Hooks equipped with magnets can increase catches of blue shark (Prionace glauca) by longline fishery

Porsmoguer, Sebastián Biton; Bănaru, Daniela; Boudouresque, Charles F.; Dekeyser, I.; Almarcha, Christophe

doi:10.1016/j.fishres.2015.07.016

Cited by 20 publications

(10 citation statements)

References 25 publications

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“…While the species appears relatively resilient in some areas the catch of blue shark has dramatically declined in others. In the Atlantic, total catch has been relatively consistent over time (ICCAT, 2020) even though blue shark represents about 60% of the Spanish and Portuguese longline bycatch (Porsmoguer et al, 2015). Conversely, abundance in the Mediterranean Sea declined by 96.5% over 56 years (Ferretti et al, 2008).…”

Section: Perspectives For Research Management and Policymentioning

confidence: 99%

Global-Scale Environmental Niche and Habitat of Blue Shark (Prionace glauca) by Size and Sex: A Pivotal Step to Improving Stock Management

et al. 2022

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Blue shark (Prionace glauca) is amongst the most abundant shark species in international trade, however this highly migratory species has little effective management and the need for spatio-temporal strategies increases, possibly involving the most vulnerable stage or sex classes. We combined 265,595 blue shark observations (capture or satellite tag) with environmental data to present the first global-scale analysis of species’ habitat preferences for five size and sex classes (small juveniles, large juvenile males and females, adult males and females). We leveraged the understanding of blue shark biotic environmental associations to develop two indicators of foraging location: productivity fronts in mesotrophic areas and mesopelagic micronekton in oligotrophic environments. Temperature (at surface and mixed layer depth plus 100 m) and sea surface height anomaly were used to exclude unsuitable abiotic environments. To capture the horizontal and vertical extent of thermal habitat for the blue shark, we defined the temperature niche relative to both sea surface temperature (SST) and the temperature 100 m below the mixed layer depth (Tmld+100). We show that the lifetime foraging niche incorporates highly diverse biotic and abiotic conditions: the blue shark tends to shift from mesotrophic and temperate surface waters during juvenile stages to more oligotrophic and warm surface waters for adults. However, low productivity limits all classes of blue shark habitat in the tropical western North Atlantic, and both low productivity and warm temperatures limit habitat in most of the equatorial Indian Ocean (except for the adult males) and tropical eastern Pacific. Large females tend to have greater habitat overlap with small juveniles than large males, more defined by temperature than productivity preferences. In particular, large juvenile females tend to extend their range into higher latitudes than large males, likely due to greater tolerance to relatively cold waters. Large juvenile and adult females also seem to avoid areas with intermediate SST (~21.7-24.0°C), resulting in separation from large males mostly in the tropical and temperate latitudes in the cold and warm seasons, respectively. The habitat requirements of sensitive size- and sex-specific stages to blue shark population dynamics are essential in management to improve conservation of this near-threatened species.

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Section: Perspectives For Research Management and Policymentioning

confidence: 99%

Global-Scale Environmental Niche and Habitat of Blue Shark (Prionace glauca) by Size and Sex: A Pivotal Step to Improving Stock Management

et al. 2022

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“…Additionally, magnets have been used experimentally to modify fish behavior, for example to divert or attract certain species from/to fishing gears. Strong magnets have been used, with mixed results, to reduce shark bycatch in baited fisheries (Hart and Collin 2015, Porsmoguer et al 2015, Richards et al 2018, and in freshwater, magnets placed at the entrances of fykenets increased catches of perch (Perca fluviatilis), roach (Rutilus rutilus), rudd (Scardinius erythrophthalmus), and bleak (Alburnus sp.) (Formicki et al 2004).…”

Section: Magnetic Disturbances and Animal Behaviormentioning

confidence: 99%

Electric and magnetic senses in marine animals, and potential behavioral effects of electromagnetic surveys

Nyqvist

Durif

Johnsen

et al. 2020

Marine Environmental Research

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…The ampullary electrosensory system of primitive fishes and elasmobranchs consists of pores and gel-filled canals that are highly sensitive at short-distances to low-frequency electrical stimuli produced by biotic and abiotic sources (Jordan et al, 2013;Kajiura et al, 2010;Kalmijn, 1971). Records of shark depredation of electronic biologgers suggest electroreceptive attraction (Kerstetter, Polovina, & Graves, 2004) and Porsmoguer, Bănaru, Boudouresque, Dekeyser, and Almarcha (2015) found that magnets on hooks increased catch rates of blue shark (Prionace glauca; Carcharhinidae). Other recent research demonstrates deterrent effects of electropositive metals, magnets, and semiochemical repellents on by-catch of sharks and sturgeon, although results are temperature-and species-specific and may be superceded by social cues when fishes aggregate (Bouyoucos, Bushnell, & Brill, 2014;Brill et al, 2009;Hutchinson et al, 2012;O'Connell, Stroud, & He, 2012;Robbins, Peddemors, & Kennelly, 2011).…”

Section: Sensory Ecologymentioning

confidence: 99%

What makes fish vulnerable to capture by hooks? A conceptual framework and a review of key determinants

et al. 2017

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Considerable time and money are expended in the pursuit of catching fish with hooks (e.g., handlining, angling, longlining, trolling, drumlining) across the recreational, commercial and subsistence fishing sectors. The fish and other aquatic organisms (e.g., squid) that are captured are not a random sample of the population because external (e.g., turbidity) and underlying internal variables (e.g., morphology) contribute to variation in vulnerability to hooks. Vulnerability is the probability of capture for any given fish in a given location at a given time and mechanistically explains the population‐level catchability coefficient, which is a fundamental and usually time‐varying (i.e., dynamic) variable in fisheries science and stock assessment. The mechanistic drivers of individual vulnerability to capture are thus of interest to fishers by affecting catch rates, but are also of considerable importance to fisheries managers whenever hook‐and‐line‐generated data contribute to stock assessments. In this paper, individual vulnerability to hooks is conceptualized as a dynamic state, in which individual fish switch between vulnerable and invulnerable states as a function of three interdependent key processes: an individual fish's internal state, its encounter with the gear, and the characteristics of the encountered gear. We develop a new conceptual framework of “vulnerability,” summarize the major drivers of fish vulnerability, and conclude that fish vulnerability involves complex processes. To understand vulnerability, a shift to interdisciplinary research and the integration of ecophysiology, fish ecology, fisheries ecology and human movement ecology, facilitated by new technological developments, is required.

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Hooks equipped with magnets can increase catches of blue shark (Prionace glauca) by longline fishery

Cited by 20 publications

References 25 publications

Global-Scale Environmental Niche and Habitat of Blue Shark (Prionace glauca) by Size and Sex: A Pivotal Step to Improving Stock Management

Global-Scale Environmental Niche and Habitat of Blue Shark (Prionace glauca) by Size and Sex: A Pivotal Step to Improving Stock Management

Electric and magnetic senses in marine animals, and potential behavioral effects of electromagnetic surveys

What makes fish vulnerable to capture by hooks? A conceptual framework and a review of key determinants

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