New research points to major threats to the world’s oceans and fish populations as a direct result of overfishing and climate change.
The University of Adelaide’s findings are published in the current issue of the Proceedings of the National Academy of Sciences. The research team analyzed more than 600 published ocean experiments, all pointing to grave circumstances for ocean health.
According to the research, major coral-based ecosystems, which support 25 percent of marine species, could face catastrophic losses by 2050 unless greenhouse gas emissions are significantly reduced. Australia's Great Barrier Reef has reportedly lost half of its coral cover in the last three decades due in large part to climate change.
“Overall, we found there’s a decrease in species diversity and abundance irrespective of what ecosystem we are looking at. These are broad scale impacts, made worse when you combine the effect of warming with acidification,” associate professor Ivan Nagelkerken of Adelaide University told the Guardian.
“We are seeing an increase in hypoxia, which decreases the oxygen content in water, and also added stressors such as overfishing and direct pollution. These added pressures are taking away the opportunity for species to adapt to climate change.”
The researchers note that plankton populations will increase significantly as water temperatures continue to warm, but “this abundance of food will not translate to improved results higher up the food chain,” reports the Guardian.
According to researchers, animals higher up the food chain have a “limited scope” in being able to deal with the increase in carbon dioxide dissolution.
“The world’s oceans absorb about a third of all the carbon dioxide emitted by the burning of fossil fuels,” reports the Guardian. “The ocean has warmed by about 1C since pre-industrial times, and the water increased to be 30% more acidic.”
According to the World Wildlife Fund, nearly half of the world’s population relies on either wild-caught or farmed seafood as their primary source of protein.
“These effects are happening now and will only be exacerbated in the next 50 to 100 years,” Nagelkerken told the Guardian. “We are already seeing strange things such as the invasion of tropical species into temperate waters off south-eastern Australia. But if we reduce additional stressors such as overfishing and pollution, we can give species a better chance to adapt to climate change.”
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Reef image via Shutterstock