摘要:

The River Don in South Yorkshire has suffered abuse from a legacy of pollution that dates back to the Industrial Revolution. Population growth and urban development have resulted in the use of the river for the discharge of mining, sewage, and industrial effluents. Despite considerable efforts to reverse the ecological impacts of these abuses, the river still suffers from continuing pollution from these sources. As a consequence, fish and macroinvertebrate fauna of the river remain restricted due to water quality problems. The macroinvertebrate fauna comprised only 12 taxonomic families and generally consisted of pollution-tolerant species with low species diversity. The fishery consisted of stocked brown trout and grayling, and there appeared to be little or no recruitment of these fishes through reproduction. Other native fishes occurred in low numbers.

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663741

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Rainbow trout (Oncorhynchus mykiss) annual production was estimated over two years in Laurel Branch and South Fork Citico Creek, Tennessee. Both streams are softwater, second order streams of the southern Appalachian Mountains with low inherent productivity (alkalinity <100 μeq·L−1or 5 mg·L−1as CaCO3). Annual production over the two years averaged 12.4 kg·ha−1in Laurel Branch and 6.2 kg·ha−1in South Fork Citico Creek. The majority of annual production (77%) occurred during the December-April period in Laurel Branch and was dominated by age-2 trout (44%). Though lower overall than Laurel Branch, annual production in South Fork Citico Creek was also dominated by age-2 trout (47%) but was more evenly distributed throughout the year. Seasonal mean flows and water chemistry measures were related to production and growth rates of age-1 and age-2 trout but not age-0 or age-3 trout. Annual production estimates represented the lowest reported values for rainbow trout and were similar to regional estimates for brook trout (Salvelinus fontinalis). Findings suggest that trout production in these streams is below worldwide averages for infertile streams and may be related to abiotic factors which may in effect regulate salmonid production in these streams annually.

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663742

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This study examined use of deep pools (>0.8 m mean depth) based on thermal characteristics by adult summer steelhead in Steamboat Creek, Oregon. Steamboat Creek had a heterogenous thermal profile, with some segments exceeding the preferred temperature of steelhead. Deep pools were scarce (4% of the total habitat types), and 39% of them were identified as cool pools (mean bottom water temperature 19°C). Adult summer steelhead were found primarily in deep pools, avoiding other habitats such as glides, riffles, and even cool tributary junctions. Adult abundance in deep pools did not show significant variation between years and was inversely associated with mean bottom temperature. Use of cool pools was estimated to be 11 times the use of warm pools. However, the presence of unoccupied cool pools suggested that other ecological variables may be involved in pool selection.

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663743

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Golden crayfish (Orconectes luteus) specimens were collected in the Mississippi River at Grand Tower, Jackson County, Illinois in September and October 1999. This locality is the most eastern on record for the species and the most southern in Illinois. The high stream order habitat from which these crayfish were collected is generally not consistent habitat compared with preferred smaller order stream habitats used in other parts of the species' range. Previous collections of O.placidusfrom the Mississippi River may in fact be O.luteus.

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663744

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663745

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0270-5060    

DOI:10.1080/02705060.2000.9663730

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor