The Spawning Grounds of Plaice. 43 



water spawning does not take place, and newly spawned eggs are rarely 

 found there. Neither ripe plaice nor newly spawned eggs are found 

 in the sandy bays of the East Coast of Scotland, and they are also 

 absent from the shallow waters of such localities as the Dornoch Firth 

 and Burghead Bay. Proximity to the shore is not the dominant factor 

 regulating the distribution of ripe plaice, although large numbers of 

 freshly spawned eggs are often found close to the land in localities 

 where there is a rapidly shelving coast line and where conditions are 

 otherwise suitable. Spawning plaice do not penetrate far into the 

 estuary of the Firth of Forth. The fifty-fathom line lies very close to 

 the coast on the East Coast of Scotland, so that spawning is confined to 

 a very narrow belt close to land. Few, if any, plaice spawn under the 

 shelter of the islands. 



Although newly spawned plaice eggs are found widely distributed in 

 the zone within the fifty fathoms, with the exception of the shallow 

 coastal area, spawning is most intensive in the intermediate depths. 

 The frequency of spawning plaice is very low in depths between forty 

 and fifty fathoms, and consequently freshly spawned eggs are not 

 numerous in that extensive area to the east of Orkney. Outside the 

 Moray Firth area, in depths between forty and fifty fathoms, spawning 

 plaice are likewise of rare occurrence. The distribution of the newly 

 spawned plaice eggs agrees even in detail with the known seasonal 

 distribution of adults, for although large plaice are found more widely 

 distributed throughout the year, even at depths of seventy fathoms, 

 there is a segi'egation in the lesser depths during the spawning period. 

 It is only in Statistical Areas XXIV. and XXX., where the depths 

 appear suitable, that large plaice are found to be absent in the spawning 

 months. This statement is supported both by the market statistical 

 records and by the absence of plaice eggs over these areas during the 

 spawning months. 



But although spawning plaice are found widely distributed, with the 

 exceptions already mentioned, over the intermediate depths indicated, 

 they are not uniformly distributed, and the extent of distribution as 

 well as the principal spawning time are not alike in the different 

 localities. Even in any particular locality there are earlier and later 

 years, good and bad years, for the annually recurring spawning 

 phenomenon. 



The facts as elucidated in the present communication are sufficient 

 to show that " there are considerable differences from place to place as 

 regards the commencement of the spawning period." 



In general, the East Coast of Scotland is a late spawning area for 

 plaice. 



In the Dornoch Firth, however, spawning begins very early, and in 

 favourable years a few plaice may spawn even in late November, so 

 that the height of the spawning season may be reached before the end of 

 January. 



In the area to the east of the May Island there is more difficulty in 

 defining the earliest date of spawning, but the evidence at present to 

 hand shows that plaice may spawn here in December. The question 

 of fixing the beginning of the spawning period here is difficult on account 

 of the low frequency of spawning plaice in this area. 



There is a retardation in the time of spawning from the coast 

 outwards. This phenomenon is extremely well marked in the records 



