Zooplankton community responses to fish stock management of Lake Vesijärvi, southern Finland: changes in cladoceran body size in 1999–2003

2005 ◽  
Vol 29 (1) ◽  
pp. 488-490 ◽  
Author(s):  
Kirsi Vakkilainen ◽  
Timo Kairesalo
Keyword(s):  
Body Size ◽  
Zooplankton Community ◽  
Fish Stock ◽  
Stock Management ◽  
Community Responses

Zooplankton community responses to regional-scale weather variability: a synoptic climatology approach

2015 ◽  
Vol 62 (3) ◽  
pp. 189-198 ◽  
Author(s):  
AL Primo ◽  
DG Kimmel ◽  
SC Marques ◽  
F Martinho ◽  
UM Azeiteiro ◽  
...  
Keyword(s):  
Regional Scale ◽  
Zooplankton Community ◽  
Synoptic Climatology ◽  
Community Responses ◽  
Weather Variability

Ecosystem development in Lake Volkerak-Zoom: concept and strategy

1995 ◽  
Vol 31 (8) ◽  
pp. 239-243 ◽  
Author(s):  
W. Ligtvoet ◽  
S. A. de Jong
Keyword(s):  
Water Level ◽  
Fish Stock ◽  
Ecosystem Development ◽  
Optimal Conditions ◽  
Stock Management ◽  
Key Factors ◽  
Integrated Water Management ◽  
Ecological Concepts ◽  
Freshwater System ◽  
Water Level Management

In the 6000 ha Lake Volkerak-Zoom, a new freshwater system in the estuarine southwest of The Netherlands, biomanipulation is used as a tool in ecosystem development. The basic ecological concepts for ecosystem development are described. Key factors in the integrated water management are fish stock management and water level management, geared towards creating optimal conditions for northern pike, the dominant predator in mesotrophic waters. The main aspects of the water level management and the fish stock management are outlined.

Zooplankton community responses to chlorpyrifos in mesocosms under Mediterranean conditions

2008 ◽  
Vol 71 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Patricia López-Mancisidor ◽  
Gregoria Carbonell ◽  
Ana Marina ◽  
Carlos Fernández ◽  
José V. Tarazona
Keyword(s):  
Zooplankton Community ◽  
Community Responses ◽  
Mediterranean Conditions

Optimal Fisheries Investment under Uncertainty

1983 ◽  
Vol 40 (12) ◽  
pp. 2080-2091 ◽  
Author(s):  
Anthony T. Charles
Keyword(s):  
Optimal Investment ◽  
Fish Stock ◽  
Investment Strategies ◽  
Economic Optimization ◽  
Stock Management ◽  
Investment Under Uncertainty ◽  
Capital Costs ◽  
Wide Range ◽  
Full Analysis ◽  
Fishing Fleets

A full analysis of optimal fisheries investment strategies must take into account high levels of uncertainty in future fishery returns, as well as irreversibility of investment in specialized, nonmalleable fishing fleets. A stochastic optimization model is analyzed using dynamic programming to determine optimal policy functions for both fleet investment and fish stock management within an uncertain environment. The resulting policies are qualitatively similar to those found in the corresponding deterministic case, but quantitative differences can be substantial. Simulation results show that optimal fleet capacity should be expected to fluctuate over a fairly wide range, induced by stochastic variations in the biomass. However, the performance of a linear-cost risk-neutral fishery is fairly insensitive to variations in investment and escapement policies around their optimum levels, so that economic optimization is "forgiving" within this context. A framework of balancing upside and downside investment risks is used here to explain the roles of several fishery parameters in relation to optimal investment under uncertainty. In particular, the intrinsic growth rate of the resource and the ratio of unit capital costs to unit operating costs are found to be key parameters in determining whether investment should be higher or lower under uncertainty.

scholarly journals Modelling stock–recruitment relationships to examine stock management policies

2007 ◽  
Vol 64 (5) ◽  
pp. 870-877 ◽  
Author(s):  
A. Kimoto ◽  
T. Mouri ◽  
T. Matsuishi
Keyword(s):  
Prediction Error ◽  
Management Strategies ◽  
Fish Stock ◽  
Data Sets ◽  
Stock Management ◽  
Spawning Stock ◽  
Stock Recruitment ◽  
Management Policies ◽  
Leave One Out ◽  
High Recruitment

Abstract Kimoto, A., Mouri, T., and Matsuishi, T. 2007. Modelling stock–recruitment relationships to examine stock management policies. – ICES Journal of Marine Science, 64: 870–877. Simulation studies are used widely for fish stock management. In such studies, forecasting future recruitment, which can vary greatly between years, has become an essential part of evaluating management strategies. We propose a new forecasting algorithm to predict recruitment for short- or medium-term stochastic projections, using a stock–recruitment relationship. We address cases in which the spawning stock has dropped below previously observed levels, or in which predicted recruitment is situated close to the maximum observed level. The relative prediction error of seven existing algorithms was compared with that of the new model using leave-one-out cross-validation for 61 data sets from ICES, the Japanese Fisheries Agency, and PICES. The new algorithm had the smallest prediction error for 49 of the data sets, but was slightly biased by the precautionary treatment of predictions of high recruitment.

scholarly journals Zooplankton community responses to the mixture of imazethapyr with imazapic and bispyribac-sodium herbicides under rice paddy water conditions

2014 ◽  
Vol 44 (8) ◽  
pp. 1392-1397 ◽  
Author(s):  
Geovane Boschmann Reimche ◽  
Sérgio Luiz de Oliveira Machado ◽  
Renato Zanella ◽  
Michele Câmara de Vicari ◽  
Fernando Piccinini ◽  
...  
Keyword(s):  
Half Life ◽  
Zooplankton Community ◽  
Rice Paddy ◽  
Paddy Fields ◽  
Community Responses ◽  
Paddy Water ◽  
Adult Copepod ◽  
Water Conditions ◽  
Rice Paddy Fields

The aim of this study was to assess the effect of concentrations of imazethapyr, imazapic, and bispyribac-sodium herbicides on zooplankton community (Cladocer, Copepod and Rotifer) in rice paddy fields. The decrease of half-life dissipation (DT50) of the herbicides under study in water was: imazethapyr, imazapic, and bispyribac-sodium with an average of 3.75, 3.73 and 1.91 days, respectively. The mixture of imazethapyr with imazapic caused change in the analyzed zooplankton, with an increase in the densities of Cladocer and adult Copepod groups, while bispyribac-sodium caused a reduction of density in Copepod group, both adults and nauplii, in the initial samples. Among the groups, Rotifer was slightly sensitive to the herbicides.

scholarly journals Eco-evolutionary dynamics in urbanized landscapes: evolution, species sorting and the change in zooplankton body size along urbanization gradients

2017 ◽  
Vol 372 (1712) ◽  
pp. 20160030 ◽  
Author(s):  
Kristien I. Brans ◽  
Lynn Govaert ◽  
Jessie M. T. Engelen ◽  
Andros T. Gianuca ◽  
Caroline Souffreau ◽  
...  
Keyword(s):  
Body Size ◽  
Evolutionary Dynamics ◽  
Spatial Scales ◽  
Zooplankton Community ◽  
Urban Heat Islands ◽  
Integrated Analysis ◽  
Large Species ◽  
Species Sorting ◽  
Cladoceran Species ◽  
Urbanization Gradients

Urbanization causes both changes in community composition and evolutionary responses, but most studies focus on these responses in isolation. We performed an integrated analysis assessing the relative contribution of intra- and interspecific trait turnover to the observed change in zooplankton community body size in 83 cladoceran communities along urbanization gradients quantified at seven spatial scales (50–3200 m radii). We also performed a quantitative genetic analysis on 12 Daphnia magna populations along the same urbanization gradient. Body size in zooplankton communities generally declined with increasing urbanization, but the opposite was observed for communities dominated by large species. The contribution of intraspecific trait variation to community body size turnover with urbanization strongly varied with the spatial scale considered, and was highest for communities dominated by large cladoceran species and at intermediate spatial scales. Genotypic size at maturity was smaller for urban than for rural D. magna populations and for animals cultured at 24°C compared with 20°C. While local genetic adaptation likely contributed to the persistence of D. magna in the urban heat islands, buffering for the phenotypic shift to larger body sizes with increasing urbanization, community body size turnover was mainly driven by non-genetic intraspecific trait change. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.

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