Study calls for conserving straddling stocks

A new University of British Columbia study concludes that closing high seas to fishing could boost catches in coastal waters by 10 percent, helping people cope with anticipated losses of fish due to climate change.

The study found that climate change is projected to alter the sharing of potential catches of straddling fish stocks between countries, with tropical countries losing out over the next few decades.

Large-scale transformation of international fisheries governance, through cooperatively managing the resources or closing the high seas, would help partially compensate for losses expected from climate change impacts on countries’ seafood production, according to the study, “Transform high seas management to build climate resilience in marine seafood supply,” which was published online in Fish and Fisheries, at http://onlinelibrary.wiley.com/doi/10.1111/faf.12177/full

High seas closures, the study said, are also effective in improving equitable sharing of straddling fisheries resources and enhance fish stock resilience.

Straddling stocks are fish stocks that migrate through, or occur in, more than one exclusive economic zone. The 30 stocks included in the study, and the percentage of each caught on the high seas, included skipjack tuna, 64 percent; chub mackerel, 16 percent; Chilean jack mackerel, 52 percent; Blue whiting, 17 percent; swordfish, 68 percent;

As fishing level reduces, abundance of high seas fish stocks increases, leading to density-dependent emigration into the exclusive economic zones, indirectly increasing fisheries productivity of the stocks, the study said. The result suggests that improving high seas management may create opportunities to reduce regional differences in climate change impacts. While global level impacts of climate change in these EEZs could be fully compensated for by effective management of high seas fisheries and mitigation of emissions, large impacts will remain in regions that are more sensitive to climate change, such as the tropics.

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Closing the high seas to fishing or sustainably managing its fisheries under cooperative management would strengthen fish stock resilience that compensates for the impacts from higher emissions, the study said.

The document acknowledged that challenges facing the pursuit of effective high seas management include attaining cooperation for all countries involved in fishing activities.

The issue is particularly difficult to address for vessels that are registered under foreign flags, also known as “flags of convenience.” In such instances, little or no ties exist between the owner of the vessel and the vessel’s “flag state,” the country that holds jurisdiction and control over the vessel when it is operating in the high seas.

The absence of flag state responsibility has been linked to the facilitation of illegal, unreported and unregulated fishing, a major problem facing fisheries worldwide.

Insufficient flag state monitoring and control of distant-water fleets would perpetuate the emergence of IUU fishing without drastic measures such as a closure, the study said.

While the study focused on the impact of climate change on potential catches under different fishing and climate change scenarios, the effects of revenues, costs of fishing and profits were not explored, as they were considered to be outside the scope of the study, researchers said.

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