Coral reefs show signs of growth
There is some good news from Little Cayman regarding a small increase in the coverage of live coral. A recent paper published by Dr. Carrie Manfrino and other researchers at the Central Caribbean Marine Institute includes results of a 14 year study on corals in the Cayman Islands, which show a positive trajectory for coral assemblages in Little Cayman.
Corals are a very delicate group of animals that compose a small percentage of the overall systems contained in the marine environment, but harbor up to 25 percent of the marine creatures. There are approximately one hundred countries (including Cayman) that rely on coral reefs for ecotourism attractions generating billions of dollars.
Historical local stresses caused by man on coral reefs come from increased sediment loads, organic and inorganic pollution, overfishing, physical damage, coastal development and pollution. Global effects such as acidification of sea water and climate change have already had negative effects on coral worldwide. Natural disturbances are caused by storms, unusually low tides, increased fresh water runoff and increased sea water temperatures. The combination can have long lasting negative effects on coral reefs.
Let’s use Jamaican reefs for an example. There are several large rivers on the island and poor agricultural practices over a couple of centuries have caused thousands of tons of topsoil to be washed off hillsides and into the sea aggravated by the slash and burn system of cultivation in rainforests and coastal savannah areas. There is tremendous fishing pressure from a large population with easy access to reef systems that are close to shore. Persistent use of huge numbers of fish traps and gill nets have reduced fish populations to a tiny percentage of their pre exploitation levels. The removal of the grazers like parrot fish and surgeon fish has allowed unrestrained growth of algae that competes with coral for hard substrate.
The Cayman Islands by comparison have a different situation. First of all there are no rivers and very little agriculture. However, there has been extensive extraction of reef fish by local fishermen to the point where the government was forced to protect many species particularly the iconic Nassau grouper spawning sites before they were wiped out.
About 40 percent of the shallow reef areas are now contained in marine parks. There is a big snorkeling and diving industry that is the focal point of the tourism sector so it is in everyone’s interest to have a healthy vibrant marine ecosystem.
Coral coverage in Little Cayman was reduced from 26 percent to 14 percent between 2002 and 2004 due to regional thermal stress events causing coral bleaching. The same reefs recovered well during the next ten years and by 2012 they were back to 26 percent coverage. It is a long way from the 75 percent coverage experienced in the 1970s but the needle is moving in the right direction.
The Dept of Environment has put forward a sound case for expansion of marine parks throughout the Cayman Islands to conserve the corals and reef inhabitants. This expansion will include the coral walls that surround all the islands to a depth of 200 feet. The National Conservation Law will soon be legislated according to the new government, which is much more environmentally savvy than any government we have experienced in the last decade. This new law will help conserve a number of threatened marine species. It is also a very important step on the long and arduous journey to having Little Cayman designated as a World Heritage Site.
The prerequisites for WHS status are many and include having the legal framework to conserve special places and species and the funds to support the entity. The people who live on Little Cayman want to see this happen. Let’s get it done.
It is our collective responsibility to conserve the marine environment and maintain the biodiversity of the planet.
Fish responsibly, dive safely.
Guy Harvey PhD.