Some fisheries may falter while others could become more productive as the world's waters continue to warm, according to a new study, which looks to the productivity of fisheries in the past to help predict the impact of climate change on future fisheries. While the study reveals a reduction in global fish populations over the past 80 years, the results could prove crucial for the development of successful management strategies going forward, through careful accounting for changing productivity in warmer oceans, the authors say. The planet's oceans have become a globally important source of food and economic support for rapidly growing populations. However, poorly managed fisheries and decades of intense overfishing have placed many species of fish under extreme pressure. What's more, many of these fish stocks are also being impacted by continued ocean warming due to global climate change, although the overall effect on fisheries remains largely unknown. To address this question, Christopher Free and colleagues used temperature-specific models to "hindcast" temperature-driven changes on fisheries productivity from 1930-2010. Free et al. evaluated 235 populations of 124 marine species from oceans around the world, which represented roughly 33% of the reported global catch during this time. While the results revealed a decline in global fisheries' productivity overall - with losses in some regions as high as 35% - the authors found that changes in temperature affected some species more than others. While most populations will experience a negative impact, some, like black sea bass in the Mid-Atlantic U.S. coast, are predicted to respond positively. Furthermore, the results add to results that show that historical overfishing can amplify the negative effects of climate change. While Free et al.'s study does not account for other climate-driven environmental stressors, such as ocean acidification, which can also lead to declines in marine populations, Éva Pláganyi writes in a related Perspective: "Free et al.'s study represents an important advance on earlier species-distribution-based assessments," by providing projections that are critical to the success of future planning and adaptation strategies.
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Journal
Science