by Marsh, Jesse C.

Abstract (Summary)
The blue crab (Callinectes sapidus) supports North Carolina's most valuable commercial fishery; the value of hard blue crabs landed in 2000 was over $30 million dollars. This lucrative fishery may be adversely affected by loggerhead sea turtles (Caretta caretta), which are listed as threatened under the Endangered Species Act of 1973. Crabbers in Core Sound, North Carolina, report that sea turtle damage to crab pots has become an increasingly serious issue. Turtles damage crab pots by overturning them while trying to get the bait, tearing up the bottoms and sides of the pots; this damage results in higher gear replacement costs and losses in crab catch. Experimental fishing was conducted to test for differences in crab catch and pot damage using three types of crab pots: low-profile, square mesh, and hexagonal mesh. The hexagonal mesh pot is the most common pot type used by crabbers in Core Sound, and the low-profile pot was designed to reduce the sea turtles' ability to overturn the pots. The number and size of all crabs caught in the experimental pots were recorded. An analysis of variance (ANDVA) was used to analyze the relationship between number of crabs caught per pot and the effect of pot type, location, date, the interaction of date and location, and the interaction of pot type and location. Tukey-Kramer multiple comparison tests were used to determine significant differences among treatments. There was no significant difference in crab catch between the low-profile and the square mesh pots at any of the three experimental fishing locations. There was a significant difference in catch between the low-profile and hexagonal mesh pots at one location. The lowprofile pots sustained considerably less damage than both the square mesh and hexagonal mesh pot types. In interviews with 19 Core and Pamlico Sound crabbers, crabbers estimated that 62% of all crab pot damage, and 37% of lost crab catch, is due to sea turtle damage. The low-profile crab pot has the potential to improve this situation by allowing crabbers to maintain crab catch with a reduction in gear replacement costs.
Bibliographical Information:

Advisor:Crowder, Larry; Schlesinger, William H.

School:Duke University

School Location:USA - North Carolina

Source Type:Master's Thesis

Keywords:blue crab callinectes sapidus loggerhead sea turtle caretta core sound n c pots


Date of Publication:01/01/2002

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