The ocean crisis is urgent and central to human wellbeing and life on Earth; past and current activities are damaging the planet’s main life support system for future generations. We are witnessing an increase in ocean heat, disturbance, acidification, bio‐invasions and nutrients, and reducing oxygen levels. Several of these act like ratchets: once detrimental or negative changes have occurred, they may lock in place and may not be reversible, especially at gross ecological and ocean process scales.
Risk of impact of marine fishes to fishing and climate change (including ocean acidification) depend on the species’ ecological and biological characteristics, as well as their exposure to over‐exploitation and climate hazards. These human‐induced hazards should be considered concurrently in conservation risk assessment. In this study, we aim to examine the combined contributions of climate change and fishing to the risk of impacts of exploited fishes, and the scope for climate‐risk reduction from fisheries management. We combine fuzzy logic expert system with species distribution modeling to assess the extinction risks of climate and fishing impacts of 825 exploited marine fish species across the global ocean. We compare our calculated risk index with extinction risk of marine species assessed by the International Union for Conservation of Nature (IUCN). Our results show that 60% (499 species) of the assessed species are projected to experience very high risk from both overfishing and climate change under a “business‐as‐usual” scenario (RCP 8.5 with current status of fisheries) by 2050. The risk index is significantly and positively related to level of IUCN extinction risk (ordinal logistic regression, p < 0.0001). Furthermore, the regression model predicts species with very high risk index would have at least one in five (>20%) chance of having high extinction risk in the next few decades (equivalent to the IUCN categories of vulnerable, endangered or critically endangered). Areas with more at‐risk species to climate change are in tropical and subtropical oceans, while those that are at risk to fishing are distributed more broadly, with higher concentration of at‐risk species in North Atlantic and South Pacific Ocean. The number of species with high extinction risk would decrease by 63% under the sustainable fisheries‐low emission scenario relative to the “business‐as‐usual” scenario. This study highlights the substantial opportunities for climate‐risk reduction through effective fisheries management.
While the ecological impacts of fishing the waters beyond national jurisdiction (the “high seas”) have been widely studied, the economic rationale is more difficult to ascertain because of scarce data on the costs and revenues of the fleets that fish there. Newly compiled satellite data and machine learning now allow us to track individual fishing vessels on the high seas in near real time. These technological advances help us quantify high-seas fishing effort, costs, and benefits, and assess whether, where, and when high-seas fishing makes economic sense. We characterize the global high-seas fishing fleet and report the economic benefits of fishing the high seas globally, nationally, and at the scale of individual fleets. Our results suggest that fishing at the current scale is enabled by large government subsidies, without which as much as 54% of the present high-seas fishing grounds would be unprofitable at current fishing rates. The patterns of fishing profitability vary widely between countries, types of fishing, and distance to port. Deep-sea bottom trawling often produces net economic benefits only thanks to subsidies, and much fishing by the world’s largest fishing fleets would largely be unprofitable without subsidies and low labor costs. These results support recent calls for subsidy and fishery management reforms on the high seas.
This paper surveys the current state and major trends in global fisheries; the environmental and social dimensions of fisheries; and explains how the international community has tried to meet the policy challenges associated with oceans and fisheries. The ocean and the freshwater ecosystems of the world make significant contributions to people’s well-being via the many vital social and environmental services they provide (for example, food and nutrition, employment and incomes, carbon cycling and sequestration). The impact that the increase in fishing since the 1950s has had on wild fish stocks, and the significant increase in aquaculture production in the 20th century, have resulted in severe environmental impacts. This has significant effects on marine ecosystems and the health of oceans. The erosion of the resource undermines communities’ long-term interests, including food security, employment, and income. Attempts by the global community to address challenges of sustainable production by improving the governance and management of fisheries resources range from national management of fisheries resources, to regional fisheries management organisations (RFMOs) for international fisheries stocks. These attempts have not always successfully met the challenge of balancing current and future use of fisheries.