No-take zones benefit fish, lobster populations

In 1998, lobsters in the no-take areas were larger and more abundant than lobsters in reference areas

March 10, 1999
Web posted at: 3:00 PM EST

Spiny lobster and reef fish populations are making a comeback in the Florida Keys National Marine Sanctuary's 23 no-take zones, according to results from a long-term monitoring program.

"We are surprised how quickly animal populations are responding to these no-take zones. It's probably a good indication of the intense exploitation pressure they are under. We're looking forward to many more surprises from these zones over the coming years," Ben Haskell, sanctuary science coordinator, said in a statement.

In order to protect coral reef habitat in the sanctuary, officials set up a marine zoning program in July 1997, establishing three types of no-take zones: 18 small sanctuary preservation areas, four special use areas and an ecological reserve. The zones comprise less than one percent of the sanctuary but protect much of its critical coral reef habitat, according to the National Oceanic and Atmospheric Administration. Also in 1997, the sanctuary initiated a five-year zone monitoring program looking at changes in ecosystem function and populations of key species.

Scientists led by Carrollyn Cox and John Hunt of the Florida Department of Environmental Protection compared lobster populations in 15 sanctuary no-take areas with reference sites open to fishing. The researchers found significantly more legal lobsters (carapace length greater than 76 millimeters) in no-take areas during both study years -- 1997 and 1998.

In 1997, legal lobster populations were about equal in no-take areas and reference sites. However, by 1998, lobsters in the no-take areas were larger and more abundant than lobsters in reference areas.

First-year results from a second lobster study provide additional evidence of increased abundance and size in the no-take areas. That project used a commercial fisherman fishing with traditional trap gear to compare lobster populations in Western Sambo Ecological Reserve with populations in Middle Sambo and Pelican Shoal, nearby areas that are open to fishing. Results from 1998 indicate that lobsters were significantly larger and more abundant in the reserve compared to outside reference sites.

The populations of reef fish including yellowtail snapper, hogfish and grouper were also compared between no-take zones and comparable reference sites. Grouper analysis excluded two small rarely targeted species: graysby and coney. In all cases, the highest average abundance was observed in no-take zones in 1998, the first full year of no-take protection, according to a preliminary analysis under the direction of Dr. Jim Bohnsack with the National Marine Fisheries Service. Grouper in the remote Tortugas region were more abundant than in the rest of the Florida Keys, according to Bohnsack.

The monitoring program also looks at other key species, such as coral, queen conch (Strombus gigas), fish and urchins. Coral community dynamics are being intensively monitored in three zones and reference sites by John Ogden, Richard Aronson, and Struan R. Smith. The response time for coral is expected to be much longer than that of heavily exploited and faster growing species such as lobster or fish.

The Florida Keys National Marine Sanctuary, designated in 1990, protects 2,800 square nautical miles of critical marine habitat, including coral reef, hardbottom, seagrass meadows, mangrove communities and sand flats.

For more information, contact Cheva Heck, (305)292-0311.

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