of the Fishery Board for Scotland. 



299 



50mm. They are not found in the spring or summer, but recur in the 

 autumn, with a length of about 80mm., which is increased to 100mm. 

 by the end of the year. When one year old Masterman thinks they are 

 probably about 60mm. (2| inches) long. 



In the case of the autumn herrings, the occurrence of newly-hatched 

 larvae extends over August and September, the spawning period being 

 thus of shorter duration. The larvae are somewhat shorter than the 

 spring ones, averaging between 5mm. and 6mm. 



The following Table gives Masterman's estimate of the growth from 

 month to month of the spring and autumn herrings, after hatching : — 



Month. 



Spring. 



Autumn . 



Month . 



Spring. 



Autumn. 





Mm. 



Mm. 





Mm. 



Mm. 



1 



15 



14 



8 



47 



43 



2 



20 



19 



9 



50 



47-5 



3 



27 



23 



10 



54 



52 



4 



30 



27 



11 



58 



57 



5 



35 



30 



12 



62 



61 



6 



40 



34 



18 



87 



88 



7 



44 



38 



20 



98 











24 





113 



Thus, according to Masterman, the autumn herring at two years of 

 age is rather smaller than the one-year old spring herring of the Baltic, as 

 Meyer has determined it. The rate of growth of the spring series is 

 about 4mm. to 5mm. per month, while in the winter months the growth 

 of the autumn herring in the early stages is retarded (3mm. to 4mm. per 

 month). The largest specimen in the collection measured 134mm. (5| 

 inches), which would be about 27 \ months old and belong to the autumn 

 brood. In his later work in conjunction with M'Intosh (17a, p. 422) 

 rather a different opinion is expressed. It is there supposed that the 

 herring attains sexual maturity at a length of 8-9 inches and probably 

 during the third year ; and it is stated that 3 inches and 5 inches may 

 be taken to represent a rough average of the size of a herring when one 

 year and two years of age respectively. 



The growth of the herring on the Scottish coast has also been considered 

 by Cunningham (18, p. 162). He is of opinion that the herrings 3|-5| inches 

 long (82mm. to 133mm.) taken in considerable numbers in December, in the 

 sprat fishery in the Firth of Forth, are derived from the spring herrings 

 that spawn at the Isle of May, which would give them an age of about 

 nine months. 



At Plymouth, a large number of small herrings from 4*3 to 5*5 inches 

 long, taken in May, are supposed by Cunningham to be year-old fish, 

 derived from the spawning in February and March in the previous year. 



From the above review, it is apparent that very different opinions 

 are held as to .the rate of growth of the herring and the size and age 

 when it reaches the mature condition. 



2. — The Size op the Herring when it first attains Maturity. 



The observations made by myself as to the size when maturity is 

 attained lead to the conclusion that the herring on the coast of Scotland 

 does not spawn until it has reached a larger average size than most of 

 those given above. 



