摘要:

We used three indices of diversity to compare the summertime fish and invertebrate fauna on first-order blackwater and alluvial streams (n = 4). Our results indicate that blackwater streams harbor a somewhat richer fauna than is found in the alluvial streams in eastern North Carolina.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664896

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Microtox test was evaluated as a tool to measure the presence of phorate, an organophosphate insecticide, in northern prairie wetlands. Microtox test results were inconsistent with results of otherin situtoxicity tests with aquatic invertebrates and ducklings. The Microtox test often indicated no toxicity, even though both invertebrates and ducklings died. Caution should be used when interpreting the results of the Microtox test to evaluate wetlands for pesticide contamination.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664897

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We developed a new approach for evaluating energy dynamics in fish populations and applied it to largemouth bassMicropterus salmoides.Wild fish were collected monthly and primary energy constituents (protein and lipid) were determined for specific tissues (muscle, liver, and gonad). Monthly samples were partitioned into length categories, and sex-specific log10weight-length regression equations were used to predict weights for the midpoint total lengths of stock to quality (S-Q) and quality to preferred (Q-P) length categories (250 and 340-mm TL for S-Q and Q-P fish, respectively). These weights then were adjusted by using the monthly relative weight (Wr) means of sex and length categories as correction factors to adjust for seasonal changes in plumpness to arrive at a representative monthly weight for each category. Monthly lipid and protein fractions of tissues then were multiplied by mean muscle, gonad and liver weights of these standard fish to obtain lipid and protein weights. Energy equivalents were applied to provide total energy estimates of the lipid and protein quantities. The approach provided a unique method for evaluating population energetics allowing direct comparisons among sex and length categories.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664898

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The nutrient status or streams impacted by agriculture and silviculture is little known, especially in Oklahoma and Arkansas. USA. In this research we assessed the impact of nutrients on biofilms in the Glover River, Oklahoma, which drains a watershed impacted by poultry manure, clear-cutting, and forest fertilization. We used nutrient diffusing substrata with two independent measures of biomass and N:P ratios to assess N and P limitation in this stream during 1988–1990. The substrata data revealed limitation by N. However, N:P supply ratios indicated P limitation during 1990. The nutrient regime, turbidity and discharge changed radically during the study. Caution is advised in use of nutrient diffusing substrata in streams impacted by high turbidity and high discharge.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664899

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Benthic macroinvertebrates were sampled at 10 sites on small streams in the vicinity of a molybdenum mine and mill in north-central British Columbia, Canada. Invertebrate communities exposed to elevated concentrations of molybdenum and cyanide in drainage from an open pit were taxonomically similar to those in control streams, but had slightly higher species richness and density. Molybdenum and cyanide concentrations in receiving streams were apparently not high enough to adversely affect invertebrate communities.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664900

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We evaluated the freshwater mussel fishery on Wheeler Reservoir, a 27,155-hectare mainstream impoundment of the Tennessee River in Alabama. During July 1991 through June 1992, we used a roving creel survey to conduct 285 interviews over 57 weekdays and 12 weekend days. Total harvest during the 12-month survey period was estimated to be 570 metric tons, and included 15 mussel species. The most frequently harvested species were the washboardMegalonaias nervosa, Ohio pigtoePleurobema cordatum, and butterflyElliesaria lineolata. Harvest peaked in June at 290,414 mussels. Among collection techniques, total estimated effort was highest for divers (71,160 musseler-hours). The total estimated value of the 12-month mussel harvest (in terms of money paid to harvesters) from Wheeler Reservoir was US$2,119,921.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664901

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Food habits of northern pike (Esox lucius) were documented in Lake Thompson, a shallow, windswept, eutrophic lake in eastern South Dakota. The primary food items, assessed with the Relative Importance Index, eaten by northern pike were common carp (Cyprinus carpio), crappies (Pomoxisspp.), and fathead minnows (Pimephales promelas). Common carp were eaten in midsummer and winter. Crappies were eaten primarily in the winter. Fathead minnows were an important food source throughout the year.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664902

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A survey of fishes in the Little Missouri River, North Dakota, was made in July of the unusually wet summer of 1993, following a six-year period of drought. During the nine-day study period, water velocities were high (0.4 to 0.87 m/s), and water temperatures, levels, and discharges fluctuated dramatically in response to rainfall. Only thirteen species of fishes were collected within the 190-km study reach. Of these, only three were found regularly; the others were collected in unusual habitats such as small tributary streams and beaver dams. The three common species (Platygobio gracilis, Hybognathus placitus, andRhinichthys cataructae) comprised 95% of individuals captured and are known to be well adapted to high flow. The fish community was somewhat different and much less diverse than in the past, possibly due to the preceding drought, high discharge, or rapid transition between them. Ten species found previously were not collected; five of these were abundant. Six species collected were not previously found in the study reach and two of these (Phoxinus eosandPimephales notatus) are apparently new records for the Little Missouri River. The sturgeon chub (Macrhybopsis gelida) was not collected, even though it was common in the Little Missouri River as recently as the late 1970s, and is well adapted to high flow and turbid water.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664903

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The first introduction ofMysis relictain Lake Sakakawea, North Dakota, occurred in 1974, followed by a second stocking in 1979. No evidence of survival and reproduction was immediately apparent. In 1994, several mysids were collected during a ichthyoplankton study in the tailrace below Garrison Dam, which impounds Lake Sakakawea. Samples were collected biweekly during the summer of 1994. A total of 32 mysids were observed in 23 samples from mid-July through August.

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664904

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0270-5060    

DOI:10.1080/02705060.1994.9664905

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor