A study published late last month revealed that large, permanent marine protected areas (MPAs) are critical to the recovery and conservation of old fish.
To measure the level of recovery of protected reefs, most studies focus on fish biomass. Researchers from Wildlife Conservation Society, James Cook University, and Lancaster University use a different measure of success: the life history of fish communities.
“Fish biomass has been the common way to evaluate fish communities, but what our research shows is that it does not tell the entire story,” Dr. Tim McClanahan, Senior Conservationist for WCS and co-author of the study, explained in a news release. “Analyses based primarily on fish biomass produces an incomplete and somewhat misleading scenario for fast recovery from overfishing.”
The studies that focus on biomass conclude that it takes about 20 years for biomass to recover fully. Dr. McClanahan said that’s not the case when considering life histories. Biomass is one of only a few measures of recovery that levels off after a relatively short amount of time. Other measures, like ages and feeding habits, continue to change for at least 40 years.
“What we found was a slow and continuous reorganization of the fish community well past the stabilization of biomass. A full evaluation of marine reserves needs to look at the species and their life histories and, when we do that, we see the importance of protecting ocean wilderness and making permanent and large reserves.”
“The slow growing species in marine reserves could require a century to fully recover, indicated the importance of permanent and large reserves,” McClanahan said.
The study also examined the size of the protected area, the length of time it had been closed to fishing, and the level of compliance.
“If you want to protect the longer-lived, slower growing species, you need old, large, and high compliance marine reserves” said co-author Nick Graham of James Cook University and Lancaster University. “The effective protection of the full suite of fish species and life history characteristics will depend on the establishment of large reserves with strict enforcement.”
To learn more:
- Read the news release: Large Permanent Reserves Required For Effective Conservation of Old Fish
- Read the full study: Marine reserve recovery rates towards a baseline are slower for reef fish community life histories than biomass
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