摘要:

We conducted an ichthyofaunal bioassessment on the upper Cahaba River in north central Alabama during the fall of 1995, the spring and fall of 1996, and the spring of 1997. There were trends denoting a loss of habitat stability in areas impacted by anthropogenic sources of pollution, particularly siltation. Negative longitudinal trends were recorded for the index of biotic integrity, sum of studentized residuals (after linear regression of various metrics on drainage area), and the Jaccard index. Several species of cyprinids and percids, which are sensitive to anthropogenic disturbances, are becoming less abundant in the system. We conclude that these changes are related to point and non-point sources of pollution from metropolitan Birmingham.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663602

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Drift of smallmouth bass (Micropterus dolomieu) fry was documented from Stockport Creek, a tributary to the Hudson River estuary, New York. This drift was not correlated with high flow events, very low light levels, high turbidity, or rapid temperature changes normally associated with catastrophic drift. We interpret the smallmouth bass drift in this tributary as normal export of fry spawned by potamodromous adults. The estimated magnitude of drift is large enough to be a significant addition to the estuarine smallmouth bass population.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663603

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We determined the extent of fish entrainment and impingement for a low velocity-high volume Lake Michigan water intake system where the entrance of the intake system occurred in deep waters. There was no evidence of any fish entrainment probably because of the location of the entrance to the water intake system. Fish impingement was also low and comparable to the lowest impingement found for power plant intakes. The number of impinged fish was 93 fishes for 58 sampling dates from April 23 to November 13. Of the 93 fishes, 61 were alewives, 11 were yellow perch, an the remainder included black crappie, black bullhead, bloater, bluegill, emerald shiner, johnny darter, pumpkinseed, slimy sculpin, and spotfin shiner. The impact of this intake systemon the fish community was insignificant, since the estimated total of impinged fishes during the operating season of the intake was 280.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663604

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Adult, juvenile and larval fishes were sampled in a managed isolated wetland in the Red Chute Bayou floodplain, LA from December 1994 to July 1995. Nineteen species were captured. Principal components analysis of adult fishes showed little difference between sites, but a gradient of habitats and seasons reflecting variable richness was observed. Bowfin (Amia calva), black bullhead (Ameiurus meals), spotted gar (Lepisosteus oculatus), bluegill (Lepomis macrochirus), warmouth (Lepomis gulosus), black crappie (Pomoxis nigromaculatus) and fliers (Centrarchus macropterus) were the dominant adult fishes. Juvenile and post-larval fishes had low catch-per-unit-effort and were dominated by fliers. Principal components analysis distinguished three habitat groups and significant seasonal variation in the juvenile/post-larval fish community. The ichthyofauna resembled that described for irregularly inundated isolated floodplain ponds of the lower Mississippi River valley. The relatively low diversity of this system is probably due to the isolation of the backwaters from active river cycles. The problem may be further compounded by the timing of water drawdown in late spring.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663605

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We modified the Index of Biotic Integrity (IBI) to characterize the fish assemblages and evaluate the biotic integrity of four forested streams in the Lower Ouachita Mountains Ecoregion, Arkansas. We related differences in IBI scores with corresponding differences in chemical and physical characteristics of the streams, including the varying intensities of forest management. Analysis of variance and comparison of mean IBI scores among the four streams revealed significant differences between reference and even-aged treatments and between even-aged and uneven-aged treatments (P < 0.05). Turbidity and total suspended solids were inversely related to IBI scores. Further refinement of the IBI should enable its use in the Ouachita Mountains Ecoregion to help assess site impacts, monitor trends in stream biotic integrity, and assess effectiveness of forest best management practices.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663606

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We designed a portable, modular enclosure/exclosure device forin situstream experimentation. The basic enclosure consists of interlocking panels to provide a 1 m2area, and combines the easy transportation of small cages with the modular flexibility to construct large enclosures. In field experiments, we assessed: 1) the potential for mesh size to affect the presence of fish food items; 2) the influence of the enclosure mesh on restricting stream water velocity; and 3) the ability of the enclosure to retain fish over short experimental periods. The mesh size (3.2 mm) did not impose a restriction on movement of stream invertebrates during a 14 day colonization period. Flow was impeded, but not completely restricted by the enclosure mesh. The retention of fish within the enclosures was improved through the use of mesh skirting attached to the bottom edges of the enclosure and covered with the natural stream substrata.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663607

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Oneida Lake is a eutrophic lake, located in the low, open relief of the Ontario Lake Plain in central New York state. A 1992–95 survey of the molluscan community produced 21 living species, which represents a 50% reduction in species richness over the past 70 years. Of these 21 species, six have been introduced since 1917; the most recent invader, the zebra mussel (Dreissena polymorpha) is present in numbers that exceed all other molluscan species combined. Since water quality has generally remained consistent over the years, the observed changes in the historic molluscan fauna are probably the result of biotic interactions with introduced species as well as habitat loss due to human modifications of the eulittoral environment.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663608

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Stomach contents of 425 largemouth bass were identified and quantified using the Relative Importance (RI) index over three seasons (spring, summer, and fall) from Lake Lillinonah and Pickerel Lake, Connecticut. In Lake Lillinonah during spring, aquatic insects had the highest RI, followed by crayfish and fish (primarily white perch). During summer and fall, the RI of aquatic insects decreased, the RI of crayfish remained consistent, and the RI of fish approximately doubled. Fish (primarily bluegill) was the most important diet item of largemouth bass from Pickerel Lake during all seasons. Aquatic insects were the second most important diet item during spring and summer. In Lake Lillinonah and Pickerel Lake, the RI of aquatic insects decreased and the RI of fish increased with increasing fish length; aquatic insects were most important in largemouth bass less than 300 mm. In contrast to Lake Lillinonah where the RI of crayfish and fish were of equal importance in largemouth bass ≥ 380 mm, largemouth bass ≥ 380 mm in Pickerel Lake fed almost exclusively on fish. Our results suggest that food habits of largemouth depend on the type of lake system and the dominant prey types. In Connecticut lakes that lack suitable littoral areas and associated panfish species, largemouth bass may rely on pelagic fishes and crayfish as food sources.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663609

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We determined spatial and temporal foraging characteristics of larval bluegill sunfish (Lepomis macrochirus) and longear sunfish (Lepomis megalotis)in the upper Kanawha River, West Virginia during the summer of 1989. Stomach contents were examined among habitat types (i.e., main channel, main-channel border, and shoreline habitats) and depth (surface, middle, and bottom). Diet of larval bluegill sunfish was dominated by Chironomidae, temporally and spatially. Chironomidae dominated larval longear sunfish diet in main channel and main-channel border collections from all three depths. However, along the shoreline, larval longear sunfish diet was dominated by Cladocera.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663610

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A survey of the benthic macroinvertebrate community of Dried Indian Creek, a second/third order stream in the Georgia Piedmont flowing through the city of Covington, was initially conducted in 1978. The study was repeated and expanded in 1993 to compare recent conditions with those in 1978 and to evaluate historical changes in the stream biota. The 1993 study revealed significant improvement in the structure of the invertebrate community measured by differences in the Ephemeroptera/Plecoptera/Trichoptera index values obtained from the two studies. The introduction of a tertiary phase in the wastewater treatment systems of local governments resulted in improved water quality. Furthermore, the appearance of a small wetland probably explains an improvement in conditions in the creek upstream from the original point of introduction of wastewater effluent.

ISSN:0270-5060    

DOI:10.1080/02705060.1998.9663611

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor