Artificial Propagation Of Marine Species
THE COD – DESCRIPTION OF THE FISH
The body of the cod is moderately long, compressed and tapering behind; the greatest depth is about one-fourth its length. The large head is narrowed anteriorly and is contained 3i to 4^ times iu the body length.
The mouth is large; the lower jaw is included within the upper when the mouth is closed; the maxillary extends to about middle of eye. The diameter of the eye is about half the length of the snout and one-fifth that of the head. There is a conspicuous barbel on the chin. The number of dorsal fins is 3 and of anal fins 2; the dorsal rays are usually about 14, 21, and 19 in the respective fins, and the anal rays are 20 and 18. ‘
The ventral fins are well developed, with about 7 rays. The cycloid scales, with which the body is covered, are very small. The air-bladder is large and thick. The color varies greatly, depending on food, kind of bottom on which found, and other
conditions.
Fish taken offshore in deep) water are usually olivaceous on the back and whitish beneath; the so-called rock cod, found in shoaled water among rocks and kelp, vary in color from green to deep red. The back and sides are covered with small, round, reddish-brown spots. The lateral line is conspicuous, of a whitish color. The fins are dark.
From other species of the family, taken in the same waters, the cod is readily distinguished. From the haddock it differs in having a pale, instead of a black, lateral line; in its spots (absent in the haddock), and in its larger maxillary bone, which reaches past the eye, while in the haddock this bone does not extend to the eye.
The features distinguishing the pollock from the cod are the smaller size, the projecting lower jaw, the uniform coloration above, the sharp snout, the smaller barbel, etc. The hakes have only 1 anal and 2 dorsal fins, a filamentous prolongation of the first dorsal ray, and a ventral fin consisting of two or three very long filamentous rays.
The status of the cod of the North Pacific Ocean is somewhat uncertain. It has generally been considered identical with the Atlantic species, but its smaller air- bladder and other features may entitle it to recognition as a distinct species.
Cod are widely distributed in the North Atlantic Ocean. To the north they range far beyond the Arctic Circle, and to the south as far as Cape Hatteras, although they are not common south of New Jersey.
The cod of the IS North Pacific Ocean is found from Bering Sea south to Oregon and Japan.
The movements of cod are not well understood. They go in schools, but in much less dense bodies than do mackerel, herring, and menhaden, and when moving from one ground to another they are in more compact schools than when out the feeding-grounds.
The movements on and offshore and from bank to bank are due to several causes, among which are the effects of water temperature, the presence or absence of food, and the spawning instinct. In the winter months there is a well-marked movement of large bodies of codfish to the shores of the New England and Middle States, and important fisheries are there carried ou in regions from which cod are absent at other times.
This movement seems to be chiefly for the purpose of finding shallow grounds for spawning. That the cod sometimes makes very long journeys is shown by their capture on the New England coast with peculiar hooks in their bodies which have been identified as similar to the hooks employed by the French cod fishermen on the Grand Banks.
Although sometimes found in shallow water, cod are essentially deep water fish, preferring water from 20 to 70 fathoms deep and being found even at a depth of 300 fathoms. Those caught for market are usually taken at depths of 20 to 40 fathoms.
The cod takes its food on the bottom, at the surface, or at intermediate points. It is an omnivorous and extremely voracious feeder, consuming all marine animals of suitable size. Favorite articles are bivalve mollusks, crabs, lobsters, starfish, and fish. Among the fish consumed in large quantities are capelin, lant, herring, alewives, menhaden, mackerel, and haddock, although many others are also eaten. The abundance and movements of such fish have an important relation to the presence and abundance of cod in a given region.
WEIGHT AND GROWTH OF COD
The largest cod recorded from New England waters weighed 211 pounds and was over 6 feet long; it was taken on a trawl off the northern Massachusetts coast in May, 1895. The capture of a number weighing from 100 to 175 pounds could be cited, but those exceeding 100 pounds in weight are by no means common, and even 75-pound cod are not numerous.
The average weight of the larger-size cod caught in the shore waters of New England is about 35 pounds; on Georges Bank, 25 pounds; on the Grand Banks and other eastern grounds, 20 pounds; the average weight of the small-size fish caught on all these grounds is about 12 pounds.
Observations in Massachusetts of the rate of growth of the cod show that those 1^to 3 inches long are about 6 months old ; those 9 to 13 inches long, and weighing 7 or 8 ounces, are li years old ; those 18 inches long, and weighing 2 to 2^ pounds, are 21 years old; and those about 22 inches long, and having a weight of 4 to 5 pounds, are 3^ years old.
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