24 lU;i'OliT UN THE PRKSENT STATE UF KNOWLEDGE 



plentiful supply of food in the shape of young fish of other species. 

 The idea, which is so prevalent amongst fishermen on the English coast, 

 that the mackerel taken in the autumn are a different race of fish from 

 those taken in spring, does not seem to be suggested by the American 

 fishermen. 



NovEMBEU AND DECEMBER : Europc. — Mackerel fishing is practically 

 closed in November and December on all the European coasts, though 

 a few fish are still taken in the North Sea in November, and a still 

 smaller number in the English Channel. Mackerel landed at Plymouth 

 are caught 15 to 20 miles south-west of Start Point, and about the 

 same distance from the Eddystone. On the west coast of France the 

 fish may be entirely absent, or a small number may be taken in both 

 November and December. On the south coast of Ireland, in favourable 

 years, fishing on a small scale may be continued up to Christmas. 



America. — In America fishing ceases and the mackerel fleet is laid up 

 in November. The fish are observed to leave the Gulf of St. Lawrence in 

 large shoals, passing out by the same routes as they entered, viz., around 

 the north of Cape Preton Island or through the Straits of Canso,* and 

 they remain absent until the following summer. 



Extent and Causes of the Migration of tbe Mackerel. — Both 

 the extent of the migrations of the mackerel, and the causes which 

 bring about those migrations, are very imperfectly understood. For a 

 long time both have been subjects for speculation amongst naturalists, 

 but little definite or certain information has been arrived at. 



Brown Goode,t who has discussed the general question of the migra- 

 tions of pelagic fishes with some fulness, regards the temperature of 

 the sea-water as one of the most important factors influencing their 

 movements, and this view is shared by most naturalists who have paid 

 attention to the subject. According to Brown Goode the appearance of 

 the mackerel off the coast of America is synchronous with an average 

 weekly temperature of not less than 45° F. in the harbours. At this 

 time the temperature in the open sea is somewhat lower, and mackerel 

 will remain active and contented at a temperature of 40°, or even less. 

 Green:!: has shown that on the south-west coast of Ireland mackerel 

 are first taken in the spring in large numbers off the land when the 

 surface temperature of the sea is 50° F. At the same time he mentions 

 that the smaller boats, shooting their nets close to the shore and in 



• CuLLiN.s, J. W. RrpoH of [/..S. Fish Com., 1881, p. 121. 



+ "History of the Mcnhadeu." U.S. Fish. Com. Report, 1877, especially iij). 50-70. 

 " Materials for a History of the Mackerel Fishery." U.S. Fish. Com. Report, 1881. 

 X "Notes ou the Irish Mackerel Fisheries."- Bull. U.S. Fish. Com., 1893, p. 357. 



