摘要:

The Fish and Wildlife Service has formed an organization to engage in commercial fishery education. This section will prepare and collect instructional motion-picture films, film strips, manuals, leaflets, displays, and other visual material; arrange demonstrations; offer consulting services; sponsor training courses in colleges; and arrange cooperative training programs with fishery organizations. Training will include tested and approved methods for fishing, handling of products, distribution, fish cookery, and sanitation.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[118:FCTE]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

The production of lake trout, Cristivomer namaycush (Walbaum), in the United States waters of Lake Huron was highest in the earliest years for which there are statistical records, averaging 2,362,000 pounds in 1879–1894. The general level of yield was much lower but relatively stable in 1895–1939, during which period the catch averaged 1,685,000 pounds. The most recent years have seen a rapid and calamitous decline in the output; setting a new record low each year, the take decreased from 940,000 pounds in 1940 to only 38,000 pounds in 1946.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[121:TITLTF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

Little Thessalon River is an important spawning ground for the sea lamprey, as compared with Desbarats, MacBess, Livingstone, and Lauzon Creeks. More research is necessary to determine the reasons for this difference.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[148:RIOTSL]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

The life history of the sea lamprey is briefly outlined. Mature adults are anadromous, spawning chiefly in May and June and dying shortly thereafter. The larvae pass 4 to 5 years in the sand, gravel, and silt banks of the spawning stream before transforming into the parasitic stage. After becoming fitted for a parasitic life, they live as free-swimming adults, parasitic on fish, from 1 1/2 to 3 1/2 years before becoming sexually mature and ready to spawn and die.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[160:ABHOTS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

The use of chlorinated hydrocarbons, namely trichlorbenzene, ortho-dichlorbenzene, and mono-chlorbenzene is indicated for the control of aquatic vegetation in localized areas. Ortho-dichlorbenzene is best because it settles fast and does not impart any great amount of odor or taste to the water. These chemicals, which are relatively insoluble in and heavier than water, sink to the bottom and sterilize it for a period of time. Trichlorbenzene is least satisfactory as it disperses far past the limits of the area to which applied. It also imparts a disagreeable odor and taste to the water and fish. It is possible that trichlorbenzene, with an emulsifier added, might prove an effective fish poison.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[177:LWCIMO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

Many species of aquatic plants can be prevented from growing in fish rearing ponds by the application of commercial fertilizers in the right amounts. The total cost of controlling plants and producing a crop of fish with fertilizers lessens the expenditure for labor in the fall draining period and justifies the use of additional fertilizer.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[183:TCOAPW]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

Data gathered during two summers from five ponds at the Wolf Lake Hatchery near Kalamazoo, Michigan, showed little correlation between the rate of survival and the intensity of stocking bluegill yolk fry. Ponds stocked at rates that ranged from 2,500 to 323,000 yolk fry per acre were drained at the end of the first summer, the first winter, and the second summer. Not more than 40 percent of the fry stocked in the spring survived the first summer in any pond. By the end of the second summer as few as 1 percent and not more than 20 percent of the original stock remained. Fish that were stocked at lesser intensities grew faster than those stocked more heavily. Competition from Iowa darters apparently seriously impaired the survival of bluegill yolk fry in one pond during the first summer. In another pond green sunfish, that entered as young of the year through the water supply during the first summer, became dominant over the bluegills in number and total weight by the end of the second summer. Under the most favorable conditions for growth (little competition and ample food) bluegill yolk fry grew so rapidly that they spawned when 12 months old and reached an average total length of 6 inches in 17 months.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[190:ROSAGO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

Fish populations were checked in three Minnesota trout streams by the electrical-shock method. Total weights of fish per acre varied from an average of 251.1 pounds in 18 streams of the Root River system to 50.3 pounds in the North Shore system. Trout (brook, brown, and rainbow) varied from 17.3 percent of the total in the former system to 72.0 percent in the latter. The structure of the trout population in the northern streams showed more or less normal size distribution but in the other systems 6- to 9-inch trout predominated almost to the exclusion of the smaller fish. It is presumed that in the latter streams most fish are derived from planted stock.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[204:FPISMT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

The longjaw (Leucichthys alpenae) was found at all of the 109 stations fished in the open lake during 1930–1932 and at 29 of the 32 stations in Green Bay in 1930 and 1932. Koelz (1929) found the longjaw at 35 localities, 33 of which were different from those fished in 1930–1932. The species was most abundant in water with a depth of less than 70 fathoms, but was found as deep as 97 fathoms. The longjaw was estimated to be about 4 1/3 times as abundant along the east shore of southern Lake Michigan as along the west shore in 1930 and 1931. The abundance along the east shore in 1930–1931 was estimated to be approximately equal to that in northern Lake Michigan in 1932. The best explanation for the relative scarcity of L. alpenae along the west shore is that a more intensive fishery, with smaller sizes of mesh, was operating on a separate population.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[215:TAGADO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

The changes in angling produced by current deflectors in a 1,605-foot section of Hunt Creek, a Michigan brook trout (Salvelinus fontinalis) stream, were studied over an 8-year period, 3 years before and 5 years after placement of the devices. Data on changes in the physical character of the stream, the fish population, and the bottom food supply also are presented for 1 year before and 3 years after installation of deflectors. The methods used to measure these various changes are given.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1946)76[248:TEODIA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor