Dear MPA News:
In light of your article on invasive species (MPA News 6:6), it is worth noting that marine protected areas, if not planned carefully, could unintentionally enhance populations of such introduced species. As a case in point, federal no-take zones now under consideration to restore stocks of deepwater reef fishes off the Atlantic coast of the southeastern US could benefit populations of the introduced Pacific red lionfish, whose areas of maximum abundance in the region coincide with several sites proposed for bottom-fishing prohibitions by the (US) South Atlantic Fishery Management Council.
One of the objectives of the proposed no-bottom-fishing zones is to protect areas where multiple species spawn at various times of the year. Some of the proposed sites contain spawning grounds for more than 20 species of native reef fishes. It is likely, however, that conditions at these sites also favor spawning in red lionfish; in fact, there is substantial evidence of spawning by this species in the region.
This presents a conundrum for fishery managers. In management’s effort to protect native deepwater reef fishes, populations of an invasive species might benefit, including enhancement of spawning success and recruitment to other reefs downstream. Because this venomous species probably has few predators in its post-settlement stage on Atlantic reefs, it is likely to compete with the species that managers want to protect, and may further contribute to declining populations. It is known that red lionfish eat small fishes and decapod crustaceans that are important prey for native fishes in the region, and are likely to affect diversity of assemblages of those species and their prey, predators, and competitors.
Management agencies should consider locating MPAs that are outside of the current range of the red lionfish; at this point in time, there are still areas with little overlap between the target fishery stocks and the invasive species. Otherwise, managers should consider allowing managed harvest of red lionfish within MPAs should such closures be implemented. The nine proposed sites, some with nearby alternatives (14 total sites), will be offered for public comment in mid-2005, with possible implementation by mid-2006.
George R. Sedberry, H. Scott Meister, Phil Weinbach
Marine Resources Research Institute, South Carolina Department of Natural Resources, P.O. Box 12559, Charleston SC 29412, USA. Tel: +1 843 953 9814; E-mail: email@example.com