摘要:

The drag-net fishery of California accounts for most of the production of fresh fish for the northern and central California markets. This fishery, which is carried on almost entirely by “paranzella” drag nets, produces about twelve million pounds of fish a year, of which 75 per cent are various flounders that inhabit the waters along the California coast. Because of the tremendous waste of small unmarketable fish, due to the small-sized mesh in the drag nets, an investigation was inaugurated to test the escapement alive of different sized fish through various sizes of mesh, and likewise to measure the effectiveness of the escapement of fish through different parts of both experimental and commercial drag nets. It was found, that by increasing the size of mesh in the sacks or cod-ends of these drag nets, a large percentage of the small unmarketable and immature fish was permitted to escape alive, without reducing the total catch of marketable fish. The drag-net industry in California voluntarily adopted the recommendations for the enlargement of mesh sizes and is now enjoying greater catches per unit of effort.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[106:SGITCD]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

Since 1936 the California Division of Fish and Game has collected statistics on the ocean sport fishery as a part of its management program. Operators of pleasure fishing boats make out daily reports on the catches of their passengers. Annual catches average 2,000,000 fish with a weight of 6,000,000 pounds. The tabulated reports show: monthly and annual catches of each species; the catch, according to locality, of all species combined and of certain important species; the monthly and annual number of fishermen and number of boat trips; and the number of boats reporting each month and during the year.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[111:TYOFSO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

This paper traces very briefly the history of the smallmouth black bass in the State of California from the time of its introduction to the present day. The Central Valleys Bass Hatchery, recently constructed near Sacramento, California, is described. Methods and results of the propagation of smallmouth black bass are reviewed in an account of the operations in the 1938 season at this new California bass hatchery.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[119:SBBPIC]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

California has had in operation for three years a system whereby the angler is requested to make on his application for an angling license a voluntary record of the number of fish which he caught the preceding year, listed by species and by county in which they were caught.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[125:ACRIC]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

Eggs of Coho salmon (Oncorhynchus kisutch) were planted in gravel, and placed in open and in covered hatchery baskets in hatchery troughs to determine the possibility of the production of differences in eye diameter by incubation under the different conditions. No significant difference was found between any two of the three lots. In the gravel planting a number of eggs was unaccounted for, which fact may explain the high rates of efficiency obtained by basing estimates of losses in redds only upon the number of dead eggs remaining in the gravel.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[132:COCSFF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

The eggs from five adult sea-run silver salmon (Oncorhynchus kisutch) were divided into two lots: 8,239 eggs were buried in gravel in a standard hatchery trough and 7,500 placed in a standard hatching basket as a control. Natural conditions were simulated as closely as possible with the gravel eggs. The eggs required 772.3 temperature units (t.u.) to maximum hatch (control), 1,084.3 t.u. to earliest emergence from the gravel, and 1,155.6 t.u. to maximum emergence from the gravel. Initial to final emergence required at least thirty-eight days. Of the eggs buried, 10.2 per cent emerged from the gravel. In the control, 65.9 per cent of the eggs hatched and 48.2 per cent survived to the time that the experimental fish had finished emerging from the gravel. Examination of the gravel and the dead eggs in it at the conclusion of the experiment and observations made during previous experiments support the view that silt carried by unusually severe floods smothered many of the eggs in the gravel. This fact seems to account in large part for the small percentage of salmon emerging from the gravel. Fifty-six days after initial emergence from the gravel, the experimental fish averaged 23.8 fish per ounce (1.19 grams each, live weight) while the control lot averaged 27.6 fish per ounce (1.13 grams each). During these fifty-six days only forty-eight of the experimental fish died, whereas the mortality in the control lot for the same period totaled 905. In the final two weeks, however, the average daily mortality in the control was only one fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[135:AEIHSS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

A concentration of 3 p.p.m. of copper sulphate was effective in killing fish in the acid waters of four Nova Scotian lakes. The plankton and the bottom fauna were almost entirely destroyed. Rooted aquatic vegetation was largely unaffected. About a year elapsed before plankton and aquatic insects returned in quantity. Mollusks have not repopulated the lakes. Considerable copper remained in the waters for some time, but there was evidence that much was in a combined, non-toxic form.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[141:CSARAF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

The effectiveness of artificial stocking as compared with natural propagation is one of the most fundamental problems in fish management. Recent studies show that natural spawning is much more efficient than was formerly supposed, the hatch often comparing favorably with that at hatcheries. Good results from artificial stocking have been obtained in so-called barren waters and with the use of large fish. Frequently, however, stocking has been a failure and whether it has been generally successful is still problematical. Results of some recent studies on the effects of stocking are summarized. It is believed that a major cause of the failure of stocking is the lack of complete correspondence between the ecological requirements of the fish and the environment. The great need for further studies is stressed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[158:APATMO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

摘要:

A small urn-shaped peritrichous protozoan, apparently an undescribed species, was found on the gills and bodies of largemouth and smallmouth black bass in ponds at Leetown, West Virginia. A heavy mortality among a lot of fingerling largemouth bass probably resulted from suffocation due to the organisms on the gills. Specimens of the parasite, preserved in formalin, measured about 57 microns in length and 24 microns in maximum width. The base of the animal consists of a circular disc about 6 microns in diameter. No evidence was found that the sucker-like attachment disc penetrated the epidermal cells of the host causing necrotic tissue. The anterior or upper end of the animal has a ciliary disc and two rows of cilia. The body is without cilia and is annulared. The macronucleus is very large, has the shape of an inverted cone and occupies much of the lower half of the body. The small micronucleus apparently lies in the slightly concave surface of the upper part of the macronucleus, although there is doubt on this point. This new species was named Scyphidia micropteri after Micropterus, the generic name of the smallmouth black bass, one of its hosts. The species recently was found by Dr. H. S. Davis on gills of largemouth black bass collected in Radnor Lake, Tennessee, which indicates a wide geographical distribution of the parasite.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[169:SMANPP]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1939)69[176:POOTEH]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1940

数据来源: Taylor