Distribution of Plaice Eggs — Moray Firth. 29 



in the " a " stage was found in the surface net at Sutors of Cromarty, 

 N.W.N. U miles. 



The few eggs found within the area were well advanced in develop- 

 ment, so that plaice apparently do not spawn in the immediate vicinity 

 of the Cromarty Firth. 



(^) Stations along the N.IV. shore of the Moral/ Firth. 



Four stations along the north-western coast of the Moray Firth, 

 namely, Sinclair Bay, Noss Head, Lybster, and Helmsdale were very 

 thoroughly investigated on 21st March 1906. Vertical haul and hori- 

 zontal hauls at surface 5 metres mid-water and bottom were made 

 with the cheese-cloth nets at each locality. The relative frequencies 

 of the eggs are compared by taking the total eggs captured in the 

 horizontal hauls at each station. The following are the results : — 



N.W. shore of Total eggs in horizontal hauls. 



Moray Firth. m. 5 m. mid- water, and bottom-hauls. 



Developmental Stages. Total. 



Sinclair Bay . 

 Noss Head 

 Lybster 

 Helmsdale 



At Lybster, which is situated half-way between Noss Head and Helms- 

 dale, the number of plaice eggs in the " a " stage is insignificant in com- 

 parison with the number to the north and south. The Noss Head 

 station is, however, of more importance than Helmsdale. The relations 

 of these three stations are very complex. The high frequency of newly 

 spawned eggs at Noss Head proves that it is an important spawning 

 area. But if spawning had begun much earlier than March then all 

 these earlier spawned eggs have been carried away from the locality. 

 If the records from Lybster and Helmsdale are taken into consideration 

 it does not seem likely that such eggs were carried along the coast to 

 the south, the number of eggs advanced in development being so few 

 at Lybster. Conversely, if Helmsdale is an earlier spawning area 

 there is no drift along shore to the north. But the eggs in the later 

 stages of development at Helmsdale may be derived from the south. 

 Off Tarbet Ness on the 20th March 1906 the numbers obtained in hauls 

 similar to those made at Helmsdale were : 



a |3 y S 



Tarbet Ness . . .452 122 70 4 



So, too, the number of eggs in the different stages of development taken 

 at Station VIII., Moray Firth, on 15th March 1906, in a surface haul 

 only, were : 



oc (d y h 



Station VIII., Moray Firth (surface haul) . 110 93 21 



Although there is a slight rise in the relative proportion of the eggs in 

 the later stages of development at Helmsdale this agrees very closely 

 with those two stations towards the south. 



The shallow water conditions in Sinclair Bay probably account for 



