摘要:

Irruptions of gizzard shad, Dorosoma cepedianum (Le Sueur), in North Twin Lake, Iowa in 1954 and 1955 provided opportunities for investigating certain basic ecological relationships of this species. Of the approximately 358 plankton species and varieties found in North Twin Lake, 260 were encountered in shad digestive tracts. On a volume basis, phytoplankton (primarily Cyanophyta and Chlorophyta) constituted the bulk of young-of-the-year and yearling gizzard shad food. Crustacean zooplankton were important food elements of recently hatched individuals.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[80:UOPBJG]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

A method is described for sexing striped bass Roccus saxatilis (Walbaum) by use of a serrated-jaw ear forceps. The instrument is used to extract gonads from dead fish in samples of commercial catches, without incurring damage to the fish which affects the market quality. The gonads are examined later in the laboratory and are identified as male or female. The technique has proven satisfactory in large scale sampling of commercial catches.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[104:AMODTS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

During the period 1951–56, 127,430 pounds of panfish and trashfish have been removed with fyke nets from 45 ponds in Massachusetts in an attempt to improve gamefish populations. Removal has ranged from less than one to 146 pounds per acre annually. Data from four ponds ranging in size from 20 to 269 acres are presented in detail. Where removal was intensive, growth rates of panfish increased markedly. Growth rates of gamefish, especially chain pickerel and largemouth black bass, which were returned to the water, showed a slight decrease or no change. Older panfish, remaining after thinning operations, showed less increase in growth rate than did younger fish spawned during or after the operations. No major changes in species composition in favor of gamefish were apparent. It is concluded that the fyke netting has increased growth rates of the species being thinned but has not materially improved gamefish populations.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[108:EOROPA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Age-and-growth data are presented for 11 species of fish from three habitats in the Salt River, Missouri; a dredged upstream station, an unmodified lower station and an intermediate middle station. The middle station is 46 stream miles from the upper station and 69 stream miles from the lower station. Compared to growth data from the central United States, carp, (Cyprinus carpio), smallmouth buffalo (Ictiobus bubalus), freshwater drum (Aplodinotus grunniens), green sunfish (Lepomis cyanellus) and white sucker (Catostomus commersoni) grew moderately fast; gizzard shad (Dorosoma cepedianum) at an average rate. River carpsucker (Carpiodes carpio) grew very slowly at the upper station and slightly slower than average at the middle and lower stations. Channel catfish (Ictalurus punctatus), flathead catfish (Pilodictis olivaris), northern redhorse (Moxostoma aureolum), and white crappie (Pomoxis annularis) grew slowly. All but one of the more abundant species showed a trend toward faster growth downstream; a phenomonen also noted in other Missouri streams. The differences in growth indicate little movement between stations. Freshwater drum of the 1947 year class were very abundant and they and all freshwater drum competing with them grew slowly. Minimum desirable length for angling in this stream is reached by carp (14 inches), buffalo (12 inches) and white crappie (7 inches) in the third year; green sunfish (6 inches) in the fourth year; and catfishes (12 inches) in the fifth and sixth years.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[116:GOTFIT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Return of planted fin-clipped juveniles of fall-migrating chinook salmon (Oncorhyncus tshawytscha) as 3- and 4-year-old spawners is considered in relation to four different rearing methods. Four groups of salmon, of about 30,000 each, were first reared for 78 days in fresh-water and all eventually planted in estuarial waters (salinity about 22 parts per 1,000) at the mouth of the Samish River. Highest return of spawners to the Samish River (0.75 percent) was from juveniles subjected to a 5-day conversion to 75 percent sea water after fresh-water rearing and prior to stocking. Second highest return (0.47 percent) was from fish planted directly after fresh-water rearing. Third highest return (0.26 percent) was from fish subjected to an 8-day conversion to 100 percent sea water followed by 25 days of rearing in sea water. Lowest return (0.19 percent) was from fish handled as the preceding but having a 60-day rearing period in salt water. Sizes of fish in a planting were respectively 150, 150, 49, and 25 to the pound. Rearing in and conversion to salt water was carried out about 30 miles by water from the Samish Hatchery where the fresh-water rearing was done. Migrational timing on return to the Samish River was similar for marked fish and unmarked fish in the run

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[132:RMATRO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Study of age and rate of growth of the American Shad (Alosa sapidissima) in three southeastern coastal rivers (St. Johns River, Florida, Neuse River, North Carolina and Susquehanna River, Maryland) shows similar growth rate in these three streams and a body-scale relationship that can be described by the parabolic equation, y = 22.58χ2+ 34.96x + 0.41. When allowance is made for differences in aging methods, it appears that growth was similar to that reported in the literature for shad from two Canadian populations. Little difference was found in length of males and females of the same age but males matured earlier and were generally more abundant in commercial catches. The annulus appears to be a true year-mark on scales of shad spawning for the first time and results from aging of these fish from scales are not in conflict with known facts about the shad. Spawning marks are considered to be year-marks for “repeater” shad, that is, shad that have spawned more than once, but this has not been validated.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[139:AAGOTA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Eggs and resulting larvae of chinook salmon (Oncorhynchus tshawytscha) were exposed continuously to several intensities of fluorescent light (wavelength 3350 to 6000 A. with mean of 5800 A.) for a period extending from 24 hours after fertilization through absorption of the yolk-sac. At an intensity of 157 foot-candles all eggs died before the eyed stage; at 116 foot-candles all eggs died before hatching; and at 88 foot-candles mortality from premature hatching was as much as 35 percent higher than for controls incubated in near-darkness and receiving 0.02 foot-candles. Not more than 37 percent of the eggs exposed to 88 foot-candles hatched, compared to 74 percent for the controls. Most of the larvae of the 88 foot-candle group died by the time the yolk-sac was absorbed compared to a mortality of 30 percent by the controls during a similar period. Chinook salmon eggs under artificial light hatched sooner than those in near-darkness and the larvae from the light-reared group, when compared to the controls, were more sluggish, more darkly pigmented, smaller, and slower in absorbing their yolk-sacs. Of the two experimental lots of chinook eggs, one yellow- and one orange-colored, the yellow eggs hatched more quickly.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[151:SEOALO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

An angler opinion survey was begun at Castle Lake, Siskiyou County, California, during the summer of 1957. Approximately 200 anglers were asked standardized questions in an attempt to determine how the opinions of trout fishermen about species, minimum acceptable size, and size-number balance could best be obtained. The sample of anglers was too selective to yield data of broad application. However, the technique of questioning was developed sufficiently to permit its use on a more random sample. Visual aids were used to break through prestige considerations and cliches and obtain true preferences.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[163:POAITF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Mature hybrids among brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), rainbow trout (Salmo gairdneri), and lake trout (Salvelinus namaycush) involving reciprocal crosses, backcrosses and three-way crosses were utilized to test fertility and to present photographic records of external charcteristics.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[172:AAFOTH]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Equipment is described whereby aerial planting of fish in Oregon's high mountain lakes can be done by two men. By utilizing a hydraulic loader, one man can fill the airplane transportation tank in 40 seconds. The plane need be on the ground only four minutes between flights. The aeration system described makes possible safe transportation of fry at a density of 1.75 pounds per gallon for at least one hour. Description of the equipment, results of experiments with aeration equipment, costs of operation and a brief survey of the literature are presented.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1957)87[182:OAFP]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor