The Wildlife Conservation Society (WCS), in an article last Friday, claims that the experience of some “super reefs” off the coast of Africa demonstrates that effective fisheries management may help coral reefs survive ongoing climate change.
Human activity may represent the greatest threat to coral reefs living in Earth’s oceans. Global warming, coral mining, pollution (organic and non-organic/chemical), over-fishing, blast fishing and the digging of canals and access ways into islands and bays are the most serious threats to these ecosystems.
In the face of warming ocean waters due to climate change, some coral reefs off East Africa are demonstrating unusual resiliency. Throughout the world’s seas, rising surface temperatures make reefs susceptible to fatal “bleaching”— a sickness that occurs when coral species discharge the algae that live within their tissues. New research by the WCS shows that the “super reefs” can get by when fisheries management improves.
Drs Tim McClanahan and Nyawira Muthiga of WCS, who were part of the team of researchers, found “super reefs” in the waters between northern Madagascar, northern Mozambique, Tanzania, and southern Kenya. Their existence makes them a high priority for future conservation action.
Some 45 percent of the corals in the Tanzania region were wiped out in 1998 by a bleaching event. Contrary to usual recuperation estimates, they recovered rapidly. WCS conservationists monitored these reefs, and continue to protect the corals by training park staff in protected areas. The researchers attribute the reef recovery partly to bans on commercial fishing. Such closures allow the reef fish to thrive, and the fish, in turn, keep the algae population in check. Without enough fish to feed on the algae, it would otherwise smother the corals. Those sites without any specific management measures remain degraded; one site has experienced an explosion of sea urchins—in this number considered to be pests that feed on corals.
The scientists also found that the structure of the reefs plays a major factor in their resiliency. Tanzania’s reefs are particularly complex and experience unusual variations in current and water temperatures. These factors promote the survival of a higher diversity of coral species, including those that can quickly re-colonize after bleaching.
McClanahan sees the resilience of Northern Tanzania’s reefs as a promising sign. “This gives cause for considerably more optimism that developing countries can effectively manage their reefs in the face of climate change,” he said.
WCS is actively engaged in conservation efforts for nearly 90 percent of the world’s tropical coral reef species in priority seascapes in Belize, Indonesia, Papua New Guinea, Fiji, Kenya, and Madagascar.
From Fiji to Glover’s Reef, the Western Indian Ocean Marine Science Association (WIOMSA) and the Tiffany & Co. Foundation have provided generous support for Dr. McClanahan’s research, which examines the ecology, fisheries, climate change effects, and management of coral reefs at key sites throughout the world.
Copyright (c) 2004 Richard Ling
Copyright © 2009 by Marine Science Today, a publication of OceanLines LLC