30 Fishery Board for Scotland. 



the fall in frequency of the plaice eggs as compared with those at Noss 

 Head. 



(h) 58° 5' N. ; 3° 13' W. 



Plankton collections were taken 14 miles east of Helmsdale on 

 23rd March 1907, and no newly spawned eggs were found in the surface 

 haul. We have already seen that spawning was late in other localities 

 in season 1906-1907, and the absence of newly spawned eggs in this 

 area may be due to this cause. The large number of eggs in later stages 

 of development shows that this area is invaded by eggs from earlier 

 spawning regions. 



(k) Berriedale. 



The frequency of plaice eggs was very low when collections were 

 made off Berriedale on 7th February 1910. Newly spawned eggs, of 

 which there were four, were all taken at the surface, and they make only 

 8*7 per cent, of all the plaice eggs collected on the station. This 

 locality lies to the north of Tarbet Ness, where the frequency and the 

 relative proportion of newly spawned eggs were much higher even two 

 days previously. 



The evidence, so far as it goes, seems to show that spawning is later 

 from Tarbet Ness towards Helmsdale, and that there is a drift of some 

 of the earlier spawned eggs in this direction. 



(1) Smith Bank. 



It is unfortunate that this locality, which has always been looked 

 upon as a favom'ite spawning area for plaice, has only been visited once, 

 namely, on 21st March 1906. A very large number of eggs was taken in 

 the plankton nets on this occasion, but the results when compared with 

 those of Noss Head for the same date show that plaice were not 

 spawning in any number on Smith Bank, but that the most favoured 

 locality was close to Noss Head. 



Total eggs in horizontal hauls from 

 m., 5 m., mid-water, and bottom. 

 Developmental Stages, 

 a |3 y 6 



Smith Bank . . .10 274 370 8 



Where have the large number of eggs in the later stages of develop- 

 ment come from ? Observations made at Station XVI., Moray Firth, 

 which lies a few miles south of Smith Bank, may be helpful in this 

 relation. At Station XVI., even as early as January, most of the eggs 

 were in the later stages of development, and the same result was noted 

 in March. Indeed, in the month of January, 60 of the 63 eggs captured 

 had already passed through the initial stages of development. Now, 

 it has been shown already that the neighbourhood of Station XVI. is 

 a late spawning area, even although eggs in the later stages of develop- 

 ment are the first to appear in the plankton in the area. There seems 

 to be no doubt therefore that if Smith Bank is a spawning area it is a 

 late one, and that before spawning begins within the area eggs in the 

 later stages of development have already been carried into the locality 

 from other and earlier spawning grounds. 



