OF THE HABITS AND MIGRATIONS OF THE MACKEREL. 5 



as early as January, As already stated, however, spawning fish were 

 never obtained by them until Marcli and April. The small fish, 

 2-10 cm. (f to 4 inches) long in April and May, are considered to 

 have reached 10-13 cm. {4 to 5 inches) by August, and 15 to 18 cm. 

 (6 to 7 inches) by the end of the year. In the following February 

 fish from 20 to 24 cm. (8 to 9h inches) are taken, the age of which 

 Marion considers to be twelve months ; and since these fish have their 

 reproductive organs well developed, he is compelled to ask, not without 

 some hesitation. Does the mackerel spawn when only one year old ? 



The question of the rate of growth of mackerel in the English 

 Channel is discussed by Cunningham,* and he also gives detailed 

 measurements of a large number of these fish caught in fine-meshed 

 nets in November, which varied in length from 15 to 20 cm. (G to 

 8 inches). The length of the larva at the time of hatching he states 

 to be 4"23 mm.f He also describes some young mackerel obtained by 

 Holt I in the North Sea. Twelve specimens taken on July 9th measured 

 from 6 to 9 mm. (-24 to '36 inch) ; three taken on the 27th and 28th 

 July were from 13-5 to 19'25 mm. ('54 to '77 inch). The largest of the 

 specimens already showed the adult characters, and Cunningham regards 

 them as being from one to two months old. 



Day§ states, on the authority of Matthias Dunn, that at Mevagissey 

 young mackerel are plentiful in the bays in August and September, 

 when they are about 3 inches (7 to 8 cm.) long, reaching 6-7 inches 

 (16 to 18 cm.) in November. They then leave for the deep sea, and 

 return again in the following June, when they are 8 or 9 inches (21 to 

 23 cm.) long. 



The best account of the growth of the mackerel in America is given 

 on the authority of Capt. Atwood,|| it being stated that the specimens 

 were seen by Prof. Agassiz. According to this account the mackerel 

 spawn in Massachusetts Bay in May and the first half of June. On 

 July 10th schools of mackerel 2 inches (5 cm.) long were present in the 

 bay, which had grown to about twice the weight (say 7-8 cm. long) on 

 August 4th. During the latter part of October young fish from 6h to 

 7 inches (say 16 to 18 cm.) were taken. 



In the following table these various statements are placed side by 

 side, all the evidence at present available being included : — 



* Journ. Mar. Biol. Assoc, N.S., vol. ii. pp. 230 to 233. 



t Journ. Mar. Biol. Assoc, N.S., vol. ii. p. 71. 



J Holt himself also mentions these fish. Jouni. Mar. Biol. Assoc, vol. ii. p. 396. 



§ British Fishes, vol. i. p. 89. 



II Eeport U.S. Fish. Com., 1881, p. 114. 



