Species and size selectivity in longline fishing: a review

Løkkeborg, Svein; Bjordal, Åsmund

doi:10.1016/0165-7836(92)90084-7

Cited by 142 publications

(120 citation statements)

References 18 publications

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“…Decreases in the bycatch of some fish species could be attained through changes in bait type (Alós et al 2009) or the use of circle hooks (which have been recommended to reduce the bycatch mortality, particularly for sea turtles; Lewison et al 2004). Circle hooks could maintain or even increase the catch rates of the target species (Løkkeborg and Bjordal 1992;Woll et al 2001), especially for those species that tend to be hooked in the mouth (Løkkeborg and Bjordal 1992). In addition, circle hooks could reduce the mortality of released fish (Alós et al 2008b).…”

Section: Discussionmentioning

confidence: 99%

Hook Selectivity in an Artisanal Spotted Rose Snapper Lutjanus guttatus Fishery on the Nicoya Peninsula, Costa Rica

Mongeon

Granek

Arauz³

2013

Mar Coast Fish

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Commercial fishing is responsible for declines in both the abundance and biomass of many marine species (Ward and Myers 2005). The Marine Stewardship Council's (MSC) Sustainable Seafood Certification Program focuses on fishery modifications to reduce such impacts on marine species and ecosystems. On the Nicoya Peninsula in northwestern Costa Rica, the Costa Rican nongovernmental organization Programa Restauración de Tortugas Marinas has been working with artisanal fishers since 2007 to promote sustainable fishing practices, with the goal of applying for a sustainable fishery certificate from the MSC. To collect relevant data for the MSC application, we tested the selectivity of the hooks used in the artisanal fishery to determine how the fishery interacts with the target species, the Spotted Rose Snapper Lutjanus guttatus, as well as nontarget, bycatch species. We constructed a longline composed of equal numbers of different sized hooks (the Mustad #8 “J” style hooks commonly used in the fishery as well as smaller #10 and larger #6 hooks). Decreasing the hook size led to higher catch rates of both Spotted Rose Snapper and most bycatch species, with no change in mean size of Spotted Rose Snapper. Increasing the hook size led to decreased catch rates of both Spotted Rose Snapper and most bycatch species and an increase in the mean size of Spotted Rose Snapper. The size range of the Spotted Rose Snapper caught on this gear did not exceed that of the artisanal fishery. This study suggests that the artisanal fishery is using an appropriately sized hook to minimize bycatch rates without unduly minimizing the catch rates of the target species, though increasing hook size could exclude the smallest Spotted Rose Snapper from the fishery. Received November 27, 2012; accepted May 21, 2013

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Section: Discussionmentioning

confidence: 99%

Hook Selectivity in an Artisanal Spotted Rose Snapper Lutjanus guttatus Fishery on the Nicoya Peninsula, Costa Rica

Mongeon

Granek

Arauz³

2013

Mar Coast Fish

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“…If large Greenland halibut are able to swim for longer distances in search for food, or if the largest ones win the competition for bait, larger fish may be caught in relatively larger numbers than small ones. Thus the longline catches may not reflect the actual fish size distribution in the area (Løkkeborg and Bjordal, 1992;Engås et al, 1993). If there is a mixture of different fish-length groups in an area, the longline seem to catch the larger ones.…”

Section: Discussionmentioning

confidence: 99%

“…The selective proper ties of longline gear d e p e n d o n s e v e r a l f a c t o r s s u c h a s f e e d i n g motivation and hooking ability in different groups of fish, and competition between species and size groups when approaching the bait (Fernø et al, 1986;Ber trand, 1988;Løkkeborg and Bjordal, 1992). The number of fish of different species and size groups caught by longline gear is, therefore, influenced by numerous factors (e.g.…”

Section: Discussionmentioning

confidence: 99%

Performance and Biological Implications of a Multi-gear Fishery for Greenland Halibut (Reinhardtius hippoglossoides)

Nedreaas¹,

Soldal²,

Bjordal³

1996

J. Northw. Atl. Fish. Sci.

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Simultaneous full-scale fishing operations using bottom trawl, gillnet and longline for Greenland halibut (Reinhardtius hippoglossoides, Walbaum) were performed in the Barents Sea (ICES Divisions IIa and IIb) for two weeks in October 1992. The mesh size of the trawl codend was 135 mm, and that of the gillnets 220 mm. Additionally, seven gillnet fleets of 180 mm mesh size were set for selectivity comparison. The catch rates and the length distributions of the Greenland halibut in the catches taken by trawl, longline and gillnet were different. Gillnets almost exclusively caught fish between 60 and 70 cm, mostly mature females (about 90%). The size distribution taken by longline was wider than that taken by gillnet. Two thirds of the longline catches were females, and the proportion of immature individuals was larger (14-30%) than in the gillnet catches. The trawls, however, caught large amounts of fish between 40 and 60 cm, consisting of almost equal amounts of males and females, and 30-40% immature fish. Gear-specific selection properties were the main reasons for the observed differences.Yield-per-recruit and spawning-stock-biomass-per-recruit analyses showed that fixed gears captured proportionally fewer immature fish, and thus indicated they would provide greater spawning biomass and yield-per-recruit than would trawl gear, for an equivalent reference fishing mortality rate.

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“…This could not be the reason for selectivity absence in our study because we believe that size distribution was not homogeneous for small fishes, as adults also occurred at the sample sites. Lokkeborg and Bjordal (1992) believe that there may be a selection process before fishes find the baits, which exposes a high proportion of large species and individuals to the apparatus. Even without determining selectivity curve for the tested hooks, we expected that large hooks would capture large fishes that can bite the hook, and that small and fragile hooks would not retain large fishes for long periods, or even capture them.…”

Section: Discussionmentioning

confidence: 99%

Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil

Peixer

Petrere

2007

Braz. J. Biol.

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The Pacu Piaractus mesopotamicus is the most captured fish species in the Pantanal, Mato Grosso do Sul State, and since 1994, its maximum sustainable yield had already been exceeded. Its capture is carried out only by hooks, as mesh gears are forbidden either for professional or for recreational fishing. The aim of this study was to determine selectivity for different hook sizes used in P. mesopotamicus fishing and to verify which sizes capture only adults. Data were collected in the rivers Miranda, Aquidauana, and Vermelho, in January, March, and April 2002. Six longlines with eight hook sizes were used and we adopted the hook opening as a measure related to selectivity. Different hooks captured individuals of the same length and their medians were similar, evidencing the great overlap among sizes. Regression results showed no significant relationship between ln[ ( ) ] c l c l 2 1 ( ) and total length of captured individuals. In addition, the Kolmogorov-Smirnov test also did not detect significant differences in the size of captured fish. Several hypotheses, such as the selectivity models, shape of selection curves, scarcity of large fishes, and behavior are used in order to explain the absence of hook selectivity for this species. Size of recruitment for this gear was 28 cm of total length, when individuals are still immature.Keywords: hook selectivity, Pacu, Piaractus mesopotamicus, Pantanal, Brazil. A seletividade do anzol para o Pacu Piaractus mesopotamicus (Holmberg, 1887) no Pantanal do Mato Grosso do Sul, Brasil ResumoDesde 1994, o pacu Piaractus mesopotamicus, é a principal espécie nas capturas comerciais e esportivas no Pantanal sul-matogrossense, e seu rendimento máximo sustentável já foi ultrapassado. Sua captura só é permitida por anzóis, para as duas pescarias acima, visto que as artes de emalhe são proibidas na região. O objetivo deste estudo foi o de determinar a seletividade para diferentes tamanhos de anzóis usados na captura do pacu e verificar a partir de qual tamanho de anzol somente os adultos são capturados. Para tal, foram realizadas pescarias nos rios Miranda, Aquidauana e Vermelho, nos meses de janeiro, março e abril de 2002. Seis espinhéis contendo 8 tamanhos diferentes de anzóis foram empregados. A abertura do anzol foi adotada para expressar sua seletividade. Diferentes anzóis capturaram indivíduos de mesmo comprimento, e suas medianas foram similares, evidenciando a grande sobreposição dos tamanhos capturados. As regressões entre ln[ ( ) ] c l c l 2 1 ( ) e l não foram significativas. O teste de Kolmogorov-Smirnov também não detectou diferenças significativas nos tamanhos dos peixes capturados por diferentes anzóis. Várias hipóteses são levantadas para explicar a ausência de seletividade dessa amplitude de tamanhos de anzóis para a espécie. O recrutamento para a pesca, porém ocorre aos 28 cm de comprimento total, quando os indivíduos ainda estão imaturos.Palavras-chave: seletividade por anzol, Pacu, Piaractus mesopotamicus, Pantanal, Brasil.

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Species and size selectivity in longline fishing: a review

Cited by 142 publications

References 18 publications

Hook Selectivity in an Artisanal Spotted Rose Snapper Lutjanus guttatus Fishery on the Nicoya Peninsula, Costa Rica

Hook Selectivity in an Artisanal Spotted Rose Snapper Lutjanus guttatus Fishery on the Nicoya Peninsula, Costa Rica

Performance and Biological Implications of a Multi-gear Fishery for Greenland Halibut (Reinhardtius hippoglossoides)

Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil

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