Low oxygen levels are pushing fish into shallower waters


Fish can drown. While it may not seem like it, fish do require oxygen to breathe; it’s just that they get what they need from the oxygen dissolved in water rather than in the air. Too little oxygen spells trouble for our finned friends, which have to move or else suffer ill effects.

Unfortunately, oxygen concentrations are dropping throughout the oceans. A new study out of UC Santa Barbara and University of South Carolina is the first to document more than a dozen species moving to shallower water in response to low oxygen conditions. The research, published in Global Change Biology, spans 15 years of surveys and measurements. The authors stressed the importance of accounting for the findings in fishery management and conservation, or risk implementing strategies wildly out of step with conditions under the waves.

“This study finds that oxygen is declining at all the depths we surveyed: from 50 meters to 350 meters,” said lead author Erin Meyer-Gutbrod, “and so fish seem to be moving up to shallower regions to get to an area where the oxygen is relatively higher.” Now an assistant professor at the University of South Carolina, Meyer-Gutbrod started this analysis as a postdoctoral scholar at UC Santa Barbara.

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