Walleye (Sander vitreus) provide important recreational and commercial fisheries throughout the United States and Canada. In Colorado, more walleye are stocked every year than any other species of fish. Use of sterile triploid fish in Colorado is an important management strategy for protecting native endangered fish species from naturally reproducing populations of introduced predators like wal...

At the La Grande hydroelectric complex located in northern Quebec, Canada, mercury concentrations were measured in over 25 000 fish as part of an ongoing environmental effects monitoring program. Five fish species were monitored over a 30-year period: the non-piscivorous lake whitefish (Coregonus clupeaformis) and longnose sucker (Catostomus catostomus) and the piscivorous northern pike (Esox l...

Physiological responses to changes in energy balance are tightly regulated by the endocrine system through glucocorticoids, IGF-I and thyroid hormones. Changes in these hormones were studied in eight captive female Steller sea lions that experienced changes in food intake, body mass, body composition, and blood metabolites during summer and winter. During a period of energy restriction, one gro...

The impact of young-of-the-year (YOY) fish predation on zooplankton dynamics and cascading effects down to phytoplankton were studied in lake enclosures using different densities of larval and juvenile European perch (Perca fluviatilis). Two experiments, one in June and one in August, were performed in Lake Dagstorpssjön, a slightly eutrophic lake in Scania, southern Sweden. In our experiments,...

—We measured the initial mortality (fish judged nonreleasable at weigh-in), prerelease mortality (fish judged nonreleasable 1–2 h after weigh-in [which includes initial mortality]), and postrelease mortality (fish that died during a 5-d retention in net-pens) in 14 live-release tournaments for walleye Sander vitreus conducted in April–October 2006 and April–July 2007 in lakes and rivers in Mich...

Compared to their fossil counterparts, living brachiopods are investigated far less often, due occurrence in remote environments such as dark caves or deep environments. Due the scarcity of studies targeting situ brachiopods’ populations, large-scale information on distribution and ecological preferences is still lacking, especially hardgrounds. The extensive employment remotely operated vehicl...

Walleye Sander vitreus are commonly introduced to reservoirs and provide valued fisheries. lost though harvest natural mortality in all systems, but escapement may also reduce reservoir populations. However, the effects of harvest, mortality, loss on populations not known. Our objective was quantify two Iowa (Big Creek Lake Brushy Lake) understand how these factors limit We assessed behaviors c...

We performed dynamic linear modeling analysis on fish contaminant data collected from the Ontario Ministry of the Environment and Environment Canada to examine long-term trends of total mercury (THg) and polychlorinated biphenyls (PCBs) in Lake Erie. Several sport fish species (walleye, smallmouth bass, rainbow trout) with differences in their diet habits, food competition strategies and foragi...

Many biological and physical factors potentially affect target strength. While these sources have been identified, few studies have compared the relative effects of individual factors. Modelled and measured target strengths in non-dimensional metrics were used to compare and rank the effects of fish length, tilt, depth, and acoustic frequency on backscatter intensity. Ex situ measurements of ta...