406 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 
tion, others are destroyed by the animals of the water, and considerable 
quantities are doubtless driven upon the shore during stormy weather, ~ 
where they soon perish. 
When first hatched the little mackerel is quite transparent, its length 
scarcely exceeding one-tenth of an inch, while its diameter even with 
the comparatively large yelk-sac is so small as to allow it to pass 
through wire cloth having 32 wires to the inch. For several hours after 
hatching it remains comparatively quiet at the surface in an almost help- 
less condition, a small oil globule attached to the yelk-sac keeping it from 
sinking and causing it to lie belly upper-most. Later the umbilical sac 
with its oil globule is gradually absorbed, and the little fish begins to 
manifest greater activity, and by vigorous and spasmodic efforts pene- 
trates to the depth of an inch or so below the surface. In a few hours 
it finds little or no difficulty in swimming at various depths and even 
lies at the bottom of the vessel in which it is confined, darting off with 
surprising rapidity when disturbed. 
So far nothing is known of the rate of growth. We know of but two 
instances where small mackerel have been caught or even seen along 
our shores. The first is that mentioned by Mr. Scott, in the passage 
already quoted, of half pound fish having been taken off the Long Island 
coast in June. A second instance was made known to us by Mr. Robert 
Bosman, superintendent of a fishing station at New Point, Va., who, in 
a letter dated Norfolk, Va., September 25, 1880, says: ‘I have recently 
noticed large numbers of young Spanish mackerel, varying from four to 
six inches in length.” Assuming that the fish referred to were the young 
of the Spanish mackerel, there still remains a difficulty in determining 
the rate of growth. Some species grow very rapidly, reaching the last- 
named dimensions ina few months, while others develop more slowly and 
would not attain a weight of half a pound for several years. From our 
limited knowledge of the growth of other species we would suppose that 
the fish mentioned by Mr. Bosman as being 4 to 6 inches long in Sep- 
tember were the fry of the previous year, and were therefore about four- | 
teen months old, while the half-pounders mentioned by Mr. Scott were 
probably nearly two years old. 
B.—ORIGIN AND DEVELOPMENT OF THE FISHERY. 
8.—THE FISHING GROUNDS. 
Spanish mackerel may be taken with trolling hooks along almost any 
portion of the coast between Key West and Long Island; but as this 
method of fishing is practically restricied to a few localities the troll-line 
catch is quite unimportant. Enough are caught, however, to show that 
the species occurs, and to indicate that the fishing grounds may be con- 
siderably extended in the future. 
Professor Goode states, upon the authority of Thaddeus Norris, that 
in the Gulf of Mexico they are sometimes taken by means of hook and 
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