Fears of ‘rat-like’ ocean infestation
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.