FISH CULTURE

or Pisciculture. Propagation of the principal food fishes is conducted on a steadily expanding scale in the United States and the results Jong ago demonstrated the immense national profit derived. Many important fishes would in all probability be extinct to-day if the hatcheries had not supplied billions of young fish to help take the place of those harvested from the waters for human consumption. Such a istance is especially nece ary in the case of fresh-water fishes and such salt-water fishes as the salmon and shad, which leave the ocean to deposit their spawn in river beds and thus make total extermination po ible. The greater part of the work is now performed under the jurisdiction of the United States Bureau of Fisheries, supplemented by that of the state Fisheries Commi ions and various sportsmen’s a ociations and clubs, The United States Bureau maintains a number of hatcheries along the coast, in the chief shad and rivers, and at various points along the Great Lakes. Their product is variously utilized—part of it is distributed in the natural spawning grounds of the immediate vicinity; great quantities are shipped, principally as the very small ‘‘fry’’ and the larger (but still small) ‘‘fingerlings,’’ to all parts of the country for the stocking and replenishing of ponds, rivers, and lakes; and a small percentage are brought to maturity for breeding purposes. The commercial fisheries constitute the principal source of the fish eggs handled by the Bureau, vast numbers of eggs that would otherwise be sent to market in the fish and become an almost total lo , being obtained for incubation by experienced spawn takers. In the case of some important fishes—notably, but not exclusively, the salmons of the Pacifie Coast—where commercial fishing does not extend to or is not permitted in the spawning areas, the ripe fish are specially caught in: seines or traps—the object being the higher percentage of fertilization obtained artificially, and the greater measure of protection afforded the eggs (and their resulting young) from their many enemies and from the almost innumerable other po ible fatalities during and immediately after the. | hatching period. The eggs are first fertilized by the addition of milt from the male fish 4) and are then placed in the hatchery.,; - | + | With some varieties, the hatching - ty apparatus consists of wire-cloth bas- P, a kets held in troughs of varying size. Others, as for whitefish, shad, and j yaa! ia oval 46 | lobsters, generally consist of gla { ‘ jars, the fry as hatched being discharged into gla tanks.; e That portion of the fry which is not distributed as noted above, is held in troughs or artificial ponds until six or seven months old. A seven-months’, trough-raised, fingerling salmon avera ages from 214 to three inches in a Fifty-six species of food-fishes are ~— «| represented in the distribution figures for 1921. Fully 93% of the output consisted of the important commercial fishes, including anadromous species (i.e, those ascending rivers to spawn) of the Atlantic and Pacific seamr \gee. boards—the salmons, shad, alewife, a and striped ba ; marine species—the ~~ 7 cod, haddock, pollack, and flounders; J \: fishes of the Great Lakes—whitefish,: Jake herring, trout, pike-perch, and —— - — = Toman, yellow perch; and the buffalo-fish and Whitefish eggs in hatching jars carp of certain inland streams. Though the number of fish produced for stocking other interior waters is small by; comparison (it represents only 7% of the total) the work is of value and large popular interest. The more important of this cla are the trouts, black ba es, sunfishes, crappie, and catfishes. These are furnished free to interested persons for either public or private waters. The total output of the hatcheries during 1921 was close to five billions of fishes and fish eggs —in eluding more than two hundred you sand fingerling fish from 114 to X 3 a - — # Ma In its overland distribution the Bureau operates several specially constructed railroad cars, equipped with air-pumps and other nece ary appliances for the transportation of living fish, in addition to supplementary service by special agents traveling in ordinary baggage cars.