34 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



not strange that these fishes should be so aUke, even in many of the 

 details of their existence. 



All the fishes of the Mackerel family are, to a high degree, of 

 active and pelagic habits. This mode of life is made necessary by 

 the kind of food on which they subsist and it furnishes the most favor- 

 able conditions for their method of reproduction. The Common 

 Mackerel feeds partly upon minute surface creatures, chiefly crust- 

 aceans and larval invertebrates, and partly upon small fishes; all 

 the other species of ^lackerel- feed on other fishes, such as the herring, 

 menhaden, sand launce, etc. It is supposed that they hunt by sight, 

 since they snap at all kinds of moving objects in the water, especially 

 if they are shiny like small surface fishes. Most of them are rivals 

 of the bluefish in voracity and exceedingly fierce in their pursuit of 

 prey. The mackerels are thus for the most part surface feeders 

 and, consequently, differ widely inhabit, general activity, and manner 

 of life from those fishes, like many of the Cod family, for instance, 

 which prey largely upon the sluggish and sessile invertebrates of the 

 ocean bottom. The fishes of the Mackerel family, therefore, find 

 their most natural abode in the surface waters of the open ocean, 

 w^here there is an abimdance of all kinds of free-swimming organisms. 

 These waters, also, especially their more shoreward areas, furnish 

 conditions most favorable for reproduction. The breeding process 

 in all the mackerels is probably similar to that of such fishes as the 

 herring and cod; spawn and milt are simultaneously shed out free 

 into the water and fertilization of the eggs must, to some extent at 

 least, be a matter of*chance. The eggs are buoyant and must be 

 widely dispersed by the waves and tides. The conditions conducive 

 to the securing of the most favorable results from this method of 

 reproduction are furnished by the surface waters of the open ocean. 

 The active and pelagic habits, which are possessed in common by 

 all fishes of this famih', are thus an adaptation to the character of 

 their food and to their method of reproduction. 



Characteristic, also, of the fishes of the Mackerel family are their 

 gregarious and migratory habits. Some of the species of this group 



