OF THE HABITS AND MIGRATIONS OF THE MACKEREL. 3 



Breeding. — The spawning of the mackerel was first investigated 

 by Sars,*' in 1865, on the coast of Norway. This naturalist found 

 that the fisli spawned near the coast, sometimes nearer than at others, 

 and that the eggs floated at the surface of the sea like those of the 

 cod, from which they could be distinguished by the presence of an 

 oil globule. The same facts were ascertained in 1871 by Mr. Matthias 

 Dunn, who obtained the spawning fish on the south coast of Cornwall, 

 about six miles from land, on the night of May lOth.f 



The subject has since been investigated by other naturalists, more 

 especially by Cunningham, t at Plymouth, who has figured and described 

 the eggs and various stages of the larval fish. 



The breeding season varies in different localities, occurring con- 

 siderably later in the year in the north than in the south. 



In the Mediterranean (Gulf of Marseilles) Marion § found mackerel 

 with ripe reproductive organs chiefly in March and April, and considers 

 these two months to be the principal spawning period. No ripe fish 

 were ever found after May 19th. From the size of larv?e taken in May, 

 the same author comes to the conclusion that some fish must spawn as 

 early as January. 



At Plymouth the spawning fish are found from 14 to 50 miles from 

 the coast. Spawning takes place from the end of May to the latter 

 part of July, and, according to Cunningham, appears to be distinctly 

 limited within those times. || 



On the south-west coast of Ireland, Green If states that spawning 

 takes place in May and June. Holt** obtained ripe eggs off this 

 coast in the tow-net on April 30th and May 4th. Mackerel examined 

 on April 1st were half and three-parts ripe. On May 12th, out of 

 50 fish all the males were ripe. The females were mostly half and 

 three-quarters ripe, but a few were ripe. Ripe fish were also seen 

 as late as June 20th, the specimen examined at the latter date 

 being called by Holt " a small autumn mackerel." The same author 

 states that it appears that successive shoals approach the coast at 

 different points and spawn in the neighbourhood, the larger fish being 

 the first to arrive. 



* Report for 1875. English translation. Report of U.S. Fish. Com., 1877. 



t Land and Water, May 20, 1871, p. 353. 



X Journ. Alar. Biol. Assoc., N.S., vol. i. p. 25. 



§ Ann. Mus. Nat. Hist. Marseille Zool. A2:)pliqu6e, i., 1889. 



II Natural History of Marketable Marine Fishes, London : Macmillan & Co., Ltd., 

 1896. 



H "Notes on the Irish Mackerel Fisheries." Bull. U.S. Fish. Com., 1893. 



** (1) "Survey of Fishing Grounds on the West Coast." Royal Dublin Society. Report 

 of Council for 1801. 



(2) Scientific Transactions Roy. Dublin Soc, 1893. Fishes. 



A 2 



