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Atkinson, B. K., Ehret, D., & Wood, R. C. , Conservation osteology: Ghost traps, minimum mortality estimates, and skeletochronology of diamondback terrapins (malaclemys terrapin) - abstract. Unpublished paper presented at Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles.
Added by: Admin (06 Jan 2014 18:22:36 UTC) |
| Resource type: Conference Paper BibTeX citation key: Atkinson2012 View all bibliographic details  |
Categories: General Keywords: Habitat - habitat, Nordamerika - North America, Schildkröten - turtles + tortoises Creators: Atkinson, Ehret, Wood Collection: Program and Abstracts of the Tenth Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles |
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| Abstract |
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Ghost traps are lost or abandoned fishing gear that continue to capture aquatic organisms, causing unintentional mortality. Side-imaging sonar and spring low tide events facilitated location and retrieval of derelict traps set for Blue Crabs, Callinectes sapidus on Florida’s Gulf Coast and New Jersey’s Cape May Peninsula. The effects of ghost traps on Diamondback Terrapins were studied by conducting minimum mortality estimates of salvaged skeletal remains found in recovered crab pots. Intact terrapins are occasionally recovered; disarticulated elements, usually hyoplastra and hypoplastra, are more commonly found. Impact assessments were based on osteological characteristics, and allometry techniques were employed to determine which terrapins would have been excluded from traps fitted with bycatch reduction devices (BRDs). Skeletochronological analyses were conducted on terrapins salvaged from ghost traps and museum specimens originating from southern New Jersey and Florida, from Jacksonville southward to Key West National Wildlife Refuge. No turtles were sacrificed for this research. Terrapins experience varied climatological and thermal regimes by latitude. Environmental variance results in differing age at maturity, maximum sizes, and life history responses, and is revealed in patterns of growth retained as visible growth rings in the long bones. Humeri and femora were thin-sectioned, stained, and examined for light, wider bands referred to as marks of skeletal growth, MSGs, and darker, thin lines of arrested growth, LAGs. MSGs record rapid or steady growth; LAGs reflect periods of minimal or no growth. Background, field and lab techniques, and results will be presented and discussed. To describe this combination of bone-based investigations, the senior author coined the term “conservation osteology”. Ultimately, the aim of this study is to reduce blue crab fishery bycatch through the implementation of bycatch reduction technology (BRT), including increased use of side-imaging sonar to retrieve lost traps, and promotion of both BRDs and biodegradable escape panels. Annual activity patterns of terrapins, and climatic/thermal variables must be considered in conservation ecology and management efforts. Seasonal or temporal adjustments of fishing effort may alleviate pressure, where conflicts occur. Additional foci, on human dimensions, include surveys and interviews of crab fishers to elucidate barriers and pathways to successful BRT adoption.
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