Washington, April 6 : A new research has determined that in spite of efforts to preserve coral reef habitats through marine protected areas, their numbers are still declining.
According to a report in Discovery News, Camilo Mora from the University of California, San Diego, has carried out the research.
For the research, Mora gathered more than a decade's worth of data on the status of three major components of reef ecosystems in the Caribbean: fish, corals and macroalgae, which compete with corals for places to settle along the reef.
He combined these figures with water temperature measurements, hurricane records and information gathered from satellite images about the extent of agricultural land and human settlement near coastal areas. He also considered the locations of marine protected areas.
Mora then used statistical analysis to evaluate the effect of each of these factors on populations of fish, corals and macroalgae.
High levels of macroalgae are a sign of poor reef health.
"What we found is that marine protected areas are good only for fish, but they don't really have any positive effect on coral or on controlling macroalgae," Mora told Discovery News.
"The amount of cultivated land was the dominant factor behind high levels of macroalgae, suggesting that nutrients in the water from agricultural runoff fed algal growth," he said.
Corals are being affected by coastal development, and I think that is mostly because of sewage, added Mora.
According to Mora, climate change is contributing to the reef decline as well, with warmer water temperatures also correlated with more coral death.
Though fish can benefit from well-managed marine protected areas (MPAs) because it is possible to prevent fishing inside the boundaries, but for other problems, these zones appear to be inadequate.
"Climate doesn't respect the boundary of an MPA. Pollution doesn't know where an MPA is," said Mora. "MPAs are just not going to be enough to protect coral reefs," he added.
The report added that the combined pressures from human activities in coastal areas and climate change may be more than the reefs can handle.
According to Peter Sale, a coral reef ecologist at the International Network on Water, Environment and Health of the United Nations University, in Hamilton, Ontario, this work has helped to identify the relative importance of various factors on reef ecology.
"But, the main message of this paper is that reefs are deteriorating and it's because of us," said Sale. "What we need is regional-scale coastal management," he added.