The freshwater fish community and Brown Trout movement patterns in Little River, Saint John, New Brunswick
LE3 .A278 2015
Bachelor of Science
Environmental & Sustainability Studies
Freshwater ecosystems are a vital component in the maintenance of fish biodiversity. The presence of artificial structures and pollution in freshwater systems however, causes loss of spawning habitat, alteration of migratory routes, and a decrease in reproductive cycles. In Little River, Saint John, New Brunswick the freshwater fish community was sampled. The Brown Trout (Salmo trutta) and White Sucker (Catostomus commersonii) populations were examined to determine population characteristics including age structure. Fork length, total length and weight were recorded on site for both species. Brown Trout movement throughout Little River was also observed through inserting V9 acoustic tags into the fish and placing eight VR2w acoustic receivers throughout the system in an attempt to determine if the population consisted of anadromous or resident fish, or both, and to observe fish distribution throughout the system. Water quality throughout Little River was examined using benthic invertebrate samples collected using a kick net at a single site and a Ponar dredge at another five sites. Benthic invertebrate species were used to assess water quality, as they require specific conditions for growth and survival that differ between species. They can therefore be used as a measure of pollution tolerance. Age structure of the fish populations indicated either reduced spawning success in recent years and/or increased juvenile mortality. Species richness and therefore water quality was poorest in the lower portion of Little River, which was found to correlate with a lack of Brown Trout presence in that section of the river.
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