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Rebuilding overexploited marine populations is an important step to achieve the United Nations' Sustainable Development Goal 14—Life Below Water. Mitigating major human pressures is required to achieve rebuilding goals. Climate change is one such key pressure, impacting fish and invertebrate populations by changing their biomass and biogeography. Here, combining projection from a dynamic bioclimate envelope model with published estimates of status of exploited populations from a catch‐based analysis, we analyze the effects of different global warming and fishing levels on biomass rebuilding for the exploited species in 226 marine ecoregions of the world. Fifty three percent (121) of the marine ecoregions have significant (at 5% level) relationship between biomass and global warming level. Without climate change and under a target fishing mortality rate relative to the level required for maximum sustainable yield of 0.75, we project biomass rebuilding of 1.7–2.7 times (interquartile range) of current (average 2014–2018) levels across marine ecoregions. When global warming level is at 1.5 and 2.6°C, respectively, such biomass rebuilding drops to 1.4–2.0 and 1.1–1.5 times of current levels, with 10% and 25% of the ecoregions showing no biomass rebuilding, respectively. Marine ecoregions where biomass rebuilding is largely impacted by climate change are in West Africa, the Indo‐Pacific, the central and south Pacific, and the Eastern Tropical Pacific. Coastal communities in these ecoregions are highly dependent on fisheries for livelihoods and nutrition security. Lowering the targeted fishing level and keeping global warming below 1.5°C are projected to enable more climate‐sensitive ecoregions to rebuild biomass. However, our findings also underscore the need to resolve trade‐offs between climate‐resilient biomass rebuilding and the high near‐term demand for seafood to support the well‐being of coastal communities across the tropics. [ABSTRACT FROM AUTHOR]

Climate change is shifting the distribution of shared fish stocks between neighboring countries' Exclusive Economic Zones (EEZs) and the high seas. The timescale of these transboundary shifts determines how climate change will affect international fisheries governance. Here, we explore this timescale by coupling a large ensemble simulation of an Earth system model under a high emission climate change scenario to a dynamic population model. We show that by 2030, 23% of transboundary stocks will have shifted and 78% of the world's EEZs will have experienced at least one shifting stock. By the end of this century, projections show a total of 45% of stocks shifting globally and 81% of EEZs waters with at least one shifting stock. The magnitude of such shifts is reflected in changes in catch proportion between EEZs sharing a transboundary stock. By 2030, global EEZs are projected to experience an average change of 59% in catch proportion of transboundary stocks. Many countries that are highly dependent on fisheries for livelihood and food security emerge as hotspots for transboundary shifts. These hotspots are characterized by early shifts in the distribution of an important number of transboundary stocks. Existing international fisheries agreements need to be assessed for their capacity to address the social–ecological implications of climate‐change‐driven transboundary shifts. Some of these agreements will need to be adjusted to limit potential conflict between the parties of interest. Meanwhile, new agreements will need to be anticipatory and consider these concerns and their associated uncertainties to be resilient to global change. [ABSTRACT FROM AUTHOR]

The article presents the discussion on climate change and fishing presenting dual threats. Topics include important to the homeostasis of the Earth system exhibiting distinctive marine biodiversity and having tremendous scientific impact; and climate regulation and oxygen production through the primary production of seasonal phytoplankton blooms.

Arctic sea ice loss has direct consequences for predators. Climate‐driven distribution shifts of native and invasive prey species may exacerbate these consequences. We assessed potential changes by modelling the prey base of a widely distributed Arctic predator (ringed seal; Pusa hispida) in a sentinel area for change (Hudson Bay) under high‐ and low‐greenhouse gas emission scenarios from 1950 to 2100. All changes were relatively negligible under the low‐emission scenario, but under the high‐emission scenario, we projected a 50% decline in the abundance of the well‐distributed, ice‐adapted and energy‐rich Arctic cod (Boreogadus saida) and an increase in the abundance of smaller temperate‐associated fish in southern and coastal areas. Furthermore, our model predicted that all fish species declined in mean body size, but a 29% increase in total prey biomass. Declines in energy‐rich prey and restrictions in their spatial range are likely to have cascading effects on Arctic predators. [ABSTRACT FROM AUTHOR]

In 2017, more than 15,000 scientists from 184 countries signed a second warning letter to humanity to caution against our continued wholesale destruction of global ecosystems (Ripple et al., 2017). Here, we reaffirm their message with a similar warning specifically focused on the ocean: humanity must immediately and significantly alter our harmful trajectory in order to avoid irrevocably damaging our oceans in multiple ways that will further affect ocean health for both us and future generations. The ocean is the world's largest realm, housing an astonishing array of biodiversity that provides critical ecological functions that ultimately support life on Earth. In this paper, we outline some of the significant ongoing and imminent activities that degrade ocean health, including destructive fishing practices, oil and natural gas extraction, seabed mining, coastal development, shipping, pollution, and greenhouse-gas emissions. We end by offering potential avenues to mitigate these impacts, including the cessation of particularly harmful activities, restoration of damaged habitats, strong protection of key and representative ecosystems, reduction in waste and emissions, and global policy shifts that prioritize ecosystem health. • The ocean hosts a vast array of biodiversity that supports all life on Earth. • Ocean health is severely threatened by a large number of anthropogenic stressors. • Humanity must take immediate, transformative action to safeguard our ocean. [ABSTRACT FROM AUTHOR]