We examined the flow of mercury (Hg) from benthic invertebrates to fishes in lakes with contrasting fish community structure. The study was carried out in two whole lakes in southcentral Ontario in 1992. Both were remote from direct sources of contamination and were chosen because of their physical and chemical similarities. Although the fish communities in the two lakes were qualitatively simi...

We investigated the growth rate, winter survival, presmolt size, and emigration timing of juvenile coho salmon (Oncorhynchus kisutch) in response to salmon carcasses and in-stream wood. Experimental trials were conducted during two consecutive years and pre-winter fish size and densities differed between years. Sixteen pens with emigration traps were built in a side-channel of the Mamquam River...

The presence of small steelhead (Oncorhynchus mykiss; averaging 55 mm fork length) influenced the growth of larger juvenile steelhead (90 mm fork length) during a 6-week experiment conducted in North Fork Caspar Creek, California, in summer 1994. In fenced replicate deep stream sections in this small stream, growth of the larger steelhead was greater in treatments in which small steelhead const...

Many demersal fish species rely on benthic prey as food sources for part of, or in some cases, all of their life history. We investigated the relationships between prey and predator abundance and prey size and predator mouth gape size for nine demersal fish species. Of the species analysed, four showed a significant positive increase in abundance with increasing prey abundance. Prey size is tho...

Sea lice (Lepeophtheirus salmonis) of fish-farm origin have been implicated in reducing populations of pink salmon (Oncorhynchus gorbuscha) in British Columbia’s Broughton Archipelago. Owing to the physically disruptive nature of louse attachment to fish skin in a hyperosmotic environment, we hypothesize that the impacts on fish performance are ionoregulatory in origin. Therefore, ionoregulator...

We used multiple approaches to study summer movement patterns of Bonneville cutthroat trout (Oncorhynchus clarkii utah) in the Thomas Fork drainage of western Wyoming, USA. Our objectives were to (i) document summer movement patterns of cutthroat trout, especially as related to the concepts of local turnover and displacement distances, (ii) determine if fish size and condition were related to m...

Do no-take marine reserves affect fishery yields? Manipulations of reserve status, and yield estimates, were made at two Philippine islands over two decades. Twenty-five percent and ten percent, respectively, of the coral reefs at Sumilon and Apo islands were made no-take reserves in 1974 and 1982. Biomass of target fish increased inside the no-take reserves 3to 4.5-fold over 9–18 years. Biomas...

Ocean-going juvenile salmonids heavily infected with salmon louse, Lepeophtheirus salmonis, have been observed prematurely returning to freshwater. This change in salinity preference may be an attempt either to regain osmotic balance or to remove the lice. For either hypothesis to be true, freshwater habitats must provide infected fish with a higher net fitness than saltwater habitats. The obje...