SEA-FISHERIES LABORATORY. 409 



ON THE PELAGIC FISH EGGS COLLECTED OFF 

 THE SOUTH-WEST OF THE ISLE OF MAN. 



By Andrew Scott, A.L.S. 



The following is a summary of the results of the 

 investigation of the pelagic fish eggs that were found in 

 the plankton from the area off the south-west of the 

 Isle of Man between the beginning of 1907 and the end 

 of 1912. There can be little doubt that many of the 

 eggs collected had been spawned more or less continuously 

 in the area between the limits recorded for each year. 

 Their apparent spasmodic occurrence is probably due to 

 a large extent to the drift of the water after the eggs 

 had come to the surface. Sometimes they may be carried 

 well inshore, even inside the breakwater where the 

 bi-weekly collections are made throughout the year. At 

 other times the eggs may be drifted out of the area 

 altogether, and very few will be found in the plankton. 

 It is also fairly certain that the eggs of some species of 

 fish, which may not occur in the local fauna, will drift 

 into the area from outside sources. It will be seen from 

 the records that many of the fish may have a longer 

 spawning period than was formerly suspected. This is 

 fairly well shown in the case of the rockling and the 

 dragonet. We have found dragonet eggs as early as 

 January 23rd and as late as the beginning of August 

 in hauls from places wide apart in the Irish Sea. This 

 represents a general spawning period of about seven 

 months for the dragonet, instead of from four to six 

 months. Very few of the pelagic eggs have any marked 

 character, apart from their size or the presence of an 

 oil globule, by which they may be easily identified. The 

 variation in the size of the eggs spawned by a single 



