White plague hits Cayman’s corals

TOPcoralLEAD

Cayman’s
coral reefs are being hit by a disease known as white plague, researchers into
the first study of diseased corals in local waters said.

The
plague is attacking some of the largest, slowest growing corals at a rate of 1
to 2 centimetres a day, said coral reef scientist Andy Bruckner.

“We
call it white plague because it starts at the base of the colony and looks like
wildfire going through a forest. It forms this band that spreads across the
coral, it moves up over the coral and kills it relatively quickly, in the order
of one to two centimetres per day.

“It
will advance in a line across the coral, which is really quite dramatic because
a lot of these massive corals only grow about one centimetre or less per year,”
he said.

Of
the three islands, Little Cayman was the least affected by the disease, and
Grand Cayman was the worst. Sites in the north and east of Grand Cayman with
large colonies of huge corals saw the biggest impact, having recently lost up
to 50 per cent of their tissue, Mr. Bruckner said.

The
Department of Environment is revisiting sites it checked last year to compare
the findings with those it made last summer.

“White
plague is hitting the massive corals, which are the slower growing ones and the
most important frame-builders. Because they grow so slowly, for some of these
big corals that have lost a lot of their tissue, it would take 100 years to
re-sheet back over, if it ever will,” Mr. Bruckner said.

Corals
can grow a sheet of tissue over diseased patches and can eventually recover.

The
disease, which is seen throughout the Caribbean, is most likely caused by
environmental stressors brought on by bleaching of coral colonies late last year.
Already weakened by the bleaching, the corals become less resistant to harmful
bacteria that can move in and further damage the reef, said Mr. Bruckner, who
has worked for the National Oceanic and Atmospheric Administration and the
Living Oceans Foundation.

He
said there was “quite a severe outbreak in the reefs around here” in response
to last year’s coral bleaching caused by warmer sea temperatures from El Nino.

The
scientist is in Cayman to help conduct a disease workshop and general reef
surveys.

Mr.
Bruckner and researchers examined reefs on the three Cayman Islands, surveying
10,000 corals at 48 sites. He said until the data collected during his two and
a half weeks in Cayman is examined, he could not comment on how widespread the
problem is, but he said it is clear that some species of coral have been more severely
affected.

“The
dominant frame-builder was the one probably being hit the most severe. That’s
the mountainous star coral. Those are some of slowest growing and oldest coral
in the reef. In many cases, some of those corals are 500 years old and
have already lost half of their tissue. It is really hard to say until I enter
the numbers what percentage are being affected.”

Sea
water temperatures are already creeping up locally, he said, but the severe
hurricane season forecast for this year will bring cooler water, which could
lead to an abrupt decline in diseased coral.

Mr.
Bruckner, Department of Environment officials and staff from St. Matthew’s
University School of Veterinary Medicine, all of whom took part in a coral
disease workshop in Little Cayman earlier this month, held a talk Tuesday night
to inform the public about the extent of coral disease and what can be done
about it.

The
scientists said divers can do their bit to help the reefs recover by observing,
monitoring and reporting anything unusual they see on dives to the Department
of Environment. There are other threats to coral, including some marine
wildlife like snails and damsel fish that could also be monitored and even removed,
Mr. Bruckner said.

“Corals
are in a crisis worldwide… the Caribbean has been hit really hard. We
traditionally had 50 to 80 percent living coral cover on reefs throughout the
region – most reefs now have 5 to 7 percent, Mr. Bruckner said. “The Cayman
Islands are lucky because you have a lot more coral. Even now, we found sites
with 15 to 20 per cent coral cover.”

Staff
and students from St. Matthew’s veterinary and medical school have also joined
the efforts to protect Cayman’s reefs. Lecturers Scott Taylor and Samantha
Shields from the university set up the Coral Reef Research Club and, along with
Paul Henneke, the club president, attended the workshop in Little Cayman.

“We
formed this club and the idea is to educate the veterinary students on coral
health in general… We wanted to start doing some small amounts of monitoring
reefs over time,” Ms. Shields said.

All
the researchers agree that education is a vital component in combatting the
threats to the coral reefs, which are important for the development of fisheries
and to protect land from hurricanes and rising sea levels.

TOPcoralSTORY

Diseased star coral photographed this week in a Grand Cayman reef
Photo: Submitted

1 COMMENT

  1. Recently, there was on NatGeo there was a documentary about the Pacific in which it featured the Fijian Islands programme for underwater gardening. Basically, they would go out and collect small healthy corals from overcrowded or sick areas, then take the sample to an underwater safe garden, then plant them on a concrete grid to allow them a chance to grow. Once the specimens grew to a significant size they were replanted to cultivate the reefs in new safe areas or replenish the old sick ones. Is such a programme in the works here? If not, who would be able to investigate or implement one as such? Is the Caribbean Marine Research Institute or Department of Environment aware of this type of procedure? Could that be a viable solution to this problem? The Fiji project has worked quite well & many of their sick reefs are restored & flourishing again. Their eco-tourism is a ‘poster child’ we (the Cayman Islands) should take a closer look at!

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