
Research carried out in Belize suggests that although marine protected areas are good for some fish, they might not have any significant beneficial impact on coral health:
Marine reserves help fish populations but do nothing to safeguard coral, a study has found.
Scientists analysed surveys of 87 reefs both inside and outside Glover’s Reef Marine Reserve in Belize.
The results failed to show that protection within a reserve improved coral cover, colony size, or the abundance of juvenile corals.
Instead, US researchers documented declines in the coral community both within and outside the marine reserve.
Shifts were seen from large reef-building species to small, more localised species, reflecting a general pattern seen in the Caribbean.
Study leader Dr Brittany Huntington, from the University of Miami, said: “We had hoped to find evidence of reserve protection benefiting the coral community as well as the fish community at Glover’s Atoll. Unfortunately, the coral communities on protected reefs were in no better condition than the fished reefs.”
Herbivorous fish populations and rates of macroalgae, or seaweed, growth were similar on protected and unprotected reefs. This could help explain why the reserve coral is not faring better, the scientists believe.
“The macroalgae is faster growing than corals, dominating the available free space on the reef and impeding coral growth and survival,” said Dr Huntington.
“Without greater numbers of herbivorous fishes in the reserve to consume the macroalgae that is dominating these reefs, corals have little chance at recovery.”
The findings are published in the journal Coral Reefs.
Source: The UK Press Association via Google News. See also this report from BYM Marine Environment News. The abstract from the journal article itself is quoted below:
The ability of reserves to replenish fish stocks is relatively well documented, but the evidence of their ability to induce positive effects on benthic communities remains inconclusive. Here, we test whether 10 years of reserve designation have translated into positive effects on coral communities in Glover’s Reef, Belize. Surveys of 87 patch reefs inside and outside the reserve revealed no clear indication of reserve implementation benefitting coral cover, coral colony size, or abundance of juvenile corals. Furthermore, massive broadcasting coral species exhibited greater losses over time than their smaller-sized counterparts across all sites, suggesting that local management actions have not alleviated the regional trend of high mortality for these species. We detected no difference in herbivorous fish abundances or macroalgal cover between reserve and fished sites, providing a potential explanation for the lack of cascading positive effects on the coral community. We conclude that patterns of regional coral decline are evident at Glover’s Reef, including a shift in dominance from broadcasting species to brooding species and declines in mean colony size. Our findings suggest that regional stressors are overwhelming local management efforts and that additional strategies are required to improve local coral condition.
[Photo via: World Resources Institute]