26 Fishery Board for Scotland. 



additional facts undoubtedly support tlie view that the Dornoch Firth 

 is a locality more favoured by the spawning plaice. 



On 21st March fourteen eggs were obtained in a vertical haul, and 

 twenty in a horizontal surface haul of one half-hour's duration, while 

 on 24th March 1908 there were none in the vertical haul and 136 in the 

 surface haul. This shows how careful one must be in regarding the 

 number of eggs in the surface collections as an index of the absolute 

 frequency of eggs in an area. The complete table of the hauls from 

 the different depths gives the better view of the conditions. 



24th March 1908. 

 a /3 y S Total. 



83-7 8-7 5-7 1-9 



In 1906 the eggs were mainly distributed in the middle water layers, and 

 in 1908 they were most numerous in the surface layers. Here the eggs 

 in the later stages of development are relatively more numerous in the 

 deeper water layers. The very variable salinities of water which do 

 occur, however, in such coastal areas undoubtedly also influence the 

 vertical distribution of pelagic eggs. 



The distribution of the plaice eggs along the South Coast of the 

 Moray Firth dming the month of March 1906 has already been dealt 

 with, but it is very unfortunate that the collections in January and 

 February of that year are so meagre for this area. Burghead was 

 visited in February 1906, and 14 eggs, 10 of which were in the " a " stage, 

 were taken at the sm'face. This area, however, was visited in January 

 1908, and again in March of the same year. The results of the ob- 

 servations in January from the shallow water, the intermediate depths, 

 and the deeper off-shore grounds have already been discussed. The 

 averaged results got by combining the surface mid-water and bottom 

 hauls from these three positions may therefore be compared directly 

 with the 1908 results. 



Burghead Bay (averaged results). 



How are these results to be reconciled ? The average number of eggs 

 in the " a " stage of development indicates that plaice were spawning in 

 the near neighbourhood from January to March, and that the spawning 

 was probably more intensive in January than in March. But the fact 

 tlTat the relative number of eggs in the later stages of development is 

 no greater in March than in January of the same year is proof that the 

 eggs spawned earlier than March have already disappeared from this 

 locality. 



There are considerable differences from year to year within this 



