Evaluation of Hook and Bait Type on the Catch Rates in the Western North Atlantic Ocean Pelagic Longline Fishery

Foster, Daniel G.; Epperly, Sheryan P.; Shah, Arvind; Watson, John W.

doi:10.5343/bms.2011.1081

Cited by 48 publications

(63 citation statements)

References 0 publications

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“…The frequency of sets with sea turtle bycatch in the Atlantic was highest within approximate SST ranges between 22 • C to 26 • C and 23 • C to 27 • C for loggerheads and leatherbacks, respectively. These ranges are nearly identical to those previously reported (Watson et al, 2005;Brazner and McMillan, 2008;Foster et al, 2012;Huang, 2015). The range of SST with positive sea turtle captures was more protracted in the Pacific, with the frequency of sets with sea turtle bycatch highest when SST ranged between ∼17 and 19 • C for both loggerheads and leatherbacks.…”

Section: Spatial Distribution and Sstsupporting

confidence: 87%

“…The captures of loggerhead turtles in shallow-set gear is consistent with previous studies in the same region (Watson et al, 2005;Brazner and McMillan, 2008;Foster et al, 2012) and can partially explain why rates of turtle bycatch in deepset longline fishing are an order of magnitude lower than on shallow-set gear (Gilman et al, 2006;Beverly et al, 2009). Elimination of shallow hooks as a means to reduce sea turtle bycatch has been proposed (Polovina et al, 2003;Beverly and Robinson, 2004) and tested.…”

Section: Hook Depthsupporting

confidence: 84%

“…However, regulations requiring use of fish bait to reduce sea turtle bycatch must be balanced against the potential target species catch loss, a concern that has been previously evaluated (Watson et al, 2005;Yokota et al, 2009;Curran and Bigelow, 2011;Coelho et al, 2012). Further, bait choice can also potentially increase bycatch of certain sharks or other vulnerable species (Foster et al, 2012;Santos et al, 2012;Gilman et al, 2016b). As with other bycatch reduction techniques, success in adopting these measures may be fishery dependent.…”

Section: The Role Of Bait In Bycatchmentioning

confidence: 99%

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Sea Turtle Bycatch Mitigation in U.S. Longline Fisheries

et al. 2017

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Capture of sea turtles in longline fisheries has been implicated in population declines of loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) turtles. Since 2004, United States (U.S.) longline vessels targeting swordfish and tunas in the Pacific and regions in the Atlantic Ocean have operated under extensive fisheries regulations to reduce the capture and mortality of endangered and threatened sea turtles. We analyzed 20 + years of longline observer data from both ocean basins during periods before and after the regulations to assess the effectiveness of the regulations. Using generalized additive mixed models (GAMMs), we investigated relationships between the probability of expected turtle interactions and operational components such as fishing location, hook type, bait type, sea surface temperature, and use of light sticks. GAMMs identified a two to three-fold lower probability of expected capture of loggerhead and leatherback turtle bycatch in the Atlantic and Pacific when circle hooks are used (vs. J hook). Use of fish bait (vs. squid) was also found to significantly reduce the capture probability of loggerheads in both ocean basins, and for leatherbacks in the Atlantic only. Capture probabilities are lowest when using a combination of circle hook and fish bait. Influences of light sticks, hook depth, geographic location, and sea surface temperature are discussed specific to species and regions. Results confirmed that in two U.S.-managed longline fisheries, rates of sea turtle bycatch significantly declined after the regulations. In the Atlantic (all regions), rates declined by 40 and 61% for leatherback and loggerhead turtles, respectively, after the regulations. Within the NED area alone, where additional restrictions include a large circle hook (18/0) and limited use of squid bait, rates declined by 64 and 55% for leatherback and loggerhead turtles, respectively. Gains were even more pronounced for the Pacific shallow set fishery, where mean bycatch rates declined by 84 and 95%, for leatherback and loggerhead turtles, respectively, for the post-regulation period. Similar management approaches could be used within regional fisheries management organizations to reduce capture of sea turtles and to promote sustainable fisheries on a global scale.

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Section: Spatial Distribution and Sstsupporting

confidence: 87%

Section: Hook Depthsupporting

confidence: 84%

Section: The Role Of Bait In Bycatchmentioning

confidence: 99%

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Sea Turtle Bycatch Mitigation in U.S. Longline Fisheries

et al. 2017

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“…1) that encompasses important developmental habitats for North Atlantic loggerhead turtle Caretta caretta populations (Mans field & Putman 2013). The loggerhead is one of the most common incidentally caught sea turtle species in longline fisheries that operate within the NED (Witzell 1999, Foster et al 2012). …”

Section: Introductionmentioning

confidence: 99%

Genetic stock composition of loggerhead turtles Caretta caretta bycaught in the pelagic waters of the North Atlantic

LaCasella¹,

Epperly²,

Jensen³

et al. 2013

Endang. Species. Res.

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Sea turtle populations disperse widely across oceans and migrate between terrestrial nesting habitat and distant feeding and developmental habitats. Understanding population stock structure is important for accurately assessing threats such as mortality from fishery bycatch and for defining specific demographic units of conservation concern. We compared 775 bp mtDNA control region haplotypes from 389 juvenile loggerhead turtles sampled as bycatch in the US pelagic longline fishery in the western North Atlantic Northeast Distant (NED) region to haplotype frequencies observed in 23 genetically distinct nesting stocks representing the 4 distinct population segments (DPSs) that have been identified throughout the Atlantic Ocean and Mediterranean Sea. We used Bayesian mixed-stock analysis to produce stock composition estimates for juvenile loggerhead turtles that use pelagic habitat in the central North Atlantic. We found that nearly all of the loggerheads caught in NED waters belonged to the Northwest Atlantic DPS (mean = 99.2%), with the majority coming from the large eastern Florida rookeries (mean = 84.0%). We also detected contributions from the western Florida rookeries (mean = 11.7%) and Mexico (mean = 3.5%) but found little evidence of contributions from the rookeries of the South Atlantic, Northeast Atlantic, or Mediterranean DPSs. These results will help improve specific threat assessments and are relevant to ongoing development of conservation plans that are aligned to the recent DPS listings for loggerheads.

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“…In addition, these closures can be more difficult to enforce in international waters (Senko et al 2014). Gear and bait modifications, such as circle hooks with fish bait, reduce sea turtle bycatch and mortality in some longline fisheries Chelonian Conservation and Biology, 2014, 13(2): 237-246 g 2014 Chelonian Research Foundation but are not compatible across all levels of the fishery (Watson et al 2005;Read 2007;Foster et al 2012). However, gear modifications have been shown to reduce bycatch in many settings, are more popular with fishers, and can be less costly socioeconomically than time/area closures (Senko et al 2014).…”

mentioning

confidence: 99%