Smalås, A., Strøm, J. F., Amundsen, P.-A., Dieckmann, U., & Primicerio, R. (2020). Climate warming is predicted to enhance the negative effects of harvesting on high-latitude lake fish. Journal of Applied Ecology, 57 (2), 270–282. https://doi.org/https://doi.org/10.1111/1365-2664.13535
Summary:
Ecosystems at high latitudes are exposed to some of the highest rates of climate warming on earth, and freshwater ecosystems in those regions are already experiencing extended ice‐free seasons and warmer waters. The dominant fish species in these ecosystems are cold‐water salmonids, which play a central ecological role in lake ecosystems, where they are often exposed to size‐selective fisheries, making them potentially vulnerable to both exploitation and environmental perturbations. This study employed a model approach to address the combined effects of climate‐induced water temperature increase and fishing, over the period from 1950 to 2100 on the growth, demography and vulnerability of Arctic charr Salvelinus alpinus (L.). The model predicted that higher water temperatures would increase the growth of Arctic charr, leading to larger body size at age and increased stock biomass: 80% increase in stock biomass in the absence of fishing, and 40% increase in biomass with fishing mortality of 0.3 year−1 in 2100 in comparison to 2000. In addition, climate warming will affect younger individuals more, thus elevating the vulnerability of the population to environmental perturbations. The model‐based analyses highlight the combined effects of climate change and size‐selective fishing, emphasizing the emerging vulnerability of fish populations to multiple stressors. The authors recommended careful climate‐adapted management strategies permitting only a narrow range of fishing mesh sizes for inland fisheries at high latitudes.
Policy relevant message:
High latitudes ecosystems have been exposed to some of the highest rates of climate warming on earth, with extended ice-free seasons already recorded. The dominant fish species in these ecosystems are cold‐water salmonids, which play a central ecological role in lake ecosystems. These species are often exposed to size‐selective fisheries, making them potentially vulnerable to both exploitation and environmental perturbations. Careful climate‐adapted management strategies permitting only a narrow range of fishing mesh sizes for inland fisheries at high latitudes are strongly recommended.