摘要:

Cooling water for a 220-megawatt power plant is pumped from 5 m beneath Lake Monona's surface, heated about 10 C, and discharged into the littoral zone. Maximum temperatures in the effluent-outfall area approach 35 C in summer and 14 C in winter; unheated parts of the littoral zone rarely exceed 29 C.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<663:DEABTO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Salmonid eggs are known to be sensitive to physical shock at certain stages of development. Survivability of the eggs is unknown when incubating under natural conditions and subjected to the seismic shock of underground nuclear detonations. Rainbow trout eggs were incubated to various stages of development (37.5, 75, 125 or 250 Temperature Units) in simulated redds and subjected to five sequential physical shocks of either 1, 2, 5 or 10 g. Eggs were then allowed to continue incubation to hatch or near hatch. Results indicated no significant difference in survival of eggs subjected to physical shocks of these four magnitudes at the various developmental stages when compared to eggs subjected to no shock. There was no significant difference in egg survival after shocking at 8.2 C (47 F) or at 11.1 C (52 F).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<711:SORTEA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Juvenile chinook salmon, Oncorhynchas tshawytscha, were exposed to selected levels of dissolved atmospheric gas ranging from 100 (control) to 120% of saturation, and surviving fish were then tested for maximal swimming performance.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<717:IODAGO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Continuous-flow and static bioassays were conducted at 18 C, with survival and reproduction as measures of relative toxicity of eight PCB's, Aroclor 1221 (A-1221), A-1232, A-1242, A-1248, A-1254, A-1260, A-1262, and A-1268. Three PCB-mixture bioassays were also conducted. Aroclor 1248 was the most toxic to Daphnia magna of the eight Aroclors tested in static tests; the 3-wk LC50 was 25 μg/liter. Aroclor 1254 was the most toxic PCB to Daphnia under continuous-flow conditions with a 3-wk LC50 of 1.3 μg/liter. Ninety-six-hr LC50 values for A-1242, and A-1248 on Gammarus pseudolimnaeus in continuous-flow tests were 73 and 20 μg/liter. Survival after 60 days was 52% at 8.7 μg/liter 1242 and 53% at 5.1 μg/liter A-1248. Reproduction and survival of young were good at 2.8 μg/liter A-1242 and 2.2 μg/liter A-1248. The midge Tanytarsus dissimilis, in continuous-flow tests, did not emerge in abundance above 5.1 μg/liter A-1248 or 3.5 μg/liter A-1254. The 3-wk LC50 for Aroclor 1254 was 0.65 μg/liter for larvae and 0.45 μg/liter for pupae. Tissue residues in Gammarus pseudolimnaeus ranged from 4.0 μg/g A-1254 in control animals to 552 μg/g A-1248 in scuds held for 60 days in water containing 5.1 μg/liter A-1248.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<722:EOPBPO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Nine out of 18 adult bluegills exposed for 11 months during a chronic bioassay including reproduction were killed at 80 μg/liter of cadmium in water of 200 mg/liter (as CaCO3hardness. Progeny exposed for 30 days were killed at 90 μg/liter. Adult fish spawned at 239 μg/liter and at 2,140 μg/liter, but most larvae were severely crippled 6 days after hatching at these concentrations. No effects on survival, development, or reproduction were attributable to cadmium at 31 μg/liter. The highest tissue residues were found in liver, intestine and caecum, and kidney. Cadmium concentrations increased with exposure concentration in gill, liver, and intestine and caecum, but not in kidney. At least until more information is available on cadmium toxicity in different water types, chronically toxic and “just safe” continuous exposure concentrations probably can be estimated better by relatively short-term exposures of embryos and larvae than by the use of application factors.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<729:CCTTTB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The chemical, 2-(digeranylamino)-ethanol, was tested in the laboratory and in outdoor plastic pools to determine the toxicity to a variety of cold- and warmwater fish. An interesting aspect is that the toxicant is more toxic to carp (Cyprinus carpio) than to other warmwater fish. The 96-hr LC50 (concentration producing 50% mortality) for carp is 0.0507 mg/liter, whereas that value for centrarchids ranges from 0.237 mg/liter for smallmouth bass (Micropterus dolomieui) to 0.720 mg/liter for bluegill (Lepomis macrochirus). The toxicant is significantly less toxic (P = 0.05) to bluegill in cold water (12 C) than in warmer water (17 and 22 C), and it is more toxic in hard water than in soft water. Toxicity tests with green sunfish (Lepomis cyanellus) show that the toxicant is significantly more toxic (P = 0.05) in high pH water (pH = 9.0) than in low pH water (pH = 6.0), and the toxicant detoxifies at a faster rate in pH 9 than in lower pH water. Some aquatic invertebrates are more resistant than fish to the toxicant. The chemical is a good candidate selective toxicant, but additional studies are needed to support a registration for its use.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<736:TODACS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Fathead minnows (Pimephales promelas Rafinesque) were abundant in 9 of 10 prairie pothole lakes in south-central North Dakota, selected to represent extremes in salinity. Fathead minnows were found in lakes with mean concentrations of total dissolved solids during ice-free periods ranging from 385 to 7,036 mg/liter; no fish were found in North Lake George with a mean concentration of 23,489 mg/liter total dissolved solids.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<743:AGAFHO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Over 92,000 marked fingerling smallmouth bass were stocked in Big Piney River, 1952-1955. An estimated 63,600 smallmouth bass were caught between 1953, when the first stocked fish entered the creel, and 1958 when no more marked fish were caught. Of that number, not more than 2,100 were stocked fish. This is a little more than 3% of all the bass caught and a little more than 2% return of stocked fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<757:TFOAMO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Ivlev's model of competition for food is evaluated. This model expresses ration size as a function of prey density and population size. Ivlev's model is elaborated upon by including a term concerning the size (weight) of the animal. Alternative ways in which the effect of population size upon intraspecific competition may be described are suggested. Ivlev's model and two alternatives are fit to data from an amphipod population by nonlinear regression. Results suggest that intraspecific competition affects the efficiency with which the consumer captures its food, rather than affecting the maximum amount it is capable of eating. This approach is generalized to include both intra- and interspecific competition for food.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<772:CFF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

To assess factors contributing to variation in trawl data, eight stations in Whitewater Bay, Everglades National Park, Florida were sampled each month by roller-frame trawling from December 1968 to November 1969. A total of 52,190 fishes representing 66 species was captured. Analyses of catch data for 15 of these species indicated that the number of individuals per sample conformed to the Poisson distribution at low sample densities and to the negative binomial as population size increased and aggregation or “contagion” became evident. Tests of selected methods of data transformation indicated that a logarithmic scale transformation with the negative binomial statistic k was often effective in rendering such data amenable to parametric statistical testing. Sampling procedures and tidal stage had no direct effect on catch rates, although some evidence was found for an interaction between them. Vegetation density appeared to be the most important factor determining the differences observed between stations.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<777:ASOVIT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor