OCCURRING IN THE NEIGHBOURHOOD OP PLYMOUTH. 35 



erroueous notions tliat have been held concerning the habits of the 

 mackerel. Some have supposed that there is an enormous annual 

 migration for spawning purposes from the sea round the North 

 Pole ; others, especially the fishermen, that the fish in winter 

 remained at the bottom in a torpid condition, and, what is still 

 more strange, blind. Prof. Sars believes, as is now generally held 

 for all pelagic fish, that they approach the coast chiefly in order to 

 spawn, and at other times are scattered at greater distances from 

 the shore, or in the ocean, but always in an active pelagic condition. 

 He thinks it probable that not all the mackerel taken on the coasts 

 of the North Sea pass their whole life in that area, but that many 

 enter it from the north or through the Channel. It is certain that 

 in the neighbourhood of Plymouth mackerel are often caught in 

 greater or less numbers all the year round, though there is generally 

 little fishing immediately after the spawning time, i. e. at the end of 

 July and the beginning of August. 



It is stated in the paper already referred to, " Materials for a 

 History of the Mackerel Fishery," that the spawning season on the 

 Coast of New England coincides with that observed on the British 

 Coasts, occurring in May and June in Massachusetts Bay, and in 

 June in the Gulf of St. Lawrence. As we have seen. Professor 

 Sars states that the spawning of the mackerel does not begin on 

 the west coast of Norway until the beginning of July, and that it is 

 finished about the middle of that month. He may not have been 

 able to make sufficient observations, as at Plymouth the spawning 

 period lasts more than one month. 



It may well be that the season is a little later off Norway, for I 

 find that the surface temperature on July 22nd in the Foldenfjord, 

 64° 34' N. latitude., in 18S0 was 11 "4° C, which is slightly less than 

 the temperature off the Eddystone on June 12th, 1888. Thus the 

 spawning season of the mackerel is doubtless inseparably connected 

 with a certain range of temperature, though the connection may be 

 an indirect one, through the relation of the temperature of the sea 

 to the mackerel's food. 



In the family Scombridfe, besides the mackerel are included the 

 various genera of tunnies, which are mostly of very large size, and 

 the tropical sucking-fish, Echeneis remora. Of these, so far as I 

 know, the ova and development have not been investigated, but in all 

 probability their ova are buoyant and pelagic. On the Atlantic 

 coast of North America another species of the family besides the 

 common mackerel occurs, and is the object of a regular and valu- 

 able fishery in Chesapeake Bay, at Sandy Hook, Southern Long 

 Island, and Narragansett Bay. This species is the Gybuim maculatum 

 (Mitchel), Agass. It is chiefly captured in fixed gill-nets, not in 



