Title : Impact of global climate change on apex pelagic predators of the world's oceans: Potential adaptation or tropicalization
Abstract:
Examining the consequences of worldwide climate change on fisheries is essential as it directly impacts the well-being of marine ecosystems, the sustenance of millions of individuals, and the security of global food supplies. Thus, understanding these impacts is crucial for developing adaptive management strategies for sustainable fisheries. This study aimed a comprehensive analysis on the potential responses of apex pelagic predators inhabiting in the Indian and South Atlantic oceans in response to changing climate conditions. The study analyzed sea surface temperature, salinity, and chlorophyll levels to predict species' impact by the end of the 21st century using a generalized additive model in response to normal and extreme conditions. Significant shifts in the mean temperature of catch (MTC) were forecasted for all species inhabiting the Indian and South Atlantic oceans under extreme climatic conditions (potential adaptation), but no changes in MTC were expected under normal conditions. All the species from both oceans exhibited a tendency to shift their distribution latitudinally (southward) in response to extreme conditions, while shifting longitudinally (wither east or westward) under normal conditions (potential tropicalization). In addition, South Atlantic species were predicted to experience higher latitudinal and longitudinal displacements (33-1125 kms, and 11-724 kms) compared to those in the Indian Oceans (33- 679 kms, and 45-468 kms), in normal to extreme conditions. Present study suggests that, tropical Indian ocean species like bigeye, skipjack, yellowfin tuna, swordfish and marlins are less susceptible to climate change due to higher SST preferences, while temperate Indian ocean species like albacore and southernbluefin tuna are more vulnerable compared to their counterparts in the South Atlantic ocean under changing climatic conditions. The study's results can enhance comprehension of the potential consequences of climate change on marine species, provide guidance for conservation strategies, and assist in the development of adaptive management practices for sustainable fisheries in global oceans.