of the Fishery Board for Scotland. 



219 



VI. — A REVIEW OF THE WORK OF THE 1 GARLAND ' TN 

 CONNECTION WITH THE PELAGIC EGGS OF THE 

 FOOD FISHES, 1890-1896. By Arthur T. Masterman, B.A. 

 (Cant.), B.Sc. (Lond.), Lecturer and Assistant-Professor of Natural 

 History in the University of St Andrews. 



The method which has been pursued by the ' Garland ' has been uniform 

 since the outset. The various districts have been visited and divided up 

 into stations. Samples of eggs have been taken by the tow-nets from 

 each of these at different times, and they have been preserved and 

 examined later. The aim of the work has been to increase our knowledge 

 concerning the pelagic eggs. This falls under three heads, namely : — 



1. The Determination of the Spawning A reas of each Species of Fish. 



2. The Determination of the Spawning Season of each Species. 



3. The Determination of the Direction taken by, and subsequent Fate of 



the Eggs after Spawning. 



For the two former, the undeveloped eggs alone come into the question, 

 and all the eggs which have been found and labelled in the lists, without 

 adding the stage of development at which they were caught, bring into 

 the question elements of great difficulty. The only absolutely accurate 

 method would be the immediate examination, when caught, of the eggs, 

 and only those recorded which have evidence of being freshly-spawned 

 It is evident that if the accurate determination of the three points above- 

 noted were deemed absolutely essential, the eggs should be examined and 

 identified immediately after capture, upon the spot. 



1. The Determination of the Spawning Areas of each Species of Fish. 

 — For the determination of this point the study of the pelagic eggs alone 

 can be of little use, for an egg which is still at an early stage of develop- 

 ment may yet have been carried a great distance from the spot at which 

 it was spawned. Up to a certain point, however, we may employ the 

 data for this purpose. It may, I think, be assumed that after an egg is 

 laid its normal course is inshore, so that when the eggs of a species are 

 reported to occur at a certain district we may suppose that they were 

 either spawned at that spot or further seaward. The effect of the drift 

 may be assumed to be the same on all the eggs, so that, if, for example, we 

 proceed down the Firth of Forth seaward beyond the Isle of May, and 

 first pass through areas in which occur eggs of sprat, whiting, cod, and 

 plaice, with a maximum number of sprats' eggs, and that as we proceed 

 seawards the sprats' eggs diminish, and the eggs of the whiting attain a 

 maximum in numbers, followed respectively at further distances by those 

 of the cod and plaice, the legitimate conclusion is that the maxima occur 

 in the same order seawards as are the respective spawning-areas. This 

 becomes practically a certainty, if the maximum numbers are at an earlier 

 stage of development. The results thus attained may be checked by those 

 obtained by the capture of spawning adults. In areas where eggs 

 at an early stage occur in profusion, and the spawning adults are also 

 caught, we can pronounce with certainty as to their being the normal 

 spawning-grounds of the species under consideration. In those, on the 

 other hand, such as the inner waters of St Andrews Bay, with regard to 

 plaice, where eggs occur but the spawning adults are not caught, the 

 balance of evidence must be in favour of the assumption that the eggs 

 have drifted inshore from other parts. 



