, and especially in the case of lemon soles at St. Andrews 

 and Cullercoats, in order to arrive at a really rehable ' hatching 

 table ', for all commercial species of fishes. 



The Larvae 



On hatching out, the larvae measure 0-13 inch to 017 inch 

 (3-5 to 4-5 mm.). Their outstanding characteristic is hardiness. 

 Mcintosh tells us they are so hardy ' that a number lived about 

 six days in a small glass cell 2 inches by J inch deep, the water 

 being filled up as it evaporated '. That is, as fish culturists 

 know, about as severe a test as any baby fish could be called 



1 i. e. to the fact that they float at the surface longer than other flat fishes 

 [see p. 147 (footnote)]. 



2 British Marine Food Fishes, p 366. 



2 About 455,000 to the quart. 

 2497 







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