Sunday, December 16, 2012

Invasive Crab Survey Update

Habitat Trays help researchers monitor exotic crab species.

As one of the 28 reserves in the National Estuarine Research Reserve system, the GTM Research Reserve is charged with implementing national-level long-term research programs, investigating relevant regional and local-level research questions, and facilitating related research efforts by visiting scientists and students conducting research in the myriad estuarine and coastal habitats within the reserve.

A GTM Research Reserve
volunteer holds up a blue crab.
For the past ten years, an Invasive Crab Survey has been a part of this research. Because it is impossible to predict where and when a particular species will successfully invade a particular habitat, researchers at the GTM Research Reserve have been focusing on already established invasive crabs to predict the likelihood, direction, and rate of spread of the nuisance species. The researchers are monitoring crab species within the GTM Research Reserve to determine their diversity, detect new invasions, document seasonality of both native and invasive populations, and determine trends in species composition and abundance over time.

Ten different species of crab have been collected over the course of the survey, but one of the most interesting findings is one that will cause excitement amongst seafood enthusiasts who enjoy stone crabs (Menippe mercenaria). Although we have only collected 35 crabs during the survey, our results over the past two years suggest that stone crab populations in NE Florida might be increasing, something we will continue to monitor with interest as the survey continues.

Habitat Trays help researchers monitor populations of exotic crabs. The bars on the graph below illustrates the number of stone crabs per tray out of seven Habitat Trays, while the line illustrates the Florida Fish and Wildlife’s annual commercial landings data for NE Florida in the form of catch per unit effort (lbs of crab/trip). 

To learn more about the research being done at the GTM Research Reserve, visit our research page.

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