Development and observations of a spiny dogfish Squalus acanthias reduction device in a raised footrope silver hake Merluccius bilinearis trawl

Chosid, David M.; Pol, Michael; Szymanski, Mark; Mirarchi, Frank; Mirarchi, Andrew

doi:10.1016/j.fishres.2011.03.007

Cited by 24 publications

(16 citation statements)

References 18 publications

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“…acanthias by incorporating an excluder grid on the trawls used in a fishery for silver hake Merluccius bilinearis (Mitchill, 1814) successfully reduced catches of S . acanthias and improved the quality of the catch in the codend (Chosid et al , ). The 50 mm bar spacing used in this study allowed commercial quantities of the target species still to be caught, but this bar spacing may not be suitable for other fisheries targeting other species.…”

Section: Discard Mortality Of Elasmobranchs By Gearmentioning

confidence: 99%

A review of capture and post‐release mortality of elasmobranchs

Ellis

Phillips

Poisson

2016

Journal of Fish Biology

128

108

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There is a need to better understand the survivorship of discarded fishes, both for commercial stocks and species of conservation concern. Within European waters, the landing obligations that are currently being phased in as part of the European Union's reformed common fisheries policy means that an increasing number of fish stocks, with certain exceptions, should not be discarded unless it can be demonstrated that there is a high probability of survival. This study reviews the various approaches that have been used to examine the discard survival of elasmobranchs, both in terms of at-vessel mortality (AVM) and post-release mortality (PRM), with relevant findings summarized for both the main types of fishing gear used and by taxonomic group. Discard survival varies with a range of biological attributes (species, size, sex and mode of gill ventilation) as well as the range of factors associated with capture (e.g. gear type, soak time, catch mass and composition, handling practices and the degree of exposure to air and any associated change in ambient temperature). In general, demersal species with buccal-pump ventilation have a higher survival than obligate ram ventilators. Several studies have indicated that females may have a higher survival than males. Certain taxa (including hammerhead sharks Sphyrna spp. and thresher sharks Alopias spp.) may be particularly prone to higher rates of mortality when caught.

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Section: Discard Mortality Of Elasmobranchs By Gearmentioning

confidence: 99%

A review of capture and post‐release mortality of elasmobranchs

Ellis

Phillips

Poisson

2016

Journal of Fish Biology

128

108

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“…Our meta-analysis quantifies the vertical distribution of a range of commercially important North Atlantic species as they enter and pass through a demersal trawl gear. Hence our results can be used to develop and adapt gears such as low headline and coverless trawls (Krag et al 2015) and trawls with raised footropes (Chosid et al 2011;Bayse et al 2016) which have already been shown to be effective in a number of fisheries. Our analysis suggests that, in the first instance, it should be possible to separate the three categories of (i) haddock, whiting and saithe, (ii) cod, plaice and lemon sole and (iii) monkfish and nephrops.…”

Section: R a F Tmentioning

confidence: 88%

“…Differences in the behavioural reaction of fish to trawl fishing gears, from when they first become aware of its approach and their interaction with the doors, sweeps and trawl mouth, to their possible entry into the net and passage to the codend, plays a key role in the selective performance of many trawl designs (Wardle 1993;Ryer 2008;Winger et al 2010). Trawls have been developed with raised doors and sweeps to reduce the herding of some species into the path of the trawl mouth (Rose et al 2010;He et al 2015), and with raised fishing lines and low or cut-back headlines to exploit differences in how fish behave as they enter the gear (Chosid et al 2011;Krag et al 2015;Bayse et al 2016). Fishing gears have been fitted with large mesh panels in the forward or centre sections of the trawl (Thomsen 1993;Madsen et al 2006;Beutel et al 2008;Holst and Revill 2009;Campbell et al 2010;Kynoch et al 2011) and with selective devices such as square mesh panels and rigid, flexible and netting grids (Isaksen et al 1992;Catchpole and Revill 2008;Valentinsson and Ulmestrand 2008;Drewery et al 2010) in the extension and/or the codend to encourage escape as fish pass through a gear.…”

Section: R a F T D R A F T Introductionmentioning

confidence: 99%

A meta-analysis of vertical stratification in demersal trawl gears

Fryer

Summerbell

O’Neill

2017

Can. J. Fish. Aquat. Sci.

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A meta-analysis is presented of fishing trials that use trawl gear with horizontal separator panels to direct fish into an upper or lower codend. The analysis is applied to eight North Atlantic species: the gadoids cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), and whiting (Merlangius merlangus), the flatfish lemon sole (Microstomus kitt) and plaice (Pleuronectes platessa), and monkfish (Lophius piscatorius) and Nephrops (Nephops norvegicus). The proportion of fish that rise above the separator panel decreases as the height of the leading edge of the panel increases for six of the eight species. Only monkfish and Nephrops have no significant dependency on panel height. Cod is the only species for which separation depends on the horizontal distance of the leading edge of the panel from the ground gear, with the proportion of cod going above the panel increasing the farther the panel is from the ground gear. The time of day only affects the separation of plaice, with a greater proportion going above the panel at night than during the day.

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“…Simple changes such as altering the material of longline leaders can allow sharks to bite through and escape if captured, and changing the type of bait used can result in differences in species attracted to the hook in the first place (Gilman et al ., ; Ward et al ., ). Adding ‘escape grates’ to trawl nets resulted in 88% of spiny dogfish caught as bycatch being released, (Chosid et al ., ). Putting electromagnetic materials on longline hooks reduced bycatch of juvenile sandbar shark Carcharhinus plumbeus by 2/3 (Brill et al ., ).…”

Section: Target‐based Fisheries Management Policy Tools Focusing On Smentioning

confidence: 97%

Shark conservation and management policy: a review and primer for non‐specialists

Shiffman

Hammerschlag

2016

Animal Conservation

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There is increasing concern for the conservation of sharks among scientists, environmental conservation advocates, and the interested public, but misunderstanding among policy non-specialists about which conservation and management policies are available, and which might work best for certain situations, persists. Here we present a review of fisheries management and conservation literature relating to sharks. Policies are broadly divided into target-based policies that aim for sustainable fisheries exploitation (e.g. fisheries quotas) and limit-based policies that aim to prevent all fisheries exploitation of entire taxa (e.g. marine reserves). A list of the pros and cons of each policy is included, as is a decision tree to aid in selection of the most appropriate policy. Our goal is that this paper will allow policy nonspecialists, including scientists without policy training, environmental activists, and concerned citizens, to make informed decisions when advocating for shark conservation.

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Development and observations of a spiny dogfish Squalus acanthias reduction device in a raised footrope silver hake Merluccius bilinearis trawl

Cited by 24 publications

References 18 publications

A review of capture and post‐release mortality of elasmobranchs

A review of capture and post‐release mortality of elasmobranchs

A meta-analysis of vertical stratification in demersal trawl gears

Shark conservation and management policy: a review and primer for non‐specialists

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