摘要:

Adult brook trout (Salvelinus fontinalis) were fed p, p′-DDT-3H; eggs obtained from these fish were fertilized, and incubated; and the developmental stages were analyzed for the degree of metabolism of the DDT. About 35% of the p, p′-DDD-3H in the eggs at the time of fertilization was converted to p, p′-DDE-3H and p, p′-DDD-3H by the time of yolk depletion in the fry.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<782:TDODIB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Some hydrophobic chemicals may reach plateau levels in fish only after several months of continuous exposure. Therefore, an accelerated test procedure, based on kinetics, was developed using an isomer of PCB's (polychlorinated biphenyls): 2,2′,4,4′-tetrachlorobiphenyl. The rates of uptake and clearance of 2,2′,4,4′-tetrachlorobiphenyl were determined by analysis of rainbow trout (Salmo gairdneri Richardson). These trout were exposed to 1.6 and 9.0 μg/liter for five days and then transferred to fresh water. A nonlinear regression analysis was used to estimate the rate constants for uptake and clearance, and the bioconcentration factor at steady-state was calculated from the rate constants. For 2,2′,4,4′-tetrachlorobiphenyl, the bioconcentration factor at steady-state was 9550 ± 1610 in trout muscle.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<785:BOTIRT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

During the summer of 1969 the effect of the standard serial application of malathion used in mosquito control (85.7 g/hectare) on juvenile brown and white shrimp, Penaeus aztecus Ives and P. setiferus (Linnaeus) was examined under field conditions in a saline marsh near West Galveston Bay, Texas. Water samples contained a high concentration of malathion (2.0-3.2 ppb) immediately after application and a progressive reduction thereafter. Shrimp at treated stations exhibited mortalities ranging from 14 to 80%. Malathion concentrations in live shrimp taken from the test sites were consistently higher (0.5-3.2 ppm) than concentrations measured in dead shrimp removed during the same period (0.5-2.1 ppm). No deaths attributable to malathion were observed at the control stations and no detectable traces of malathion were observed in water or shrimp samples removed from the control stations during the experiments. It was concluded that malathion was the most likely contributor to brown and white shrimp mortalities observed at the treated station.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<793:EOAMOJ>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Chlorine and chlorine-ammonia compounds have been reported to be toxic to various species of freshwater fish. We have found that the basis of this toxicity in at least one species is the oxidation of hemoglobin to methemoglobin, producing death of the fish due to anoxia.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<800:CMIF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A procedure for wet digestion of fish tissue that utilizes nitric, sulfuric, and perchloric acids can digest 1 g of fish tissue in approximately 45 minutes. This procedure allows for the preparation of large numbers of samples and is suitable for the analysis of Cd, Cu, Mn, Zn, and probably other heavy metals by atomic absorption spectroscopy. The method eliminates the problem of clogging of the aspirator tube of the atomic absorption unit.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<803:AMFWDO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Gross exophthalmos in one or both eyes of yearling spring chinook salmon (Oncorhynchus tshawytscha) was caused by postorbital, granulomatous inflammatory tissue that developed in response to invasion of the site by Corynebacterium sp., the causative agent of bacterial kidney disease.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<805:KDPLIS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In recent years, tannin has been used to decrease adhesiveness of walleye eggs during artificial propagation. Spermatozoa samples were taken from ripe male walleye to investigate the effect of tannin concentrations on spermatozoa motility or fertilizing capacity. A statistically significantrelationship in reduction of spermatozoa motility with increasing tannin concentrations resulted. Consequently, tannin does influence the fertilizing capacity of walleye spermatozoa and hence during artificial propagation should not be added until the second rinse after fertilization.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<808:TEOTOT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Nitrogen and phosphorus budgets for two catfish raceways near Durant, Oklahoma, during 1972 and 1973, indicated that 18 to 64% of the total nutrient inputs accumulated in the raceways' sediment. Both N and P inflow/outflow levels were relatively constant throughout the study. Levels of nitrite-N, nitrate-N, ammonium-N, and organic-N were generally higher in the outflow than the inflow, but were typically within recommended water quality limits. Similarly, average total and soluble P concentrations increased in the raceways, doubling from inflow to outflow. Nevertheless, the increased N and P levels did not result in serious problems due to algae or other aquatic growths. Moreover, the health and growth of the catfish remained good. Present raceway management and catfish production practices seem to pose no particular water quality problem.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<811:NAPLIW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The Weiss saturometer, an instrument which measures dissolved gas tensions, was evaluated and compared with gas chromatographic apparatus. With vigorous shaking the saturometer equilibrated with dissolved gas tension only after fifteen to twenty-five minutes in moderately supersaturated water. Paired analyses by gas chromatography and the saturometer did not differ significantly. Both methods (gas chromatography and the Weiss saturometer) appear to offer advantages in specific applications, and the method of choice for dissolved gas analysis remains dependent on individual requirements. The need for conscientious operation of the saturometer by an experienced operator was apparent.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<816:ACEOTW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

An improved “bubbling tube” elutriator apparatus for separating stream insects and other macroinvertebrates from stony substrates is described. In test runs the apparatus separated, by a float-over principle, 26 different taxa in 6-min operating time per sample. Almost 100% separation was achieved for dominant insects Cheumatopsyche sp., Hydropsyche simulans, Neochoroterpes mexicanus, Stenelmis sp., Simulium sp., and Chironomidae. The device can also be used to successfully wash eggs of stoneflies and other aquatic insects from large volumes of sand-gravel substrates in a minimum amount of time.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1975)104<821:AIEFSS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor