Abstract
Given the potential for rising global temperatures and changing oceanic conditions to affect marine organism distribution, the implications of climate change on marine ecosystem are a major concern. Thus, this study used ensemble modelling and two "Representative Concentration Pathway" scenarios (2.6 and 8.5) to investigate the effects of expected climate change on Indo-Pacific King mackerel and narrow-barred Spanish mackerel distribution in the Taiwan Strait. The findings of our study indicated that the geographical range of both species in the Taiwan Strait currently spans from 22 to 25.50N and 118 to 1210. Both species showed peak distribution in the regions where the sea surface temperature, sea surface chlorophyll, sea surface salinity, and sea surface height were 25–27 °C, 0.35-0.45 mg m-3, 33.5–34.5 PSU, and 0.625–0.675 m, respectively. Both RCP 2.6 and 8.5 scenarios indicated a habitat gain of 50% to 80% by 2045–2050 for the Indo-Pacific king mackerel. RCP 8.5 predicted a greater loss of habitat for the Indo-Pacific King mackerel (-30% to -70%) than RCP 2.6 (-7% to -15%) by the end of 2095–2100. On the other hand, 30% to 90% of habitat gain was observed from 2045–2050 to 2095–2100 for the narrow-barred Spanish mackerel under RCP 2.6. However, according to the RCP 8.5 scenario, a significantly greater extent of habitat loss was projected, ranging from -60% to -80%, compared to the habitat loss projected under the RCP 2.6 scenario, which ranges from -2% to -10% for the narrow-barred Spanish mackerel. Present results indicated that both mackerel species will have a significant adverse impact by the end of the 21st century under RCP 8.5, whereas possible chances of habitat gain were anticipated under RCP 2.6. The populations of both mackerel species in the Taiwan Strait have already collapsed, and organisations responsible for fisheries management need to implement ecosystem-based management strategies to maintain biologically sustainable levels of species stock. By incorporating the present knowledge into managerial strategies, decision-makers can make well-informed decisions that may also safeguard the other fisheries of the Taiwan Strait and the people who depend on them under evolving climatic circumstances.
Keywords: Climate change, Ensemble modeling, Mackerel fishery, Representative Concentration Pathway, Sustainability