50 research outputs found
Recommended from our members
Role of benthic and littoral fish in the productivity and ecology of the Lake Washington drainage
Recommended from our members
Development of a systematic sampling scheme for the Lake Washington drainage
To determine productivity of fish, we will require an estimate of relative abundance that can be expanded later into estimates of biomass. Our work has shown that much of the fish production in Lake Washington is in the form of nonsalmonid and nongame species, such as peamouth and northern squawfish. As the title of our proposal indicates, we are attempting to develop a systematic sampling scheme that eventually will allow us to estimate the relative abundance of the key species, or perhaps all 35 species, of fish that inhabit the drainage and to expand
these estimates into terms of biomass or energy
Recommended from our members
A portable vertical gill-net system
Studies of vertical as well as horizontal distributions of fishes often require the use of gill nets hung vertically from the surface to the bottom. By using gill nets in this fashion it is possible to sample the entire water column as a continuous variable
Strategies to Control a Common Carp Population by Pulsed Commercial Harvest
Commercial fisheries are commonly used to manage nuisance fishes in freshwater systems, but such efforts are often unsuccessful. Strategies for successfully controlling a nuisance population of common carpCyprinus carpio by pulsed commercial harvest were evaluated with a combination of (1) field sampling, (2) population estimation and CPUE indexing, and (3) simulation using an exponential semidiscrete biomass dynamics model (SDBDM). The range of annual fishing mortalities (F) that resulted in successful control (F= 0.244–0.265) was narrow. Common carp biomass dynamics were sensitive to unintentional underharvest due to high rates of surplus production and a biomass doubling time of 2.7 years. Simulations indicated that biomanipulation never achieved successful control unless supplemental fishing mortality was imposed. Harvest of a majority of annual production was required to achieve successful control, as indicated by the ecotrophic coefficient (EC). Readily available biomass data and tools such as SDBDMs and ECs can be used in an adaptive management framework to successfully control common carp and other nuisance fishes by pulsed commercial fishing