2l6 MARKETABLE BRITISH MARINE FISHES 



spawning, but remain on rather deeper grounds during the 

 spawning season. We have seen that plaice are not known to 

 occur at all at depths greater than 50 fathoms. The spawning 

 grounds may from our present knowledge be taken to be from 

 10 to 40 fathoms. The distance from shore varies with the 

 locality. Dr. Fulton found that on the east coast of Scotland 

 plaice do not spawn in territorial waters, that is within the three 

 mile limit, and this is generally true for the south and west coasts 

 of England, and the Irish Sea. But on the west coast of Ireland, 

 where the declivity of the sea-bottom is so much steeper, 

 spawning plaice were found in inshore waters, for instance in 

 Blacksod Bay and the Kenmare River. Smith Bank, 18 to 20 

 fathoms in depth, 10 to 15 miles off the Caithness shore, has been 

 found in the inquiries of the Scottish Fishery Board to be 

 specially distinguished by the number of plaice spawning there 

 in spring. It is also a good plaice ground at any time, because 

 there are beds of horse mussels upon it, on the smaller specimens 

 of which the fish feed. On the south coast ripe plaice are found 

 on all the usual trawling grounds, along the Cornish coast inside 

 and outside the Eddystone and in the neighbourhood of the 

 Wolf Rock off Mount's Bay. 



The eggS) or spaivn. The eggs of the plaice are among the 

 largest floating eggs of fishes known : they are a little less than 

 T Vth inch in diameter. Actual measurements by different 

 observers have ranged from r65 to 1*95 mm. They can be 

 recognised without difficulty from other similar eggs among a 

 number taken from the sea by means of this large size. The 

 egg is round, the yolk is undivided and without oil globule. 



Plaice eggs naturally develop in the sea when the temperature 

 of the water is low, and the development is therefore slow, and 

 it is also slower than that of the eggs of other species even at the 

 same temperature. At the temperature of 53 F. in the Plymouth 

 establishment the eggs hatched in 10 to 12 days. At a lower 

 temperature at Granton in 1886 the development took more 

 than 27 days. The larva when newly hatched is like that of the 

 flounder and dab, but much larger. It is about !th inch in 

 length. The mouth is not open, the end of the intestine runs 

 down immediately behind the yolk. There are black and yellow 

 specks of pigment on the sides of the body and head, but none 

 on the yolk-sac, nor on the larval median fin. 



