of the Fishery Board for Scotland. 337 







II. 



III. 



Year 



of 

 Age. 



Year. 



Range. 



Mean. 



Mean. 



Range. 



Observed 



Computed. 



Min. 



Max. 



Mean. 



1 









605 



45-76 



62 









2 



(1) 



113-121 



117 



113 



94-139 



112 



110 



122 



116 



3 



(2) 



156-164 



160 



159 



142-186 





158 



170 



164 



4 



(3) 



190-198 



194 



200 



177-228 





206 



218 



212 



5 



(4) 



217-225 



229 



238 



218-265 





254 



266 



260 



6 



(5) 



237-245 



241 



257 



240-257 





302 



314 



308 



Column I. shows Jenkins' results, Column II. shows my own results, 

 and Column III. shows the results obtained by Masterman, and the 

 size at the later stages, computed at the mean rate of increase of 4mm. 

 to 5mm. It will be observed that my results and those of Jenkins 

 agree remarkably well, when a year is added to the age he assigns to 

 his various series. 



In the later work of Masterman and M'Intosh (17a) it is suggested 

 that 3 inches (76mm.) and 5 inches (127mm.) represent a rough 

 average of the size of the herring when one year and two years of age 

 respectively ; and that sexual maturity is attained when it is between 

 8 and 9 inches (203-228mm.) in length and probably three years of age. 

 This, however, involves a more rapid growth than the facts warrant, and 

 is not consistent with the results of Masterman's own earlier paper. 



The earlier authors referred to at the beginning of this paper as a 

 rule under-estimated the rate of growth of the herring. The most 

 correct are those of Malm, Sars and Nilsson. It is interesting to 

 observe that the estimate of the fishermen of Bohuslan, Sweden, as 

 given by Nilsson, is accurate ; and that the estimates of the Scottish 

 fishermen (three or seven years) was much nearer the truth than those 

 of the naturalists. 



The elucidation of this question of the growth of the herring has an 

 important bearing on several fishery problems. Compared with most 

 fishes caught by lines or trawls, it is clear that the herring, caught by 

 drift-nets, has a great advantage, inasmuch as no immature herrings 

 are caught in this way, no less than four generations of undersized or 

 immature herrings escaping through the meshes. 



It may also help to explain such problems as the presence every 

 summer for a period of years of large herrings in the deep water of 

 Upper Lochfyne, and their absence for a period of years. It is quite 

 possible that these herrings belong to one and the same shoal, which has 

 accustomed itself to the route of migration and the locality, and which 

 is ultimately fished out or destroyed. It may also serve to explain the 

 presence in the loch of small herrings in autumn and winter without 

 supposing that they were spawned there. Such little herrings are one 

 year old and more, and could therefore easily make their way into the 

 loch from the spawning grounds in the outer part of the Clyde. 



