摘要:

Brook trout (Salvelinus fontinalis) generally select areas of upwelling spring water for spawning under natural conditions. When presented with suitable gravel containing an artificially controlled aquifer of about 0.1% the area of a circular tank, female trout selected spawning sites that were either in close proximity to the upwelling water or adjacent to it in 21 of 22 trials. Average time lapse for completion of spawning was about 30 hours. Use of a tank several times larger than 1.9 m2would probably improve conditions for making more precise observations on discrimination of aquifers under laboratory conditions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<416:UWAAFI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Travel time for yearling chinook salmon (Oncorhynchus tshawytscha) to migrate the 370 km downstream from the Salmon River to Ice Harbor Dam was compared during 3 years prior (1966–68) and 4 years after (1970–74) impounding of the Snake River behind Lower Monumental and Little Goose dams. Prior to impounding, fish averaged 15 days of travel time to Ice Harbor Dam during low flows (1,000–2,000 m3/s) and 9 days during moderate flows (2,300–4,000 m3/s). After the new impoundments, average travel time was increased to 31 days in low flows and 20 days in moderate flows–a measured delay of 16 and 11 days, respectively.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<422:DMOYCS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Juvenile sockeye salmon (Oncorhynchus nerka) were exposed to lethal levels of air-supersaturated water (120 percent, 125 percent, 130 percent total gas saturation) containing different oxygen-nitrogen ratios and different carbon dioxide concentrations. Fish mortality was not significantly different at different carbon dioxide levels (1.7 to 22.0 mg/liter CO2) when tested at the same total gas saturation concentrations. Total gas saturation levels are much more important than the O2/N2ratios, as fish mortality will not occur unless total gas saturation exceeds 100 percent, regardless of the O2/N2ratios. There was a significant decrease in mortality when the ratio of oxygen to nitrogen was increased while holding the total percent saturation constant. Much more extensive and severe signs of gas bubble disease developed at high O2/N2ratios than at low O2/N2ratios, indicating that oxygen plays a significant part in forming external emphysema and lesions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<425:CDAORA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Using a channelled avoidance trough, immediate behavioral reactions of blacknose dace to a domestic sewage effluent and its toxic constituents, chloramines, free chlorine, and ammonia, were investigated. Two avoidance indexes were computed from time spent and number of entries by the fish into a test solution channel and a clean water channel. The time avoidance index was found to be a more sensitive measurement than the entry avoidance index for fish behavioral reactions. On the basis of the time avoidance index, the fish did not avoid unchlorinated sewage effluent and ammonium chloride solution in concentrations as high as 270 mg/liter as ammonia-nitrogen. The fish did avoid chlorinated sewage effluent, chloramines, and free chlorine. The degree of fish avoidance increased as total chlorine concentration increased. The threshold avoidance concentration under the test conditions was 0.13 mg/liter as total chlorine for chlorinated sewage effluent, 0.18 mg/liter for chloramines, and 0.61 mg/liter for free chlorine (DPD colorimetric method). The degree of fish avoidance and the pattern of behavioral responses to chlorinated sewage effluent were almost identical with those to chloramines, but different from those to free chlorine. The results suggest that chloramines are the major factor causing avoidance reaction of blacknose dace to chlorinated sewage effluent.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<430:IBROBD>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Bluegill (Lepomis macrochirus Rafinesque) eggs, fry, juveniles, and adults were exposed to H2S concentrations to determine acute toxicity. Seventy-two-hour LC50 for eggs was 0.0190 mg/liter; 96-h LC50 for 35-day-old fry was 0.0131 mg/liter, for juveniles 0.0478 mg/liter, and for adults 0.0448 mg/liter. Exposure to lower levels of H2S resulted in some acclimation. Chronic exposure to sublethal levels of H2S for up to 826 days resulted in no egg deposition at 0.0022 mg/liter and reduced deposition after 97 days at 0.0010 mg/liter. Growth was adversely affected at levels from 0.0031 to 0.0107 mg/liter H2S depending on the life history stage at which chronic exposure was started. When exposure was started with eggs, the lower level retarded growth. Food consumption was reduced at 0.0085 mg/liter H2S. Time to anesthesia with MS:222 was reduced at levels from 0.0014 to 0.0031 mg/liter H2S. The most sensitive stage to acute toxicity was the feeding fry and to chronic toxicity was the spawning adult.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<442:TOHSTV>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Common shiners, Notropus cornutus, were exposed to 3 ppm ferric hydroxide for periods from two to eight weeks. Ferric hydroxide resulted in initial changes in serum protein, glucose, Na and K ions, but these changes did not adversely affect the internal dynamics of the fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<450:EOFHSO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Groups of zebrafish, Brachydanio rerio, were injected with antigens prepared from infectious pancreatic necrosis virus (IPNV) or Proteus vulgaris. Zinc appeared to suppress the immune response against Proteus vulgaris, but not against IPNV.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<456:TTOZTT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A simple, accurate technique has been devised to sex externally channel catfish, Ictalurus punctatus, regardless of body size or state of gonadal maturation. Male catfish have a single urogenital opening; females have two openings partitioned by a septum—an anterior genital pore, and a posterior urinary pore. In male fish, a single probe can be inserted into the urinary bladder through the urogenital pore. Female fish are differentiated from males by the insertion of two probes, one into the urinary bladder through the urinary pore and the second into the oviduct through the genital pore.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<460:ATFSCC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Forty m/ale channel catfish (Ictalurus punctatus) of two age groups and two stocks (domestic and wild) were compared in an experiment to study morphological and physiological characteristics of their testes and sperm cells from May through October. The gonosomatic index for 36 normal catfish examined averaged 0.25%. An average of 82.7% spermatozoa were alive with an average motility score of 2.96. These fish had an average gonadal sperm concentration of 7.1 X 109spermatozoa per g wet testicular tissue. The testes were found to be composed of 2/3 spermatogenic and 1/3 glandular tissue. There were no morphological changes observed in the characteristics of the spermatogenic tissue during the period of study. The 3-year-old fish were consistently larger than the 2-year-olds, and the domestic fish were larger than the wild stock in each age group, which probably caused most of the differences in characteristics when comparisons were made.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<463:ASSOCC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Three activators, eight extenders, and three protective agents at two concentration levels each were used to determine the best combination that will maintain in storage the viability of channel catfish (Ictalurus punctatus) sperm cells. There was a highly significant (P < 0.01) difference in motility score among activators. Saline (0.65%) gave the highest motility score. Extended sperm cells became motile when activated after 2 months of storage at 4 C. Extender I (Truscott and Idlers Hfx #1) with 10% dimethyl sulfoxide (DMSO) and 2 hours equilibration produced the highest motility scores after freezing of 24 hours or 1 week. Freezing rate was controlled by placing vials of sperm in a double-layered, kapok-lined paper bag and freezing at the height of 127 mm above the liquid nitrogen level.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<469:POCCS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor