摘要:

Centrarchid harvest was compared to gross photosynthesis in a small desert impoundment. Average annual gross photosynthesis for benthic plants and plankton was equal to 14,100 pounds per acre (1.6 kg/m2) of oxygen or primary photosynthate over a 3-year period. Average annual harvest of centrarchids (largemouth bass and black crappie) was 138 pounds per acre live weight, which is equal to 0.98 percent of gross photosynthesis. Considered as dry biomass, centrarchid harvest equaled 0.15 percent of gross photosynthesis. When examined with regard to degree of habitat exploitation by centrarchids, fishing intensity, population turnover, competition from other fish, and cycles of recruitment, harvest of centrarchids was judged to be near the potential maximum. By the same standards, however, channel catfish production and harvest were judged to be considerably lower than what might be achieved with more effective recruitment and fishing. For the foregoing reason the relation between total fish harvest (channel catfish plus centrarchids) and gross photosynthesis was not considered to be valid for making total harvest predictions based on knowledge of gross photosynthesis. Possible effects on interpretation of gross photosynthesis of photic depth, organic import, dominant producer of plants, and deferred entry of plant forage into the food chain are discussed. Precision of estimate of major elements used in computing the harvest/photosynthesis ratio is also considered.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[1:PPAFHI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Recapture of marked adult white suckers (Catostomus commersoni) showed evidence of homing to specific spawning sites at Many Point Lake in northern Minnesota. The pattern of recaptures also indicated a recurring time pattern for return of individual fish, some fish consistently returning to spawning sites earlier in the spawning run than others.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[13:HTOSWS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Though the use of rotenone is a common procedure in freshwater fishery management, little is known of its effect on zooplankton. Fern Lake, a shallow dystrophic lake in western Washington, was treated with 0.5 p.p.m. of 5 percent rotenone powder in June 1960. Biweekly sampling of the open water, shore edge, and marsh area prior to and for 6 months following treatment provided quantitative and qualitative measurements of zooplankton populations. Open-water species were completely removed, and remained absent for over 3 months. Organisms along the shore edge resisted the effect of rotenone, but eventually disappeared for several weeks. Those species inhabiting the dense weed patches did not all succumb to rotenone. The rare appearance of large numbers of males and usually early ephippial-egg-bearing female Cladocera were observed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[17:TEOROZ]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Standing crops of fish in representative Oregon farm ponds were estimated by marking and recapture or by draining and enumeration. Most of the ponds were in the Willamette Valley, but a few were in central and southern Oregon. The average standing crop of bluegills (Lepomis macrochirus) was about 130 pounds per acre, and was similar to standing crops reported by workers in other states. The average standing crop of largemouth bass (Micropterus salmoides) for 12 ponds was 104 pounds per acre. Central Oregon ponds appeared to support more pounds of bass per acre than western Oregon ponds.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[25:SCOFIO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

This paper is based on a questionnaire which was answered by the fishery departments of each of the United States except Alaska and Hawaii. There was an increase in the number of states that permit general underwater spearfishing; from 42 percent in 1957 to 73 percent in 1960. Over 30 species classified as rough fish could be speared legally in states that allowed spearfishing in 1960. Limits were liberal, the spearfishing season was generally unrestricted, and only three states required spearfishermen to have special licenses. Fourteen states had various kinds of restrictions on the types of impaling devices used by spearfishermen; i.e., explosive guns, spring- and rubber-operated guns, or hand-held spears. Eleven states indicated that illegal activities by divers were or threatened to become law enforcement problems.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[30:TSOSAT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

In 1957, when control of the sea lamprey appeared imminent, production of lake trout (Salvelinus namaycush) in hatcheries was increased. Coincident with this increase, certain diseases of lake trout became evident. One disease, cataract, results in permanent damage to the eye

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[34:CIHLT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Catchable-sized, hatchery-reared rainbow trout (Salmo gairdneri) undergoing survival tests in controlled sections of a mountain stream repeatedly declined in coefficient of condition for several months after being stocked. Examples of the extent of this decline, together with records of stream temperatures and associated mortality are used to demonstrate the relationship among poor body condition, rising temperature, and breakdown of trout vitality during the critical late-winter period. Possible advantages of fall stocking and of breeding some hatchery trout for superior adaptability are discussed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[39:BCWTAO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Movements of three spawning populations of walleyes (Stizostedion vitreum vitreum) are described from 1,174 tag recoveries reported by anglers, and from additional recoveries in experimental fishing gear. Most walleyes returned to the same spawning area in successive years. The Scriba Creek spawning population showed a gradual dispersal from the spawning area in May and June, and the population attained its widest distribution in late summer. Although the three spawning populations intermingled during summer, differences in the summer distributions of the populations were evident. Marking during the fall suggested that most walleyes remained in a limited area except during the spawning period. The Oneida Lake data demonstrate that widely distributed recoveries of walleyes tagged at one spawning site in a lake do not constitute satisfactory evidence of population homogeneity.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[47:DAMOMW]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Mark-and-recapture estimates of the number of hatchery-reared brook trout (Salvelinus fontinalis) have been made each April and October since October 1956 in Ford Lake (10 acres) and Hemlock Lake (6 acres), at the Pigeon River Trout Research Station, Vanderbilt, Michigan. Fish were captured by angling, by trapping with wire traps, and by shocking with direct current at night with underwater lights. A permit-type creel census insured a nearly complete record of the catch.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[53:SEONMO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Under hatchery conditions Gyrodactylus elegans is one of the principal parasites of the golden shiner. It becomes epizootic in the spring at temperatures of 40 to 60° F. It spreads rapidly and causes pronounced mortality. The operational procedure in shiner hatcheries requires both pond and tank treatment. For pond treatment 25 p.p.m. formalin gives excellent control. In tanks 50 p.p.m. for 14 hours gives satisfactory control.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1963)92[60:COEOGE]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor