Effects of circle versus J-style hooks on target and non-target species in a pelagic longline fishery

Kerstetter, David W.; Graves, John E.

doi:10.1016/j.fishres.2006.03.032

Cited by 118 publications

(163 citation statements)

References 8 publications

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“…However, there are many other non-target species, such as seabirds, marine mammals, and sharks bycaught in pelagic longline fisheries. Several studies and symposiums have evaluated the effectiveness of circle hooks across and found that reductions are not necessarily achieved for all non-target bycatch species taxa (Kerstetter and Graves, 2006;Serafy et al, 2012;Huang, 2015). In some cases, circle hooks may increase bycatch of sharks (see Gilman et al, 2016b).…”

Section: Ecosystem Level Impacts Of Findingsmentioning

confidence: 99%

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: Ecosystem Level Impacts Of Findingsmentioning

confidence: 99%

Sea Turtle Bycatch Mitigation in U.S. Longline Fisheries

et al. 2017

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“…New information by Kerstetter et al [14] from the Caribbean Sea demonstrates that escolar migrate to shallower waters (< 250 m) at night and deeper waters (> 250 m) during the day. In addition, Kerstetter and Graves [17] showed, with hook timer technology, that escolar taken in the Mid-Atlantic Bight region had long hooked durations (i.e., time on the line) suggesting that escolar were caught on the line shortly after the gear was set. Again, this could explain why escolar catch rates were probably higher for sets in the Atlantic Ocean versus those in the Pacific Ocean.…”

Section: Abundance and Distributionmentioning

confidence: 99%

“…Escolar is a mesopelagic fish that migrates from deep (200-885 m) to shallow waters (< 150 m) at night to feed [13,14]. Besides a few studies describing its occurrence in commercial fisheries [4,[15][16][17], the biology and ecology of this species has yet to be completely investigated. To date, most published studies describe the escolar's indigestible wax esters and oily flesh, which can cause undesirable affects on human stomachs [18,19].…”

Section: Introductionmentioning

confidence: 99%

Evolving Fisheries: Today`s Bycatch is Tomorrow`s Target Catch - Escolar (Lepidocybium flavobrunneum) Catch in the U.S. Pelagic Longline Fishery~!2009-10-26~!2009-11-25~!2010-04-07~!

Levesque¹

2010

TOFISHSJ

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Wildlife and fisheries management are based upon economics: the law of supply and demand controls the direction of commercial fisheries. In the U.S. pelagic longline fishery, one example of a bycatch species that has received little research attention because of its lower economic value is the escolar (Lepidocybium flavobrunneum). Given its importance as a secondary market species, the main objectives of this paper are to provide information on fishing characteristics, relative abundance, distribution, and size composition of escolar catch in the U.S. pelagic longline fishery operating in the western North Atlantic. The overarching goal is to emphasize the importance of evaluating, managing, and conserving lower-valued species. Findings show that escolar nominal catches significantly vary by geographical area, month, and year. Most escolar are caught in the Gulf of Mexico and off the Florida East Coast (FEC), but mean catch rates are greatest in the FEC and Sargasso Sea. Escolar catch rates are greatest in April, November, and December. Overall, escolar catch rates are stable, which suggests that overfishing is not occurring in this part of the Atlantic.

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“…However, when comparing the annual catch of fish living to dead, we find an increase in live fish between the years 2007 and 2008, showing the influence of the circular hooks, which gradually replaced the hook type "J" from 2007, as reported by Kerstetter and Graves (2006); Pacheco et al (2011).…”

Section: Equationmentioning

confidence: 67%

Factors that determine the quality of bigeye tuna, caught in the western tropical Atlantic Ocean

Nóbrega

Mendes

2014

Arq. Bras. Med. Vet. Zootec.

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Tuna are highly prized in Oriental cuisine, and the bigeye tuna (Thunnus obesus) is of great commercial importance. Quality is assessed by the tuna meat quality, freshness, texture and fat, which can be altered by factors inherent to capture, such as days of onboard storage, months of the year, whether the catch was living or dead, fish weight and year. These factors were correlated to identify those that affect quality. We obtained data from nine vessels, from January 2007 to April 2010, creating an information bank of 21,908 bigeye tuna. Fish quality and parameters were related using multiple linear regression analysis, in which the variables were included in the model by a stepwise procedure (F>4). We found that live catch, heavier fish and fewer days of storage positively affected the quality, and that there is a seasonality of quality related to biological factors, which are not amenable to control.Keywords: fishing, Thunnus obesus, tuna, sensory analysis RESUMO Os atuns são peixes muito apreciados na culinária oriental, e a albacora-bandolim (Thunnus obesus)

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Effects of circle versus J-style hooks on target and non-target species in a pelagic longline fishery

Cited by 118 publications

References 8 publications

Sea Turtle Bycatch Mitigation in U.S. Longline Fisheries

Sea Turtle Bycatch Mitigation in U.S. Longline Fisheries

Evolving Fisheries: Today`s Bycatch is Tomorrow`s Target Catch - Escolar (Lepidocybium flavobrunneum) Catch in the U.S. Pelagic Longline Fishery~!2009-10-26~!2009-11-25~!2010-04-07~!

Factors that determine the quality of bigeye tuna, caught in the western tropical Atlantic Ocean

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