Climate effects on fish in Sweden : Species-Climate Information Sheets for 32 key taxa in marine and coastal waters

Abstract

The purpose of this publication is to summarize the state of knowledge on the effects of environmental variability and climate change for individual species and stocks based on literature review, giving species-climate information for 32 key taxa in Swedish marine and coastal waters. The report is written in English. The extent and scale of recent changes in climate due to global warming is unprecedented and causes increasing effects on ecosystems. In oceans, ongoing warming leads to, for example, increased water temperatures, decreased ice cover and effects on hydrology and water circulation patterns that can in turn influence salinity. The environmental alterations affect species distribution, biology, and hence also the delivery of marine ecosystem services and human well-being. The results of this review on the effects of environmental variability and climate change on marine taxa are presented as species-climate information sheets designed in a user-friendly format aimed to enhance accessibility for professionals spanning different fields and roles, including e.g. scientific experts, NGOs affiliates and managers. The species-climate information sheets presented here cover 32 key taxa selected among the economically and ecologically most important coastal and marine fish and crustacean species in Swedish waters. The species-wise evaluations show that climate change leads to a wide range of effects on fish, reflecting variations in their biology and physiological tolerances. The review also highlights important data and knowledge gaps for each species and life stage. Despite the high variability and prevailing uncertainties, some general patterns appeared. On a general level, most fish species in Swedish marine and coastal waters are not expected to benefit from climate change, and many risks are identified to their potential for recruitment, growth and development. Boreal, marine and cold-adapted species would be disadvantaged at Swedish latitudes. However, fish of freshwater origin adapted to warmer temperature regimes could benefit to some extent in the Baltic Sea under a warming climate. Freshwater fish could also be benefitted under further decreasing salinity in the surface water in the Baltic Sea. The resulting effects on species will not only depend on the physiological responses, but also on how the feeding conditions for fish, prey availability, the quality of essential fish habitats and many other factors will develop. A wide range of ecological factors decisive for the development of fish communities are also affected by climate change but have not been explored here, where we focused on the direct effects of warming. The sensitivity and resilience of the fish species to climate change will also depend on their present and future health and biological status. Populations exposed to prolonged and intense fishing exploitation, or affected by environmental deterioration will most likely have a lower capacity to cope with climate change effects over time. For both the Baltic Sea and the North Sea, it is important to ensure continued work to update and improve the species-climate information sheets as results from new research become available. It can also be expected that new important and relevant biological information and improved climate scenarios will emerge continuously. Continued work is therefore important to update and refine the species-climate information sheets, help filling in currently identified knowledge gaps, and extend to other species not included here. Moreover, there is need to integrate this type of species-level information into analyses of the effects of climate change at the level of communities and ecosystems to support timely mitigation and adaptation responses to the challenges of the climate change.