Warming oceans, acidification, oxygen depletion and other changes are impacting marine animals, and these impacts include the displacement of certain species of fish. To understand these changes, an international team of scientists led by the University of Kiel (CAU) created an environmental model of the warm period 125,000 years ago (Interglacial Eemian) using samples of sediment from the current system. Humboldt off the coast of Peru.

Research shows that a warming Humboldt Current could have far-reaching consequences and that warming oceans are a major threat to the world’s fish supply.

Experts found that under warmer conditions, small goby-like fish dominated the environment, while important food species such as anchovies were repelled. The results are independent of management or fishing practices in the region.

“The conditions of this past hot period that we were able to reconstruct from our samples can certainly be compared to current development and put into context with future scenarios,” said the study’s first author, Dr Renato Salvatteci.

“According to this, there is a clear diet shift towards smaller fish that feel more comfortable in warm, low oxygen conditions. We conclude from our results that the effects of human-induced climate change may have a stronger influence on the evolution of stocks in the region than previously thought. “

The area off the coast of Peru is one of the most important fisheries in the world, providing about eight percent of the total world catches of marine species. About ten percent of the world’s anchovies are caught in this region, most of which is processed into fishmeal for aquaculture projects abroad. Smaller fish survive better in warmer, less oxygenated waters.
Research shows that warming oceans in the upwelling area of ​​the Humboldt Current may soon reach an irreversible tipping point. Beyond this threshold, the commercial fisheries that form an important part of the global food supply chain could begin to collapse.

“Unlike the current state dominated by anchovies, the last interglacial was characterized by considerably smaller fish (mesopelagics and gobies) and very low anchovy abundance,” the study authors wrote.

“These small species of fish are more difficult to harvest and are less palatable than anchovies, indicating that our rapidly warming world poses a threat to the world’s fish supply.”

The study is published in the journal Science.

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Through Zach fitzner, Terre.com Editor-in-chief