Diamondback terrapin mortality in the American eel pot fishery and evaluation of a bycatch reduction device

Radzio, Thomas A.; Roosenburg, Willem M.

doi:10.1007/bf02696072

Cited by 2 publications

(4 citation statements)

References 13 publications

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“…We measured all captured crabs from carapace tip‐to‐tip on a measuring board to the nearest mm (following Roosenburg and Green 2000, Cole and Helser 2001, Radzio and Roosenburg 2005) and determined gender. We recorded daily crab catch information and a Global Positioning System (GPS) location for each pot.…”

Section: Methodsmentioning

confidence: 99%

“…These tools could protect terrapins from interactions with active crab operations. We suggest a strategy for North Carolina blue crab fishery managers whereby no‐fishing zones established nearshore for the period with the highest recorded by‐catch (i.e., spring) and enforced in combination with the widespread use of BRDs on all pots that fisher have set (e.g., blue crab pots and traps to catch American eels [ Anguilla rostrata ]; Radzio and Roosenburg 2005) may be the best currently available option for mitigating terrapin by‐catch in crab pots. Although these 3 management strategies will have to take local conditions into consideration and target catch and by‐catch will vary among years and locations, all strategies should be exportable to other coastal blue crab fisheries along the Atlantic and Gulf coasts where terrapins are present.…”

Section: Management Implicationsmentioning

confidence: 99%

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Mitigating by‐catch of diamondback terrapins in crab pots

Hart

Crowder

2011

J Wildl Manag

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Chronic by-catch of diamondback terrapins (Malaclemys terrapin) in blue crab (Callinectes sapidus) pots is a concern for terrapin conservation along the United States Atlantic and Gulf of Mexico coasts. Despite the availability of by-catch reduction devices (BRDs) for crab pots, adoption of BRDs has not been mandated and by-catch of terrapins continues. We conducted experimental fishing studies in North Carolina's year-round blue crab fishery from 2000 to 2004 to evaluate the ability of various BRDs to reduce terrapin by-catch without a concomitant reduction in the catch of blue crabs. In 4,822 crab pot days fished, we recorded only 21 terrapin captures. Estimated capture rates were 0.003 terrapins/pot per day in hard crab experimental fishing and 0.008 terrapins/pot per day in peeler experimental fishing. All terrapin captures occurred from April to mid-May within 321.4 m of the shoreline. Longer soak times produced more dead terrapins, with 4 live and 4 dead during hard crab experimental fishing and 11 live and 2 dead during peeler experimental fishing. The 4.0-cm BRDs in fall and 4.5-cm and 5.0-cm BRDs in spring reduced the catch of legal-sized male hard crabs by 26.6%, 21.2%, and 5.7%, respectively. Only the 5.0-cm BRDs did not significantly affect the catch of legal-sized hard male crabs. However, BRDs had no measurable effect on catch of target crabs in the peeler crab fishery. Our results identify 3 complementary and economically feasible tools for blue crab fishery managers to exclude terrapins from commercially fished crab pots in North Carolina: 1) gear modifications (e.g., BRDs); 2) distance-to-shore restrictions; and 3) time-of-year regulations. These measures combined could provide a reduction in terrapin by-catch of up to 95% without a significant reduction in target crab catch. ß 2011 The Wildlife Society.

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Section: Methodsmentioning

confidence: 99%

Section: Management Implicationsmentioning

confidence: 99%

Mitigating by‐catch of diamondback terrapins in crab pots

Hart

Crowder

2011

J Wildl Manag

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“…), drowning in crab and eel pots (Roosenburg et al . ; Radzio & Roosenburg ; Dorcas et al . ; Grosse et al .…”

Section: Introductionmentioning

confidence: 99%

“…While terrapin harvesting in Maryland has been discontinued (Roosenburg et al 2008), terrapins still face a myriad of threats, including mortality from boat strikes (Roosenburg 1991;Cecala et al 2008), drowning in crab and eel pots (Roosenburg et al 1997;Radzio & Roosenburg 2005;Dorcas et al 2007;Grosse et al 2009), habitat loss and fragmentation (Roosenburg 1991;Wood & Herlands 1997) and predator introductions (Feinberg & Burke 2003). As male terrapins are smaller and disperse longer distances than do females (Sheridan 2010), they are particularly vulnerable to dispersal-related mortality.…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal analysis of gene flow in Chesapeake Bay Diamondback Terrapins (Malaclemys terrapin)

et al. 2015

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There is widespread concern regarding the impacts of anthropogenic activities on connectivity among populations of plants and animals, and understanding how contemporary and historical processes shape metapopulation dynamics is crucial for setting appropriate conservation targets. We used genetic data to identify population clusters and quantify gene flow over historical and contemporary time frames in the Diamondback Terrapin (Malaclemys terrapin). This species has a long and complicated history with humans, including commercial overharvesting and subsequent translocation events during the early twentieth century. Today, terrapins face threats from habitat loss and mortality in fisheries bycatch. To evaluate population structure and gene flow among Diamondback Terrapin populations in the Chesapeake Bay region, we sampled 617 individuals from 15 localities and screened individuals at 12 polymorphic microsatellite loci. Our goals were to demarcate metapopulation structure, quantify genetic diversity, estimate effective population sizes, and document temporal changes in gene flow. We found that terrapins in the Chesapeake Bay region harbour high levels of genetic diversity and form four populations. Effective population sizes were variable. Among most population comparisons, estimates of historical and contemporary terrapin gene flow were generally low (m ≈ 0.01). However, we detected a substantial increase in contemporary gene flow into Chesapeake Bay from populations outside the bay, as well as between two populations within Chesapeake Bay, possibly as a consequence of translocations during the early twentieth century. Our study shows that inferences across multiple time scales are needed to evaluate population connectivity, especially as recent changes may identify threats to population persistence.

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Diamondback terrapin mortality in the American eel pot fishery and evaluation of a bycatch reduction device

Cited by 2 publications

References 13 publications

Mitigating by‐catch of diamondback terrapins in crab pots

Mitigating by‐catch of diamondback terrapins in crab pots

Spatiotemporal analysis of gene flow in Chesapeake Bay Diamondback Terrapins (Malaclemys terrapin)

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