摘要:

Blue gourami do not appear to produce bacterial growth inhibiting antibodies against Proteus vulgaris. However, bacterial agglutinins are produced. The mean antibody titers produced at one and two weeks after the second antigen injection were 64-128 and 32, respectively.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<289:TIROTB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Two white shrimp, Penaeus setiferus, with external and histological characteristics of both male and female, are considered hermaphrodites. Both were infected with protozoan microsporidial parasites, Thelohania sp., probably Thelohania penaei.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<292:HWSPSP>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Wild and hatchery-produced shrimp were stocked in two impoundments off Bayou Jean Lacroix in 1968 and 1969. Maximum annual harvest was 141.2 kg/hectare of wild shrimp averaging 119 mm in total length (73 count per kg, heads on) from an impoundment in which attempts were made to remove predators and competitors. Harvest in an impoundment in which predators and competitors were not removed was 48.2, 79.1, and 161.9 kg/hectare of wild shrimp, blue crabs, and large fishes, respectively. Lack of predator control resulted in about a four-fold decrease in survival of marked white shrimp (Penaeus setiferus). Daily growth rates of juvenile and subadult brown shrimp (P. aztecus) ranged from 1.3 to 1.9 mm and 0.27 to 0.5 mm, respectively, during the investigation. Brown shrimp remaining in an impoundment for the entire 200-day annual growing season attained 164 mm. Subadult white and pink (P. duorarum) shrimp grew at rates of 0.48 and 0.18 mm/day, respectively. A marking-recapture study indicated that 70% of subadult brown shrimp were captured during 5 nights of harvesting at an impoundment weir in June, while only 53% of subadult white shrimp were recovered during 22 nights in November. Peak egress of subadult and adult brown shrimp during spring and summer occurred during full and new moons. An apparently causal relationship between decreasing water temperature and white shrimp egress was observed. White shrimp did not survive impoundment life during the winter of 1968-69.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<296:ECOPSI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Five ponds treated with agricultural limestone and five control ponds were stocked with Tilapia aurea and fertilized every 2 weeks with ammonium nitrate and triple superphosphate. Initially, total hardness and total alkalinity of the waters in the 10 ponds averaged 7.8 and 13.7 mg/liter, respectively. Liming caused a fourfold increase in total hardness and total alkalinity. Limed ponds had higher rates of phytoplankton productivity and yielded a 25% greater weight of fish than control ponds.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<308:EOALOW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Two studies were conducted with channel catfish fry (Ictalurus punctatus) fed diets containing four levels of pantothenic acid activity (10, 25, 66, and 250 mg/kg diet). Supplemental pantothenate markedly improved growth rate, survival, and feed conversion, and prevented a loss of appetite, clubbed gills, and sluggishness. The results of these experiments suggest that diets fed to catfish fry should contain at least 250 mg of pantothenic acid per kg of diet.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<313:PASODF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In three studies on the effects of frequency of feeding on channel catfish (Ictalurus punctatus), optimal growth and food efficiency were obtained from groups fed to satiation two times per day. Gains in weight were substantially reduced in groups fed only one time per day and were not enhanced by feeding four times per day. The fact that food efficiencies were similar in fish fed one, two, and four times per day indicated that food intake and not utilization was the growth limiting factor. In a study with automatic feeders, fish fed 24 times per day had significantly poorer gains and food efficiencies than those fed four or eight times per day.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<317:TEOFOF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Several experiments were conducted on relationships between oxygen consumption of channel catfish (Ictalurus punctatus) and environmental dissolved oxygen concentrations, feeding status, weight of fish, and temperature. Estimates of oxygen consumption under culture conditions were obtained by determining the rate of oxygen depletion in a still tank without aeration. Respiratory dependence (decrease in oxygen consumption rate with a decrease in environmental oxygen concentration) in both well-fed and fasted fish was noted at oxygen concentrations between 1 and 7 milligrams/liter. The oxygen consumption rates obtained one hour after feeding were higher than those taken immediately after feeding or from fasted fish. A log-log relationship between oxygen consumption and body weight of fish (2.3-1,006 g) was demonstrated. The slope (b) for the equation, oxygen consumption = (a) (weight)bwas 0.80 for both well-fed and fasted fish. The relationship between oxygen consumption and environmental temperature was linear over the range 24-28 C for well-fed fish and 24-30 C for fasted fish. The Q10's for plots for the well-fed and fasted fish were 1.9 and 2.3, respectively; thus the data were in accord with van't Hoff's Law.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<322:TIOVCC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The effect of dietary fiber level on growth and carcass composition of channel catfish and on pond water quality was studied by feeding fingerlings (30 per 20 m2pond) practical type feeds that contained identical nutrient components but graded levels of fiber ranging from 2 to 20%. After 200 days, fish fed the 2%-fiber feed had gained 3,132 kg/hectare; this was significantly (P < 0.05) more than fish fed the 14%-fiber feed (2,468 kg/hectare) or 20%-fiber feed (2,532 kg/hectare), but not the 8%-fiber feed (2,705 kg/hectare). Fiber level had no significant effect on composition or dress-out percentage of the carcasses. In the last 30 to 60 days, the ponds receiving the higher fiber-diets showed lower dissolved oxygen than the others. Although previous work has indicated that added cellulose is beneficial in purified fish diets, results from this study suggest that fiber provides no nutritional benefit in production-type feeds for channel catfish and when fed in large amounts may lower water quality.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<328:VOFIPD>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The growth of hybrid sunfish (male bluegill, Lepomis macrochirus x female green sunfish, L. cyanellus) and channel catfish (Ictalurus punctatus) below 15 C was determined in ponds on natural food and in cages on artificial feed. In all cases, the hybrids gained weight, while the channel catfish lost weight.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<333:GOHSAC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Eyed eggs of chinook salmon (Oncorhynchus tshawytscha) were planted in the Abernathy (Washington) incubation channel at concentrations of 7,180, 10,764, and 14,349 eggs/m2of gravel. Numbers of eggs planted were 200,000, 240,000, and 200,800, and survivals to the downstream migrant stage were 78.5, 85.0, and 79.1%, respectively; the differences were not statistically significant. The concentration of 14,349 eggs/m2is near the capacity of the channel. This stocking rate is 10 times that commonly recommended for artificial spawning channels. Egg concentration was apparently limited only by the physical capacity of the gravel.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<335:EOECIA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor