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Olaf Jensen

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Recruitment often varies substantially in fish populations, and residual variability may have serial autocorrelation due to environmental effects even after accounting for a stock-recruitment relationship. However, the likely magnitude of variability and autocorrelation in recruitment has yet to be formally estimated. We therefore developed a hierarchical model for recruitment variability and autocorrelation and applied it to data for 154 fish populations. Results were similar when using either the Ricker or Beverton-Holt stock-recruitment model, and showed that autocorrelated recruitment has a marginal standard deviation of 0.74 (SD = 0.35) and a mean autocorrelation of 0.43 (SD = 0.28) when predicting for an unobserved...
Categories: Data, Publication; Types: Citation
Abstract (from American Fisheries Society): Climate change is a global persistent threat to fish and fish habitats throughout North America. Climate-induced modification of environmental regimes, including changes in streamflow, water temperature, salinity, storm surges, and habitat connectivity can change fish physiology, disrupt spawning cues, cause fish extinctions and invasions, and alter fish community structure. Reducing greenhouse emissions remains the primary mechanism to slow the pace of climate change, but local and regional management agencies and stakeholders have developed an arsenal of adaptation strategies to help partially mitigate the effects of climate change on fish. We summarize common stressors...
Categories: Publication; Types: Citation
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Quantifying the Impacts of Climate Change on Fish Growth and Production to Enable Sustainable Management of Diverse Inland Fisheries
Fisheries managers in Midwestern lakes and reservoirs are tasked with balancing multiple management objectives to help maintain healthy fish populations across a landscape of diverse lakes. As part of this, managers monitor fish growth and survival. Growth rates in particular are indicators of population health, and directly influence the effectiveness of regulations designed to protect spawning fish or to promote trophy fishing opportunities. Growth, combined with reproduction and survival, also determines the amount of fish biomass available for harvest, known as population production. Changing water temperatures can influence growth and production of managed fish species in multiple complex ways, increasing the...
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Science to Inform the Management of Bluegill Fisheries as a Social-Ecological System Under a Changing Climate
Recreational fisheries offer invaluable benefits to the communities they serve, including economic support, food security, and enhanced social connection with natural areas. In North America, bluegill are one of the most important species in terms of providing accessible, harvest-oriented recreational fisheries. In Wisconsin, they are the most caught, most harvested, and second-most targeted species in the state’s recreational fishery. Climate change offers further challenges. Warming temperatures and associated impacts have the potential to affect fish communities and their habitat with unpredictable implications for angler behavior, which can then cause further impacts on fish populations. Significant knowledge...
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