Sea urchin die-off reported in Mauke

Saturday February 04, 2017 Written by Published in Environment

Cook Islands Climate Change has received reports of sea urchins die-off in the waters near Mauke. In October last year, marine experts were baffled to note the rapid die-off of vana (sea urchins) in the waters near Avarua area.

The die-off later spread throughout Rarotonga.

Climate Change Cook Islands advisor Dr Teina Rongo said they were still investigating the cause of this massive wipeout of the affected species Echinothrix dideama which is consumed by locals.

Specimens of affected sea urchins have been sent to Cawthron Institute in Nelson, New Zealand for analysis to learn more about the bizarre die-off.

Rongo said Cawthron researchers were testing for the various marine toxins plus virus/bacteria to determine which one was responsible for the die-off.

“I am still waiting for these guys in New Zealand to finish their analysis. Hopefully I will get some response from them soon,” he said.

Cawthron Institute’s technical consultant, research and development Sam Murray in an email to Dr Rongo said since the start of January, they had been busy testing the urchin samples.

So far, they had tested for congeners  in11 different toxin classes.

“So far all congeners, across the various toxin classes, have been below the limit of detection. The limit of detection levels change between toxins and each will be presented upon completion of the project,” Murray said.

Dr Rongo earlier said the loss of sea urchins from the marine ecosystem could cause a possible algal bloom in affected waters.

Algal bloom is already an issue for the tourism industry with the recent proliferation of the unsightly weed at Muri lagoon, one of the top tourist spots in the country.

“Sea urchins are important grazers on the reef. They remove the sea weed, allowing corals to grow which is important for our reefs,” Rongo, who holds a PhD in Marine Biology, said.

“This problem occurred in the Caribbean in 1980s and it took 13 months for the disease to spread from Panama throughout the Caribbean.

“The consequence of this was a setback to the reef community of Caribbean from a coral-dominated to an algal-dominated system. Till this day, these reefs of Caribbean have not recovered.

“Therefore, the die-off of sea urchins is not good for us. We can’t afford to face a similar consequence.”

Meanwhile people have been asked not to eat vana until further notice due to a possible health hazard. 

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