Fears of ‘rat-like’ ocean in­fes­ta­tion

China Daily (Hong Kong) - - WORLD -

CAN­BERRA — Small “weedy” fish de­scribed as the cock­roaches or rats of the ocean could dom­i­nate the world’s seas if ocean acid­i­fi­ca­tion con­tin­ues at its cur­rent rate, re­searchers at the Univer­sity of Ade­laide said on Fri­day.

For the first time, re­searchers have man­aged to demon­strate the ef­fects of ocean acid­i­fi­ca­tion, and ac­cord­ing to Univer­sity of Ade­laide ma­rine ecol­o­gist Ivan Nagelk­erken, fish di­ver­sity would be re­duced as a re­sult of changes to the ecosys­tem.

In a state­ment, Nagelk­erken said ocean acid­i­fi­ca­tion nega- tively af­fected large sea plants such as kelp, which is used by medium-sized preda­tors to hide from larger preda­tors.

He said if kelp dis­ap­pears but “low grassy turf ” re­mains, as hap­pened in the univer­sity’s stud­ies, then smaller, “weedy” species would thrive due to hav­ing fewer preda­tors and more places to hide.

“The re­sult is a lot of what are known as weedy species — the ma­rine equiv­a­lent of rats and cock­roaches, and plenty of them around but no one will re­ally want to eat them.”

Nagelk­erken said ocean acid­i­fi­ca­tion had one ma­jor neg­a­tive ef­fect, and that was that bio­di­ver­sity within the ocean would be lost due to hav­ing higher num­bers of fewer species of fish.

“If we look at the to­tal num­ber of fish we ac­tu­ally see that these in­crease un­der ocean acid­i­fi­ca­tion but lo­cal bio­di­ver­sity is lost,” Nagelk­erken said.

He said the fu­ture ef­fects of ocean acid­i­fi­ca­tion could be fur­ther mit­i­gated by re­strict­ing the over­fish­ing of those medium-sized preda­tors to en­sure the nat­u­ral food chain re­mains in­tact.

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