Almost half of the fish stocks shared by countries


According to a new UBC study, climate change will force 45% of fish stocks that cross two or more Exclusive Economic Zones to significantly leave their historic habitats and migration routes by 2100, a challenge that could lead to a international conflict.

By 2030, when the United Nations Sustainable Development Goals are expected to be met, 23% of these “transboundary” fish stocks will have altered their historic habitat. the modeling study also predicted that 78% of Exclusive Economic Zones (EEZs) – where most fishing activities take place – will experience at least one change in fish stock. By 2100, this will climb to 45% of stocks, with 81% of EEZs experiencing at least one stock change if nothing is done to stop greenhouse gas emissions.

“It’s not just a problem of stocks leaving or arriving in new EEZs, but of stocks being shared between countries, completely changing their dynamics,” said lead author Dr Juliano Palacios-Abrantes, who led the study at the UBC Research Institute. Oceans and Fisheries (IOF). Now a postdoctoral fellow at the University of Wisconsin-Madison, he said the study provides a timeline that suggests these changes have already been underway since the turn of the 21st century. “We will see even more dramatic changes by 2030 and beyond, given current emission rates. Many fisheries management agreements to regulate shared stocks have been established over the past decades, with rules that apply to a world situation that is not the same as today.

The study followed the evolution of the ranges of 9,132 transboundary fish stocks, which represent 80% of the catches made in the world.s EEZ, beginning in 2006 and projecting to 2100.

Changes in stock distribution will affect catches. By 2030, 85% of the world’s EEZs will have experienced a change in the volume of their transboundary catches that exceeds the normal annual variation. It’s a change that Dr Palacios-Abrantes says will increase tensions over which countries can claim majority ownership of certain stocks, especially since between 2005 and 2010 fishing for transboundary species has total about $76 billion in revenue.

In the 1980s and 1990s, a change in the distribution of various salmon stocks disrupted fisheries agreements between Canada and the United States and contributed to the overfishing problems of these stocks. Such conflicts will be amplified in the future and could derail international agreements, Dr Palacios-Abrantes said.

Countries located in tropical regions such as the Caribbean and South Asia will be the first to be affected by the increase in water temperature, but countries in the North will also be affected. Overall, 10 shared stocks in Canada and the US Pacific are expected to change by 2033.

“By providing estimates of the magnitude and timing of projected changes, our study offers tangible benchmarks around which to examine the impacts of climate change and negotiate equitable policies for sustainable management,” said co-author, Dr. Colette Wabnitz (she she), Principal Investigator at Stanford’s Center for Ocean Solutions and IOF Research Associate.

The study makes a number of suggestions to avoid the worst possible conflict outcomes, such as small-scale agreements that allow fishing fleets to fish in neighboring countries’ waters while offering a share of the catch or profit.

It will also require a rebalancing and renegotiation of many of the catch quota agreements that are already in place. And any action to mitigate climate change should help reduce the predicted changes, the authors say.

“We need to accept that climate change is happening and then act quickly enough to adapt fisheries management regulations to take it into account,” said co-author Dr Gabriel Reygondeau, research associate at IOF.

That means countries must be willing to work with each other to prevent potential species conflicts due to climate change and keep the industry profitable and sustainable, he said. “We assessed where potential change and conflict could emerge and when it will occur by following climate models and scenarios. At some point, scientists can no longer help and the question becomes: does politics want to deal with the effects of climate change on primary resources and production now?

The study ‘The timing and magnitude of climate-induced range shifts in transboundary fish stocks challenges their management” was published in the journal Biology of global change.

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