Effects of turbidity on the foraging abilities of brook trout (Salvelinus fontinalis) and smallmouth bass (Micropterus dolomieu)

Sedimentation is the major pollutant of waters in North America. Most research on the effects of increased sedimentation has focussed on its effects on stream habitat and its ramification on the reproductive potential of fish. Although relatively large sediment loads may be necessary to alter stream habitat, only small loads are needed to raise mean stream turbidity levels. Turbidity may be an important, yet relatively unexamined factor in stream fish production. With this, I sought to determine the influence of elevated turbidity on the foraging abilities of two predatory species representing both cold and warm water stream habitas, brook trout (Salvelinus fontinalis ) and small mouth bass (Micropterus dolomieu).;This research was conducted in an artificial stream at West Virginia University and consisted of determination of effects of turbidity on reactive distance and foraging success of both species and determination of the effects of turbidity on brook trout mean daily consumption and specific growth rates. During reactive distance and foraging success experiments, three fish were tested at a time creating a situation of competition. (Abstract shortened by UMI.)

Aquatic-terrestrial linkages in Appalachian streams: Influence of riparian inputs on stream habitat, brook trout populations, and trophic dynamics.

Riparian zones play a major role in the structure and function of headwater stream ecosystems. Inputs of leaf litter from riparian zones are the primary energy source for secondary production in these streams and inputs of large woody debris (LWD) help shape stream habitat. Riparian zones of Appalachian streams were degraded by past timber harvest activities. Streamside management zones (SMZs) now protect the riparian zone by limiting timber harvest activities near streams. The objective of this study was to examine aquatic-terrestrial linkages and how habitat and food resources influence brook trout ( Salvelinus fontinalis) populations in Appalachian streams. LWD was experimentally added to eight streams in the Middle Fork River watershed, Randolph Co., WV to determine if stream habitat and prey availability could be enhanced. Stream habitat was assessed and brook trout populations were monitored for one year prior to, and three years following habitat manipulations. Invertebrate drift and brook trout diets were collected to determine the effects of LWD additions on trophic dynamics and to assess the importance of terrestrial invertebrate prey to brook trout energetics. LWD additions had little effect on stream habitat by three years post-manipulation. Brook trout populations fluctuated over time, but did not show a consistent increase. Although, the number of locations where leaf litter was stored increased, invertebrate drift did not increase following the addition of LWD. Likewise, prey consumption by brook trout was not influenced by the LWD additions, but diet composition showed a shift with the proportion of the diet comprised of the shredder functional feeding group increasing by two years post-habitat manipulation. Terrestrial invertebrates comprised a large portion of the yearly consumed energy by brook trout. The results of this study illustrate the important linkage between terrestrial and aquatic systems in the trophic dynamics of headwater streams. However, the duration of the study was likely not long enough to detect significant changes in stream habitat and brook trout populations due to LWD additions. The benefits of these habitat manipulations may not be realized for several more years. These initial results may help guide resource managers in future stream restoration efforts

Session B7- Evaluating brook trout genetic response to population isolation

Brook trout (Salvelinus fontinalis) reside in a range of habitats including headwater streams where populations may become periodically isolated. Demographic consequences of population isolation include increased potential for localized extinction. Genetic consequences for population isolation, or populations of sustained small numbers, include increasing susceptibility to inbreeding, the expression of negative fitness traits, and overall loss of genetic variability, which may increase the risk of localized extinction. Reestablishment of connectivity -with larger populations through periodic gene flow into these small populations may act to offset loss of genetic diversity. Restoring population connectivity and degraded headwater habitats, especially those that historically harbored wild brook trout populations has been a focus of restoration efforts. To understand the degree of genetic isolation among headwater brook trout populations, we examined how variability in connectivity between brook trout populations bas resulted in the partitioning of genetic variation within a number of headwater brook trout populations in two locations: Nash Stream, New Hampshire, and Pennsylvania. Both locations bad multiple headwater brook trout populations, but varied by how populations were potentially isolated. In Nash Stream, potential causes of isolation were culverts or waterfalls. In Pennsylvania, isolation could be due to larger geographic distance, culverts or dams, or areas of poor stream quality. In both locations, overall estimates of variation in allele frequency among populations were high, indicating that populations were significantly genetically different, but the effect of the different barrier types varied based on the likely amount of gene flow allowed. For example, in Pennsylvania, significant correlations of genetic diversity were only observed with the presence of impaired stream sections, but not geographic distance or barrier effect. Understanding the effects of barriers on genetic diversity and gene flow can be useful to guide efforts to restore connectivity between populations

Fisheries 9RO1R1RYHPEHUZZZÀVKHULHVRUJ GUIDELINES AND REVIEWS AFS Completes Assessment, Issues New Guidance Regarding Hatchery Operation and the Use of Hatchery-Origin Fish

BACKGROUND The American Fisheries Society (AFS) is the oldest, larg-HVW DQGPRVW LQÀXHQWLDOSURIHVVLRQDORUJDQL]DWLRQGHYRWHG WR ¿VKHULHVFRQVHUYDWLRQDQGLQWKLVFDSDFLW\WKH$)6KDVURXWLQH-ly assessed the contributions of hatcheries to natural resource management and issued recommendations to guide natural re-VRXUFHPDQDJHUV LQEHVW XVHVRI KDWFKHU\RULJLQ¿VK)RU WKH past several decades, the Society has explored these issues in a formalized process conducted at approximately 10-year in-tervals to assess contemporary issues related to hatcheries and management of aquatic resources. Representatives of the Fish Culture and Fisheries Management Sections came together in WRDQVZHUWKHTXHVWLRQ)LVKFXOWXUH¿VKPDQDJHPHQW¶V ally? ” in a symposium entitled “The Role of Fish Culture in Fisheries Management. ” In 1994, AFS reexamined the issue