II.-GEOGRAPHICAL DISTRIBUTION OF THE GADIDE OR THE COD FAMILY, IN ITS RELATION TO FISHERIES AND COMMERCE.

By KARL DAMBECK.*

A.-CHARACTERISTICS OF THE GADIDÆ.

Next to the herring, the cod is perhaps the best known and most important family of fishes, on account of its extended and very productive fisheries and commerce. The study of its characteristics and general distribution, however, is not only interesting to the fisher and business man, but also to the naturalist, on account of their bearing upon the relations existing between currents, temperature, saltness, and depth of the ocean; the modes of distribution of animal and vegetable life, and many other unsolved problems. According to the careful and reliable investigations of Dr. Albert Günther, of the British Museum, the family comprises 22 genera, 60 species, and numerous varieties. Of these, 9 genera, with 41 species and several varieties, are especially important, viz: Gadus, with 19 species; Merlucius, with 3; Phycis, with 5; Molra, with 3; Motella, with 5; Brosmius, with 2; Couchia, with 3, and Raniceps and Lota, with 1 species each, while the other 13 genera, with their 19 species, are simply connecting and transitional forms in this large series of widely distributed fish, and are far less numerous in individuals as well as in species. The fertility appears to decrease in the individual in proportion to this multiplicity of genera and species. We may, for instance, find with the ling and the cod three to nine

Gaea, 1877, III, pp. 158, 224, 345, 422.-Revised by Tarleton H. Bean.-Dambeck's paper is compiled from various sources, some of them antiquated, and, consequently, containing no reference to recent discoveries. Many statements offered as facts are untrue, and others doubtful. Some generalizations are made from insufficient data, some are entirely founded on error. After making due allowance for misstatements and conclusions of uncertain value, there still remains much that is interesting. The nomenclature which he accepts differs from that adopted by many American authors, hence a brief synonomy is given:

Lota vulgaris (maculosa) = Lota maculosa, (Le S.) Rich.

millions of fully-developed eggs, while Lotella and Halargyreus have only a few thousand.

The cod family has a remarkable tendency to variation, as is most strikingly apparent in the difficulty of defining genera and species; the species show many varieties (Gadus morrhua, near Great Britain, bas two, a light-colored one in the north and a dark one in the south), the genera, numerous species, &c., throughout the whole family. The caudal or tail fin is never placed at the end of the terminal vertebra, but has its lower portion slightly in front of it, and even unites sometimes with the anal fin; the scales are frequently ctenoidal, and thus also similar to those of the fishes of former ages. Sometimes the eyes are very large, which is usually considered as peculiar to the more recent forms of fishes, as the number of barbels also is most probably an indi cation of the stage of development, increasing or diminishing with the antiquity of the fish. The head is often comparatively small, as with Brosmius vulgaris; often large, as with Gadus macrocephalus, and some times the lower jaw is elongated and hook-shaped-a mark of antiquity, according to the analogy of the salmon. I therefore conclude that the family is still in the process of development, namely, from fresh-water into salt-water fish. I do not assert, however, that the saltness of the ocean is greater at present than in former ages, but I wish to state the fact that the codfish, Gadida, also at previous periods lived in regions of the sea where the water was but slightly salt; for in the present time, too, they live more particularly in fresh and brackish water, or in sea-water of not more than 2 to 3 per cent. of salt.†

The Lota vulgaris is a true fresh-water fish in the lakes and rivers of Central, Northern, and Eastern Europe, Northern Asia, and northern North America, and yet, according to Pallas, it also occurs in the Arctic Ocean, on the coast of Siberia, as far as Indigirka, and according to Rathke in the Black Sea, and according to Yarrell in the Frith of Forth. Others live in the open ocean, but their old habit drives them into the rivers again. Thus the cod migrates up the Tweed. The Gadus macrocephalus, according to Pallas, frequents the ocean around Kamtschatka and America, but ascends the rivers in May and returns to the ocean in August and September, after remaining about four months in fresh

water.

They all live in regions of the sea where the water contains but little salt, especially at the mouths of rivers, fresh-water basins, ports, &c. They require a temperature of the water of from 39° to 44°; the Lota vulgaris can endure a somewhat lower temperature, and the southern forms, Physiculus and Uraleptus, will bear a somewhat higher; thus the family belongs to the temperate zone, and its occurrence indicates unmistakably a medium temperature, even where such might not be

* The gadoids, as now limited, all have cycloid scales.-T. H. B.

+ Microgadus tomcodus has been transferred suddenly from salt water to a fresh-water aquarium and kept alive for months.-T. H. B.

expected, whether it be in the arctic or tropical regions.* At spawning time, when the northern forms develop greater vital activity and possess a higher temperature of the blood, they seek for water of from 350 to 370, as it may be found in February and March upon the southern coast of Spitzbergen, at the Loffoden Islands, in the fiords of Finmark, and at the Faroes, in May and June on the Banks of Newfoundland, Gulf of St. Lawrence, and Labrador; the southern forms, however, are smaller and less lively, and live in uniform temperature; they, therefore, only migrate at spawning time to the near coast, but usually from water of considerable depth. The former migrate in a horizontal direction; the latter in a vertical one. The Gadida, then, are fresh-water and migratory fish. They are voracious, and subsist upon marine vegetation as well as upon animals; they are omnivorous, and consequently readily adapt themselves to their surroundings.

Professor Mobius found in the stomach of Gadus morrhua, L., large pieces of Ulva lactaca and Zostera marina, two marine plants, besides shells, snails, crabs, and fishes. The above-mentioned variations in color generally indicate differences in depths at which they live, and comprise white, yellowish, brown, speckled, green, and black. Every species, it is true, lives at different depths at different seasons, but all are capable of living at considerable depth, even the fresh-water species, some of which inhabit fresh water at considerable elevations, especially in Europe. This fact seems also to prove their fresh-water origin, as does the size of their gill openings, which enables them to absorb the requisite amount of oxygen from the deep fresh water, always less rich in that element than salt or surface water. Therefore, in seeking after fresh water and deep water they are perfectly in accordance with their habits. The following tables will show the depths and elevations at which the Gadida live, as well as the temperature of the water, and the proportions of salt contained in it:

Gadus morrhua has been taken by the United States Fish Commission in from 34° to 46° F. Lota maculosa endures a much higher temperature in the Connecticut River, the Ohio, and the Missouri.-B.

+ Variations in color coincide with changes in the colors of surrounding objects upon the feeding-grounds.-B.

B.-GENERAL DISTRIBUTION.

As to their general distribution, they occupy a portion of the frigid zone, but preferably the temperate zone of the northern hemisphere, especially the Arctic, Northern Atlantic, and Northern Pacific Oceans, as well as the fresh waters of northern North America, Europe, and Asia. They occur, however, sporadically in the torrid zone, and southern hemisphere. Individuals are most numerous on the coasts of Newfoundland, Nova Scotia, and Labrador, and in the neighborhood of the Loffoden Islands, Norway, Finmark, Iceland, the Faroe, and British Islands, that is, on the coasts of both continents, and on the line where the Arctic and North Atlantic Oceans meet. This region may therefore be named the domain of the Gadida, and to it belong particularly the 9 genera of the above tables, with 41 species; the other 13 genera, with 19 species, belong to the southern temperate and torrid zone, and to the Pacific and Indian Oceans, viz, the extreme limits of the domain. Whether these latter are the remnant of a southern Gadida fauna, or are simply straying members from the northern one is difficult to decide, but most probably the latter is the case. The northernmost limit is in general 77° north latitude, and the southernmost, in the Atlantic, 300 north latitude. The middle region, therefore, between 450 and 620 north latitude, stretches from Newfoundland to Great Britain and Scandinavia. In the Pacific Ocean the boundary runs from Northern China, at Chusan, northward along the west coast of Japan and the Kurile Islands to the southern extremity of Kamtschatka, and across to the Aleutian Islands by Kodiak, Sitka, and the islands of the west coast of North America to San Francisco. In the tropics these fish are found on the east coast of the Phillippines, and at the mouth of the Ganges in one genus and species, Bregmaceros Macclellandi. Only one genus and species is found in the Atlantic of the southern hemisphere, namely, the Phycis brasiliensis at Montevideo, likewise but one genus and species in the Pacific on the coast of Chili, Merlucius Gayi, and 2 genera with 3 species at New Zealand, Lotella and Pseudophycis. This is not surprising, since the coasts of Chili and New Zealand are under the influence of the cold antarctic currents, and Montevideo of the cold Cape Horn current, so that the antarctic drift ice even reaches at times up to that latitude. The fresh, cool water of the Hoang Пo, Yangtsekiang, Brahmapootra, and La Plata is favorable to the existence of Gadida.

. Statistics show that the fisheries of the cod, which seem to be the most developed of the family Gadida, are most productive at Newfoundland and the Loffoden Islands, points 870 geographical miles apart. About midway lie Iceland and the Faroe Islands, which seem to form an inclosed region bounded on the north by Spitzbergen, Bear Islands, and Loffoden Islands. The center of this wide, oval, oceanic trough is most probably the northern home of the Gadida. Between Cape Charles, Cape Farewell, Southwestern Iceland, and the Gulf