8.3 western mediterranean case study · the number of trawlers doubled in mallorca from 35 to 70...

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This projecthas received funding fromthe European Union’s Horizon 2020research and innovation programmeundergrantagreementNo633680

8.3 WesternMediterraneancasestudy

byAntoniQuetglas,BeatrizGuijarro,EnricMassutí(IEO)

8.3.1 BriefpresentationoftheCSandfisheriesconcerned

TheWesternMediterraneancasestudywillfocusontwocontrastingareasintermsoftheecosystemproductivity, exploitation pattern, and types and rates of discards: the French and Spanish Gulf ofLions-CatalancoastandtheBalearicArchipelago.Theseareasencompassthreedifferentgeographicalsubareas (GSAs), defined by the General Fisheries Commission for the Mediterranean (GFCM;www.gfcm.org)fortheassessmentandmanagementofMediterraneanstocks(Figure19):1)BalearicIslands(GSA5);2)NorthernSpain(GSA6);and3)GulfofLions(GSA7).

Figure19:MapoftheMediterraneanSeashowingthethirtygeographicalsub-areas(GSAs)establishedbytheGeneralFisheriesCommissionfortheMediterranean(GFCM).ThemainstudyareascoveredundertheWesternMediterraneanCaseStudyareshowninred:BalearicIslands(GSA5),NorthernSpain(GSA6)andGulfofLions(GSA7).

The Gulf of Lions is the most productive area in the western Mediterranean owing to the winterupwelling and the discharges of rivers, whereas the Balearic Islands constitute an especiallyoligotrophicareawithinthegeneraloligotrophyoftheMediterranean(Estrada,1996).

Ineachofthesetwomainareas,twobathymetricstrata,middleslopeanddeepshelf,willbeusedasparallel‘studysystems’.Atthedeepshelf,theEuropeanhake(Merlucciusmerluccius)isthedominantspeciesexploitedbydifferentgeartypes(trawlers,long-liners,gill-netters),whileatthemiddleslope,theredshrimp(Aristeusantennatus)dominatesthecatchesandisexploitedexclusivelybytrawlers.



Hakeand red shrimp from theGulf of Lions are shared stocks exploitedby theFrenchandSpanishfleets.TheFrench trawler fleet is the largestboth innumberof boats and landings (41%and72%,respectively).ThesecondlargestfleetistheFrenchgillnetters(41and14%respectively),followedbytheSpanishtrawlers(11and8%,respectively),andtheSpanishlong-liners(6and6%,respectively).

Historically,thenumberoffishingvesselshasremainedverylowintheBalearicIslandscomparedtonearby areas. The number of trawlers doubled inMallorca from 35 to 70 units between 1965 and1977,buthasdecreasedprogressivelysincethentothe28currentvessels.IntherestoftheBalearicIslands, thecurrentnumberoftrawlers isevenlower:7 inMenorca,8 inIbizaand2 inFormentera.Thesevaluesare clearlyvery far from the totalnumberofvessels inGSA6, for instance,where thefleethasdecreasedfrom810trawlersin1998tothecurrent550units.

TrawlfishingexploitationinGSA5ismuchlowerthaninGSA6and7;thedensityoftrawlersaroundtheBalearic Islands is oneorderofmagnitude lower than in adjacentwaters (Massutí andGuijarro2004).Duetothislowerfishingexploitation,thedemersalresourcesandecosystemsinGSA5areinahealthier state than in GSA 6 and 7, which is reflected in the population structure of the maincommercial species, and in the higher abundance and diversity of elasmobranch assemblages(Quetglasetal.,2012).

Trawldiscards fromtheshelfconstituteup to55-70%of thecatchandarecomposedmainlyofredalgaeandechinodermsinGSA05,whereastheyonlyrepresent23-48%andaredominatedbyfishinGSA06(Sánchezetal.2004,Ordinesetal.2006).

8.3.2 Causesofdiscarding

TheEuropeanProjectDiscardsoftheWesternMediterraneantrawlfleets (ContractNºMED94/027),analyzed the composition, both from a quantitative and qualitative point of view, of the trawl fleetdiscardsindifferentareasoftheWesternMediterranean(GSA1,5,6and9).Thisprojectwascarriedoutduring1995-1996andincludedtwoportsfromtheBalearicIslands(PalmaandAlcudia).Onboardsamplingallowedcollectingcatchanddiscarddataatthreedifferentbathymetricstrata:A(<150m),B(150-350m)andC(>350m).

InstratumA,thediscardedfractionwascomposedofspecieswithoutcommercialinterestsuchalgaeandechinoderms,whichrepresented52%and20%ofthetotalcatchinPalma(PM)andAlcudia(AL)respectively (Figure 20). In stratumB, discards represented 50% (PM) and 40% (AL) of catch, andincluded mainly fish; a large bulk of the discard (47% PM, 35% AL) corresponded to marketablespecies, but of lowor almost no commercial value in the study area (e.g.Boopsboops orTrachurusspp.). In stratumC, thediscarded fractionwasmuch smaller, less than20%of the total, and itwascomposedmainlyofspecieswithoutcommercialvalue,suchasmacruridsormyctophids.

Inconclusion, thediscardedbiomassalwaysconstitutedan important fractionof thetotalcatch,butdiscardsprincipallyaffectedspeciesofnoorlittlecommercial interest.Thediscardofspecieswithahighcommercialvalue(e.g.octopus,shrimp,Norwaylobster)wasveryloworzero.



Figure20:Catchcomposition(%kg/h)bystratumatPalmadeMallorcaandAlcudia(BalearicIslands).FromCarbonelletal.(1997).

Usingdatafromthisproject,Sartoretal.(1998)analyzedthediscardsofcephalopodsinthedifferentareas.Ingeneral,discardingofcephalopodswasminimalbymassinallbathymetricstrata,only0.06-1.69% of total catch or 0.10-5.23% of the total discarded catch. However, in terms of number ofspecies, the discarded componentwas notable. In terms of commercial importance of the differentspeciesandstudyareas,threegroupswereidentified:speciesthatarealmostentirelyofcommercialinterest, species that are always rejected (mainly bathyal cephalopods) and species for which thediscardpercentagesarevariable(e.g.Alloteuthisspp.,Sepiaorbignyana).

Bellidoetal. (2014)analyzed theconsequencesof the landingobligation for theMediterranean; themainfindingsofthisworkaresummarizedinthetwofollowingparagraphs.From300speciescaught



intheMediterranean,onlyaround10%areconsistentlymarketedand30%areoccasionallyretained(dependingonthesizesandmarketdemands)whereasupto60%arealwaysdiscarded.

Total discards in the Mediterranean are estimated at 18.6% of the total catch. Discards differdependingon thecountry.Forregulatedspecies, Italywithmore than40%of landingsbyweight isfollowed by Spain (5%) and Slovenia (5%) as countrieswith the highest discard rates (Figure 21).Reasons for discarding are highly variable and they can be driven by economic, sociological,environmental or biological factors. These factors often act together; it is quite difficult to separatethem, especially in multispecies fisheries. In the Mediterranean, discards are characterised byextremelyhighspeciesdiversitywithahighpercentageofnon-commercialcatchandhighvariabilityintotaldiscardrateduetoseasonality.

Figure21:Proportionofcommercial(L)anddiscarded(D)fractionsbyweightofthecatches(a)andtotalcatches(b)takenduringtheperiodfromyear2009to2012intheSpanishMediterranean.FromBellidoetal.(2014).

ForFrance,SpainandGreece, thehighestdiscardratesforcommercialspecieswereassociatedwith‘low value’ pelagic species such as sardine and horsemackerel. The length data supplied by Spainsuggests thatmuchof thediscardingwasnotonlyassociatedwith fishbelowminimumlandingsize(MLS)butalsobecauseofhighgrading, suggesting thatonly the largerspecimenswereretained formarketing purposes. Conversely, high value species such as hake, shrimp and monk/anglerfish allexhibited very low discard rates and examination of the length data suggests that a considerableproportionofthefishlandedforsalewerebelowMLS,suggestingthatdiscardingwasmainlyinducedbyqualityissuesandmarketforcesratherthananylegalconstraints.

Finally,thereisaPhDThesisspecificallydevotedtothediscardsfromthetrawlfleetfromtheGulfofLions (Mallol, 2005). A total of 68 hauls (c.a. 300 h trawling) on board a commercial trawlerwerecarried out betweenMarch 1998 andMarch 2000 (Figure 29). In terms of biomass, discardswererepresentedbyfish(88.01%),echinoderms(7.75%),crustaceans(1.50%),cephalopods(0.78%)andotherspecies(1.96%).Thediscardedbiomasswashighestontheshelfandlowestonthemiddleslope;


This projecthas received funding from

the European Union’s Horizon 2020

research and innovation programme

undergrantagreementNo633680

regardingseasons,discardsweresignificantlyhighest insummer,coincidingwiththerecruitmentof

mostcommercialspecies(Figure23).

Mallol(2005)identifiedthefollowingmaincausesofdiscarding:

1. Compliancewith regulations onminimum landing sizes (MLS). This includes species of high

commercialvalueundertheMLS(e.g.M.merluccius,M.poutassou,Z.faber,L.budegassa),butalsosomespeciesabovetheMLSwhichare,however,belowthesizeconsideredcommerciallyrelevant(e.g.M.poutassou,P.blennoides,L.caudatus,S.scombrus).2. Avoidance of lower fish prices owing to marked saturation, which occur specially in small

pelagicspecies(e.g.S.pilcharcus,E.encrasicolus,Trachurusspp.).3. Non-commercialvalue,affectingprimarily tospeciesor familieswithoutcommercial interest

suchasmyctophids,macrouridsandcallyonimids.

4. Accessorycatchesoflowormoderatecommercialinteresttakeninsuchalowquantitiesthat

donotworthpackaging.Thisapplies,forinstance,tosepiolidsandsomefish(e.g.C.macrophthalma,B.boops,M.dypterigia)andcrustacean(e.g.M.intermedia,S.membranacea)species.5. Bad condition of commercial species which are damaged by the effects of trawling or

overloadednet.

6. Missedcommercialspeciesthatareunnoticedduringthesortingprocess.

Thelasttwocausesofdiscardinghavebeennoticedinallthemaintaxonomicgroups:fish(e.g.Mullusspp.,P.erythrinus),crustaceans(e.g.A.antennatus,N.norvegicus),cephalopods(O.vulgaris,E.cirrhosa,L.vulgaris)andechinoderms(S.regalis).

Figure22:MapoftheGulfofLionsshowingthelocationofthe68haulsfromthecontinentalshelf(blue),upperslope(yellow)andmiddleslope(red)analysedbyMallol(2005).



Figure23:Mean(±S.E.)ofbiomass(kg·h-1)perdepthstratum(A:50-200m;B:200-400;C:>400m)(left)andperseason(H:winter;P:spring;E:summer;T:autumn)(right)ofabottomtrawlerfromtheGulfofLions(Mallol,2005).Green:totalcatch;blue:commercialcatch;dottedred:discards.

8.3.3 Effectsofdiscarding

Theecologicalimpactofdiscardsgoesfarbeyondsingle-speciesdemographiceffects,sincediscardedbiomasscanalterecosystemstructurebyfavouringscavengers(Tudela2004).Toourknowledge,theonly work dealing with this issue in the westernMediterranean is based on photographic surveyscarried out off the Catalan coast, and focuses on the estimation of the consumption rate of fisherydiscardsbyscavengers(BozzanoandSardà,2002).Abaitedcamerasetontheseaflooratadepthof100and300minareassubjectedtotrawlingwithcontinualdiscardswereused.Discardedmaterialseems to enter demersal food webs quite quickly, as suggested by the high consumption ratesrecorded.Thisstudyshowedthat fishingcan favouraspeciesbybothremoving itscompetitorsandindependentlyincreasingitsfoodavailabilitythroughdiscards.Atthecommunitylevel,acontinuoussupplyofdiscardscanalterthediversityandabundanceofbenthicspecies,affectingthefunctionalityanddistributionofecologicalniches(Bellidoetal.2014).

Unaccounted fishing mortality from discards may affect the fisheries assessment and management(Johnsen and Eliasen, 2011), which can even contribute to problems of overfishing (Bellido et al.2014).

However,discardsmayalsohavepositiveeffectsonecosystemproductivity(Tsagarakisetal.,2014)andbeimportantfoodsourcesforseabirds(Martínez-Abraínetal.,2002)andthiscanbebeneficialforcertainpopulationsinoligotrophicareassuchastheMediterranean(Bellidoetal.2014).

TherearefewworksanalyzingtheeconomiceffectsofdiscardingintheMediterranean.Bellidoetal.(2014) reported thatonepossible consequenceof thenewregulationmaybe the increase in illegalmarketing of fish below theminimum size. Landing, storage and transportation of juvenileswill belegalandthiscansimplifycommercializationviablackmarket.ASWOTanalysisreportedtheoverallbalance was detrimental to the implementation of the new CFP, with 72.6% of negative aspects(WeaknessesandThreats)and27.4%ofpositiveaspects(StrengthsandOpportunities).



ThereisalsoalackofworksanalysingthesurvivalofdiscardsthrowntoseainthepresentCaseStudy.Observations derived from experiments on aquaria carried out on board bottom trawlers from theCatalan Sea indicate low mortality of crustaceans, whereas survival rates of fish are highlyheterogeneousandvarystronglyamongspecies(e.g.0%forTrachurusspp.and100%inScyliorhinuscanicula)(Sánchez,2000).

8.3.4 DiscardData

8.3.4.1 Discardsampling

DiscarddataarecollectedatseaundertheSpanishObserversonBoardSamplingProgramme,fundedbytheDataCollectionFramework(EC,199/2008).Forsamplingpurposes,onlythemajormetiersareconsidered,whichareselectedusingarankingsystem.Onlythosemetierswhoseaccumulatedsharesin landings, value and effort are included in the top 90% are selected. For this reason, themetierssampled can changed with the years. The best information on discards comes from the followingmétiersofthebottomtrawlfleet(OTB:Bottomottertrawl):OTB_DEF(demersalspecies),OTB_MDD(mixeddemersalanddeepwaterspecies)andOTB_DWS(deepwaterspecies)fortheBalearicIslandsandOTB_DEFandOTB_DWSfortheSpanishfleetoperatingintheGulfofLions.

Thesamplingdesign isnotprobabilitybased,stratifiedbyarea(GSA),withportandtripasprimaryand secondary sampling unit respectively. Information on discards is used as inputs in the stockassessments of themain target species carried out annually in the frameworkof theGFCMand theSTECF. These stocks are: 1) In the Balearic Islands: Merlucciusmerluccius,Mullus barbatus,Mullussurmuletus,Aristeusantennatus,NephropsnorvegicusandParapenaeuslongirostris;and2)IntheGulfofLions:M.merlucciusandM.barbatus.InthecaseoftheGulfofLions,theseassessmentsarecarriedoutusingdatasetsfromboththeSpanish(IEO)andFrench(IFREMER)fleets.

ThesamplingcoverageforeachmetierinbothareasissummarizedinTable11.ThemeancoverageintheBalearicIslandisaround0.5%forOTB_DEFandOTB_DWSand0.75%forOTB_MDD.IntheGulfofLions,thecoverageishigher,withameanaround1%forOTB_DEFandaround2%forOTB_DWS.

Table11:Samplingcoveragebymétier,forthetwoareasincludedintheWesternMediterraneancasestudy(BalearicIslandsandGulfofLions)during2012-2014.

Area Metier Year Totaltrips

Sampledtrips

Coverage(%)

BalearicIslands OTB_DEF 2012 5140 28 0.54

2013 5471 18 0.33

2014 5457 24 0.44

OTB_DWS 2012 3200 12 0.38

2013 2767 13 0.47






2014 2675 14 0.52

OTB_MDD 2012 2227 12 0.54

2013 2064 15 0.73

2014 2170 20 0.92

GulfofLions OTB_DEF 2012 2229 20 0.90

2013 1923 15 0.78

2014 2044 18 0.88

OTB_DWS 2012 541 13 2.40

2013 726 12 1.65

2014 666 14 2.10

8.3.4.2 MeasuringDiscards

Values of total landed and discarded biomass (in tons) for the main species under the minimum

landingsize (MLS)EuropeanRegulation(EC,1967/2006)bymétierareshown inTable12(Balearic

Islands)andTable13(GulfofLions).

Table12:LandedanddiscardedbiomassbymétierfromtheBalearicIslandsduring2012-2014.

Métier SpeciesLandings(t) Discards(t)

2012 2013 2014 2012 2013 2014

OTB_DEF ANE 0.01 NA NA 0.00 NA NA

DPS 3.56 5.77 4.70 0.41 0.32 0.01

HKE 43.98 89.79 85.40 6.44 12.65 4.87

HMM 47.86 38.08 1.00 9.24 0.19 0.77

HOM 23.64 18.79 82.19 3.80 17.65 15.26

MUR 69.93 57.55 64.97 5.54 0.08 2.72

MUT 14.93 12.30 1.13 0.37 0.00 0.00

NEP 13.04 11.26 19.96 0.06 0.00 0.00

PAC 14.39 11.43 8.67 0.62 0.68 0.11

PIL 0.07 0.22 0.05 0.00 19.30 2.38



RPG 0.78 0.84 0.88 0.00 0.00 0.00

SBA 8.81 7.02 8.23 0.62 0.00 0.02

SRG 12.03 3.91 2.52 0.56 0.00 0.09

OTB_DWS HKE 9.63 9.70 15.69 0.00 0.00 0.00

NEP 8.42 3.58 4.65 1.19 0.00 0.00

SBA 0.04 NA NA NA NA NA

OTB_MDD DPS 0.61 0.43 0.89 0.00 0.00 0.00

HKE 7.58 9.22 17.17 0.06 0.40 0.69

HMM 9.75 7.23 0.29 4.53 0.92 0.04

HOM 4.82 3.57 23.41 0.03 0.82 11.52

MUR 15.58 12.13 14.29 0.00 0.00 0.00

MUT 3.33 2.60 0.25 0.00 0.00 0.00

NEP 8.04 3.98 6.19 0.87 0.00 0.03

PAC 3.13 2.26 1.54 0.00 0.07 0.00

SBA 1.92 1.39 1.47 0.00 0.04 0.01

SRG 1.33 1.06 0.79 0.01 0.00 0.00

ANE: Engraulis encrasicolus; DPS: Parapenaeus longirostris; HKE: Merluccius merluccius; HMM: Trachurusmediterranaeus;HOM:Trachurustrachurus;MAZ:Scomberspp;MUR:Mullussurmuletus;MUT:Mullusbarbatus;NEP:Nephropsnorvegicus;PAC:Pagelluserythrinus;PIL:Sardinapilchardus;RPG:Pagruspagrus;SBA:Pagellusacarne;SBG:Sparusaurata;SBR:Pagellusbogaraveo;SRG:Diplodusspp.

Table13:LandedanddiscardedbiomassbyyearandmetieroftheSpanishOTBfleetfromtheGulfofLions.

Métier SpeciesLandings(t) Discards(t)

2012 2013 2014 2012 2013 2014

OTB_DEF ANE 3.97 2.00 1.98 45.00 1.40 3.53

DPS 1.70 2.02 2.76 0.30 0.29 0.03

HKE 154.40 187.57 184.66 1.16 0.13 2.29

HMM 2.83 2.21 4.90 0.00 0.00 0.00

HOM 53.10 41.39 63.76 10.08 2.81 0.20



MAZ 27.25 36.67 40.76 8.02 0.21 0.13

MUR 0.20 0.25 9.49 0.00 0.00 0.00

MUT 28.82 36.89 40.45 0.17 0.01 0.05

NEP 23.54 18.17 18.94 1.01 0.01 0.06

PAC 8.54 7.08 7.18 0.02 0.00 0.00

PIL 1.64 0.66 0.69 1.69 0.00 0.23

SBA 15.49 8.01 9.74 0.00 0.00 0.38

SBG 0.88 2.13 0.33 0.00 0.00 0.00

SBR 2.08 1.88 3.28 0.00 0.04 0.03

SRG 2.14 1.92 0.87 0.00 0.00 0.00

OTB_DWS HKE 3.52 6.81 8.38 0.00 0.16 0.00

MAZ NA 0.02 NA NA 0.00 NA

NEP 1.33 1.73 1.13 0.04 0.33 0.01

SBR 0.11 0.09 NA 0.00 0.00 0.00

ANE: Engraulis encrasicolus; DPS: Parapenaeus longirostris; HKE: Merluccius merluccius; HMM: Trachurusmediterranaeus;HOM:Trachurus trachurus;MAZ:Scomberspp;MUR:Mullussurmuletus;MUT:Mullusbarbatus;NEP:Nephropsnorvegicus;PAC:Pagelluserythrinus;PIL:Sardinapilchardus;RPG:Pagruspagrus;SBA:Pagellusacarne;SBG:Sparusaurata;SBR:Pagellusbogaraveo;SRG:Diplodusspp.

The2012-2014 average discard biomass rates for theBalearic Islands are shown in Figure 24. Theaverage percentage of discards is in general lower than10% formost of the species subjected to aregulation, except for three species T. trachurus (HOM) and S. pilchardus (PIL) in OTB_DEF and T.mediterraneus(HMM)inMDD.Smallpelagicspeciesarebycatchspeciesforthebottomtrawlfleetinthis area and their importance is highly variable, both in terms of catches (their catchability showsimportantoscillations)andintermsoftheirfinaldestination(theyarelandedordiscardeddependingondifferent factors, includingmarket interest).ThiscanbeseeninTable11, inwhichtheirbiomass(bothlandedanddiscarded)variessignificantlyamongyears.

The 2012-2014 average discard biomass rates of the Spanish OTB fleet from the Gulf of Lions areshowninFigure25.Theaveragepercentageofdiscardsisingenerallowerthan10%formostofthespeciessubjectedtoaregulation,exceptagainforthecaseofsmallpelagicspecieslikeE.encrasicolus(ANE) and S. pilchardus (PIL) in OTB_DEF. Similarly of what happens in the Balearic Islands, theirimportanceishighlyvariable,asitcanbeseeninTable12.



Figure24:Averagepercentageofdiscards,bybiomass,fortheBalearicIslands(2012-2013)bymetierandspecies.Errorbarsindicatestandarderrors.ANE:Engraulisencrasicolus;DPS:Parapenaeuslongirostris;HKE:Merlucciusmerluccius;HMM:Trachurusmediterranaeus;HOM:T.trachurus;MAZ:Scomberspp;MUR:Mullussurmuletus;MUT:M.barbatus;NEP:Nephropsnorvegicus;PAC:Pagelluserythrinus;SBA:P.acarne;SBR:P.bogaraveo;PIL:Sardinapilchardus;RPG:Pagruspagrus;SBG:Sparusaurata;SRG:Diplodusspp.

Figure25:Averagepercentageofdiscards,bybiomassoftheSpanishOTBfleetfromtheGulfofLions(2012-2013)bymetierandspecies.Errorbarsindicatestandarderrors.ANE:Engraulisencrasicolus;DPS:Parapenaeuslongirostris;HKE:Merlucciusmerluccius;HMM:Trachurusmediterranaeus;HOM:T.trachurus;MAZ:Scomberspp;MUR:Mullussurmuletus;MUT:M.barbatus;NEP:Nephropsnorvegicus;PAC:Pagelluserythrinus;SBA:P.acarne;SBR:P.bogaraveo;PIL:Sardinapilchardus;RPG:Pagruspagrus;SBG:Sparusaurata;SRG:Diplodusspp.

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75

ANE DPS HKE HMMHOMMUR MUT NEP PAC PIL RPG SBA SRG

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OTB_DEF

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HKE NEP SBA

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OTB_DWS

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DPS HKE HMM HOM MUR MUT NEP PAC SBA SRG

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ANE DPS HKE HMMHOM MAZ MUR MUT NEP PAC PIL SBA SBG SBR SRG

%OTB_DEF

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OTB_DWS



8.3.5 Methodsforreducingdiscards

Duringthelastdecades,theGFCMrecommendedtheimprovementoftrawlselectivity,stressingalsothe incongruence thatminimum landingsize (MLS)establishedby theEuropean legislationwas, forsome species, higher than their length of first capture with the gear traditionally used in theMediterranean(40mmdiamondmeshcod-end).TheGFCMencouragedstudies,andorganizedseveralworkshops (GFCM, 2005a, 2007, 2008, 2010), aimed at improving the trawl selectivity in order toreducediscardsandovercomethatcontradiction(GFCM,2001).

Most of those studies assessed the effects of changing either the size of the diamond mesh (e.g.Dremière,1979;Aldebert&Carriers,1990;Sardàetal.,1993;D’Onghiaetal.,1998;Mytileneouetal.,1998; Ragonese et al., 2001, 2002, 2006; Carlucci et al., 2006; Tosunoǧlu et al., 2008; Aydin et al.,2011) or its geometry fromdiamond to squaremesh (e.g. Stergiou etal., 1997a, 1997b; Petrakis&Stergiou, 1997; Mallol et al., 2001; Mallol, 2005; García-Rodríguez & Fernández, 2005; Sardà et al.,2006; Guijarro &Massutí, 2006; Bahamon et al., 2006, 2007a; Ordines et al., 2006; Baro &Muñoz,2007; Lucchetti, 2008; Ateş et al., 2010; Sala et al., 2008; Aydin et al., 2011). Sala et al. (2006)combined sea trials analyzing the increment of the mesh size with a reduction of the number ofmeshesinthecircumferenceofthecod-endwithcomputersimulationsandSalaetal.(2010,2011a)assessed the effect of mesh size and configuration and codend circumference. Few studies haveanalysed the effect of hexagonalmeshes in the cod-end (Tosunoǧlu et al., 2009; Aydin et al., 2009,2010).Adetailedreviewofsizeselectivityperformancefordifferentcod-endshasbeenmaderecentlywithintheframeworkoftheDISCTACHproject6.

Other studies have explored the efficiency of sorting grid systems (Sardà et al., 2004, 2005, 2006;Bahamonetal.,2007b;Massutíetal.,2009;Salaetal.,2011b).Thissystemwasinitiallyusedinshrimpfisheriestopreventcatchinglargefishandturtles,butintheMediterraneanithasbeentestedwiththeoppositeobjective,allowingtheescapementofjuveniles.InformationaboutsquaremeshpanelsintheMediterranean is scarce, being limited to some comments by Sardà et al. (2004) and two studiesdeveloped in the Tyrrhenian Sea (Belcari et al., 2005) and very recently in the Balearic Islands(Massutíetal.,2014).Lastly,theeffectoftwinethicknessonthesizeselectivityhasalsobeenassessed(Salaetal.,2007;Massutíetal.,2015).

Some of the above mentioned studies were done on the basis of the Council Regulation (EC) Nº1967/2006,of21December2006,concerningmanagementmeasuresforthesustainableexploitationoffisheryresourcesintheMediterraneanSea.ThisRegulationestablishedthereplacementofthe40mmdiamondmeshcod-endbya40mmsquaremeshcod-endor,underthedulyjustifiedrequestofthe shipowner, by adiamondmeshof 50mm.Thismeasurewasnot implementeduntil 2010, andmost vessels (>90% since estimations of the European Commission 7 ) benefited from theexceptionalityof the50mmdiamondmeshcod-end,despite the lackof scientific informationaboutthe selectivity of this net in the north-westernMediterranean. The only information comparing the 6PilotProjectoncatchanddiscardcompositionincludingsolutionsforlimitationandpossibleeliminationofunwantedby-catches in trawl net fisheries in the Mediterranean (DISCATCH). DG MARE European Commission Contract NºMARE/2012/24Lot2.7Informede laComisiónalParlamentoEuropeoyalConsejosobre laaplicacióndelartículo9,apartado3,delReglamento(CE)nº1967/2006delConsejorelativoalasmedidasdegestiónparalaexplotaciónsostenibledelosrecursospesquerosenelmarMediterráneo.Bruselas10.7.2012,COM(2012)370final,8pp.



selectivity of 40mm squaremesh cod-end with 40 and 50mm diamondmesh cod-ends has beenprovidedveryrecentlybyZapata(2015).Thisstudyhascomparedcatchesandsizecomposition,bothfromlandingsanddiscards,obtainedbythethreetypesofmeshundercommercialconditions,usingdatafromthescientificmonitoringofthebottomtrawlfleet,developedbetween2009and2013intheBalearicIslands.

Table14:Lengthoffirstcapture(L50,withselectionrangebetweenbrackets;fishes:TLincm;cephalopods:MLincm;

crustaceans:CLinmm)forsomeofthemaincommercialspecies,estimatedfordifferentmeshshapecod-ends(40mmDMand

SM;exceptfor◊,◊◊and◊◊◊,inwhich34-35.5,50and60mmDMwereused)andsortinggrid(SG15andSG20;∗:withguidingfunnel;∗∗:withoutguidingfunnel)bysomeauthorsatdifferentareasofthewesternMediterranean:(i)BAL(BalearicIslands;presentstudy,Guijarro&Massutí,2006;Ordinesetal.,2006);(ii)NEC(north-easternIberiancoast;Sardàetal.,2006;Bahamonetal.,

2007b);(iii)CEC(centralIberiancoast;García-Rodríguez&Fernández,2005);(iv)GOL(GulfofLions;Dremière,1979;Aldebert

&Carriers,1990;Mallol,2005).MLS:minimumlandingsizeestablishedbytheCouncilRegulation(EC)Nº1967/2006,of21

December2006,concerningmanagementmeasuresforthesustainableexploitationoffisheryresourcesintheMediterranean

Sea.

Species MLS Area DM SM SG15 SG20

Lepidorhombusboscii --BAL 9.9(2.4) 10.2(1.5) 9.1(5.2) 12.1(5.6)

GOL 11.7(5.0) 11.0(4.0) -- --

Merlucciusmerluccius 20

BAL 10.6(3.3) 15.2(3.3) 10.9*(5.1) 18.9*(3.4)

NEC 10.1(3.1) 16.0(3.2) 5.9*(3.5) 17.2*(6.2)13.2**(3.6)

CEC 10.3(3.1) 14.6(4.0) -- --

GOL

7.5(2.5)10.2-12.8◊12.4-13.016.3◊◊19.5◊◊◊

20.0(7.4) -- --

Micromesistiuspoutassou --BAL -- 20.1(2.5) -- 16.1*(6.0)CEC 14.0(1.7) 18.3(2.2) -- --

GOL 12.1(1.6) 20.6(1.8) -- --

Mullusbarbatus 11

NEC -- -- -- 10.4*(3.9)

CEC 7.8(2.0) 13.7(2.2) -- --

GOL 9.1(3.0) 12.4(2.7) -- --

Mullussurmuletus 11BAL 4.5(5.8) 12.2(2.1) -- --CEC 8.7(1.7) 13.2(2.3) -- --

Phycisblennoides --

BAL 12.2(3.0) 14.4(4.0) 8.7*(7.9) 10.9*(5.6)

NEC 9.8(2.6) 15.0(3.0) -- 10.9**(6.4)

GOL 11.4(2.7) 17.2(3.6) -- --

Trachurusmediterraneus 15 BAL 13.7(2.1) 15.2(3.0) 7.6(7.0) 11.2(7.1)

Nephropsnorvegicus 20BAL -- 26.6(3.4) 21.2*(6.7) 23.8*(8.6)

NEC -- 22.0(6.5) -- 20.5**(9.3)



Parapenaeuslongirostris 20 BAL 16.6(3.7) 20.2(2.3) 21.4*(13.2) 25.7*(11.4)

Octopusvulgaris -- BAL 3.5(2.1) 6.0(2.2) -- --

Thesizeselectivityparametersestimatedatdifferentareasofthenorth-westernMediterranean,using40mm diamondmesh (DM) and 40mm squaremesh (SM) cod-ends, and sorting gridswith a barspacing of 15 and 20 mm (SG15 and SG20, respectively), show high variability (Table 14). It isprobablyduetothedifferentconditions(experimentalandcommercial),methodologies(e.g.coveredcod-endandtwintrawlmethods),characteristicsofthetesteddevices(e.g.gridsurfaceandmounting,net material andmounting), gears, vessels used and areas and seasons surveyed. Trawl selectivitydepends on gear (e.g. twine thickness, knotted/non-knotted mesh), vessel, environment andbiocenosis,amongotherfactors(Wilemanetal.,1996;MacLennan,1992;Salaetal.,2007).However,itisevidencedasimilartendency,withvaluesoflengthoffirstcapture(L50)withSMcod-endandSG20clearly higher than with SG15 and DM cod-end. The comparison between the size selectivityperformanceofSMcod-endandSG20showssomedifferences,beingSMcod-endmoreefficientthanSG20 for most species off the Balearic Islands, but not showing marked differences in the north-easternIberiancoast(Bahamonetal.,2007b). Inanycase, theresultsobtainedforsomespeciesarediverse. ForMerlucciusmerluccius, L50 estimated in theBalearic Islands (18.9 cm) is very similar tothatobtainedbySardàetal.(2004)andBahamonetal.(2007b),withsimilarselectivitydevices(18.8and17.2 cm, respectively).Bycontrary, the sameauthorshavealso reportedvaluesof14.2 cmand~13 cmwith SG20 (Sardàetal., 2005, 2006).TheL50with SMcod-endestimated inour study area(15.2cm)issmallerthantheonereportedbySardàetal.(2006)withaSMnon-knottedcod-end(18.5cm).Accordingtotheseauthors,thesedifferencescouldbeduetotheuseofaknottednet,trawledatalowerspeed,intheBalearicIslands.Moreover,itmustbealsoconsideredthattheseparationprocessofthegridismorecomplexthanfornormalmeshselection,combiningbothselectionatthegridandtheverticalbehaviourof the fish.Thus, thebehaviourofM.merluccius, swimminghigh in the trawl,couldalsobeonthebasisofthehighsortingefficiencyofthegridsassessed,withspacedbarsintheirupperpart.TheselectionrangeofsortinggridsweresubstantiallywiderthanthoseestimatedforDMand SM cod-ends (Table 14), indicating that the sorting performance of the gridswas not yet fullysatisfactory,allowingahigherescapementofbigspecimensthanDMandSMcod-ends.

TheincrementoftheL50observedwith40mmSMcod-endandSG20,withrespecttothetraditional40mmDMcod-end, increased thepercentageofescaped individualssmaller than theMLS formostspecies (Table 15). The only exceptionwasLophius spp., since in this case both themesh size andshapeandtheseparationbetweenbarsinthegridswereclearlynotlargeenoughtoallowunder-sizedindividuals to escape. This is a typical situation in multi-species fisheries throughout the world(Sainsbury, 1984; Liu etal., 1985) and also in theMediterranean,where trawl catches are containsmanyspecieswithcontrastingbodysizesandshapes(e.g.Petrakis&Stergiou,1997).Similarresultshave been obtained by comparing 40 mm DM, 50 mm DM and 40 mm SM cod-ends (Zapata,2015;Table16).



Table15:Percentageofnumberofundersizedspecimensretainedinthecod-endofthebottomtrawl(smallerthanminimumlandingsize;%<MLS)andpercentageofnumberofundersizedspecimensescaped,inrelationtothetotalnumberofundersizedspecimenscaptured(%<MLS-ESC),bydepthstrata(SH:shelf;SL:slope),fordifferent40mmmeshshapecod-ends(DMandSM)andsortinggrids(SG15andSG20)offBalearicIslands.

Species MLS Depth Device n %<MLS %<MLS-ESC

Lophiusspp. 30

SH

DM 47 63.6 0.0SM 96 37.5 0.0SG15 89 83.2 0.0SG20 35 34.3 0.0

SL

DM 242 70.0 0.0SM 146 78.2 0.0SG15 26 42.3 0.0SG20 30 40.0 0.0

Merlucciusmerluccius 20

SH

DM 106 26.4 3.6SM 129 21.7 39.3SG15 8409 56.8 5.9SG20 17338 68.7 22.8

SL

DM 1680 11.7 11.2SM 1073 6.8 23.3SG15 309 0.6 0.0SG20 258 1.5 25

Mullussurmuletus 11 SH

DM 686 13.9 14.6SM 2031 9.3 74.7SG15 17 0.0 --SG20 13 0.0 --

Trachurusspp. 15 SH

DM 2899 19.5 36.2SM 3356 13.3 78.3SG15 4495 46.3 24.0SG20 2801 27.5 37.7

Nephropsnorvegicus 20 SL

DM 2605 0.0 --SM 3858 0.0 --SG15 86 1.2 0SG20 95 0.0 --

Parapenaeuslongirostris 20 SL

DM 20829 0.23 26.5SM 26827 0.0 --SG15 525 0.0 --SG20 491 0.0 --

Table16:Percentageofindividuals(%)undertheMinimumLandingSize(MLS),establishedbyEuropean,NationalandRegionalregulations,andunderthelengthatfirstmaturity(L50mat),estimatedintheBalearicIslands,usingdatafromthescientificmonitoringofthebottomtrawlfleet,developedbetween2009and2013.40D:40mmdiamondmeshcod-end;50D:50mm-diamondmeshcod-end;40S:40mm-squaremeshcod-end.Fish:totallengthincm;Crustaceans:carapacelengthinmm;Cephalopods:mantlelengthincm.AdaptedfromZapata(2015).

Species MLS %<MLS L50mat %<L50mat

40D 50D 40S 40D 50D 40S



Mullussurmuletus 11 1.9 0.6 0.7 15♂;17♀1 52.5 53.9 39.5

Spicarasmaris 11 3.7 4.1 0.7 11-132 24.3 45.2 10.4

Merlucciusmerluccius 20 55.0 31.8 66.6 323 97.8 97.0 98.3

Lepidorhombusboscii 15 42.4 60.5 81.4 11♂;14♀4 33.1 56.8 70.6

Phycisblennoides -- 19♂;20♀5 86.2 76.5 64.8

Scyliorhinuscanicula -- 43♂;44♀6 93.9 93.8 95.1

Galeusmelastomus -- 44♂;49♀7 99.9 99.5 100

Aristeusantennatus -- 19♂;25♀8 25.4 25.7 25.7

Nephropsnorvegicus 20 0.0 0.2 0.0 309 17.9 21.1 10.2

Loligovulgaris -- 16♂;19♀10 96.4 94.9 97.7

Octopusvulgaris -- 8♂11 52.1 54.8 56.81Reñonesetal. (1995); 2Lozano-Cabo (1953); 3Oliver (1993); 4Vassilopoulouetal. (1997); 5Rotllantetal. (2002);

6Capapé et al. (2008a, 2008b); 7Rey et al. (2005); 8Guijarro et al. (2008); 9Orsi-Relini et al. (1998); 10Vila et al.

(2010);11MinimumlengthofmatureindividualsfromQuetglasetal.(1998)

Onthewhole,thechangeinthemeshgeometryofthecod-end(from40mmDMto40mmSM)shouldbenefitboththeenvironment,bydecreasingdiscardsandhencetheimpactofthetrawlgearsontheecosystems,andthetrawlfishery.Itwouldrecovertheexploitationpatternofthemaintargetspeciesinthisfishery,whichcurrentlyshowclearsymptomsofover-fishing8,byreducingthefishingpressureonsmallfish,generatingimprovementsinthestateoftheseresourcesandbenefitsintheiryieldperrecruit.Offnorth-easternIberiancoast,Bahamonetal.(2007a)estimatedanimmediatereductionupto 20% in the yieldper recruit ofM.merluccius after the implementation,with an increment >50%withinthefollowingfiveyears.Duringthefirstyearsofthelastdecade,thischangeinthemeshshapecod-endwas also estimated as an efficientmanagementmeasure to reduce the over-exploitation ofthis species in theGulf of Lions,Northern Iberian coast and theBalearic Islands (GFCM, 2005b). Inaddition, the40mmSMcod-endhascontributed to solve theabovementioned incongruenceof theCouncilRegulation(EC)Nº1967/2006withrespecttotheMLSandtheL50forsometargetspeciesofthe bottom trawl fishery. This is the case of Mullus spp., Nephrops norvegicus and Parapenaeuslongirostris,whichestimatedL50with40mmSMcod-end(andalsowithSG20forbothcrustaceans)aregreaterthantheirMLS(Table4).However,thesepositiveeffectsdependonthesurvivalrateoftheescapedindividuals,buttheonlystudyonthattopichasbeendevelopedintheeasternMediterranean(Metin et al., 2004) and there is no information in the western basin. In addition, for other targetspecies such asM.merluccius the L50with 40mmSM is still far below itsMLS and formost targetspeciesbothL50andMLSaresmallerthantheir50%lengthatfirstmaturity(Table6).Inthissense,alot ofwork is still needed to improve themanagement of the size selectivity of theMediterraneanbottomtrawlfishery,whichhasbeendescribedaslegallyandecologicallyunsuccessful(Stergiouetal.,2009).Maybethereisnotasinglesolutionsuitableforallspecies,anditcouldbenecessarytheuseofmultipleselectionsystems.Thecombinationofmeshsize/shapeinthecod-endwithgridsystemsandsquaremeshpanelsshouldbeapotentialsolution.

8Communication from the Commission to the European Parliament and the Council Concerning a consultation on FishingOpportunitiesfor2015undertheCommonFisheriesPolicy.Brussels,26.6.2014,COM(2014)388final,17pp.



8.3.6 EcsosytemmodellingoftheWestMediterraneanCaseStudy

8.3.6.1 GolfeofLion

Anapplicationof the ISIS-Fishmodelwill bedeveloped in the context of theDiscardLessproject inorder toevaluate the combined impactof themanagementplan for theMediterranean seawhich isbasedoneffortcontrolandthe implementationof the landingobligation.The fisheryunderstudy isthe demersal trawler fishery targeting hake in the Gulf of Lion. The structure of themodelwill bedefined according to the results of preliminary analyses of the fishery structure and dynamics. Thefleets and the set of target species to describe aswell as the spatial structuration to adoptwill bedetermined. Then a model of fishing behavior including discard behavior will be developed andcoupledtotheISIS-Fishmodel.

8.3.6.2 BalearicIslands

TheEcopathmodelcoversthegeographicalsub-area5(BalearicIslands;Figure19)establishedbytheGeneralFisheriesCommissionfortheMediterranean(GFCM).

Themodeldescribesthethreedomains(pelagic,demersalandbenthic)andthetrophicstructureandbiomass flows from50 to800metersdepth.Themodel is composedof55 functionalgroups(Table17), includingprimaryproducers,detritus,seasnowanddiscards.Eachgrouphasspeciesofsimilarsize, habitat, diets, consumptions, mortalities and production. A total of 5 groups of fisheries wereincluded:bottomtrawl,small-scale,purse-sine,bottomlong-lineandsurfacelong-line.Thefollowinginformationhasbeenusedformodelconstruction:i)1691researchpapers;ii)3databases(24bottomtrawlsurveys,samplingonboardfishingvesselsanddailysalesbills);andiii)reportsfromtwostockassessmentworkinggroups:GFCMandICCAT.

According to the model trophic flows (Figure 26), discards are exclusively consumed by turtles,Audouinseagullsandotherseabirds.

TheBalearicIslandsEcopathmodelwasdevelopedintheframeworkoftheSpanishnationalprojectsLIFE+ INDEMARES (LIFE07/NAT/E/000732) and IDEADOS (Plan Nacional; CTM2007-65844-C01-01/MAR).Themodelhasbeenpresentedat the IDEADOSWorkshop(PalmadeMallorca,Nov-2012;http://www.ba.ieo.es/ideados/index.php/cworkshop2), the XVII SIEBM Symposium (Gijón, Sept-2014;http://www.siebm.org/2012/)andis includedintheLIFE+INDEMARESreport(Morantaetal.2014).



Figure26:TrophicflowsoftheEcopathmodelfromtheBalearicIslands.

4

3

2

1

Dolphins

Seabirds

Audouin seagull

Turtle

Apex pelagic fishes

Bonitos

Dolphin fish

Anglerfish

Adult hake

Small hakeDemersal fish 1

Deep demersal fish 1

Demersal fish 2

Mullet

Flat fish

Deep demersal fish 2

Plankton feeders fish

Deep plankton-feeders fishesSmall pelagic fishes

Horse mackerel

Rays

Sharks

Dogfish

Squids

SepiaOctopuses

Gastropods

Bivalves

Red Shrimp

Norway lobster Spiny lobsterWhite shrimp

Epibenthic-feeders crustacean Infaunal-feeders crustacean

Migr zooplank-feeders crustaceanNo migr zooplank-feeders crustacean

Detritus-feeders decapods

Deposit-feeders crustacean

Detritus-feeders crustacean

Sea star

Sea urchins

OfiuridsDeposit-feeders echinodermCrinoids

Benthic susp. feeders InfaunaSuprabentos

JelliesMacrozooplankton

Micro-Mesozooplakcton

FitoplanktonAlgaeDiscards

Sea snowDetritus

www.discard

less.eu

110

ThisprojecthasreceivedfundingfromtheEuropeanUnion’sHorizon2020researchandinnovationprogrammeundergrantagreementNo633680

Table17:FunctionalgroupsusedintheBalearicIslandsEcopathm

odel.

1.Dolphins:Tursiopstruncatus,Stenellacoeruleoalba

2.Seabirds:Calonectrisdiomedea,Hydrobatespelagicus,Phalacrocorax

aristotelis,Puffinusmauretanicus

3.Audouinseagull:Larusaudouinii

4.Turtle:Carettacaretta

5.Apexpelagicfishes:Thunnusthynnus,Xiphiasglaucus

6.Bonitos:Sardasarda,Auxisrochei

7.Dolphinfish:Coryphaena

hippurus

8.Anglerfish:Lophiusbudegassa,Lophiuspiscatorius

9.Adulthake:Merlucciusm

erluccius

10.Smallhake:M

erlucciusmerluccius

11.Demersalfish

1:Trisopterusminutus,Scorpaena

elongata,Scorpaenaporcus,

Epinephelusspp.,Zeusfaber,Pagruspagrus,Synodussaurus,Congerconger,Scorpaena

scrofa,Pagellusacarne,Pagellusbogaraveo,Serranuscabrilla,Trachinusdraco,Uranoscopusscaber,Syngnathusacus,Phycisphycis,Ophichthusrufus,Chelidonichthysgurnardus,Chelidonichthyslucerna,Balistescarolinensis,Ophidion

barbatum

12.Deepdem

ersalfish1:Chlorophthalm

usagassizi,Microm

esistiuspoutassou,Helicolenusdactylopterus,Gadiculusargenteusargenteus,Sym

bolophorusveranyi,Epigonusspp.,Phycisblennoides,Nem

ichthysscolopaceus,Chauliodussloani,Stom

iasboa,Lampanyctuscrocodilus,Hoplostethusm

editerraneus,Lepidion

lepidion,Moram

oro,Nettastomamelanurum

,Notacanthusbonaparte,Lepidopuscaudatus,Trachyrincusscabrus,M

olvadypterygia,Gaidropsarus

biscayensis,Gnathophismystax

13.Demersalfish

2:Triglalyra,Lepidotriglacavillone,Lepidotrigla

dieuzeidei,Scorpaena

loppei,Scorpaenanotata,Dactylopterusvolitans,Gobiusniger,

Odondebueniabalearica,Blenniusocellaris,Callionym

usmaculatus,

Lesueurigobiusfriesii,Lesueurigobiussanzoi,Diplodusspp.,Pagelluserythrinus,Serranushepatus,Corisjulis,Thalassom

apavo,Sym

phoduscinereus,Serranusscriba,Xyrichthysnovacula,Chelidonichthyscuculus,Chelidonichthyslastoviza

14.Mullet:M

ullusbarbatus,Mullussurm

uletus

15.Flatfish:Arnoglossusimperialis,Arnoglossuslaterna,Arnoglossusrueppelii,

Arnoglossusthori,Bothuspodas,Citharuslinguatula,Lepidorhombusboscii,

Lepidorhombusw

hiffiagonis,Microchirus

spp.,Soleaimpar,Soleavulgaris,

Symphurusnigrescens,Synaptura

kleinii

16.Deepdem

ersalfish2:Argentinasphyraena,Nezum

iaaequalis,Polyacanthonotusrissoanus,Caelorinchuscaelorhincus

17.Plankton-feedersfish:Caprosaper,Macroram

phosusscolopax,Deltentosteusquadrim

aculatus,Crystallogobiuslinearis,Pomatoschistusspp.,Aphia

minuta,

Spondyliosomacantharus,Spicaram

aena,Spicarasm

aris,Centracanthuscirrus,Chrom

ischromis,Anthiasanthias,Cepolam

acrophthalma

18.Deepplakton-feedersfish:M

ictófidos

19.Smallpelagicfish:Engraulisencrasicolus,Sardinapilchardus,Sardinellaaurita,

Boopsboops

20.Horsemackerel:Scom

berscombrus,Trachurusspp.

21.Rays:Leucorajacircularis,Leucorajanaevus,Rajaasterias,Rajabrachyura,

Rajaclavata,Rajamiraletus,Rajam

ontagui,Rajapolystigma,Rajaradula,Raja

rondeleti,Rajaundulata,Dipturusoxyrinchus,Myliobatisaquila,Dasyatis

pastinaca

22.Sharks:Squalusacanthias,Centrophorusgranulosus,Dalatiaslicha,Mustelus

mustelus,Torpedom

armorata,Etm

opterusspinax,Galeusmelastom

us

23.Dogfish:Scyliorhinuscanicula

24.Squids:L.forbesi,L.vulgaris,I.coindetii,T.sagittatus,H.reversa,H.bonnellii,A.m

edia

25.Sepia:S.officinalis,S.elegans,S.orbignyiana,Sepiettaow

eniana

26.Octopuses:E.cirrhosa,S.unicirrhus,P.tetracirrhus,O.salutii,B.sponsalis,E.moschata,O.vulgaris

27.Gasteropods:Aporrhaispespelicani,Aporrhaisserresianus,Astraearugosa,

Bolinusbrandaris,Calliostomaspp.,Cancellaria

cancellata,Cassidariatyrrhena,

Cymatium

corrugatum,Euspira

fusca,Fusinusrostratus,Lunatiasp.,Naticaspp,

Phaliumundulatum

,Ranellaolearia,Turritella

spp.,Xenophoracrispa

28.Bivalve:Acanthocardiatuberculata,Aequipecten

opercularis,Anadaradiluvii,

Anomiaephippium

,Callistachione,Chlamysoppercularis,Chlam

ysvaria,Glossushum

anus,Glycimerissp.,Laevicardium

oblongum,M

ytilusedulis,Mytilus

galloprovincialis,Ostreaedulis,Pectenm

aximus,Pinnanobilis,Pteriahirundo,

Pycnodontecochlear,Venusverrucosa

29.Redshrimp:Aristeusantennatus

30.Norway

lobster:Nephropsnorvergicus

31.Spinylobster:Palinusspp.

32.Whiteshrim

p:Parapenaeuslongirostris

33.Epibenthic-feederscrustaceans:Acanthonyx,Bathynectes,Eriphia,Eualus,Gnathophyllum

,Herbstia,Homola,Inachus,Lam

brus,Ligur,Liocarcinus,Maja,

Macropipus,M

acropodia,Maja,Paractaea,Parom

ola,Parthenope,Pilumnus,

Pisa,Polycheles,Portunidae,Squilla,Stomatopoda,Xantho

34.Infaunal-feederscrustaceans:Acanthonix,Achaeus,Atelecyclus,Calappa,Chlorotocus,Crangon,Corystes,Ebalia,Ethusa,Eucrate,Eurinom

e,Geryon,Gnathophyllum

,Goneplax,Ilia,Lysmata,M

edorippe,Monodaeus,Palaem

onidae,Palicus,Philocheras,Pontocaris,Pontophilus,Processa,Sicyonia,Solenocera,Thia

35.Migr.zooplank-feederscrustaceans:Acanthephyra,Gennades,Oplophoridae,

Pasiphaea,Sergestes,Sergia

36.Nomigr.zooplank-feederscrustaceans:Aristaeom

orpha,Plesionika

37.Detritus-feedersdecapods:Dardanus,Diogenes,Dromia,Galathea,M

unida,Paguristes,Pagurus

38.Deposit-feederscrustaceans:Alpheus,Brachynotus,Callianassa,Thoralus,Upogebia,Calocaris,Jaxea,Thalassinidea

39.Detritus-feedersshrimps:Lophogaster,Pandalina,Palaem

on,Nebalia

40.Seastar:Astropecten,Chaetaster,Anseropoda,Echinaster,Hacelia,Marthasterias,Luidia

41.Seaurchins:Centrostephanus,Cidaris,Echinus,Paracentrotus

42.Ofiurids:Ophiura,Ophiocomina,Ophioderm

a…

43.Deposit-feedersechinoderms:Holothuria,Stichopus,Spatangus…

44.Crinoids:Antedonmediterránea,Leptom

etraphalangium

45.Benthicsusp.Feeders:Poriphera,Ascidians,cnidarios,briozoos…

46.Infauna:Anfipods,polyquetos,isopods…

47.Suprabenthos:Eufausiaceos,misidaceos,anfipodos…

48.Jellies:Jellyfishes,apendicularians,Salpaspp.,Pyrosoma…

49.Macrozooplankton:>5m

mMeganyctiphanes,euphausiacea

50.Micro-M

esozooplankton:<5mm:Copepods,crustaceanlarvae,tintinids,

ostracods

51.Phytoplankton:Microalgae

52.Algae:Cystoseiraspp,Osmundaria,Peyssonnelia,m

aerl…

53.Discards

54.Seasnow

55.Depositdetritus






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8.3 western mediterranean case study · the number of trawlers doubled in mallorca from 35 to 70...

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