ICES/FAO Working Group on Fish Technology and Fish Behaviour Questioning the effectiveness of implemented technical measures under the EU landings obligation: the Basque Otter Bottom Trawl fishery case study Nekane Alzorriz, Luis Arrregi, Bent Herrmann, Manu Sistiaga, Jan Jaap Poos (Lisbon, 4-7 May 2015)

The Fleet & the gear The fleet 7 vessels, (37-42 m) Fishing mainly in ICES VIIIabd Targeting demesal species (Monkfish, megrim, hake, squids, red mullet,…) The trawl Footrope length 80-90-100 m Floatline heith 1,8-2,4 m Wingspread 22-26 m Towing speed 4 knots Not very much evolution in last 30-40 years. The evolutions have been focused on trawl doors (from wood to steel doors), bridles (covered with netting to increase wing length) and towing speed (from 3,5 to 4,0 Knots)

Technical measures Codend “Reg. (EC) 494/2002” Material < 6 mm single twine or < 4 mm double twine 100 free meshes around (When 100 mm) or 120 free meshes around (When 70 mm) 100 mm Minimun mesh size or 70 mm mesh size and < 15% Hake When 70 mm mesh Size: Selective Device “Reg. (EC) 51/2006” Square Mesh Panel (SMP) > 2 meter long & >1 meter width Twine single < 4 mm Mesh size > 100 mm Set 12 meshes before the codend.

Sampling during 2010-2012 in OTB operating in Bay of Biscay Year Metier Total trips Sampled trips Sampling coverage % 2010 OTB_DEF_>= 70 166 5 3,01% OTB_MCF_>= 70 99 2 2,02% 2011 124 7 5,65% 129 5,43% 2012 102 3 2,94% 162 11 6,79% Fishing and Sampling effort by metier (DCF Level 6) during 2010-2012. Sampled hauls during 2010-2012. Size proportional to discarded catch (Kg)

Metier: Demersal Discards: - Horse mackerel, dogfish, mackerel and blue whiting > 70% of total discarded weight. - 78 species; 57 of them included in “other species” Landings: - 67 species. Very mixed-species fishery. Main target species: Hake, Monkfish and Megrim.

Metier: Mixed Cephalopod & Demersal Discards: - Horse mackerel and Mackerel >60% of total discarded weight. - 89 species discarded (including invertebrates) Landings: - European squid, common cuttlefish and striped red mullet ≈ 50% of landings - 70 species (including invertebrates)

Fleet situation regarding discards According to new EU policy and the fleet exploitation pattern referring to discards. Discard ban could be a threat for the fishing activity. Solutions were needed OPPAO Fishermen Organization required from AZTI to start a project dealing with discard reduction, focused on commercial species. All experiments were carried out on board commercial vessels.

Sea trials and data collection A total of 73 hauls between Nov 2011 and July 2013 Species selected were bib (BIB), hake (HKE) and red mullet (MUR) X Total selectivity estimation (SMP + C) 15 hauls under commercial fishing conditions ◊ Selection properties of the SMP alone 58 hauls under a research survey of fish abundance

Methodologies used Total selectivity estimation (SMP + C) Dual selection model: Zuur et al. (2001) and O’Neill et al. (2006) Based on a logit size selection model, following the procedure described in Sistiaga et al. (2010) Parameters for the SMP: CSMP, L50SMP and SRSMP Parameters for the C: L50codend and SRcodend Parameters for the combined selectivity: L50dual and SRdual Selection properties of the SMP alone “SMP only size selection” with the same estimation procedure as the 3 compartment setup Based on a logit model, similar to the one described in Herrmann et al. (2013)

Methodologies used Fall- through experiment: To assess the potential size selection of the SMP and to solve potential problems with the estimation of the CSMP Constraint: L50SMP ≥ 0.5 * L50fall Herrmann et al. (2009) Parameters of the SMP: L05fall , L50fall and SRfall L05fall can be interpreted as the size of fish with 95% escapement probability through the SMP

Methodologies used Selectivity data were analyzed using SELNET Herrmann et al. (2012) Selection parameters Accounting for the uncertainty in estimation due to: Within and between haul- variation Subsampling in data Fit statistics based on the p-value Retention / Escapement probability of undersized individuals

Fall- through experiment Results Fall- through experiment Potential selectivity of the SMP BIB HKE MUR L50fall (cm) 26.10 (25.46-26.71) 50.55 (49.53-52.74) 31.49 (30.52-31.52) SRfall (cm) 1.72 (0.10-2.48) 0.10 (0.10-0.18) (0.10-0.10) L05fall (cm) 23.79 (22.73-26.37) 50.41 (49.39-52.61) 31.36 (30.39-31.39) p- value 0.98 1.00 12

Total selectivity estimation (SMP + C) Results Total selectivity estimation (SMP + C) 3 compartment setup 13

Total selectivity estimation (SMP + C) Results Total selectivity estimation (SMP + C) BIB HKE MUR L50 (cm) SMP 13.05 (13.05 - 27.52) 37.58 (25.50 - 37.63) 20.52 (16.01 - 20.56) Codend 18.08 (16.31 - 19.47) 20.29 (17.54 - 24.19) 13.36 (4.89 – 18.68) Dual 18.15 (16.45 - 19.50) 20.44 (17.82 - 24.47) 13.47 (5.56 - 18.77) SR (cm) 5.51 (0.10 - 21.34) 0.10 (0.10 - 100.0) (0.10 - 5.91) 4.45 (3.73 - 5.29) 8.40 (5.65 - 11.34) 13.04 (6.31 - 32.80) 4.41 (3.73 - 5.18) 8.61 (5.94 - 11.72) 13.19 (6.28 - 33.33) CSMP 0.15 (0.01 - 0.70) 0.02 (0.00 - 0.11) 0.01 (0.01 - 0.02) Dual retention <MLS (%) * 51.45 (22.06 - 68.18) 45.20 (16.83 - 63.51) SMP escapement <MLS (%) 1.73 (0.00 - 10.41) 0.87 (0.39 - 1.57) C escapement <MLS (%) 46.82 (28.69 - 74.90) 53.93 (35.41 - 82.07) p- value 0.51 0.77

Selection properties of the SMP alone Results Selection properties of the SMP alone 2 compartment setup 15

Selection properties of the SMP alone Results Selection properties of the SMP alone BIB HKE MUR 2012 2013 L50SMP (cm) * 49.51 (40.47-49.98) 39.64 (26.27-46.56) 29.56 (15.75-31.49) 23.42 SRSMP (cm) 0.10 (0.10-6.36) 7.80 (0.10-20.05) (0.10-11.73) (0.10-100.0) CSMP 0.00 0.04 (0.03-0.07) (0.03-0.09) 0.01 (0.00-0.02) (0.00-0.06) SMP escapeme nt <MLS (%) (0.00) 4.10 (2.29-6.83) 4.84 (2.95-8.27) p- value 1.00 0.03 0.90 0.98 16

Conclusions Multispecific fishery with more than 20 marketable species, with different morphological characteristics and MLS. Difficult to find a single selectivity device that satisfied all species. Fall-through experiment have demonstrated that the SMP would allow the release of inmature and undersized fish. The contact values for all three species suggest that the SMP contribution to the selectivity is very small. Less than 4% of the hake and red mullet were predicted to have a chance to escape through the SMP. The selectivity for these three species is mainly attributed to the codend. The limited effectiveness of the SMP for these species in this fishery highlights that gear-specific regulations should be tested before implementation.

Paper submitted to ICES Journal of Marine Science Title: Questioning the effectiveness of implemented technical measures under the EU landings obligation: the Basque Otter Bottom Trawl fishery case study Authors: Nekane Alzorriz1*, 2, Luis Arrregi2, Bent Herrmann3, Manu Sistiaga4, Jan Jaap Poos5 1 European Commission, Joint Research Centre; Institute for Protection and Security of the Citizen; Maritime Affairs Unit G.03; TP 051, 21027 Ispra (VA), Italy. 2 AZTI-Tecnalia; Marine Research Division; Txatxarramendi ugartea w/n; 48395 Sukarrieta; Spain. 3 SINTEF Fisheries and Aquaculture, Fishing Gear Technology, Willemoesvej 2, 9850 Hirtshals, Denmark. 4 SINTEF, Department of Marine Environmental Technology, Norway. 5 Wageningen IMARES, Institute for Marine Resources and Ecosystem Studies, PO Box 68, 1970 AB IJmuiden, The Netherlands. * Corresponding author; tel: +39 0332 783515; fax: +39 0332 789658; e-mail: nekane.alzorriz@jrc.ec.europa.eu