42 Fishery Board for Scotland. 



higher at Tod Head, from five to twenty miles offshore, than either in 

 the inshore or the offshore area. There is a distinct indication of this 

 same condition in the results of the observations made in March 1909 in 

 the line of stations at right angles to the coast. At the Station Tod 

 Head, W./S. | S. 5 miles, the frequency was very high on 29th March 

 1911. Here on this date 86 eggs were taken, and 82 of them were 

 recently spawned.* 



This zone of higher density apparently extends parallel to the coast 

 as far north as the neighbourhood of Aberdeen, for a number of obser- 

 vations made in this belt give very significant figures. For example, 

 at Stonehaven, W./N. | N., 19 miles, on 29th March 1911, 20 newly 

 spawned eggs were got in the surface cheese-cloth net, while 40 were 

 taken in the Petersen Young Fish trawl at the surface. Again, at 

 Girdleness, W./N. | N., 10 miles, on 7th March 1912, 64 newly spawned 

 eggs were taken in the cheese-cloth nets from surface, mid-water, and 

 bottom. In addition, a large number of eggs in the later stages of 

 development were also taken in this vicinity in the month of March. 

 Eggs in the later stages of development had already been collected in 

 February, before the newly spawned ones had appeared in the area, 

 thus showing that a large number of these eggs in the later stages of 

 development in March have been carried into the area. 



Observations have also been made in the shallow off-shore area 

 which lies between Tod Head and the Firth of Forth, but the frequencies 

 are very low, and most of the eggs were in the later stages of development. 



The experiments which have been conducted in the coastal area on 

 the East Coast of Scotland, south of the Moray Firth, indicate that the 

 earliest spawning does not fall much before the beginning of February, 

 even in favourable years, and that the frequency of newly spawned 

 eggs in the first quarter of the year is never high even in the most 

 favom'ed localities. The results also indicate that plaice do not spawn 

 in the very shallow water close to the shore, that few plaice spawn 

 further than twenty miles off-shore, that most of the spawning plaice 

 are confined to a narrow belt which runs parallel to the coast from the 

 neighbourhood of Montrose northwards to the vicinity of Aberdeen ; 

 and, finally, that plaice eggs are carried into this belt from earlier 

 spawning areas, and that these eggs in the later developmental stages 

 appear in this belt before the freshly spawned eggs. 



We are now in a position to correlate the isolated observations made 

 and to take a wider and more general survey of the facts ascertained 

 regarding the distribution of spawning plaice and the occurrence of 

 their pelagic eggs in the Northern North Sea. 



In many localities within this wide area plaice spawn in depths of 

 less than fifty fathoms, and the fifty-fathom contour line marks the 

 outer limit of distribution of newly spawned eggs. In very shallow 



* Dr. Fulton (S.F.B.R., xx., 1901): "On the East of Scotland the spawning 

 period extends as a rule from the end of January until the beginning of May, 

 the maximum, according to the proportion of spawning fishes, being in March. 

 This agrees with the limits of the spawning of the plaice in confinement in the 

 ponds at Dunbar and the Bay of Nigg." 



(S.F.B.R., viii., 1889): "In January and February very large ripe plaice 

 congregate on grounds at distances from about 8 or 10 to 20 miles off the East 

 Coast. In the neighbourhood of the Firth of Forth and St. Andrews Bay these 

 shoals are mainly found about 8 or 10 miles off ; off Montrose they may occur 

 up to 25 miles." 



