36 Fishery Board for Scotland. 



There is a marked increase in the frequencies of plaice eggs in the 

 month of February, but throughout the period under review spawning 

 seems to have been most intensive in February 1905. Eighty-eight 

 eggs, of which 81 were newly spawned, were captured on the 28th of 

 this month. On 17th February 1906 the frequency of the eggs was 

 almost as high, and over 90 per cent, were newly spawned. Fewer eggs 

 were found on the February visits in the other years, and in 1908 none 

 were present in the plankton collections. A very high percentage of 

 the eggs caught in this locality in February were in the initial stages of 

 development. 



Our knowledge concerning the conditions within this area in March 

 is derived from observations made at Stations VIII. and IX. The 

 total number of eggs found on any occasion was small, but it is perhaps 

 of more significance that the proportion of those in the later stages of 

 development has not increased greatly. The following table gives the 

 percentages of eggs at the different developmental stages in the four 

 months in this area : — 



I 



Station 44 (56° 20' N. ; 1° 49' W.). 



Numerous observations have been made at this locality, but they 

 have unfortunately been confined to the months of December and 

 February. The December records give negative results for plaice eggs, 

 and even in February the frequency is extremely low. In February 

 1908 no plaice eggs were found on the 13th of the month, and on the 

 23rd February 1910 one only was taken. The greatest number 

 occurred on the 5th of February 1907, when only two of the eighteen 

 eggs from the different water layers were in the " a " stage of develop- 

 ment. If the separate records for the month of February are combined 

 it is found that only a small percentage of the eggs is in the intial stages 

 development. These records may be contrasted with those obtained 

 at Station 45 in February. 



Percentages at the developmental stages in February : 



a |3 y 5 



Station 45 . . 90-6 3-5 5-9 . . 



Station 44 . . 26-2 45-2 28-6 . . 



This phenomenon is somewhat similar to that found on the line of 

 stations which stretches east from Tarbet Ness in the Moray Firth, so 

 that it would appear as if spawning was later the fm-ther east from the 

 May Island. This hypothesis is further strengthened by observations 

 which were made at 56° 17' N. ; 1° 58' W. on 7th March 1912. On this 

 date 113 eggs were captured in that vicinity, and 111 of these were 

 newly spawned. The frequencies obtained are much greater than 

 any obtained at an earlier date, so that it would appear as if the maxi- 

 mum spawning period within this area does not occur before March. 

 The area between Stations 45 and 44 must be regarded as a real spawn- 



