Guana Tolomato Matanzas Reserve, Florida

Guana Tolomato Matanzas Reserve, Florida

Exotic Crab in the Guana Tolomato Matanzas National Estuarine Research Reserve

The Guana Tolomato Matanzas National Estuarine Research Reserve is one of nine estuarine research reserves involved in a pilot study to detect exotic (nonindigenous) crabs in local waters. The research has both spatial (where we set up the crab collectors) and seasonal (what time of the year the crabs are collected) components that allow for: 1) early detection of the arrival of exotic species, 2) tracking and predicting the direction and likelihood of invasive range expansion by those exotic species and 3) monitoring the abundance and diversity of native crabs before, during, and after the invasion process. At the GTM Reserve, crabs are obtained using experimental collecting devices, identified, measured and sexed four times a year (winter, spring, summer and fall) in patchy mud and oyster habitat. Currently, the participating reserves represent comparable estuaries that have been invaded by, or that have not yet been invaded by, particular exotic crabs. The GTM Reserve represents an estuary invaded by at least one species of exotic crab, the Indo-Pacific swimming crab, Charybdis hellerii. As the name suggests, this species is native to the Indo-Pacific region, but has successfully invaded such areas as the Mediterranean, Caribbean and Florida. The Indo-Pacific swimming crab is thought to have been transported to the Caribbean in the ballast water of trans-Atlantic vessels prior to 1987 and the transport of this species is still a concern today. In 1995, the crabs were discovered in the Indian River Lagoon estuarine system and have since been reported by fisherman and researchers in coastal waters of northeast Florida.

With the recognition of potential negative economic, ecological and evolutionary impacts, the introduction of exotic species into estuarine waters is becoming both a local and world-wide concern. Although the threat to our native crab populations is not known at this time, it is important for people most likely to encounter exotic crab species (e.g., commercial fisherman, scientists, schoolteachers, resource managers and conservationists) to become familiar with the Indo-Pacific swimming crab as an initial step towards limiting the extension of its range. To aid in the education process, the GTM Reserve plans to hold a Coastal Decision Maker Workshop in 2003 that will be open to all interested parties (workshop date to be announced). Other educational aids will include: 1) laminated “Least Wanted Species” cards with information about this and other nonindigenous crabs that the GTM Reserve will distribute to a variety of local user groups and 2) a searchable web site for people who are aware of the problem but seek further information.