FIS workshop on Global synthesis of climate impacts on fish distribution and growth and implications for Scottish fisheries: FIS028

The aim of FIS028 was to determine whether the spatial distribution and individual growth rates of marine fish show a coherent set of responses globally that are consistent with physiological, ecological and logical expectations. Ifso, then this knowledge could provide a firm foundation for forecasting the impacts of future climate warming in Scottish waters and elsewhere. Experts from the UK, Australia, US, Canada, Norway, Iceland, Denmark, and Germany attended a 5-day workshop with eight scientists from US, Canada, Australia, and Chile participating in workshop discussions remotely. Recognising the importance of communicating current scientific knowledge in an accessible way, a public event was held to share global and local perspectives on the impacts of climate change on distribution, productivity and management of commercial fish stocks. The discussions resulted in a range of general insights about climate impacts on fish distribution and growth, including how the fishing industry will need to adapt, that are summarised below. Global evidence of distributional shifts There is ample evidence of changes in the distribution of marine species occurring worldwide that generally, but not always, result in shift poleward and/or towards deeper waters. These distributional changes are often associated with warming, although the occurrence of density-dependent habitat selection, and the impact of fishing pressure were also noted to affect distribution. Improving data collection and reporting of fish distribution would contribute towards our understanding of distribution changes of commercial marine species. Global evidence on changes in individual growth There is limited but growing support for temperature impacts on growth rates of individual that are consistent with the physiological expectation that warmer waters result in smaller adult body sizes. Consequently, there has likely been unrecognised, climate-driven declines in yield of commercial fish stocks in regional seas that have already experienced strong warming trends. Differential vulnerability of fish stocks to climate change Quantitative vulnerability assessments are being used to describe risks and identifying priority stocks for conservation or adaptation measures. Global-scale assessments of the vulnerability of marine resources suggests that the vulnerability of UK fisheries resources is small compared to other regions. On more regional scales, vulnerability analyses are useful for identifying commercial stocks that should be prioritised for adaptation planning. Vulnerability of fishing industry to storminess There is evidence suggesting that frequency and intensity of storms will increase in the Northeastern Atlantic. The vulnerability of fisheries
to changes in storminess is unclear at present. Vulnerability assessments for specific fishing industries should be examined by incorporating appropriate measures of exposure, sensitivity and adaptive capacity to storms. Policy adaptation A research base is developing to prepare ocean governance, specifically policy, for the reality of climate-driven shifts in distribution of fish resources. It would be useful to explore the range of policy levers that are available to deal with this problem and summarise global experience. Economic and structural drivers of adaptation Climate effects on fisheries can be complex
because they arise from different physical, biological and economic drivers and different fleets react differently to these drivers. Scenario modelling using available economic data could be used to identify different adaptation pathways specific for different fleets conditioned on the most likely biological impacts.
Bottom-up versus top-down approaches to adaptation Approaches to national adaptation planning were reviewed for Australia, UK and US. These examples differed in the degree to which there was a centralised national approach and how feasibility of various adaptation options were evaluated. Salience of climate change to the fishing industry In general fishers perceive climate change
to operate on time scales that are too long to be of relevance to day-to-day operations. An example from Australia illustrated how quickly the attitude of fishers could change when presented with first-hand experience of extreme weather events and scientific knowledge that is communicated effectively.
Innovation in developing an evidence base for tracking climate change The fishing industry generates a wealth of standardised information that has yet to be fully captured by scientists. For example, industry-generated roe data has yielded valuable evidence of shifts in spawning times of North Sea cod. It would be useful to consider future data needs so that appropriate databases can be developed.