Incorporating sea turtle interactions in a multi-objective programming model for Hawaii's longline fishery

Pradhan, Naresh C.; Leung, PingSun

doi:10.1016/j.ecolecon.2005.12.009

Cited by 13 publications

(7 citation statements)

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“…sensory-based experiments, Southwood et al, 2008), or have resulted in economic losses and social conflicts (e.g. area closures, banning the fishery, reduction of fishing effort, Pradhan and Leung, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…For instance, in the Hawaii-based longline fishery, shallow sets (o100 m) were banned for parts of 2001 to 2004, which eliminated captures of shallow-dwelling loggerhead sea turtles (Caretta caretta) (Polovina et al, 2003). In the Hawaiian swordfish (Xiphias gladius) fishery, following a closure of four years, the fishery was reopened with a number of conditions such as a maximum annual quota for the entire fleet of 17 loggerhead and 16 leatherback (Dermochelys coriacea) sea turtles, restricted annual fishing effort, prescribed use of fish bait and large 18/0 circle hooks instead of squid bait and 9/0 J-hooks, and 100% observer coverage (Gilman et al, 2006(Gilman et al, , 2007Pradhan and Leung, 2006). In the US Atlantic fishery, circle hooks are also mandatory, while the International Commission for the Conservation of Atlantic Tunas (ICCAT), encourage their use throughout the Atlantic Ocean (Watson and Kerstetter, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery

Sales¹,

Giffoni²,

Fiedler³

et al. 2010

Aquatic Conservation

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ABSTRACT1. Incidental catches by the pelagic longline fishery is a major global threat for loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles.2. The reduction of incidental capture and post-release mortality of sea turtles in the Brazilian pelagic longline fishery, operating in the south-western Atlantic Ocean, was investigated by comparing the performance of 18/0 circle hooks with 9/0 J-type (control) hooks. Hook selectivity experiments were performed between 2004 and 2008, in a total of 26 trips, 229 sets and 145 828 hooks. The experimental design included alternating control and experimental hooks along sections of the mainline.3. An overall decrease in capture rates for loggerhead turtles of 55% and for leatherbacks of 65% were observed when using circle hooks. In addition, deep-hooking in loggerheads decreased significantly from 25% using J-hooks to 5.8% with circle hooks, potentially increasing post-release survival.4. Circle hooks increased catch rates of most of the main target species, including tunas (bigeye Thunnus obesus and albacore T. alalunga), and sharks (blue Prionace glauca and requiem sharks of the genus Carcharinus), with no difference in the capture rates of yellowfin tuna (T. albacares), shortfin mako shark (Isurus oxyrinchus), hammerhead sharks (Sphyrna lewini and S. zygaena), and dolphinfish or mahi mahi (Coryphaena hippurus). On the other hand, a significant decrease in the capture rate of swordfish (Xiphias gladius) was detected when using circle hooks.5. Overall, results support the effectiveness of using circle hooks for the conservation of loggerhead and leatherback sea turtles, with positive effects on capture of most target species of the south-western Atlantic longline fishery.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery

Sales¹,

Giffoni²,

Fiedler³

et al. 2010

Aquatic Conservation

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“…Maximizing the fleet-wide profit objective separately (p1 max) resulted in the fleet-wide profit of $29.587 million and corresponding revenue of $74.241 million which are about 136 and 34% increase in profit and revenue from the base scenario, respectively. Solving for maximizing the fleet-wide profit separately (p1 max) without the spatial and seasonal dimension in the model resulted in the fleet-wide profit of only about $12.400 million and corresponding revenue of about $65.200 million (Pradhan and Leung, 2006a). Thus, one can see the dramatic increase in efficiency with the added dimensions.…”

Section: Resultsmentioning

confidence: 96%

“…The model in Pradhan and Leung (2006a) is expanded by including spatial and seasonal dimensions. The model considers fleet heterogeneity and fishers' micro-behaviours to realistically depict the fishery and to capture the potential efficiency gains.…”

Section: The Modelmentioning

confidence: 99%

“…Considering these concerns, the multi-objective mathematical programming model by Pan et al (2001) was, therefore, modified to incorporate the issue of sea turtle interactions by Pradhan and Leung (2006a). The work by Pradhan and Leung has been further expanded in this study by adding spatial and seasonal dimensions, as it is presumed that a more refined optimization in terms of economic and environmental efficiency gains may be achieved with these added features.…”

Section: Introductionmentioning

confidence: 98%

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Sea turtle interactions with Hawaii's longline fishery: an extended multi-objective programming model incorporating spatial and seasonal dimensions

Pradhan¹,

Leung²

2008

Applied Economics

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Endangered and protected sea turtle interactions with the pelagic longline fishery have become an important fishery policy concern recently. A multi-objective programming model for Hawaii's longline fishery that incorporated sea turtle interactions (Pradhan and Leung, 2006a) has been extended with spatial and seasonal dimensions. The synergetic effect of these added features indicate that there exists better economic and environmental efficiency gains in terms of higher profit and reduced turtle interactions, compared to the base case without these added dimensions, by reconfiguring fishing efforts across space and seasons. There also exists a trade-off between fleet-wide profit and turtle interactions. The current fishery policy related to sea turtle interactions disallows capturing all the potential efficiency gain, as the number of turtles allowed to get interacted severely limits swordfish-targeted longline fishing that uses conventional technologies. Restricting longline fishery to operate sub-optimally would result in average shadow value of $15 957 and $60 908 per turtle in terms of lost profit and revenue, respectively. These shadow values are higher than those estimated from earlier model without the spatial and seasonal dimensions. Adaptation to 'turtle-friendly' fishing technologies is among the many strategies that would allow for higher optimal fishing efforts and also leading to higher overall welfare and towards more responsible fishery.

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Fishery externalities and biodiversity: Trade-offs between the viability of shrimp trawling and the conservation of Frigatebirds in French Guiana

Martinet¹,

Blanchard²

2009

Ecological Economics

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Sustainable management of natural resources, and in particular fisheries, must take into account several conflicting objectives. This is the case in the French Guiana shrimp fishery for which profitability objectives imply a reduction in the fishing activity. On the one hand, this fishery has negative externalities on marine biodiversity due to discards. On the other hand, this fishery has positive externalities on the economy of the local community and interestingly enough on a protected seabird species in the area (the Frigatebird that feeds on discards). In this paper, we examine the viability of that system considering two sustainability objectives: an economic objective in terms of the profitability of the fishing activity, and a conservation objective in terms of the Frigatebird population. For that purpose, we have developed a dynamic model of that bioeconomic system and study here the trade-offs between the two conflicting objectives. It provides a means to quantify the necessary give and takes involving the economic and ecological objectives that would ensure a viable management solution. Our study confirms the relevance of the viability approach to address natural resource management issues, which should lead to the development of new tools for the arbitration of conflicting sustainability objectives. In particular, such tools could be used as a quantitative basis for cost-benefit analysis taking into account environmental externalities.

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Incorporating sea turtle interactions in a multi-objective programming model for Hawaii's longline fishery

Cited by 13 publications

References 10 publications

Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery

Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery

Sea turtle interactions with Hawaii's longline fishery: an extended multi-objective programming model incorporating spatial and seasonal dimensions

Fishery externalities and biodiversity: Trade-offs between the viability of shrimp trawling and the conservation of Frigatebirds in French Guiana

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