Coral reefs mending, but fish stock declining

BY JANICE BUDD Associate editor Sunday buddj@jamaicaobserver.com

Friday, March 30, 2012

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A group of marine biologists say they have found signs of recovery of Jamaica's depleted coral reefs in the critical fishing resource area known as the Pedro Bank.


At the same time, they have warned that there must be proper management of the reefs if it is to be preserved as a food source.


The Pedro Bank is a very unique area almost three-quarters the size of mainland Jamaica, most of which is underwater. The bank is composed of sand, coral reefs, deep reefs, seagrass beds, and three coral cays known as the Pedro Cays.


It is located approximately 50 miles or 80 kilometres south-southwest of the island and is one of the biggest offshore banks in the Caribbean Basin. Because of its size and distance from mainland Jamaica and its relatively intact biological systems, it is supposed to be one of the country's last remaining healthy marine ecosystems.


According to the Nature Conservancy website, it's also the primary harvesting area for the largest export of Queen Conch from the Caribbean region and a potential refuge for several endangered coral species


"With an estimated 99 per cent of mainland Jamaica's reefs in danger, the coral reefs on Pedro Bank are vital to long-term reef conservation in the country. In July 2004, the bank was declared an underwater cultural heritage site by the Jamaica National Heritage Trust...," reads the website.


But intensive fishing and too many people people living on the Pedro Cays are threatening the survival of the bank as a viable and functioning ecosystem.


"The reefs in the Caribbean are really in a deep crisis. We've been living in a very stable climate since the last Ice Age and that steady stable climate is starting to change dramatically now. Those corals that have been around for thousands of years in the Caribbean, all of a sudden, they are living in a new environment and being stressed dramatically," said Captain Phil Renaud, Executive Director, Khaled bin Sultan Living Oceans Foundation (LOF).


"Then with all this fishing pressure, taking away a lot of the fish that live in harmony, wholistically with the coral reef, that takes away a lot of the resiliency of the reefs and that's a bad combination," added the oceanographer.


He was speaking last Thursday at the wrap-up session of a two-week diving expedition on the Pedro Bank.


The charity's expert marine dive team, which departed the island on Tuesday, was here on invitation from the Government of Jamaica conducting coral reef surveys off the Pedro Bank.


The primary scientific goals of the expedition were to "characterise the coral reef ecosystems; identify their current status and major threats; and examine factors that enhance their resistance to, and recovery from major disturbance events".


Local scientists were given an opportunity "to work alongside the team and experience hands-on training with the use of the latest technologies, assist in data collection, and receive first-hand access to the data generated," Captain Renaud observed.


That local team included representatives from the National Environment and Planning Agency (NEPA), Fisheries Division of the Ministry of Agriculture and Fisheries, Centre for Marine Sciences of the University of the West Indies, and the Nature Conservancy.


"Its an incredible opportunity, it is a once-in-a-lifetime opportunity. None of us have the wherewithal, the resources, this kind of equipment, the diving platforms that LOF was able to provide and allow us to use. It really was an incredible opportunity for Jamaican researchers to meet and work with international researchers, from the US, from England, from all over, people who had dedicated their whole lives to coral reef work," said Nathalie Zenni, marine and fisheries specialist with the Nature Conservancy Marine and Fisheries project.


Jamaica's coral reef cover has fallen from an estimated average of 60 per cent in the 1960's to less than seven per cent in the late 1990's.


While the dramatic decline has been largely due to the frequency and intensity of natural disasters, such as storms and hurricanes, over-fishing and other direct acts of humans, is said to have played a major part in the irreparable damage to the island's coral reefs.


But Living Oceans says there is reason for hope, after mapping the Pedro Bank.


The dive teams saw some unique coral species, some of which they thought would never be found on Pedro Bank. They also saw a lot of very large colonies of coral, a source of encouragement for the marine biologists, since thriving coral, means a thriving sea.


What's more, the colonies show signs of recovering from the dreaded coral bleaching. This phenomenon is described by the National Oceanic and Atmospheric Association as what happens when water is too warm, causing corals to 'spit out' the algae (zooxanthellae) living in their tissues, turning the coral completely white. In 2005, half of the coral reefs in the Caribbean died in one year due to a massive bleaching event.


It takes a while for corals to recover from 'bleaching', but there are obvious signs of just that on the Pedro Bank, said Dr Andrew Bruckner, chief scientist, Global Reef Expedition with Living Ocean Foundation.


"We saw a lot of corals that are starting to show signs of recovery, but there was also evidence of widespread disease on the reef colonies, some 30 per cent of them showing dark spots of disease," he said.


There is also another reason for cautious optimism, said Dr Bruckner, who was able to compare previous dives in the Caribbean sea in the 1970's to his most recent trips underwater at Pedro Bank.


Brucknor said disease practically wiped out the Elkhorn and Staghorn coral, which was critical to undersea ecology as they are the building blocks of reefs.


But a week ago, the divers found signs of rebirth of the endangered species on Blowers Rock and the Pedro Cays undersea reef shelf.


"What was really intriguing at Pedro Bank is we also found a lot of places were we saw small colonies had begun to grow back, which had become exceedingly rare in the Caribbean. And then at Blowers Rock we found this huge patch of the coral. So we saw signs of recovery."


But the absence of lobster and large fish species on the dives were cause for alarm, said Bruckner.


"I thought I would see a lot of big fish, and we really didn't. There were groups that were entirely missing. We had pretty high diversity, but there were entire species of groupers missing. We didn't see any snapper and we didn't see any of the large predators. We saw one barracuda on one reef, of all the locations that we dove."


The other thing that was disturbing is the depletion of the Blue Tang, which are critical to the health of the coral reef. They normally travel in huge schools comprised of thousands, but not on the Pedro Bank.


"In all the dives I did, I just saw one school. In all the places I have been, I have never seen so few of these," said the marine biologist.


But the greatest matter of concern is what is happening to the traditional Jamaican dinner table staple, the parrot fish. Dr Bruckner, says not only are they smaller than they used to be, but they are having a sexual identity crisis.


"These things change sex. They start out as female, they get to a certain size and they change into males. But what we are seeing out on these reefs, is the parott fish are all females. What happens if you have only females?" he asked. The obvious answer being that the fish cannot reproduce.


It's a big concern, he said, because the popularity of the parrot fish has led to over-fishing and the fish cannot get to the size where they can change sex. He urged letting the fish grow to a larger size before harvesting in order to allow the fish to repopulate.


This and other concerns resonated with members of the Jamaican research team working alongside LOF, including Nathalie Zenni of the Nature Conservancy.


"There has been very little management of the area. ...The resources of the bank, although they are still bad, in comparison to other areas in Jamaica, the corals are doing quite well. But the reef populations are heavily depleted and if we don't change out management regime, if we don't put effective management in place, essentially immediately, then we won't have a fisheries out there in a couple of years," said Zenni.


The LOF survey will inform the development of a network of marine protected areas including fish sanctuaries that build connectivity, resiliency and the protection of vital larval supplies, fish stocks and keystone habitats.


The Pedro Bank reefs were last surveyed in 2005.


The Living Oceans Foundation is a privately funded foundation dedicated to the conservation and restoration of living oceans and has pledged to champion their preservation through research, education and a commitment to 'Science Without Borders'.


  

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