Fisheries Oceanography最新文献

Exploring the impacts of climate variability on the marine fishery ecosystems in the Southwest Atlantic Ocean is conducive to establishing an ecosystem-based approach for the protection and rational utilization of fishery resources. In this study, long-term fisheries data, 23 environmental data from the entire Southwest Atlantic, and 25 global climate data have been used to explore the regime shift of the fishery ecosystem and the response of fishery resources to climate change from 1950 to 2018. The results indicated that changes in the Southwest Atlantic fishery ecosystem exhibited a significant nonstationary trend, and there were three noteworthy regime shifts in 1976/1977, the late 1980s, and the late 20th century. The temperature, sea surface height, water runoff, and cloudiness were the environmental variables with the greatest impact on fishery resources within the Southwest Atlantic Fishery Ecosystem, while zonal wind speed and air temperature yielded a more significant impact on low latitude areas. In terms of climate indices, fishery resources have the most obvious response to the Global Mean Land-Ocean Temperature Index and Antarctic Sea Ice Extent, and the Atlantic Multidecadal Oscillation had an intense impact on low latitude areas concurrently. The study highlights the climate-related nonstationary changes in the Southwest Atlantic fishery ecosystem.

Offshore wind energy development on the Mid-Atlantic Bight (MAB) portion of the Northwestern Atlantic continental shelf could have adverse impacts on the future of the Atlantic surfclam, Spisula solidissima, fishery. The current and potential future areas designated for offshore wind energy development overlap with the present-day and projected Atlantic surfclam fishing grounds and so could limit the fishery. Fishery impacts imposed by displacement of fishing outside wind farm areas and possible restrictions on vessel transit through the wind farms were simulated using a spatially explicit fishery model. The distribution of catch, hours fished, landings per unit effort (LPUE), time at sea, fishing mortality, and the number of fishing trips were projected for five time periods encompassing the period of 2016–2055. Simulations showed a significant decline in the mean of all fishery metrics (apart from LPUE) as the area of wind farm restrictions increased in scale. Impacts were consistently larger when vessel transit through and fishing within offshore wind areas were prohibited. Impacts were also larger for MAB regions off New Jersey and Delmarva than regions farther north and east. These simulations highlight the necessity of evaluating future conditions as warming temperatures shift the surfclam range relative to the immobile wind farm locations. The offshore wind industry must consider projected long-term impacts of developmental expansion on surrounding sedentary benthic species and the commercially important fisheries that rely on them.

Climate change poses a significant threat to marine ecosystems, potentially altering the distribution of marine organisms and causing many species to migrate towards the poles. The habitat changes of species targeted for fishing are likely to affect fishing activities and the livelihoods of coastal communities. Hence, the present study analyzed the distribution of Indo-Pacific king mackerel (IKM) in the Taiwan Strait (TS) by using ensemble modeling and considering two representative concentration pathway (RCP) scenarios (2.6 and 8.5) to assess the implications of predicted climate change. Four species distribution models incorporating sea surface height, chlorophyll, salinity, and temperature were used as inputs to create an ensemble model that replicated IKM distribution under current ocean conditions. The ensemble habitat model does not show monotonic decrease of IKM habitat but reveals more complex change in the 21st century with a hump around 2050. By end of the century, IKM is predicted to decline under RCP 8.5 scenario more seriously than under RCP 2.6. The study highlights the need for adaptation measures in managing IKM fisheries in the TS, emphasizing the importance of considering non-unidirectional habitat changes in the global oceans as well.

The distribution of fish larvae and other planktonic organisms is highly heterogenous and influenced by a complex interplay of physical, behavioural and ecological processes operating across different scales. Information on patterns and scale of resulting patchiness in plankton distributions is pivotal for understanding the bio-physical linkages, trophodynamics and ecological strategies in the marine pelagic environment. In this study, we examine the distribution and degree of patchiness of four fish larvae species and their copepod prey, placing specific emphasis on the scale of patterns in both horizontal and vertical dimensions. Our sampling effort encompassed a 120 km long transect of stations covering a frontal area in the southern North Sea, employing depth-stratified net sampling at varying station distances. Our results show distinct distributional patterns and migratory behaviours among different taxa of both larvae and their copepod prey, yet some commonalities were apparent. Across all species, we observed increased patchiness at larger spatial scales, significantly influenced by day/night fluctuations and hydrography. The overall findings highlight the dynamic nature of patch distributions and underscore the strong impact of hydrographic interfaces, whether vertically oriented pycnoclines or horizontally structured hydrographic fronts. These insights into bio-physical linkages deepen our understanding of the mechanisms driving larval survival, prey availability and overall ecosystem dynamics.

Antarctic krill (Euphausia superba; krill) and the pelagic tunicate (Salpa thompsoni; salps) are crucial to the Southern Ocean ecosystem, and krill supports the largest fishery in the Southern Ocean in term of catch. Given recent climatic changes in the northern Antarctic Peninsula (NAP), the distribution of krill and salps are shifting poleward. Unlike krill, salps thrive in warmer water temperatures and can form large blooms under favorable conditions, potentially outcompeting krill for resources. However, krill are ecologically more important, serving as a primary food source for higher trophic levels. The interspecific interactions, including hotspots and ecological niches, of krill and salps in the NAP were therefore investigated using historical datasets and species distribution models. We found that both spatial separation and overlap occurred between krill and salps hotspots, with the primary overlap occurring around Elephant Island. Furthermore, there was a significant overlap in their ecological niches, suggesting that they may have similar ecological requirements. This study emphasized the importance of krill and salps interactions in the Southern Ocean ecosystem. The krill habitat and therefore food web of the Southern Ocean could be influenced significantly if salps continue to shift poleward in the future. The information provided in this study aids in the conservation and management of the Southern Ocean ecosystem.

The Atlantic surfclam, Spisula solidissima, and ocean quahog, Arctica islandica, are biomass dominant bivalve species on the eastern North American continental shelf, both supporting lucrative commercial fisheries in the Mid-Atlantic with a combined value of about $53.6 million in ex-vessel revenue per year. The thermal tolerance of Atlantic surfclam is generally below 20 °C, whereas the boreal ocean quahog resides in colder waters maintained by the Mid-Atlantic Bight Cold Pool. Climate-induced warming of bottom water temperatures is thought to be linked to the observed distributional shift of the Atlantic surfclam population into waters historically dominated by ocean quahogs. As climate change is expected to continue, this study investigated the future distributions of the two species from years 2016 to 2095 using projected bottom water temperatures and a temperature-dependent population dynamics model. Simulations show the progressive colonization of Atlantic surfclams offshore into the region earlier occupied by the Cold Pool throughout the 79-year projection, beginning between the mid-2040s and mid-2050s, effectively compressing ocean quahog habitat on all sides. Ocean quahogs are shown to be vulnerable to climate-induced warming on both the southern, inshore, and offshore portions of the continental shelf, ultimately restricting their habitat by the end of the 21st century to the remaining core of the Cold Pool off Long Island. Atlantic surfclams, however, are likely to be less vulnerable to climate-induced warming, ultimately increasing their geographic footprint across the MAB. Model projections indicate a large-scale reorganization event of the continental shelf benthic community structure throughout the remainder of the 21st century.

The Atlantic surfclam, Spisula solidissima supports a lucrative commercial fishery in the Mid-Atlantic Bight (MAB) worth roughly $30 million in revenue per year. Rapid climate change is expected to modify the geographic range of the Atlantic surfclam, with consequences for the surfclam fishery. This study evaluated fishery-based indicators projected from 2020 through 2095 based on anticipated changes in the geographic range and biomass of the Atlantic surfclam, using a Spatially Explicit, agent-based Fisheries and Economics Simulator (SEFES). Simulations generally showed a positive trend in Atlantic surfclam biomass throughout the next three-quarters of the 21^st century as the clam's range continues to shift offshore and northward along the continental shelf. A general decrease in fishing mortality rate is projected given the present fleet capacity, with a simultaneous increase in catch and landings per unit effort (LPUE), signaling future potential growth in the surfclam fishery. Regionally, forecasts show biomass expanding into deeper waters particularly off New Jersey, Long Island, and southern New England starting in the early 2050s, whereas populations on Georges Bank and off Delmarva gradually decline. Trends in time spent fishing, catch, and LPUE parallel those of biomass in each region. These results can inform managers and business interests that rely on this fishery, as well as other users of the continental shelf, to provide a basis for the development of anticipatory management for the socio-ecological and economic impacts that may result from future changes in the Atlantic surfclam range and carrying capacity consequent of climate change.