Fisheries

Fish Kills: Unprecedented temperature threatens marine eco-system

Thousands of dead fish are washing up on the shores of Coral Coast as a result of the recent high temperature, with a local expert saying reefs could lose a significant amount of coral if seawater temperatures remain high. Victor Bonito, a marine ecologist who operates a conservation organisation named Reef Explorer Fiji published pictures of the […]

Peni Shute

February 9, 2016 4:14 pm

Thousands of dead fish are washing up on the shores of Coral Coast as a result of the recent high temperature, with a local expert saying reefs could lose a significant amount of coral if seawater temperatures remain high.

Fish kills recorded Monday in Votua Photo: Reef Explorer Fiji
Fish kills recorded Monday in Votua along Coral Coast. Photo: Kiniviliame Ravonoloa.

Victor Bonito, a marine ecologist who operates a conservation organisation named Reef Explorer Fiji published pictures of the fish and said the hot sunny days have caused the “fish kills’’.

This is the worst thermal (heat) stress event I’ve witnessed on Coral Coast reefs during the 10 years I’ve lived here.

While he counted up to thousands the fish at the site he visited, he said people all along the coast had reported similar events happening since Sunday.

It has been happening all along the Coral Coast. These photos were taken near Votua Village.
I had reports of this dead fish from all the way down next to Mango Bay resort, down by Namatakula all the way down to Malevu and im sure it went to the other side of Sigatoka as well.
According to Bonito, the fish kills began on Sunday and he estimates it will continue today because it is only a part of the larger problem of coral bleaching.

Newswire contacted the Ministry of Fisheries and Forests who confirmed receiving information from officials near the area.

The Ministry of Fisheries and Forests would like to advise people living in villages along the Korolevu to Namada coastline to refrain from eating any dead fish along their coasts as they maybe harmful to human health.

The fisheries ministry said their officials have begun investigations into the “cause of the deaths of the multitudes of fish along the Korolevu to Namada coastline”.

Bonito, who has lived and worked in the area since 2004 said the last major coral bleaching occurrence happened in 2000 but the fish lost was not as much.

This is linked to the high temperatures which have caused the coral to lose its symbiotic algae that live inside, and they bleach, they turn white.
Some of these corals have already died. If they are without the algae for some time, they die.  The bleaching really just started last week.

He said the fish kills were extremely devastating for the area given the existence of successfully run Marine Protected Areas on the coast.

Reef Explorer Fiji has equipment in the water to measure water temperature, and Bonito confirms it recorded 5 degrees Celsius higher than normal in the area.

The water has been peaking around 35, 35 degrees out on the reef flats.
The sea temperature is around 30 degrees right now.
So what happens is on the reef flats when the tide goes down, it really heats up and so these fish have died because of the lack oxygen.

He said the calm seas, clear sunny weather prevalent lately could lead to more coral bleaching and adds his research shows the effect may not be limited to shallow reefs.

As calm seas and clear skies have prevailed, seawater temps on the nearshore reefs have heated up to 35-36C+ during low tides causing corals in these nearshore lagoon areas to become severely bleached over the last week and many have already died.
Corals in deeper areas are now also showing signs of heat stress as mean seawater temperature starts to exceed 30C.

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Severe coral bleaching in Votua Village’s marine protected area taken on 9 February. Photo: Reef Explorer Fiji

Bonito said if seawater temperatures do not cool off in the next day or so, we will lose a significant amount of coral from the reef that would take over a decade to recover under ideal circumstances.

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