February 9, 2023

Manx shearwater flies over the sea. Credit: Jamie Carby

Researchers from University College Cork (UCC) have found that cloudier waters, partly caused by climate change, are making it more difficult for seabirds to catch fish.

On Little Saltee, a small island off the coast of Ireland, the researchers attached small trackers to the feathers of Manx shearwaters. The aim of the study, published in Proceedings of the Royal Society B, was to understand how underwater visibility affects the ability of seabirds to forage for fish and other prey. It is the first study to examine the impact of ocean clarity on the diving ability of seabirds.

Climate change is making the oceans increasingly cloudy

Jamie Darby, a marine ecologist in the School of Biological Environmental and Earth Sciences and UCC’s MaREI Center, and lead author of the study, says that “the chemical and physical properties of the planet’s oceans are changing at an unnatural rate, causing challenges for marine life. One consequence of climate change is that large parts of our oceans are becoming cloudier.”

Darby and the research team examined the diving patterns of the black-and-white Manx shearwaters in relation to local environmental conditions such as cloud cover and water clarity. More than 5000 different dives were recorded and using publicly available databases, and a range of relevant information on weather patterns and ocean conditions was collected.

Climate change could make it harder for seabirds to feed, study finds

Manx shearwater flies over the sea. Credit: Jamie Darby

Difficulty finding food

The study found that the birds dived deeper when sunlight was able to penetrate further underwater, suggesting visibility is key to their ability to dive for food. As the planet warms and the ocean becomes cloudier, this finding is important because it means seabirds will have to overcome this challenge.

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“Our findings support the idea that the birds needed sufficient sunlight to forage at depth. While this study examined one particular seabird, the results can be extended to other animals. Many visually dependent predators would struggle to find food if human activities continue to cloud the oceans,” said Jamie Darby.

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More information:
J. Darby et al, Underwater visibility limits the foraging behavior of a diving pelagic seabird, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.0862

Provided by University College Cork

Quote: Climate change could make it harder for seabirds to feed, study finds (2022, July 28) retrieved July 28, 2022 from https://phys.org/news/2022-07-climate-harder-seabirds.html

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