Distribution of Plaice Eggs — Moray Firth. 21 



and five in the " y " stage the surface collection of the Peterson Young 

 Fish Trawl. This station is therefore not far from the outer limit of 

 the distribution of spawning plaice. 



Stations 33 and 34. 



Station 33 (58° 3' N. ; 1° 32' W.) and Station 34 (58° 17' N. ; 1° 03' 

 W.), are fifteen miles apart, and lie on the straight line east from Tarbet 

 Ness, but outside the Moray Firth area. No plaice eggs were taken 

 here on any occasion in the month of December. In the month of 

 January eggs appeared at Station 33, and on 26th January 1905 four 

 were taken in the Petersen Young Fish Trawl from the bottom layers. 

 These eggs were all well advanced in development, and the embryo had 

 reached the "y" .stage. By the month of February eggs had also appeared 

 as far east as Station 34, and two in which the embryo was almost ready 

 to hatch out were obtained in a cheese-cloth net at the bottom. A few 

 eggs were also captured at Station 33 in this month in the lower water 

 layers. The embryo was in the "3 " stage in one of these, while the 

 others were all more advanced in development. 



In March surface hauls only were taken at Station 34, and four 

 eggs were got, of which two were in the " y " stage, that is in an earlier 

 stage of development than those found the previous month in the 

 same locality. At Station 33, however, on the last day of March 1905, 

 eggs were got in the first stages of development. The number is not 

 large, and is exceeded by that in the later stages of development. 



Thus the conditions deduced from the records at these outer stations 

 are in harmony with those found at the inner stations on this line. 



Summarising the results of the observations made along the line 

 east of Tarbet Ness for the months of December, January, February, 

 and March, we reach the following conclusions : — 



1. Plaice spawn along this line as far east as Station 33. 



2. Spawning plaice occur in greatest numbers at the inner stations. 



The Dornoch Firth area is the principal spawning ground, 

 but there may be a slight variation in the distance off-shore 

 of the most favoured locality from year to year. 



3. Plaice spawn earliest at the inner stations. 



4. Spawning on these inner grounds may begin in favourable years 



as early as the last days of November. 



5. The maximum time of spawning in the Dornoch Firth is about 



the middle of January. After this there is a steady decline 

 in the intensity of spawning. 



6. Plaice begin to spawn later, and the time of maximum spawning 



is also later in an easterly direction. 



7. Newly spawned plaice eggs are the first to appear in the 



plankton of the Dornoch Firth area, and eggs in the later 

 stages of development increase in relative abundance in 

 the later months. 



8. Eggs in the later stages of development are the first to appear 



in the plankton of the off-shore stations. They appear as 

 early as December at Station 29, later at the stations 

 further east. They do not appear before March at Station 

 34. 



