Date Thesis Awarded

4-2024

Access Type

Honors Thesis -- Open Access

Degree Name

Bachelors of Science (BS)

Department

Biology

Advisor

Randolph Chambers

Committee Members

Mathias Leu

Robert Hicks

Abstract

The diamondback terrapin (Malaclemys terrapin) is the only turtle species native to North America with specific morphological and physiological adaptations to estuarine environments. Along with many other pressures contributing to population declines, terrapins frequently become trapped and drown as bycatch in crab pots used in the commercial and recreational blue crab (Callinectes sapidus) fishery. A wealth of evidence supports the use of inexpensive bycatch reduction devices (BRDs) that can be attached to the entrances of these traps, which leads to a marked decrease in terrapin bycatch while not reducing crab catch dramatically. Virginia is the only mid-Atlantic state with a prominent crabbing fishery but without legislation requiring the use of BRDs, owing largely to pushback from a strong lobby of commercial crabbers. To examine potential alternatives to BRDs, we designed three prototypes of a “terrapin release hatch,” constructed to allow terrapins to escape traps and to retain crabs. Each prototype used different diameter elastic cords (3/32”, 3/16” and 1/4/”) to cover openings on the tops of crab pots. Based on results of an eight-week field study completed in Yorktown, Virginia, the 3/16” prototype allowed 50% of trapped terrapins to escape while retaining 88% of the commercial crab catch. Further tests will be required to develop a more effective terrapin release hatch that approaches the functionality of BRDs. An important focus moving forward will be the ongoing absence of BRD legislation in Virginia, and the possible pursuit of federal legislation to promote terrapin conservation via BRD use, to ensure that all crabbers in all states are held to the same standard.

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