objetivo al salmonete Mullus surmuletus salmonete al objetivo especie que como tiene trasmallo con artesanal pesquería una hemos estudiado trabajo este En Resumen besugo besugo M. surmulletus especies siendolas identificadas, fueron especies 48 de Un total Canarias). Tenerife de este (islas costa la en pesca de zonas dos yen diferentes malla de tamaños tres con total of 48 species were identified with with were identified of species 48 total Islands). A of coast East Tenerife (Canary the at grounds 2fishing around sizes mesh net surmuletus Mullus mullet stripped red targeting fishery net trammel artisanal an work we studied this In Abstract Keywords Union elasmobranchs. protected European of the catches future reduce will that practices fishing made on be to suggestions allow and fishing artisanal the about knowledge to contribute to intended increasing are study of the Findings weight. and represented 51.14%catch fishings total elasmobranch the experimental of the during caught also was shark Union angel protected European weight. catch 37.61% reaching percentages high in were represented of total Elasmobranchs increased. size mesh as caught catches of abundance proportion the in decrease aclear showed sizes mesh Experimental weight. 89.77%represented catch 10.23%, and of total respectively, Sparisoma cretense, parrotfish and Canarias. Palabras clave Unión por la protegidos Europea. elasmobranquios los de capturas las futuro un en reducir que puedan pesca de prácticas sobre las sugerencias realizar permiten y artesanales pesquerías las de conocimiento incremento del al pretenden contribuir estudio este de resultados Los 51,14% el yrepresentó totales. experimentales capturas las de peso del squatina Squatina angelote El 37,61% totales. alcanzando alto, capturas porcentaje un en las de tados peso del represen estuvieron elasmobranquios Los capturas. las de proporciones abundancias de las en disminución clara una observó se utilizada malla de tamaño el que aumentamos medida A totales. capturas las de peso del 89,77% el representaron y10,23%, respectivamente, cartes TRAMMEL NET FISHERY IN THE CANARY ISLANDS CANARY THE IN FISHERY NET TRAMMEL Pagellus acarne PESQUERÍAS LAS EN ELASMOBRANQUIOS DE INCIDENTAL CAPTURA . Catches and discards were evaluated on 30 fishings trials using 3 experimental experimental 3 using trials on fishings 30 were evaluated discards and . Catches Revista Scientia Insularum Scientia Revista Squatina squatina Squatina discard, : bycatch, ELASMOBRANCH BYCATCH ON ARTISANAL ON BYCATCH ELASMOBRANCH : captura accidental, descarte, Squatina squatina descarte, accidental, : captura , protegido por la Unión Europea, fue también capturado durante las pescas pescas las durante capturado también fue Unión por la , protegido Europea, Alberto BritoAlberto &José Hernández Carlos José Mendoza*, Carlos Dorta, Carmelo y la vieja Sparisoma vieja yla cretense CON TRASMALLO EN LAS ISLAS CANARIAS ISLAS LAS EN TRASMALLO CON DOI: http://doi.org/10.25145/j.SI.2018.01.006DOI: being the most frequently captured. Catches and discards discards and Catches captured. frequently most the being , 1; diciembre 2018,, 1; pp. 87-102; diciembre e-2659-6644 ISSN: . Evaluamos las capturas en 30 pescas experimentales experimentales pescas 30 en capturas las . Evaluamos M. surmuletus , artisanal fishery, Canary Islands. fishery, Canary , artisanal , las más capturadas. Las capturas ydes capturas Las capturadas. más , las , axillary seabream seabream , axillary , pesca artesanal, islas islas , artesanal, pesca Pagellus acarne

, el , el - -

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 87 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 88 Tenerife, Canary Islands, Spain. Corresponding author: [email protected] author: Corresponding Spain. Islands, Tenerife, Canary none of these have been carried out in southern Atlantic waters. out southern Atlantic in none carried have been of these al. (Stobutzki fisheries longline and have considered only trawl of elasmobranchs discards and 1999; (Cortés on 2000). bycatch of ecosystem Most studies the tioning al. et Stevens trophic func and role structure the in play afundamental they such as webs, and (Heuter 1998). predators at or are near, food top the Most of elasmobranchs marine have designed been quotas most for fishing species which teleost many to sustain are sufficient that pressures under fishing populations their able less to sustain are 2001). Frisk al. et 2000; al. et Stevens 2000; Hislop 1998; al. et Dulvy and (Walker (at long size) and lifespan. late maturation alarge slow growth, size, body maximum large elasmobranchs: characterize that by a defined factors number of are Cliff and tner 1999;Hazin 1998; 1990; 1999; Goosen (Brito and al. et Smale Casey strategies and Pratt Win life vulnerable to overexploitationalso (Bonfil are to duefisheries 1994). Elasmobranchs 2001). al. (Borges et nets or gill longlines like gears other static than higher are nets from trammel rates discard have 2001) shown that studies al. et several and southern (Erzini Europe in fisheries small-scale theamong significant most are net fisheries trammel Artisanal Maynou Merino 2003; and al. et (Lleonart consideration bycatch or discards into do not which take data on landings based are they when existent and place in and legislation (e.g.Hall, constraints 1996). marketing ratios),strategies, ing fishing (e.g. hang size, mesh characteristics on gear gear, the the largely depends of discards importance relative the Thus, fisheries. mixed-species and gears of different selectivity unavoidable is due to size 2005). subsequent and bycatch al. general, et discarding In (Catchpole factors social and bycomposition, environmental determined are which by bycatch affected are (Clucas 1996). of crew practices the ability sorting Discarding or grading capacity, storage high boats fishing are reasons 2000). discarding Other al. et (Hall size below legal poor condition the in are are and value, or no commercial have little specimens for as such anumber of reasons occurs Discarding high. are rates January 2011, and capture, retain onboard, transship and landing is forbidden is by landing 2011, and January onboard, transship retain capture, and 1880-1884). (Couch 1822; bottom-dwelling are they Day as nets trammel and trawls in bycatch 2005; Coelho and Erzini 2008); few have focused on trammel net fisheries and net fisheries on trammel 2008); have focused few Erzini and Coelho 2005; Angel sharks Squatina squatina sharks Angel andelasmobranchs most fisheries in unmanaged is Bycatch of elasmobranch fromcommon are acomponent fish discard and theElasmobranch bycatch of the aroundworld strategies have fisheries management no Most small-scale discard and gears of fishing byWorldwide, avariety captured are species many epartamento de Biología , Geología y Edafología. Universidad de La Laguna, Laguna, La de Universidad y Edafología. Geología Animal, Biología de epartamento *

D et et Megalofonou 2005; al. et Clarke 2003; al. et Carbonell 2002; al. et Squatina squatina 2002; Coelho and Erzini 2002). These life strategies 2002).strategies life These Erzini and Coelho 2002; al. et 1. INTRODUCTION has been fully protected in European waters since since waters protected European in fully been has Linnaeus , 1758

are highly susceptible to susceptible highly are . 2008). - - -

value as the angel shark ( shark angel the as value commercial with elasmobranchs including of species of range awide consists area this Bycatch in nets. by the caught accidentally are species additional but that it known is Islands) at a latitude between 28° between at alatitude Islands) area Study 2.1. discards. and to used reduce bycatch be could how sizes mesh different by suggesting fishery (2) to contribute to improvement net artisanal of trammel the allowed in is and fishery island, net Tenerife where trammel areas fishing in mel nets tram 1758. were:study experimental an this objectives of (1)main The characterize to Tenerife’s around have studied bycatch never related been and catches ( coastline 2001). al. Borges et 2000; al. et (Hall dynamics on population, ecosystem trophic impacts and the to evaluate and gears fishing from different rates of discard knowledge able we better need species mullet mullet strippet Red March. to fromseason February fishing and a restricted boats fishing artisanal has 9 authorized harbor Candelaria of 2005/04).fishery net trammel The European Unionn. European regulation 7.77 observed in total. The total length of each the panel nets was 70 m. After retrieving retrieving After was 70 m. thenets panel each of length The total total. in observed of deployments, 30 respectively,A total 18 were areas, South 12 and and at North thewherechose scientist grounds previously. fishing experimental in mdepth 40 and 10 Trammel were between each. nets set nets 2or 4 panel with simultaneously used mm), and80 (50,60 sizes different net were mesh with nets trammel experimental boat ( fishing artisanal the day.same for tookaboard over one days place Fishing 10 full fishing crew asingle 2010. accompanied observer March same the experimentation During 2010 werefrom followed February practices to fishing Normal weight. catch and size catch composition, catch effort, fishing fishing, duration of area, fishing to the lating design2.2. Experimental south. the to one and one of grounds, Candelaria north to the two in separated and allowed net is trammel where area order in by were scientists to selected cover wholegrounds the fishing and2-3-person a crew. Fishing fromCandelaria boat fishing artisanal (length) a5 m out using carried force scale).conditions was wind (2-3 Sampling Beaufort (fig. of Candelaria

-

1 7.4 (11.6 knots Mullus surmuletus The sampling area is located off the southeast coast of coast the southeast off is located area Tenerife(Canary sampling The but fisheries artisanal Island represented by Canary highly Trammel are nets To study the development of experimental fishings we collected all data re data all To collected we development the fishings study of experimental La Orca)

1 ). The average wind speed at the sampling sites ranged from: sitesranged thesampling ).at wind speed The average on 2 fishing areas (north and south). In each fishing day,and south). three fishing (north areas each In on 2fishing

± 2. MATERIAL AND METHODS AND MATERIAL 2.

1 S. squatina S. Linnaeus .67). Experimental fishings were performed with good sea sea good with wereperformed .67). fishings Experimental o 44/2012. vulner To conserve and bycatch manage , ) and Smooth-hound Mustelus mustelus Smooth-hound and )

1 1758 1-22'

was the target species of the studied fishery, of studied the species target the was

N a nd 16°

2 1-25'

W , in the municipality municipality the , in Linnaeus, Linnaeus, BOC - - -

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 89 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 90 2.3. Data analyses officinalis common the and Sparisoma cretense acarne Pagellus seabream axillary including fish were several to supplement value commercial Mullus surmuletus their had that some fish all retained The crew discard. andto which to retain fish which then netwho fishermen bydecided from the the were untangled net, specimens each Data regarding each specimen caught were analyzed after being ascribed to one of ascribed being after were analyzed caught specimen each regarding Data to one net or sample panel unit. weight were and standardized abundance Capture (2 of amount or used number 4). of total by net panels the divided catch total the (Capture Per CPUE and was Unitlength effort of Effort).unitfishing per Catch of weight, ground catch abundance, on fishing and size of mesh effect the to evaluate Primer were using performed of variance Analyses cm). (total length, measured and level,(totalto weighed counted, species weight, g) under fishermen judgment, identified or discards catches were in sorted mens caught weight were recorded. were weight and (TL) and werelength identified discards All size. catch orvalue below legal the Figure 1. Mean abundance, weight (g), length (cm) and CPUE of catches, discards discards of catches, (cm) CPUE and length (g), weight abundance, 1. Mean Figure and elasmobranchs for the three different experimental mesh sizes in the artisanal artisanal the in sizes mesh experimental different three the for elasmobranchs and Total catch was recorded for each of the 30 experimental fishings. All speci All fishings. Total experimental of 30 recorded for the each was catch Specimens were discarded if they were damaged, of little or no commercial or of no little commercial were damaged, they if wereSpecimens discarded trammel net fishery off the east coast of Tenerife (Canary Islands). of(Canary coast Tenerife east the off fishery net trammel Linnaeus , 1758, common Octopus the octopus vulgaris Linnaeus, 1758. Linnaeus,

6 +P fishery income; among these these among income; fishery ermanova software in order in software ermanova Risso, 1827Risso, and and Cuvier, 1797 parrotfish -

used to estimate the p-value (Anderson 2001). (Anderson p-value the to estimate used low, number very of the permutations was When species. a Monte Test Carlo was elasmobranch out for individual were carried study, analyses this in additional sis empha particular received elasmobranchs Since discards. and groups: catches two mesh size was increased from 50 mm, to 60 mm to 80 mm (fig. mm to 80 from 50 mm to mm, 60 2). increased was size mesh as net declined discards and The catches catches. number of elasmobranch total the squatina of weight,S. terms In catches. elasmobranch total the weight. for 37.61% accounting 1Squatiniform, and 1 Carchariniform catch of total the (17caught 40,730 specimens; g.). 1 Torpediniform, were 2 Rajiforms, these Among letus were surmu M. catches in species most abundant the caught, number of individuals followed other by species, any Squatina squatina of(26.83%) of Mullus surmuletus weight,catches terms In 6) Cabezo del Socorro (28° Socorro del 6) Cabezo Islands. North Area: 1) Central de Caletillas (28° Caletillas de 1) Central Area: North Islands. Candelaria (28° Candelaria (28° (28° , Figure 2. Location of experimental fishing grounds off the east coast of Tenerife, Canary Canary ofcoast Tenerife, east the off grounds fishing of experimental Location 2. Figure 16° Pagellus acarne

21'

12'

A total of 48 species were identified during the experimental fishings (table 1).fishings experimental the were of species 48 identified A total during 23' Mustelus mustelus

55"

04"

13"

N, 16° N,

N, 16° N,

W), 8) Los Barrancos (28° Barrancos 8) Los W),

21'

21'

17" 25'

and Sparisoma cretense and 31"

24"

N, 16° N,

W), 3) Cabezo del Pozo (28° Pozo del 3) Cabezo W),

19'

W) and 10) La Punta de la Hondura (28° Hondura la de Punta 10) La and W) was the most abundant species, representing 52.94% representing species, most abundant the was of

55"

22'

N, 16° N,

04"

W) 5) Cabezo la Barca (28° Barca la 5) Cabezo W) 3. RESULTS 3.

21'

13'

37"

56"

W). South Area: 7) Casa Quemada (28° Quemada 7) Casa Area: South W).

N, 16° N,

2 . A total of 5 elasmobranch species were species of 5elasmobranch . Atotal 2'

2 7"

24' 21'

N (19.23%). the considering When

27" 22" , 16°

N, 16° N, W), 9) Recodo de la Hondura Hondura la de 9) Recodo W),

2 1'

22' 2 0"

22'

11' 04" was higher than that of that than higher was

W

02" 48" ), 2) Cueva de La Barca Barca La ), de 2) Cueva

N, 16° N, made up 51.14% made of

W), 4) La playa de de playa 4) La W), N, 16° N,

21'

25' 17"

11"

W) and W)

14'

W).

52"

N, N,

- -

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 91 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 92 Mesh size (mm) 60 60 60 60 60 60 60 60 60 60 60 60 60 60 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 TABLE 1. TOTAL CATCHES FORSPECIES CAUGHT DURING THE EXPERIMENTAL FISHING USING TRAMMEL NETS ABOARD ORCA’ ‘LA OFF THE EASTCOAST Promethichthys prometheus Pagrus pagrus Pagrus auriga Pagellus erythrinus Pagellus acarne Mustelus mustelus Mullus surmuletus Lithognathus mormyrus Diplodus vulgaris Diplodus sarguscadenati Diplodus puntazzo Chromis limbata Boops boops Bodianus scrofa Synodus saurus Synapturichthys kleini Spondyliosoma cantharus Sparisoma cretense Squatina squatina Serranus atricauda Sepia officinalis Sarpa salpa Pseudocaranx dentex Promethichthys prometheus Pagrus pagrus Pagellus erythrinus Pagellus acarne Mustelus mustelus Mullus surmuletus Diplodus vulgaris Chromis limbata Boops boops Species OF TENERIFE (CANARY ISLANDS) ubr()Wih g (%) Weight (g) (%) Number 7 68 45 24 21±1.19 22.1 22.49 24350 36.89 173 225 8 .21. ±1.16 18.7 0.82 886 2.56 12 246 9736 34±1.69 23.4 3.61 3907 4.69 22 81.362 .41. ±1.16 18.6 5.84 6320 16.63 78 123 4 .11. ±0.97 14.4 0.51 549 2.35 11 .34003 63±1.06 46.3 0.37 400 0.43 2 .12902 25 0.22 239 0.21 1 .11801 23.5 0.18 198 0.21 1 .715 .52. ±2.38 25.4 1.35 1459 1.07 5 .560 .37. ±19.69 73.5 5.73 6200 0.85 4 .12001 6- 26 0.18 200 0.21 1 .45105 18±6.25 21.8 0.54 581 0.64 3 .17 .71. - 16.1 0.07 78 0.21 1 .11401 65- 16.5 0.10 104 0.21 1 .51701 43±1.71 14.3 0.15 157 0.85 4 .95805 07±3.46 20.7 0.53 578 1.49 7 .12002 6- 26 0.23 250 0.21 1 .47706 08±2.57 30.8 0.65 707 0.64 3 .12001 15- 31.5 0.18 200 0.21 1 .11001 35- 23.5 0.14 150 0.21 1 .220 .22. ±4.07 24.7 2.12 2300 1.92 9 .11801.017- 107 10.00 10830 0.21 1 .32002 15±1.41 21.5 0.22 240 0.43 2 .58207 58±4.57 15.8 0.78 842 0.85 4 .11001 3- 23 0.14 150 0.21 1 .320 .35 ±1.41 55 2.03 2200 0.43 2 .13002 45- 44.5 0.28 300 0.21 1 .44204 33±5.13 23.3 0.43 462 0.64 3 .34004 3±1.41 23 0.40 430 0.43 2 .740 .56. ±4.27 61.5 4.25 4600 1.07 5 .33903 2±0.71 22 0.31 339 0.43 2 .18 .72. - 22.5 0.07 80 0.21 1 Specimens Catches Total Catch Mean Length (cm) ±SD 80 80 80 80 60 60 60 60 60 60 60 50 50 50 50 50 50 50 50 50 50 80 80 80 80 80 80 80 80 80 60 60 60 60 60 60 60 Torpedo marmorata Taeniura grabata Dasyatis pastinaca Bothus podas Trachinus radiates Synodus synodus Stephanolepis hispidus Scorpaena maderensis Scorpaena canariensis Trigloporus lastoviza Bothus podas Taeniura grabata Synodus synodus Stephanolepis hispidus Scorpaena notate Scorpaena canariensis Pomadasys incises Polymixia nobilis Bothus podas Aulostomus strigosus Abudefduf luridus Synodus saurus Sparisoma cretense Squatina squatina Scorpaena scrofa Sarpa salpa Pagellus erythrinus Mullus surmuletus Boops boops Balistes capriscus Synodus saurus Spondyliosoma cantharus Sphyraena viridensis Sparisoma cretense Sepia officinalis Sarpa salpa Pseudocaranx dentex 021 7024 53±2.99 25.3 2.49 2700 2.13 10 .450 .94. ±4.80 45.2 4.99 5400 0.64 3 .110 .14 - 47 1.11 1200 0.21 1 .110 .05 - 50 1.20 1300 0.21 1 .18 .81 - 19 0.08 83 0.21 1 .45905 38±13.4 23.8 0.55 599 0.64 3 .11901 75- 27.5 0.17 179 0.21 1 .42202 48±1.04 14.8 0.21 222 0.64 3 .71601 18±1.10 11.8 0.15 166 1.07 5 .33103 95±4.95 19.5 0.31 331 0.43 2 .11000 3- 23 0.09 100 0.21 1 .72601 48±2.54 14.8 0.19 206 1.07 5 .110 .14. - 49.5 1.11 1200 0.21 1 .33002 5±1.41 25 0.28 300 0.43 2 .42602 57±1.15 15.7 0.25 266 0.64 3 .41901 45±1.73 14.5 0.17 189 0.64 3 .13 .31 - 12 0.03 34 0.21 1 .53003 89±0.85 18.9 0.32 350 0.85 4 .18 .71. - 18.5 0.07 80 0.21 1 .41001 77±0.58 17.7 0.17 180 0.64 3 .13002 7- 57 0.28 300 0.21 1 .42602 3±0.00 13 0.20 216 0.64 3 .510 .73. ±3.97 36.1 1.57 1700 0.85 4 .42302 3±2.78 33 0.25 273 0.64 3 .110092 0 - 104 9.24 10000 0.21 1 .110 .82 - 24 1.48 1600 0.21 1 .12302 6- 26 0.22 233 0.21 1 .11000 15- 21.5 0.09 100 0.21 1 .58007 29±2.68 22.9 0.74 800 0.85 4 .28007 11±0.70 21.1 0.74 800 1.92 9 .310 .23 ±4.24 32 1.02 1100 0.43 2 .513 .43. ±5.93 30.5 1.24 1339 0.85 4 .32201 98±1.06 19.8 0.19 202 0.43 2 .36006 18±7.42 51.8 0.64 690 0.43 2 .79408 92±4.62 19.2 0.88 954 1.07 5 .820 .11 ±2.06 16 2.31 2500 1.28 6 .19 .819 0.08 90 0.21 1 Discards

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 93 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 94 artisanal trammel net (e.g bycatch 15 trammel Gonçalves waters, Peninsula -49% Iberian in artisanal 2002). recorded here of rates were lower other studies in Discard reported to those 2001; al. et al. et (Borges seiners Erzini purse for reported pelagic been have also (27%) 2004). However, rates al. et lower discard mean (Gonçalves seiners purse 2002), 2001; 50.5% al. et and al. 62% et (Borges for Erzini trawlers for demersal (Monteiro 37% gear: active using fisheries scale nets) to larger compared trammel using those as fisheries static (such scale lower small are in rates Discard abundance. catch total fishery, byconstituted the a which number were10.23% discarded species the of 21 total In 2006). different al. et (Erzini and pocketing entangling wedging, gilling, - work nets fish to catch these by which of mechanisms probably due variety to the size. of mesh different usage from the derived be can elasmobranch regarding action management no clear and clear less were discards for obtained catches buton results size of mesh effect aclear revealed (e.g., 2001). size al. with et Jennings exponentially obtained declines The results generally abundance that fact to attributed the be net can mesh larger by the catches in decrease The areas. ground fishing of studied the all consistent across was that a result to mm, 80 from 50 mm to mm, 60 increased was size net mesh as cantly net fishery.signifi declined The numbercatches trammel of this in caught species (table (table species elasmobranchs 2) for and elasmobranch 3). the including discards to equated 72.79% weight. which catch catch of total individual total 32.47% represented and 18.76%abundance weight.Elasmobranchs of total of the 67.53% and of abundance 18.75% reached Discards weight. of total of terms in boops (table 9teleosts and 1).elasmobranchs Boops bogue Thewas most species numerous (24.29% weight). catch size of catch total of total 7.07% and of only 3.31% abundance terms reached Elasmobranchs weight. of total 17.40% 92.93% reached and of abundance terms weight.Discards in of total in bony 26 and fish 1elasmobranch (table 1 , 1). 82.60% Catches reached weight (28.59%). catch of total percentage for ahigh accounted group they this in number in (2.17%), catch of total the percentage small of dueindividuals size to the up only made a 4.93% and elasmobranchs of abundance Although weight. of total terms 6.84% in reached 95.07% and of weight.Discards abundance terms of total (table corals) and 1). urchins sea 93.16% (primarily reached invertebrates Catches in 24 bony and fish, someplus 3elasmobranchs ferentother 1cephalopod, species: Linnaeus, 1758, Linnaeus, followed by The diversity of species caught by trammel nets in the current study was was thecurrentstudy in nets trammel caught by diversity of species The great a number of therewas that revealed study this in obtained The results catches, between variation source any of of effects There were no significant The 80 mm mesh trammel nets captured a total of different a 4 total species: 13 captured nets trammel mm mesh 80 The captured: were of species different 28 atotal size mesh of mm Using nets 60 of dif 28 consisted nets trammel mesh 50 mm with obtained Captures 2001), 2001) al. et (Borges al. trawlers et to 70% for deepwater crustacean 4. DISCUSSION 4. M. surmuletus . Catches reached 81.25% reached . Catches terms in - - TABLE 2. ANALYSIS OF VARIANCE FOR ABUNDANCE, WEIGHT, LENGTH AND CATCH PER UNIT EFFORT (CPUE) OF CATCHES, DISCARDS AND ELASMOBRANCHS USING 3 DIFFERENT MESH SIZES (50, 60 AND 80 MM) AND FISHING GROUNDS (NORTH-SOUTH); M = MESH; FG = FISHING GROUND; PS-F = PSEUDO F STATISTIC; *= P-VALUE (< 0.05) OBTAINED WITH MONTE CARLO TEST Abundance Weight Length CPUE MS Ps-F P MS Ps-F P MS Ps-F P MS Ps-F P Catches M 1771.2000 5.883 0.184* 3.4992E7 2.315 0.297* 137.650 0.635 0.626* 1.1507E7 6.299 0.179* FG 291.340 0.845 0.397 8.0681E5 4.6864E-2 0.841 119.220 0.534 0.474 25389 7.381E-3 0.936 MxFG 301.070 0.874 0.495 1.5115E7 0.877 0.444 216.710 0.972 0.422 1.8268E6 0.531 0.630 Res 344.450 1.7216E7 222.910 3.4397E6 Discards M 3.005 0.882 0.441* 9.6358E5 1.958 0.341* 55.671 0.414 0.785* 36511 0.980 0.611* FG 5.338 2.549 0.121 9.4149E5 0.571 0.586 20.910 9.2103E-2 0.774 71687 0.674 0.539 MxFG 3.405 1.626 0.231 4.9206E5 0.298 0.879 134.460 0.592 0.570 37247 0.350 0.845 Res 2.093 1.6465E6 227.030 1.0622E5 Elasmobranchs M 0.216 0.213 0.875* 3.4204E6 0.688 0.588* 518.150 0.494 0.634* 3.8347E5 0.442 0.772* FG 2.450 1.266 0.329 4.6529E6 0.456 0.526 1125 1.042 0.326 5.2488E5 0.302 0.597 MxFG 1.016 0.525 0.596 4.9701E6 0.487 0.647 1048.3 0.971 0.375 8.6577E5 0.499 0.636 Res 1.934 1.0192E7 1079.6 1.7334E6

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 95 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 96

TABLE 3. ANALYSIS OF VARIANCE FOR ABUNDANCE, WEIGHT, LENGTH AND CATCH PER UNIT EFFORT (CPUE) OF ELASMOBRANCH SPECIES USING 3 DIFFERENT MESH SIZES (50, 60 AND 80 MM) AND FISHING GROUNDS (NORTH-SOUTH); M = MESH; FG = FISHING GROUND; PS-F = PSEUDO F STATISTIC; *= P-VALUE (< 0.05) OBTAINED WITH MONTE CARLO TEST

Abundance Weight Lenght CPUE

MS Ps-F P MS Ps-F P MS Ps-F P MS Ps-F P

Squatina squatina

M 3.333E-2 0.333 0.737* 3.633E6 0.334 0.751* 371.23 0.333 0.745* 7.344E5 0.448 0.707*

FG 1.192E-1 1.788E-1 1* 22963 3.170E-3 0.896 0.3 4.042E-4 0.911 2.832E5 0.238 0.72

MxFG 0.1 1.5 0.308 1.085E7 1.498 0.299 1113.1 1.499 0.297 1.637E6 1.38 0.266

Res 6.666E-2 7.243E6 742.17 1.185E6

Mustelus mustelus

M 0.7 1 0.494* 1.036E6 1 0.498* 155.48 1 0.491* 2.59E5 1 0.49*

FG 2.7 1.975 0.235 3.888E6 1.957 0.215 607.5 1.984 0.222 9.72E5 1.957 0.241

MxFG 0.7 0.512 0.666 0.521 0.655 155.48 0.507 0.644 2.59E5 0.521 0.668

Res 1.366 306.15 4.966E5

Dasyatis pastinaca

M 3.333E-2 1 0.506* 56333 1 0.531* 83.333 1 0.51* 3520.8 1 0.496*

FG 3.333E-2 1 0.425 56333 1 0.427 83.333 1 0.333* 3520.8 1 0.409

MxFG 3.333E-2 1 0.458 56333 1 0.437 83.333 1 0.464 3520.8 1 0.452

Res 3.333E-2 56333 83.333 3520.8 Abundance Weight Lenght CPUE

MS Ps-F P MS Ps-F P MS Ps-F P MS Ps-F P

Taenuria grabata

M 3.333E-2 0.333 0.736* 48000 0.333 0.727* 77.758 0.333 0.741* 4333.3 0.351 0.752*

FG -1.133E-17 <0 -9.890E-1 <0 0.208 1.341E-3 0.911 333.33 4E-2 0.784

MxFG 0.1 1.5 0.23 1.44E5 1.5 0.271 232.86 1.499 0.296 12333 1.48 0.289

Res 6.666E-2 96000 155.31 8333.3

Torpedo marmorata

M 0.3 1 0.508* 9.72E5 1 0.502* 68.101 1 0.532* 60750 1 0.529*

FG 0.3 1 0.392 9.72E5 1 0.457 68.101 1 0.401 60750 1 0.4

MxFG 0.3 1 0.463 9.72E5 1 0.453 68.101 1 0.465 60750 1 0.465

Res 0.3 9.72E5 68.101 60750

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 97 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 98 been demonstrated to demonstrated notbeen useful. be have size mesh regarding management since alive sharks releasing us such practices to promote and fishing good sharks of protecting importance the to explain villages fishing Canarian local among 2010). acampaign to start advisable be It would also al. et Cruz la (De number of observations diver high by the suggested as Europe, in ahotspot conservation be region could for the elasmobranch and Canaries the squatina numbers of S. It high possible is that Islands. Canary the in status thespecies’ urgentconfirm an to need thereis fisheries these S. squatina obtained squatina of S. rates catch a conclusion due high relatively and to the 2015). (Nieto al. et Islands. Canary the found population around is As remaining of the all almost now that and waters, it inferred is European found throughout 1973; Bravo de Laguna and Escánez 1975).1973; ( Escánez and Angelshark Bravo de Laguna Laguna (Bravo de fishing regionsubjectbut is to intense demersal most of this Archipelago of Canarian portions the predator large across demersal important an ( Angelfish the for example endangered, as List Red on IUCN the listed already are species some sensitive areto overfishing; very Elasmobranchs stocks. fish commercial of effects adverse with of ecosystem the balance the predators would destabilize 2010), al. et (Baremore (Mullidae) long of the removal term elasmobranch in goatfishes including species fish on do feed commercial squatiniforms Although 2001, Dorta species observation).(Carmelo personal target their of benefitstocks number of the reducing predators will that belief or them due cultural to to sell the in order elasmobranchs exterminated fishermen the some In instances, alive. were still and designs. grounds, (3) (2)differentmesh use nets, of choice fishing of alternative but include: may (1) testing, of trammel the further time quire areduction soak in 2015). numbers (Nieto what al. in et and caught ( smoothhounds particularly sharks, of of smaller catches landings reported in rise rapid unregulated an been has Europe in Furthermore, area. study the in species the of due be abundance to could the which elasmobranch, most frequently caught the Mustelus mustelus composition 2002). fauna (Brito al. elasmobranch et Islands Canary the of fished or due and inherent sampled to ofcharacteristics depths range species elasmobranchs) (5 probablyelasmobranch of the different duesmaller to 37.61% number and in weight.However, in number included asmaller catch our represented 3.62% elasmobranchs catch study our In of total the catch. of total the Baeta (2005) (4.3% 16 were found caught species that catch). elasmobranch of total the regions. both between differences acceptance commercial and custom on based fisheries artisanal Peninsula Iberian than of species variety more fishermen retain canarian is probablynet 2007). This trammel due to al. et Mustelus (2010) al. et of 11 up 4% catches made which observed species elasmobranch It was noted throughout the study that most of the discarded elasmobranchs elasmobranchs most of discarded the that study notedIt the throughout was re net fishery trammel studied the in to reduce discards measures Other al. et Coelho of coast thePortugal, western on net fishery atrammel In spp.) and a detailed assessment is needed of where specific species are of needed species where is spp.) specific assessment adetailed and Squatina squatina ) which is critically endangered. Squatina endangered. squatina critically is is ) which Recibido : noviembre de 2017, de : noviembre aceptado may still be present be around still may S. squatina S. : diciembre de 2017 de : diciembre ) was formerly) was was was

by by - . Review and edition of the final draft: JCM, AB, AB, JCH. JCM, draft: edition of final and the Review JCM. draft: Original JCH. analysis: Data field and work: CD,Methodology JCH. JCM, JCH. Conceptualization: paper. “observational” this version improve early of that an referees friendly the all Weto Mario. thank also To the Cofradía de Pescadores de Candelaria and all its fishermen’s, all and To specially de Pescadores de Candelaria Cofradía the 6. AUTHORS’S CONTRIBUTION AUTHORS’S 6. 5. ACKNOWLEDGEMENT

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 99 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 100 Coelho Coelho Clucas Coelho Carbonell Clarke Catchpole Brito Brito Borges Bonfil BOC Escánez J. and de Laguna, Bravo 1-17.CM/J ICES Islands. Canary the off J. 1973. Elasmobranchii de Laguna, Bravo Baremore Baeta Anderson 2005/04. Boletín Oficial de Canarias. http://www.gobiernodecanarias.org/boc/2005/004/ Canarias. de Oficial Boletín 2005/04. , A., Pascual , A., Pascual , A., , F., Batista , R. 1994. Overview of world elasmobranch fisheries. In FAO Fisheries Technical Paper 341. Paper In FAO Fisheries Technical fisheries. of world elasmobranch 1994. Overview , R. I. 1997. A Study of the Options for Utilization of Bycatch and Discards from Marine Capture Capture Marine from Discards and of Bycatch 1997. I. Utilization for Options of the AStudy , T.C., Erzini , M.W., Borges , R., Erzini , R., , R. and Erzini and , R. , R. and Erzini and , R. 35: 531-537. 35: Sci. Fish. Atl. Northwest J. discards. and rates catch composition, catch Portugal: southern in catches elasmobranch net trammel and ic longline by-catch off southern Portugal. Hydrobiologia Portugal. southern off by-catch Fisheries. FAO fisheries circular No. 928 FIIU/C928. Rome: Rome: FAOFIIU/C928. No.928 (1997). circular FAO fisheries Fisheries. 35: Sci. Fish. 429-442. Atl. Northwest J. of Ireland. north and west elasmobranchs deepwater (Southern Portugal). (Southern las Islas Canarias. Francisco Lemus Editor. La Laguna. 419 pp. Laguna. La Editor. Lemus Francisco Canarias. Islas las 45-54. 72(1): Res. Fish. factors. environmental and social rolethe of fishery: norvegicus Nephrops 7-18. 6: Res. Fish. fishery. trawl Islands) (Balearic Mediterranean western the in of sharks Cruz de Tenerife. de 170Cruz pp. pesquero aprovechamiento ysu profundos fondos los de tiburones Los Canarias. de cartilaginosos Ichthyol Appl. J. métiers. Portugal) (southern Algarve five in practices discarding and By-catch Food and Agriculture Organization of the United Nations. Rome. 119 Rome. Nations. United of the pp. Organization Agriculture and Food 2015). 1Janaury (accesed de Pesca 11: Pesca de 169-192. Estudios de Junta la de Técnicas Publicaciones canario. archipiélago el en mobranquios Biol. Squatina dumeril shark angel Atlantic of the 102: 123-129. 102: Res. Fish. coast. west the in Portuguese fishery net trammel Can. J. Fish. Aquat. Sci Aquat. Fish. J. Can. regression. , M.J. 2001. Permutational tests for univariate or multivariat analysis of variance and and of variance analysis or multivariat univariate for tests , M.J. 2001. Permutational , I.E., Murie , I.E., , T.L., Frid , A., Alemany, A., 8: 125-136. 8: 17: 104-114. 17: Consejería de Agricultura, Ganadería y Pesca del Gobierno de Canarias. Santa Santa Canarias. de Gobierno del yPesca Ganadería Agricultura, de . Consejería , M., Maia , M., , P.J., Rabanal , K., Bentes , K., , P.J., Falcón , K., Bentes , K., , K. 2002. Age and growth of the undulate ray, undulata Raja undulate of the growth and Age 2002. , K. , L. and Officer and , L. , C.L.J. and Gray and , C.L.J. , K. 2008. Effects of fishing methods on deep water shark species caught as caught species shark water deep on methods fishing of Effects 2008. , K. , D.J. Carlson and , F., Merella UK 82(6): 987-990. UK Assoc. Biol. Mar. J. , A., Costa , A., , L., Correia , L., , J.M., Sancho , J.M., , R., Hernández , R., , L., Costa , L., 7. REFERENCES , J. 1975. Informe sobre las posibilidades pesqueras de elas de pesqueras posibilidades , J. 1975. las sobre Informe , R.A. 2005. Comparisons of trawl and longline catches of catches longline and of trawl Comparisons 2005. , R.A. , P., Quetglas , M.J. and Cabral, M.J. and , T.S. 2005. Discarding in the English north-east coast coast north-east English the in , T.S. Discarding 2005. . 58: 626-639. 58: . , J.K. 2010. Seasonal and size-related differences in diet diet in differences size-related and 2010., J.K. Seasonal , C., Lino, C., , M.E., Gonçalves , M.E., , A. and González-Lorenzo and , A. , M., Lozano , M., Aquat. Aquat. of México. Gulf northeastern the in , P.G., Monteiro 606: 187-193. 606: , A. and Románc and , A. , H. 2010. Elasmobranch bycatch in a in bycatch 2010., H. Elasmobranch , J.M.S., Lino , J.M.S., , I.J., Báez , P., 2005. Semi-pelag al. et , E. 2003. The by-catch by-catch The 2003. , E. 1998. Peces al. et , A., , G. 2002. Peces de de Peces 2002. , G. 2001. , P.G., 2001. al. et , in the Algarve Algarve the , in - -

Hall Megalofonou Hazin Gonçalves Jennings 105. 39: Res. Fish. introduction. fisheries of shark management and 1998. Science , R.E. Heuter Gonçalves Frisk Erzini Erzini Erzini De la Cruz, R., Esteban R., Cruz, la De Couch Day Dulvy Cortés , F. 1880-1884. The fishes of Great Britain and Ireland, volume 2. Williams & Noegate, Lon Noegate, & Williams 2. volume Ireland, and , F.Britain Great 1880-1884. of fishes The , M.A., Alverson , M.A., , M.G., Miller , F.H.V., , J.D., Glanville Metcalfe , N.K., , K., Gonçalves , K., , K., Costa , K., , K., Puente , K., , J. and Smith , J. and ICES J. Mar. Sci. Sci. Mar. J. ICES of sharks. levels trophic and compositions diet 1999., E. Standardized 88: 5-14. Res. fisheries. Fish. L., swordfish and tuna fisheries in the Mediterranean Sea. Fish.Sea. Bull. Mediterranean the in fisheries tuna and swordfish na 213: 127-142. Ser. Prog. Ecol. Mar. communities. invertebrate of benthic structure trophic on the bance Pollut. Bull. Algarve, CCMAR, Faro, 126 Faro, CCMAR, Algarve, do Universidade report, FCT/POCTI/BSE/43113/2001, Final of survivorship. evaluation and fishery purse-seine demersal the in (BRD) Devices Reducing By-catch Experimental ( 58: 969-981. 58: Sci. Aquat. Fish. J. study. Can. history life comparative A fishes: elasmobranch in eters 79 (1-2): 183-201. (1-2): 79 Res. Fish. fisheries. small-scale European southern in nets of trammel selectivity Size 2006. al. et Manag. Ecol. Fish. Portugal). (southern Algarve the from fisheries five from of discards composition Cyclades islands (Greece). Final Report UE-DG XIV-98/014, UE-DG 435 +annexes. Report (Greece). Final islands Cyclades and (Spain) country Basque (Spain), of Cadiz gulf Portugal), (Southern Algarve the in la Universidad de La Laguna. 39 pp. Laguna. La de Universidad la de ySociales Políticas Ciencias de Universitario Instituto Canarias. Islas las en actividad la de económicos beneficios los yde España en potencial su de Análisis España. en y rayas don-Edinburgh. 56: 707-717. 56: 283-293. Conserv. Biol. skates. in structure community in shifts and extinctions local stability, 69-92. (1): Lond. Soc. Trans. Linn. , S., Pinnegar , S., Carcharhinus acronotus , J.M.S., Stergiou , J.M.S., , J.M.S., Monteiro , J.M.S., 2005. Incidental catch and estimated discards of pelagic sharks from the the from sharks of pelagic discards estimated and catch Incidental 2005. al. et , J.M., 2007. Discards from experimental trammel nets in southern European small-scale small-scale European southern in nets trammel experimental from 2007. Discards al. et , P., Yannopoulos Olivera , M.E., Bentes , M.E., , E., Stergiou , E., , J.E. 1822. Some particulars of the natural history of fishes found in Cornwall. Cornwall. in found of fishes history natural of the 1822. particulars Some , J.E. 41: 204-219. 41: , T.J. Fogarty and 9: 31-40. 9: , J.M.S., Bentes , J.M.S., , D.L. and Metuzals and , D.L. , N.V.C.Warr Polunin and , J.K., , P.G. Broadhurst and , A., Crilly , A., , K.L., Hernando , K.L., , P., Bentes ) in coastal waters off northeastern Brazil. Fish. Bull. Brazil. northeastern off waters coastal ) in , K.I. and Hernando and , K.I. , L. and Borges and , L. , C., Damalas, C., , R, and Pascual-Fernández and , R,

+ , L., Moutopoulos , L.,

a - param of biological analysis and , M.J. 2001. Estimation nnexes. , J., Pawson , L., Coelho , L., Mar. Mar. solutions. and problems By-catch: 2000. , K.I. , M.K. 2002. Reproduction of the blacknose shark shark blacknose of the Reproduction 2002. , M.K. , D., Metrio De , J.A., Puente , J.A., , T.C. 2002. A comparative study of the species species of the study , T.C. Acomparative 2002. , M.G. and Reynolds , M.G. and , J.A. 2001. Trammel net selectivity studies studies selectivity 2001. net Trammel , J.A. , R., Corado , R., , D.K., Casal , D.K., , K.J. 2001. Impacts of trawling distur of trawling 2001., K.J. Impacts , E., Moutopoulos , E., , G., Deflorio , G., , J. 2010. Bucear con tiburones tiburones con , J. 2010. Bucear , M., Araújo , M., , J.A.H., Soriguer , J.A.H., 103: 620-634. 103: , J.D. 2000. Fishery Fishery , J.D. 2000. , M., de la Ser de la , M., 2004. 2004. , J., al. et , D.K., Arregi, Arregi, , D.K., 100: 143-148. 100: , M.C., M.C., , 14: 14: - - - ,

REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 101 REVISTA SCIENTIA INSULARUM, 1; 2018, PP. 87-102 102 Wintner Stevens Smale Pratt Nieto Walker Stobutzki Monteiro Merino Merino , H.L. and Casey and , H.L. , A., Ralph , A., , M.J. and Goosen , M.J. and , P.A. and Hislop , P.A. and , G., Morales , G., , J. and Maynou , J. and , J.D., Bonfil ICES J. Mar. Sci. day. Mar. J. present ICES the 1930 and between Sea North north-western and central the in composition species ray in Fish. fishery. Bull. (shrimp) trawl prawn atropical in bycatch as caught megalopterus 97-109. 90: NMFS Report Technical NOAA Commerce. of Department US fisheries. of the status the and systematics, biology, ecology, the in advances resources: living as T, Taniuchi Elasmobranchs and SH editors. Gruber HL, Pratt In: growth-parameters. of Holden’sestimating of review a method with fisheries, Union. European the of Office and Hydrobiologia fishery. trawl crustacean Portugal) carcharias 57: 476-494. 57: Sci. Mar. J. ICES ecosystems. marine for implications the and (chondrichthyans), chimaeras and rays, 99-107. 21: Living. Aquat. fishery. net Resour. trammel Mediterranean) (NW Majorca of the analysis Mar. Sci. , S.P. Cliff and , I.C., Miller , I.C., , P., Araújo Dulvy , G.M., Comeros-Raynal , G.M., 67: 37-49. 67: , from the east coast of South Africa. Fish. Bull. Africa. of South coast east the , from , N.K. 2015. European Red List of marine fishes. Luxembourg: Publications Publications Luxembourg: fishes. of marine List 2015. Red , N.K. European , off the Eastern Cape, South Africa. Fish. Bull. Africa. South Cape, Eastern the , off , R., Dulvy , R., - , A., Erzini , A., Nin , J.G. 1990. Shark reproductive strategies as a limiting factor in directed directed in factor alimiting as strategies , J.G. reproductive 1990. Shark , M., Heales , M., , G. 1999. Age and growth determination of the white shark, Carcharodon shark, white of the determination growth 1999., G. and Age , F. 2003. Fish stock assessments in the Mediterranean: state of the art. art. of the state Mediterranean: the in assessments , F. stock Fish 2003. , J.R.G. 1998. Sensitive skates or resilient rays? Spatial and temporal shifts shifts temporal and Spatial rays? or resilient skates 1998., J.R.G. Sensitive , A.J. 1999. Reproduction and feeding of spotted gully shark, Triakis shark, gully of spotted feeding 1999. and , A.J. Reproduction , B., Maynou , N.K. and Walker and , N.K. , K. and Castro and , K. , D.T. 2002. Sustainability of elasmobranch of elasmobranch , D.T. Sustainability Brewer and , D.S. 2002. , F. Grau and , 55: 392-402. , M.T., Kemp , M. 2001. Discards of the Algarve (Southern (Southern Algarve of the 2001., M. Discards , P.A. 2000. The effects of fishing on sharks, sharks, on fishing of effects The , P.A. 2000. , A.M. 2008. Assessment and bioeconomic bioeconomic and Assessment 2008. , A.M. 449: 267-277. 449: , J., García Criado 97: 153-169. 97: 97: 987-998. 97: 100: 800-821. 100: , M., Allen , M., , D.J.