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Filters: Tags: Environmental Biology of Fishes (X) > Extensions: Citation (X) > partyWithName: Springer (X) > partyWithName: Jacqueline F. Savino (X)

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Predation and contaminants are two possible factors in the poor recruitment of young lake charr Salvelinus namaycush in the Great Lakes. We measured the feeding rate of slimy sculpins Cottus cognatus and burbot Lota lota on young lake charr (uncontaminated young from eggs of a hatchery brood stock and contaminated young from eggs of Lake Michigan lake charr) in laboratory test chambers with a cobble substrate. The median daily consumption rate of sculpins for all tests was 2 lake charr eggs (N = 22 tests; 95% confidence interval, O-13) and 2 lake charr free embryos (N = 31 tests; 95% confidence interval, O-10). Feeding rate did not differ between hatchery and contaminated prey. Slimy sculpins continued to feed on...
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The ruffe, Gymnocephalus cernuus, is a nonindigenous percid in the Great Lakes. Ruffe are aggressive benthivores and forage over soft substrates. Laboratory studies in pools (100 cm in diameter, 15 cm water depth) were conducted to determine whether fish density (low = 2, medium = 4, high = 6 ruffe per pool) changed foraging and aggressive behaviors with a limited food supply of chironomid larvae. All fish densities demonstrated a hierarchy based on aggressive interactions, but ruffe were most aggressive at low and high fish densities. Time spent in foraging was lowest at the low fish density. The best forager at the low fish density was the most aggressive individual, but the second most aggressive fish at the...
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Behavior of largemouth bass, Micropterus salmoides, and northern pike, Esox lucius, foraging on fathead minnows, Pimephales promelas, or bluegills, Lepomis macrochirus, was quantified in pools with 50% cover (half the pool had artificial stems at a density of 1000 stems m−2). Both predators spent most of their time in the vegetation. Largemouth bass searched for bluegills and ambushed minnows, whereas the relatively immobile northern pike ambushed all prey. Minnows were closer to predators and were captured more frequently than bluegills. Even when minnows dispersed, they moved continually and eventually wandered within striking distance of a predator. Bluegills dispersed in the cover with predators. Bass captured...