A 13-year-old biological diversity study has reported that coral reefs have spontaneously been recovering in the Cayman Islands, Cayman Net News reports.
The report, published in last month’s online issue of the San Francisco-based Public Library of Science, cited Tukey’s tests that illustrated that numbers of juveniles m−2 in 2010 were significantly higher than densities in all other years, and densities recorded in 2011 also were relatively high, albeit not statistically different from densities recorded in 2004 and 2005.
Scientists monitoring the Cayman reefs noted a 40 percent decline in live coral cover between 1999 and 2004 during a period of warmer seas in the Caribbean.
“Between 1999 and 2012, spatiotemporal patterns in cover, densities of juveniles and size structure of assemblages were documented inside and outside marine protected areas using transects, quadrants and measurements of maximum diameters. Over five years, bleaching and disease caused live cover to decrease from 26 per cent to 14 per cent, with full recovery seven years later,” read the journal,A Positive Trajectory for Corals at Little Cayman Island.
“Coral reefs account for 0.01 percent of the world’s marine environment. They yield approximately 25 percent of the different species of marine organisms and generate millions of dollars for the fishing and tourism industries,” the report states.
Healthy coral reefs are essential for the tourism sector throughout the Caribbean.
“These benefits may disappear because coral reefs around the world are being degraded by local and global anthropogenic stressors that cause damage beyond that due to natural disturbances, such as large storms, hurricanes, exposure to unusually low tides, and freshwater input, read the report whose study focused on Little Cayman.
Tom Frazer, Professor of Aquatic Ecology at the University of Florida who has contributed to the authorship of the report stated that regardless of the mechanism, understanding the conditions that promote recovery of damaged coral reefs remains critical to the formulation of effective management actions.
Studies documenting recovery of corals have yielded mixed conclusions.
“Fine-scale surveys and experimental studies indicate diverse responses or the lack of a short-term response, which may be due to local oceanographic, meteorological and ecological conditions that ameliorate or exacerbate stress from disturbances; variable growth and regeneration rates among coral taxa; variation in larval supply; differences in type and extent of the most recent disturbance; and unique interactions among coincident and sequential disturbances.
According to the results cited by the journal, in both 2010 and 2011, mean cover of live coral increased by 5 per cent. Thus, coral cover increased despite a localised bleaching event recorded in 2009.
Press reports indicate that coral reefs are dying around the world. In 2012, the Australian Institute of Marine Science reported that coral coverage of the Great Barrier Reef had declined by half over the previous 27 years.
Global Coral Reef Alliance, a nonprofit organisation dedicated to maintaining reefs, considers high temperatures caused by global warming to be the biggest threat to them.
Professor Frazer said human activity such as pollution, overfishing, dropped anchors and sediment kicked up by dredging also causes chronic stress to the reefs.
For the original report go to http://caymannetnews.com/2013/12/26/caymans-corals-are-recovering-report-says/