By-catch Reduction Techniques in European Fisheries: Traditional Methods and Potential Innovations

Suuronen, Petri; Sardà, Francisco

doi:10.1007/978-1-4020-6078-6_3

Cited by 14 publications

(10 citation statements)

References 77 publications

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“…In particular, the studies carried out on sorting grids have revealed clear advantages associated with their use in mixed trawl fisheries, such as improved selectivity and by-catch reduction (e.g. Massutí et al 2009, Aydın andTosunoğlu 2011), a stable selection pattern during the tow (Suuronen and Sardà 2007), and a higher survival rate of specimens escaping from the grid bars compared with a conventional cod-end mesh (e.g. Brčić et.…”

Section: Introductionmentioning

confidence: 99%

Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches?

et al. 2018

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Mediterranean trawl fisheries are characterized by a critical combination of high fishing effort and low size at first capture for most commercial species. In this study we tested the use of sorting grids installed on bottom trawl nets to minimize the catch of undersized deep-water rose shrimp (Parapenaeus longirostris, DPS) and European hake (Merluccius merluccius, HKE). The catch of a traditional trawl net was compared with that obtained with the same net equipped with ad hoc designed juveniles and trash excluder devices (JTEDs) during an experimental survey. Three different JTEDs were tested: the first (G1-SM40) was built with a net of 40-mm square mesh; the second (G2-ST20) and third (G3-ST25) with vertical steel bars spaced 20 and 25 mm, respectively. The probability of retaining DPS and HKE by length class in trawl nets with and without JTED was analysed using generalized additive mixed models. With G1-SM40, the reduction of undersized individuals in the cod-end was about 60% and 44% for DPS and HKE, respectively. With G2-ST20, a 34% catch decrease of HKE individuals smaller than 20 cm total length was observed. A loss of marketable fractions of DPS was recorded with G1-SM40 (–25%) and G2-ST20 (30%). Finally, JTD G3-ST25 was efficient at reducing the catch of undersized specimens of DPS and HKE, but showed a higher loss of marketable fractions than the other JTEDs. Although further fishing trials would be required to maximize the sorting efficiency of the grids, the results obtained clearly indicated that grids can substantially reduce unwanted catches of undersized DPS and HKE in Mediterranean bottom trawl fisheries.

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Section: Introductionmentioning

confidence: 99%

Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches?

et al. 2018

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“…The rates of such conservation subsidies would have to be decided at the European level to avoid disadvantaging any Member State. In addition, money currently going into fishing subsidies could be used to encourage good environmental practises in the industry, such as more selective, lighter trawls (Suuronen and Sardà 2007), recovery of lost nets and rotation of fishing effort among stocks (Johannes 1998).…”

Section: Winning Over the Fishing Industrymentioning

confidence: 99%

Reforming the European Common Fisheries Policy: a case for capacity and effort controls

Cotter¹

2010

Fish and Fisheries

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, polymath, playwright, Nobel prize winner, and the most prolific letter writer in history, was an advocate of English spelling reform. He was reportedly fond of pointing out its absurdities by proving that 'fish' could be spelt 'ghoti'. That is: 'gh' as in 'rough', 'o' as in 'women' and 'ti' as in palatial.Abstract I summarize the total allowable catch (TAC) fishery management system, which forms part of the European Common Fisheries Policy (CFP) as complicated, inaccurate and ineffective. Total allowable effort (TAE), i.e. limits on fishing capacity and days-at-sea, provides a simpler, readily enforceable control to protect all species affected by a fishery. Fishing capacity of vessels in each region-gear fleet could be capped through limits on engine power, gear, crew, and fittings, and/or reducing allowances of days-at-sea for large, powerful vessels. Two basic, fishery-dependent indicators are put forward to assess sustainability of a fishery dependably even in the absence of fishery-independent data. One is socio-economic, the other is ecological. Fishery working groups within each marine region would recommend a TAE to sustain their fishery while also protecting the most critically affected species or processes. Regional working groups would supervise a consistent approach across the different fisheries in their region. A pan-European group would set policy, implement external agreements, set rules for trading TAE if necessary and harmonize fishing opportunities across regions. To ease negotiations on TAEs with the fishing industry when an ecosystem needs to recover, I propose compensation payments funded by re-direction of existing CFP subsidies that promote fishing.

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“…In contrast, when a metallic grid is used, selection of the captured individuals occurs throughout the tow. Selectivity of TD and ND dredges may be improved by (1) reducing the twine thickness and stiffness, which lowers the mesh resistance to opening (Suuronen and Sardà 2007), (2) by restricting the number of meshes, or (3) by hanging the net bag on ropes with a length lower than the stretched length of the net bag (Robertson and Shanks 1989).…”

Section: Contribution To Deadmentioning

confidence: 99%

A comparison of bycatch and discard mortality in three types of dredge used in the PortugueseSpisula solida(solid surf clam) fishery

Leitão

Gaspar

Santos

et al. 2009

Aquat. Living Resour.

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Despite the importance of the dredge fishery in Portugal, few studies have focused on bycatch and discard mortality. Catches from three types of dredge: north dredge (ND); grid dredge (GD); and traditional dredge (TD), currently used in the Spisula solida (Bivalvia: Mactridae) fishery, were compared in order to characterize bycatch and to estimate discard mortality. In TD and ND, the catch was retained in a net bag, whereas in the GD a metallic grid cage was used. Tows were carried out on sandy bottoms at depths ranging from 5 to 10 m. Bycatch differed significantly between dredges. The ratio of bycatch abundance to S. solida was 0.22:1 for ND, 0.10:1 for GD and 0.33:1 for TD. The weight ratio was 0.15:1, 0.14:1 and 0.32:1 for ND, GD and TD, respectively. Although a lower bycatch was observed for GD, higher mortality (ND: 10%; TD: 20%; GD: 36%) was estimated for this dredge. However, taking into consideration the fishing yields obtained for each dredge combined with the fact that this fishery is managed by daily quota per vessel, our results showed that, at daily quota level, discard mortality was lower when GD was used. Our study suggests that in output-controlled fisheries, there are obvious advantages in developing dredges with rigid retention structures, such as metallic grids, because these are more selective and efficient than dredges that use net bags. At species level, the bycatch mortality to attain quota varied among dredges. A "selective" and persisting significant removal of bycatch species from biota may change benthic community structure. Therefore, clam fisheries should apply exploitation strategies that are goal-oriented and adaptive to the evolution of the macrofauna communities, which might include the use of different dredge types, thereby diversifying the bycatch and consequently avoiding the cumulative removal of specific macrofauna taxa.

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By-catch Reduction Techniques in European Fisheries: Traditional Methods and Potential Innovations

Cited by 14 publications

References 77 publications

Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches?

Towards more selective Mediterranean trawl fisheries: are juveniles and trash excluder devices effective tools for reducing undersized catches?

Reforming the European Common Fisheries Policy: a case for capacity and effort controls

A comparison of bycatch and discard mortality in three types of dredge used in the PortugueseSpisula solida(solid surf clam) fishery

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