摘要:

Brown bullheads acclimated to temperatures between 3.5 and 28 C and tested in a thermal gradient trough usually preferred water temperatures above their respective acclimation temperatures. Fish tended to gravitate toward higher temperatures the longer they remained in the gradient; final preferendum was 27.3 C. Laboratory results are consistent with observed movements of Connecticut River brown bullheads into the thermal discharge canal of a power plant during autumn. It appears from both laboratory and field studies that a “temperature trap” keeps bullheads in the warm discharge canal during winter. However, brown bullheads leave the canal in spring sooner than would be predicted from temperature preference data alone.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<288:TPTOTB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Evolutionary and immunological relationships among the different genes specifying synthesis of rainbow trout (Salmo gairdneri) LDH subunits were demonstrated. A procedure was devised for the purification and concentration of specific rainbow trout isozymes which were then used for antisera production. The B41and B42autotetramer isozymes and the Group “a” isozyme system were shown by double agar diffusion to produce distinctly different antibodies. Antisera against specific isozymes showed degrees of cross-reaction depending on the relatedness of the isozymes. The LDH-C gene locus is more closely related to the LDH-B2gene than to the LDH-B1gene. Electrophoresis was demonstrated to be an efficient additional method to spectrophotometric assays to show inactivation of LDH by antibodies. LDH isozymes underwent rapid conformational change when purified and stored.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<295:IPOLDI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A hierarchical breeding design was used to demonstrate the heritability of tolerance for infectious hematopoietic necrosis (IHN) in sockeye salmon. Oncorhynchus nerka. Heritability was about 30%, indicating that artificial selection may increase the number of fish that can tolerate the disease.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<305:HOTFIH>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Several testicular and spermatological parameters of 48 male channel catfish, Ictalurus punctatus (Rafinesque) were studied during 6 months (November through April) outside the spawning season. Two stocks (a domestic and a wild one) and within each stock 2- and 3-year-old fish were compared. Within age-groups, the domestic fish were considerably larger than the wild ones. In each stock, the 3-year-olds outgrew the 2-year-olds. The testes consisted of a white spermatogenic and pink glandular part, averaging 1.14 and 0.56 g respectively. A significant increase in both parts was noticed in March, continuing during April. One 3-year-old male in each stock was azoospermic, even though these fish had well developed testes and exhibited secondary sexual characteristics. Viable sperm was present in every month at an average rate of 73.2% of the spermatozoa. The majority was in progressive motion with some vibrating in loco. The gonosomatic index averaged only 0.22%, and reached a peak value of 0.32% in April. The mean gonadal sperm concentration was 5.5 × 109spermatozoa/g wet testicular tissue and a maximum of 7.4 × 109occurred in April. Both stocks produced a similar number of spermatozoa/g. As a group, however, the testes of the older fish contained twice as many gametes per g as those of the 2-year-olds. A highly significant (P < 0.01) correlation of 0.51 existed between the width of the head (a male secondary sexual characteristic) and the gonadal sperm concentration. No pronounced differences between domestic and wild stocks were observed for most variables, but some size and/or age effects occurred.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<309:TASCOC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Treatment of channel catfish (Ictalurus punctatus) production ponds with biweekly applications of 0.84 kg/hectare copper sulfate was ineffective in reducing phytoplankton density. Three periodic applications of simazine totaling 1.3 mg/liter drastically reduced phytoplankton density. However, extended periods of low dissolved oxygen concentrations following simazine applications resulted in decreased fish yields and poor conversion ratios as compared to control ponds.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<316:COPAOC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Channel catfish (Ictalurus punctatus) were grown from fingerlings to harvestable size in earthen ponds at densities of 197 and 394 fish per 400-m2pond (49 and 98 per 100 m2) and 494 fish per 200-m2pen (247 per 100 m2) by intensive feeding of diets with or without supplemental vitamin C. The fish did not require vitamin C in their diets for normal growth or to prevent gross signs of the broken back syndrome at the two lower densities; however, at the highest density growth was 28% less while 23% of the fish showed external signs of the broken back syndrome. Percentages of collagen in bone and vitamin C in liver were statistically lower (P < 0.05) in fish fed the diet deficient in vitamin C. Serum alkaline phosphatase activity, blood hematocrit, and anterior kidney vitamin C level were not influenced by the diets. Feed processing losses of vitamin C were 18 to 27% and 46 to 62% for pelleting and extrusion, respectively. The half-life of vitamin C in stored catfish feeds was 2.6 to 2.9 months.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<321:VCIPDF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The involvement of vitamin C as a cofactor in detoxication mechanisms of fish was investigated by feeding selected amounts of the vitamin in diets of fingerling channel catfish (Ictalurus punctatus) that were concurrently exposed to toxaphene, a widely used organochlorine insecticide in the Southeastern United States. Three groups of fish were exposed continuously to each of five toxaphene concentrations—37, 68, 106, 218, and 475 ng/liter—and fed a diet containing 63, 670, or 5,000 mg/kg of vitamin C. After 150 days of toxaphene exposure, backbone collagen was significantly decreased in most fish fed the diet containing 63 mg/kg of vitamin C. However, the toxaphene concentrations of 37 and 68 ng/liter did not cause this effect in fish fed the 670 mg/kg vitamin C diet, and only the 475 ng/liter concentration significantly depressed backbone collagen in fish fed the 5,000 mg/kg diet. Spinal deformities were common among fish fed low vitamin C diets, but the incidence decreased as dietary vitamin C increased. Vitamin C concentrations in the backbones of toxaphene-exposed fish were significantly lower than in controls, which suggests that the insecticide caused a functional vitamin C deficiency in bone tissue. The reduction in mucous cell number in the skin and epidermal thickness was more evident in fish exposed to toxaphene and fed the lower two concentrations of dietary vitamin C. In most toxaphene exposures, diets containing 670 or 5,000 mg/kg of vitamin C significantly reduced whole-body residues of toxaphene and increased the tolerance of fish to chronic effects of the insecticide on growth, bone development, and skin lesions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<326:IOTAVC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Blood was removed from ten adult rainbow trout (Salmo gairdneri) on a sequential daily (7 days), weekly (4 weeks), and monthly (1 month) schedule and analyzed for hematocrit, plasma protein, acid phosphatase (AP), lactic dehydrogenase (LDH), and creatine phosphokinase (CPK). Of the parameters examined, hematocrit, lactic dehydrogenase, and creatine phosphokinase were found to be the most significant indicators of stress due to repeated sampling. We showed that, under conditions similar to those of this investigation, daily and weekly sampling of approximately 0.2% of the body weight in blood produced decidedly deleterious effects of the test organisms. Starvation was a secondary stressor and is believed to have had an influence on blood characteristics as the study entered its later phases.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<334:EOHSOS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The bluegill, Lepomis macrochirus Rafinesque, was subjected to various concentrations of hydrogen cyanide to determine the effects on long-term survival, growth, egg production, and egg hatchability. Intermittent-flow experiments were conducted using adults, juveniles, and newly hatched eggs in separate tests. Egg production was most sensitive to hydrogen cyanide, and the highest concentration with no adverse effect was below 5.2 μg/liter HCN. Fry survival through the first 6 weeks followed in sensitivity with the no-adverse-effect level occurring between 15.6 and 19.4 μg/liter HCN.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<341:CTOHCT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Coho salmon (Oncorhynchus kisutch), alewife (Alosa pseudoharengus), spottail shiner (Notropis hudsonius), and rainbow smelt (Osmerus mordax) were exposed for 30 min to residual chlorine. The alewives were tested at 10, 15, 20, 25, and 30 C, the salmon and shiners at 10, 15, and 20 C and the smelt at 10 C. Thirty-minute LC50 values were both species- and temperature-dependent. All species showed an inverse relationship between test temperatures and LC50 values. The range of LC50 values observed, with the test temperatures in parentheses, were coho salmon, 0.29 (20 C)-0.56 mg/liter (10 C); alewife, 0.30 (30 C)-2.27 mg/liter (15 C); spottail shiner, 0.53 (20 C)-2.41 mg/liter (10 C); and smelt, 1.27 mg/liter (10 C).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<346:TEOICO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor