Distribution of Plaice Eggs — East Coast. 39 



and shallower bays of the estuary, and in the first quarter of the year 

 (that is, the spawning period) their number has reached a minimum. 



There is an orderly increase in the number of adult sized plaice 

 towards the mouth of the estuary and beyond. Even at these outer 

 stations they reach their minimum in the first quarter of the year. 



" There is an orderly migration out of the Firth of the plaice as they 

 approach maturity " (Fulton). 



VII. The East Coast of Scotland, South of the Moray Firth. 



It has been stated already that the distribution of plaice eggs on the 

 East Coast of Scotland in the first quarter of the year is limited by the 

 fifty fathom line. Many observations have been made in the Northern 

 North Sea in that large area of over fifty fathoms in depth, which ex- 

 tends from 58° N. latitude northwards to 61° 30' on the edge of the 

 continental shelf. Over this extensive area on no occasion have plaice 

 eggs been captm'ed in the first quarter of the year. This deep area of 

 over fifty fathoms extends southwards as far as 56° N. latitude, and 

 forms the " Gut " lying between 0° and 2° E. longitude. This narrow 

 valley lies between the shallow coastal area of the East of Scotland, 

 south of the Moray Firth, and the shallow zone of the Fisher Bank 

 region where plaice are captm'ed in number. Notwithstanding re- 

 peated observations over the deep valley in the first quarter of the 

 year, no plaice eggs have been taken, although large numbers of pelagic 

 eggs of other species, which are known to appear in the plankton 

 later than the plaice eggs, have been found. These negative results 

 are of significance, and they are confirmed by the negative results ob- 

 tained by other methods. The analysis of the statistical data of the 

 market catches shows that large plaice are absent from these grounds 

 during the spawning months, although they may be caught there in 

 relatively small numbers at other periods of the year. 



Thus the distribution of the newly spawned eggs of plaice on the 

 East Coast of Scotland is somewhat sharply defined in an easterly 

 direction. A number of observations made within this area in the 

 neighbourhood of the fifty-fathom fine has given very poor results, 

 but they indicate that most of the spawning plaice on the East Coast of 

 Scotland are confined to the shallower water nearer the coast. 



Not only are large plaice and newly spawned eggs absent from the 

 area over the deeper water, but they are also absent from the extremely 

 shallow coastal area. Spawning plaice are not found in the shallow 

 sandy bays, and newly spawned eggs appear in proximity to the coast 

 only where there is a rapidly shelving coast line. 



No plaice eggs have been recorded in the various hauls made in St. 

 Andrews Bay, Carnoustie Bay, and Lunan Bay. Very near to the 

 shore in the shallow water at Tod Head and Red Head plaice eggs 

 were also absent. But at Tod Head, offshore in the deeper water, 40 

 eggs, of which 24 were in the early stages of development, were taken 

 in the different water layers on 27th February 1907. Also on 27tli 

 February 1907, 1| miles east of Cove, 94 eggs were captured at surface, 

 mid-water, and bottom, but of these only 2 were newly spawned. 



Off Collieston, on 14th March 1906, a surface net, in a haul of one 

 half-hom''s duration, captured 20 eggs, but only 2 of these were in 

 the initial stages of development. 



