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Disney’s shockingly cheerful song ‘Under the Sea’ paints a rosy picture about what goes on in the depths of dark waters, but world-class research supported by the University of Exeter tells a different story. In the first week of July this year, a rich variety of marine biologists and ecologists, ambassadors of fishing industries, and climate change scientists from over 20 countries gathered under the singular roof of our University, to discuss what they love to study most – fish.

They assembled to share findings about the dangerous threats faced by fish populations due to overfishing, climate change and human pollution. So, what were the findings, uncovered at the 50th Anniversary Symposium of the Fisheries Society in the British Isles?

In a dramatic display of irony, Professor Charles Tyler of the University of Exeter found that the booming usage of birth control pills is sabotaging the sex lives of fish. A fifth of male fresh-water fish in UK rivers are now “trans-gender” as a result of chemicals originating from contraceptives and anti-depressants flushed into these waters.

Clowning in an anemone. Source: Pixabay

In addition to reduced sperm quality, these fish undergo physiological changes enabling some to produce eggs and display less competitive behaviour when it comes to attracting females. While these fish have no choice in the matter, another piece of research presented at the same Symposium found that male clownfish meticulously decide to become females if their ‘wife’ is eaten, which are known to be larger and more dangerous protectors of their clan from predatory organisms such as sharks.

More importantly, they found a hole in the plot of Finding Nemo, where Nemo’s father should have actually turned into his mother after her death.

Other research showed that due to a rising ocean temperature caused by global warming, fish are shrinking. Due to a reduction in oxygen levels, it is predicted that the size of fish such as cod and haddock could shrink by 10-20% by 2050, and have them voyaging to colder waters. So when Donald Trump decided to rip up the Paris Agreement, he actually took a large bite out of your fish and chips order!

usage of birth control pills is sabotaging the sex lives of fish

Speaking of disrupted cooperation in international politics, a disruption in fish cooperation has been observed by Dr Sophie Nedelec of the University of Exeter as well. The culprit here is noise from motorboats, which inhibits the ability of a species affectionately termed ‘cleaner’ fish to eat parasites from other fish known as ‘clients’. Instead, they feed on their clients’ protective mucous layer thus severely damaging the health of coral reef fish.

If sickening and shrinking fish wasn’t enough, we are also suffocating them, as revealed by another innovative study undertaken by Dr Peter Cox of the University of Exeter, who estimated that long-term climate change leads to a decrease in primary marine production by 3% for each degree centigrade that the ocean warms. Lesser photosynthetic plant-like organisms in oceans is likely to seriously deplete oxygen needed for marine life to thrive and survive.

Thanks to this expanding body of research, we now know that it’s not looking as good down there as Disney would have us believe and there is an urgent need to fish for newer solutions to this aquatic catastrophe.

 

If you want to keep learning about our vast but suffering seas, and/or you want to do something about it, check out this piece where Jack Warren discusses the damage that humans are inflicting on coral reefs, and what we can do to prevent it

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