Size-Based Mortality of Adult Female Diamond-Backed Terrapins (<i>Malaclemys terrapin</i>) in Blue Crab Traps in a Gulf of Mexico Population

Coleman, Andrew T.; Roberge, Taylor; Wibbels, Thane; Marion, Ken R.; Nelson, David H.; Dindo, John

doi:10.2744/ccb-1099.1

Cited by 10 publications

(5 citation statements)

References 20 publications

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“…Diamondback Terrapin growth and demographic information can also help to inform region-specific management decisions (Hart et al, 2014), particularly as the species' conservation status varies by state. Region and sex-specific growth can help aid development of bycatch reduction device dimensions and configurations to reduce bycatch mortality in Blue Crab traps (Roosenburg et al, 1997;Dorcas et al, 2007;Coleman et al, 2014;Chambers and Maerz, 2018). Finally, results from this study can help to inform head-start programs that have been initiated for research purposes and to augment or establish Diamondback Terrapin populations.…”

Section: Discussionmentioning

confidence: 99%

Terrapin Station: Individual, Sex, and Site Factors Related to Turtle Growth Variability

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Midway

Gibbons

2021

Journal of Herpetology

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Section: Discussionmentioning

confidence: 99%

Terrapin Station: Individual, Sex, and Site Factors Related to Turtle Growth Variability

Harden

Midway

Gibbons

2021

Journal of Herpetology

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“…In some parts of the diamondback terrapin's range, however, reproductively mature females are small enough to enter crab traps fitted with BRDs and could be at risk (Coleman et al. ). Further, the selective loss of large numbers of smaller, adult male diamondback terrapins via drowning in crab traps also changes population demographics (Dorcas et al.…”

Section: Discussionmentioning

confidence: 99%

To BRD or Not to BRD? A Test of Bycatch Reduction Devices (BRDs) for the Blue Crab Fishery

Grubbs

Funkhouser

Myer

et al. 2018

N American J Fish Manag

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We compared two bycatch reduction device (BRD) models that were designed to maintain the catch of commercially harvestable blue crabs Callinectes sapidus while excluding diamondback terrapins Malaclemys terrapin. The Virginia BRD (VA BRD) model was a thick-plastic, 5.1-× 15.3-cm, rectangular red frame. The South Carolina BRD (SC BRD) model was a thin-plastic, 5.1-6.4-× 7.3-cm, curved rectangular red frame. Baited crab traps were fished in groups of three (no BRD, VA BRD, and SC BRD) within tidal creeks in Virginia and South Carolina. In Virginia, legal-sized blue crabs from traps with BRDs were 2 mm smaller than those from traps without BRDs. In South Carolina, significantly fewer and smaller crabs were captured in traps with SC BRDs relative to traps with VA BRDs or traps without BRDs. Shorter soak times in South Carolina may have reduced traffic flow of crabs into traps fitted with BRDs, an effect that was overcome by longer soak times in Virginia. Of the 29 diamondback terrapins captured during the Virginia study, 23 were captured in traps without BRDs, 3 were captured in traps with VA BRDs, and 3 were caught in traps with SC BRDs. The BRDs are needed for the blue crab fishery to decrease diamondback terrapin mortality in hot spots where crabbing and terrapin habitat overlap.

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“…Some BRD designs are more effective at excluding terrapins than others; likewise, studies report that BRD effectiveness at maintaining crab catch is variable (Chambers and Maerz 2018). Two BRD designs that exclude terrapins based on shell height have been studied and used in crab fisheries where required (Table 1): a 2 × 6 inch (~5.1 × 15.3 cm) rectangle (Chavez 2014;Coleman et al 2014, Upperman et al 2014Chavez and Williard 2017;Corso et al 2017;Grubbs et al 2018), and a 1.75 × 4.75 inch (~4.5 × 12 cm) rectangle (Roosenburg and Green 2000;Cole and Helser 2001;Butler and Heinrich 2007;Powers et al 2009;Rook et al 2010;Morris et al 2011;Baxter 2014;Upperman et al 2014;Jenkins 2018).…”

Section: Introductionmentioning

confidence: 99%

Bycatch reduction devices exclude diamondback terrapins and maintain blue crab catch in two Virginia tidal creeks

Reinsel,

Gibson,

Klesch

et al. 2023

Mar Coast Fish

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ObjectiveThe diamondback terrapin Malaclemys terrapin is frequently caught as bycatch in both commercial and recreational blue crab Callinectes sapidus fisheries throughout its range along the Atlantic and Gulf coasts of North America. Bycatch reduction devices (BRDs) are plastic or wire rectangles mounted in the entrance funnels of crab traps, designed to exclude terrapins while still allowing crabs to enter. In this study conducted in two tidal creeks in Virginia, USA, we assessed the effectiveness of four BRD designs, including two novel oval designs, against control traps with no BRDs.MethodsWe tested four replicates of each of the five trap treatments (1.75‐inch oval BRD, 2‐inch oval BRD, 1.75‐inch rectangular BRD, 2‐inch rectangular BRD, and a control trap without a BRD) in each tidal creek, for a total of 20 traps per creek and 40 traps total. We fitted traps with wire chimneys that extended above the high tide water line to allow trapped terrapins to surface for air. For eight weeks during summer 2021, we baited traps with Atlantic Menhaden Brevoortia tyrannus each day, beginning on Monday. Tuesday–Friday, we emptied traps of any animals inside, and recorded terrapin sex, terrapin carapace length, terrapin carapace width, and terrapin shell height, as well as blue crab carapace length.ResultWe found that all four BRD designs were highly effective at excluding terrapins and maintaining crab catch when compared to control traps. We found a significant difference (p = 0.003) in catch per unit effort (CPUE) of diamondback terrapins among treatments, with the control group (those without BRDs) having the highest CPUE (0.97 ± 0.18). All traps fitted with BRDs decreased terrapin capture significantly compared to the control group. Oval BRDs excluded more terrapins than their rectangular counterparts with the same height dimension, although these differences were not significant. We found no significant difference in CPUE of blue crabs among treatments (p = 0.392), or in the size of legal crabs caught in each treatment (p = 0.216).ConclusionThis study provides evidence of the effectiveness of both rectangular and oval‐shaped BRDs to exclude terrapins and maintain crab catch in Virginia waters, where BRDs are not currently required.

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Size-Based Mortality of Adult Female Diamond-Backed Terrapins (Malaclemys terrapin) in Blue Crab Traps in a Gulf of Mexico Population

Cited by 10 publications

References 20 publications

Terrapin Station: Individual, Sex, and Site Factors Related to Turtle Growth Variability

Terrapin Station: Individual, Sex, and Site Factors Related to Turtle Growth Variability

To BRD or Not to BRD? A Test of Bycatch Reduction Devices (BRDs) for the Blue Crab Fishery

Bycatch reduction devices exclude diamondback terrapins and maintain blue crab catch in two Virginia tidal creeks

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