Periodic Reporting for period 1 - Co-tRiP (Dolphinfish living in a warming ocean: How global climate change is reshaping the distribution, physiology and behaviour of marine migratory species and their associated fisheries.)
Période du rapport: 2018-01-01 au 2019-12-31
Fish and seafood from small-scale fisheries play a key role in global food security. In consequence, long-term management plans will need to consider the future impacts of climate change on living aquatic resources and the human communities that depend on them.
The geographical boundaries and productivity centroids of individual fisheries are changing in response to ocean warming. These changes can lead to economic disruption if a fish population becomes less or more productive or moves out of traditional fishing grounds. Dolphinfish support a commercial, artisanal and recreational fishery worldwide. The species is known to respond strongly to climate change through changes in spawning grounds, larval growth, etc. Co-tRiP addressed the ecological and socio-economic consequences of climate change on this species in the NW Mediterranean. The specific objectives of Co-tRiP included: 1) To estimate the effect of environmental variability on the extent and location of spawning grounds, spawning phenology, and growth of dolphinfish recruits; 2) To address how these effects and long-term environmental trends can be used to project the impacts of climate change; and 3) To assess how projected changes could affect artisanal fisheries in terms of phenology and production and anticipate industry/market adjustment.
Co-tRiP found for the dolphinfish in the NW Mediterranean that: 1) its predicted spawning habitat shows a remarkable expansion from the 1990s to the last; 2) its maximum expansion range was reached in the 2000s; 3) its reproductive period has been extended, bringing forward the onset of reproduction and delaying its end; 4) between 20 and 60 more days in the year may now be suitable for its reproduction compared to the 1980s and; 5) its temperature-mediated larval development and growth is also predicted to have accelerated. Overall, climate change could be signifying an increased recruitment rate for dolphinfish. Although fishery catches may affect the size of populations, making them more sensitive to other stressors such as climate change, and reduce their reproductive potential, small-scale fisheries targeting dolphinfish in the NW Mediterranean are reasonably well managed through strict control of the number of boats, allowed exclusion by date and self-imposed quota limits agreed by fishermen to control prices.
Trends in environmental conditions are expected to continue throughout the 21st century, and the cultural, social and economic conditions surrounding fisheries are expected to evolve towards even greater sustainability. FAO declared the species a priority species in 2019, and a management plan for the whole Mediterranean stock is being fostered and funded. If this were to happen, we could speak of a winning species in the face of climate change adversities.
The geographical boundaries and productivity centroids of individual fisheries are changing in response to ocean warming. These changes can lead to economic disruption if a fish population becomes less or more productive or moves out of traditional fishing grounds. Dolphinfish support a commercial, artisanal and recreational fishery worldwide. The species is known to respond strongly to climate change through changes in spawning grounds, larval growth, etc. Co-tRiP addressed the ecological and socio-economic consequences of climate change on this species in the NW Mediterranean. The specific objectives of Co-tRiP included: 1) To estimate the effect of environmental variability on the extent and location of spawning grounds, spawning phenology, and growth of dolphinfish recruits; 2) To address how these effects and long-term environmental trends can be used to project the impacts of climate change; and 3) To assess how projected changes could affect artisanal fisheries in terms of phenology and production and anticipate industry/market adjustment.
Co-tRiP found for the dolphinfish in the NW Mediterranean that: 1) its predicted spawning habitat shows a remarkable expansion from the 1990s to the last; 2) its maximum expansion range was reached in the 2000s; 3) its reproductive period has been extended, bringing forward the onset of reproduction and delaying its end; 4) between 20 and 60 more days in the year may now be suitable for its reproduction compared to the 1980s and; 5) its temperature-mediated larval development and growth is also predicted to have accelerated. Overall, climate change could be signifying an increased recruitment rate for dolphinfish. Although fishery catches may affect the size of populations, making them more sensitive to other stressors such as climate change, and reduce their reproductive potential, small-scale fisheries targeting dolphinfish in the NW Mediterranean are reasonably well managed through strict control of the number of boats, allowed exclusion by date and self-imposed quota limits agreed by fishermen to control prices.
Trends in environmental conditions are expected to continue throughout the 21st century, and the cultural, social and economic conditions surrounding fisheries are expected to evolve towards even greater sustainability. FAO declared the species a priority species in 2019, and a management plan for the whole Mediterranean stock is being fostered and funded. If this were to happen, we could speak of a winning species in the face of climate change adversities.
Co-tRiP's research activities were based largely on existing dolphinfish databases on the by-catch of the Spanish longline fishing fleet in the W Mediterranean, FAD (Fishing Device Aggregators) fleet of the Balearic Is., and the growth of individual based on otolith readings. In parallel, consensus and validated models of observed historical climatology and projected future climatology were needed.
The 1st. activity was the prediction of dolphinfish spawning habitat in the NW Mediterranean based on seawater temperature. The data sources used were the longline database and observed historical climatology. A combination of spatially explicit models allowed predictions to be made in the projected future climatology databases. The results suggest a potential future expansion of historical spawning grounds. The results were validated by comparison with other fisheries databases, such as those of the Balearic Is., Malta, Sicily, and Tunisia FAD fleets, which catch the young of the year that aggregate close to the coast during the summer and autumn months.
The 2d. activity focused on testing whether a temporal expansion of warm days leads to an expansion of spawning days and additionally to more accelerated growth of early stages hatching under these circumstances. Under a generalized global warming scenario and if the opening date of the fishery were to remain unchanged over time, higher recruitment of the population would be expected and more and larger individuals could be caught. To evaluate this hypothesis, individual growth databases based on otolith readings, observed historical climatology and projections from the RCP4.5 and RCP8.5 climatological models were used as inputs. Models were used to predict individual growth under different temperature scenarios and considering associated mortality rates. Projected catch length distributions for the end of the century yielded mean lengths between 5.1% and 12.8% longer.
The 3d. activity assessed how projected changes in temperature might affect artisanal fisheries in terms of phenology and growth and anticipate industry and market adjustment. To this end, a model integrating ecological, social and economic inputs was developed to assess the impact of plausible medium-term futures (2040-2059) on the seasonal economic profit of fishers in Mallorca. These future scenarios considered sea temperature increase based on IPCC global projections, dolphinfish population dynamics and growth, economic forecasts of future fish and fuel prices, and stakeholder views on feasible adaptations of the local management system. The scenarios pointed to an increase in profits for fishers. Options such as bringing forward the opening date of the fishing season in response to climate-induced changes in growth and body size of dolphinfish could be economically beneficial. However, this will critically depend on the evolution of unknown factors such as changes in other target species, people's consumption habits and market dynamics.
Co-tRiP's dissemination activities include the publication of 6 peer-reviewed scientific papers and 5 more under review; 4 conference participations and several mentions in journals and blogs.
The 1st. activity was the prediction of dolphinfish spawning habitat in the NW Mediterranean based on seawater temperature. The data sources used were the longline database and observed historical climatology. A combination of spatially explicit models allowed predictions to be made in the projected future climatology databases. The results suggest a potential future expansion of historical spawning grounds. The results were validated by comparison with other fisheries databases, such as those of the Balearic Is., Malta, Sicily, and Tunisia FAD fleets, which catch the young of the year that aggregate close to the coast during the summer and autumn months.
The 2d. activity focused on testing whether a temporal expansion of warm days leads to an expansion of spawning days and additionally to more accelerated growth of early stages hatching under these circumstances. Under a generalized global warming scenario and if the opening date of the fishery were to remain unchanged over time, higher recruitment of the population would be expected and more and larger individuals could be caught. To evaluate this hypothesis, individual growth databases based on otolith readings, observed historical climatology and projections from the RCP4.5 and RCP8.5 climatological models were used as inputs. Models were used to predict individual growth under different temperature scenarios and considering associated mortality rates. Projected catch length distributions for the end of the century yielded mean lengths between 5.1% and 12.8% longer.
The 3d. activity assessed how projected changes in temperature might affect artisanal fisheries in terms of phenology and growth and anticipate industry and market adjustment. To this end, a model integrating ecological, social and economic inputs was developed to assess the impact of plausible medium-term futures (2040-2059) on the seasonal economic profit of fishers in Mallorca. These future scenarios considered sea temperature increase based on IPCC global projections, dolphinfish population dynamics and growth, economic forecasts of future fish and fuel prices, and stakeholder views on feasible adaptations of the local management system. The scenarios pointed to an increase in profits for fishers. Options such as bringing forward the opening date of the fishing season in response to climate-induced changes in growth and body size of dolphinfish could be economically beneficial. However, this will critically depend on the evolution of unknown factors such as changes in other target species, people's consumption habits and market dynamics.
Co-tRiP's dissemination activities include the publication of 6 peer-reviewed scientific papers and 5 more under review; 4 conference participations and several mentions in journals and blogs.
Beyond warning about the negative consequences of climate change for humanity, Co-tRiP focused on the acceptance that recent climate change due to anthropogenic causes is a fact, that it is unstoppable in the mid-term and that, consequently, we must find ways to live under its effects, anticipate them and adapt our fisheries to the most likely scenarios. Not all the fish species we consume and not all fisheries will adapt. However, in some prominent cases, such as the dolphinfish fishery, both the species and the associated artisanal fishing fleet will respond positively to these changes. Co-tRiP has developed: 1) a spatially explicit model that will make it possible to anticipate which areas of the northwestern Mediterranean may become essential dolphinfish spawning habitat in the short, medium and long term (2040, 2060 and 2100 respectively); 2) a thermo-dependent individual growth model to anticipate the sizes of individuals entering the fishery under different scenarios of global change and 3) a coupled bio-socio-ecological and economic model that makes it possible to anticipate how the dolphinfish fishery will respond to the different configurations resulting from a world that is developing economically and politically in a context of global warming. Co-tRiP shows that even in fisheries without information on stock status, an integrated and holistic assessment of the adaptive capacities of management systems is possible.