Report: Proactive steps needed to protect global fisheries

Shrimp boats in Apalachicola, Florida.

Researchers say climate change likely to exacerbate impacts of overfishing and pollution

By Summit Voice

SUMMIT COUNTY — Overfishing and pollution have already taken a toll on global fisheries, and climate change could be the proverbial last straw for some species, according to a new study led by researchers from the University of British Columbia.

As oceans warm and become more acidic, many species will move further towards the poles and into deeper water. Some species will be smaller at maturity and increasing temperatures are also likely to affect the reproduction rate of other fish. Fisheries in a few regions, such as the far north, may benefit from climate change, but many other regions, particularly those in the tropics, can expect losses in revenues.

Regional examples show what could happen globally. For example, the reduction in landings of pelagic fisheries in Peru as a result of changes in sea surface temperature during the 1997-1998 El Niño event caused more than US$26 million of revenue loss.

“Fisheries are already providing fewer fish and making less money than they could if we curbed overfishing,” said Rashid Sumaila, principal investigator of the Fisheries Economics Research Unit at UBC and lead author of the study. “We could be earning interest, but instead we’re fishing away the capital. Climate change is likely to cause more losses unless we choose to act.”

Partly supported by the Pew Charitable Trusts, National Geographic, the World Bank and U.S. National Oceanic and Atmospheric Administration, the study is a broad view of the impact of climate change on fisheries and their profitability. It is published online today in the journal Nature Climate Change.

“Changes in temperature and ocean chemistry directly affect the physiology, growth, reproduction and distribution of these organisms,” said William Cheung, a biologist at the UBC Fisheries Centre. “Fish in warmer waters will probably have a smaller body size, be smaller at first maturity, with higher mortality rates and be caught in different areas. These are important factors when we think of how climate change will impact fisheries.”

“This study provides an early glimpse of how climate change might impact the economics of fishing,” said Sam Herrick, a NOAA scientist and co-author. “We must continue to study how climate change, combined with other factors, will affect marine ecosystems and the productivity of fishery resources.”

Biologically, maintaining more abundant populations can help increase fish’s capacity to adapt to environmental change. Curbing overfishing is crucial to making marine systems more robust and ready for changes that are already underway.

“This study highlights the potential negative impacts of climate change on the profitability of fisheries,” said Vicky Lam, UBC graduate student and co-author. “The next generation of scientists must put more effort on exploring ways to minimize the impacts of climate change.”

Fish stocks will also be more robust to climate change if the combined stresses from overfishing, habitat degradation, pollution runoff, land-use transformation, competing aquatic resource uses and other anthropogenic factors are minimized

“We have to remember that the effect of climate change on the marine environment will occur alongside the impacts on land,” said Daniel Pauly, a UBC fisheries biologist and co-author. “It will not be easy to divert resources from one sector to help another sector. This is why a strong governance system is needed – to temper the losses on the sectors that are worst hit.”

“Governments must be anticipatory, rather than reactive,” said Sumaila. “We all need to think more of the future while we act now.”

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