The fish species composition and variation of catch from the small
Contents
1. 10 15 Geometric class species A 1994 95 1998 a 1999 2000 Geometric class Fig 3 Total and yearly geometric class curve for the catch of the gillnet fishery from Jalisco Mexico Haemulon flaviguttatum and Lutjanus guttatus show predominance on some specific years Fig 5 Significant statistic differences for the total abundance and biomass of C caninus H flav iguttatum and L guttatus were found Table 3 due to the fluctuating catches of these species during 1998 DISCUSSION Fish species composition although the topic of the climatic variability has attracted the public s attention in the world during some time the 1997 98 ENSO events has specifi cally interested to different sectors of the sci entific society Droughts forest fires excessive Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 141 TABLE 3 Results of the Anova of the CPUE for the abundance and biomass Totals Effect df Error df F p level Total abundance 3 43 3 952 0 01 i Total biomass 3 43 5 307 0 00 Abundance 98 00 2 32 1 510 0 24 Biomass 98 00 2 32 0 880 0 42 Abundance 1994 95 11 33 2 193 0 04 1994 95 11 33 1 550 0 17 Abundance 1998 11 45 3 424 0 00 Biomass 1998 11 45 3 203 0 00 Abundance 1999 11 45 0 668 0 76 Biomass 1999 11 45 0 441 0 93 Abundance 2000 10 40 1 073 0 40 Biomass 2000 10 40 2 193 0 31 BY KIND OF NET Abundance 3 0 gillnet 3 43 12. OO O O O O DO QM DO OO OO Md Md O O OOo o gt 5 gt E ia Q x c cox vu o vu x E or 8 a a o go gt 2 5 YPEZ 2OOG lt 232O0 0 xX lt 22060 e Abundance Biomass 20 Scomberomorus sierra 15 5 2 S o 5 10 8 2 B amp 29 S JN g EUR MN AR Ve M 0 sr sb sb SY UO CO QOO OO YA O O O O O c DO 0d OW DO OO OO OO OO AO OOO o gt 5 Q gt c a i c nd v Q E ns o Q c np v 5 o o o o 2 42 5 POSZSZZOOQG IZ3Z2ZO O X 23200 Fig 6 Continued Variation of the CPUE in abundance and biomass for the most important species almost completely during the period of 1998 and reappearing in the following years with similar catch levels to those of the normal year 1994 95 this species had previously been reported as characteristic of periods with La Ni a conditions in the study by Madrid Vera and Sanchez 1997 250 km to the south of the present study It is necessary to point out the difference in the number of organisms caught by each one of the used gillnets being notably bigger 148 the catch obtained by the gillnet of 76 2 mm of mesh size followed by the 88 9 mm gillnet As expected smaller differences were found in biomass These differences in the catches of the smaller mesh sizes compared to the bigger ones should be due mainly to th
3. 408 0 25 Biomass 3 0 gillnet 3 43 1 095 0 36 Abundance 3 5 gillnet 3 43 4 662 0 01 Biomass 3 5 gillnet 3 43 5 962 0 00 Abundance 4 0 gillnet 2 32 3 082 0 06 Biomass 4 0 gillnet 2 32 2 934 0 07 Abundance 4 5 gillnet 3 43 14 434 0 00 Biomass 4 5 gillnet 3 43 9 525 0 00 BY SPECIES TOTAL ABUNDANCE Caranx caballus 3 43 0 869 0 46 Caranx caninus 3 43 2 575 0 07 Haemulon flaviguttatum 3 43 3 678 0 02 Lutjanus guttatus 3 43 0 650 0 59 Microlepidotus brevipinnis 3 43 0 534 0 66 Scomberomorus sierra 3 43 0 381 0 77 BY SPECIES TOTAL BIOMASS Caranx caballus 3 43 0 766 0 52 Caranx caninus 3 43 4 086 0 01 Haemulon flaviguttatum 3 43 3 526 0 02 Lutjanus guttatus 3 43 0 636 0 60 Microlepidotus brevipinnis 3 43 0 709 0 55 Scomberomorus sierra 3 43 0 503 0 68 142 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 TABLE 3 Continued Results of the Anova of the CPUE for the abundance and biomass Totals Effect df Error df F p level BY SPECIES ABUNDANCE 1998 00 Caranx caballus 2 32 0 347 0 71 Caranx caninus 2 32 2 164 0 13 Haemulon flaviguttatum 2 32 5 096 0 01 Lutjanus guttatus 2 32 3 119 0 06 Microlepidotus brevipinnis 2 32 0 429 0 65 Scomberomorus sierra 2 32 0 042 0 96 BY SPECIES BIOMASS 1998 00 Caranx caballus 2 32 0 316 0 73 Caranx caninus 2 32 3 002 0 06 Haemulon flaviguttatum 2 32 4 854 0 01 Lutjanus guttatus 2 32 3 581 0 04 Microlepidotus bre
4. PERIOD 2000 Microlepldotus brevipinnis 1129 18 45 370 57 12 80 11 100 00 131 25 Caranx caballus 508 8 30 248 53 8 58 11 100 00 116 88 Lutjanus guttatus 429 7 01 229 40 7 92 11 100 00 114 93 Haemulon flaviguttatum 538 8 79 160 68 3 95 11 100 00 114 34 Umbrina xanti 434 7 09 121 05 4 18 11 100 00 111 27 Scomberomorus sierra 193 3 15 164 15 5 67 11 100 00 108 82 Lutjanus argentiventris 174 2 84 86 51 2 99 11 100 00 105 83 Mulloidichthys dentatus 126 2 06 44 77 1 55 11 100 00 103 60 Caranx sexfasciatus 78 1 27 42 69 1 47 11 100 00 102 75 Caranx caninus 338 5 52 175 61 6 06 10 90 91 102 50 118 species 2173 35 50 1251 56 43 23 TABLE 2 Continued Values of the Relative Importance Index for the most important species of each year fishing day were caught The maximum val ues were recorded during January and October of 1998 250 organisms and 100 kg fishing day and the minimum values were recorded during September and November of 1994 25 organisms and 10 kg fishing Fig 3 The total abundance and biomass were lower during the 1994 95 period F 6 16 8 32 P lt 0 05 Table 3 Only for the monthly abundance and bio mass of the 1998 period significant statistic differences were found F 4 33 3 23 P lt 0 05 Table 3 CPUE by type of net the maximum catch in number of organisms was obtained using the 76 2 mm gillnet mesh size that caught 11 402 fishes 44 of the total 51 organisms fishing day on average followed the
5. mesh size was not used These gillnets were designed to operate on the bottom and were placed over depth ranges of 7 to 12 m The fishing opera tions were carried out during the night and the catch was separated according the gillnet type All fish caught were measured as total length TL cm and total weight TW g 134 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 Relative Importance Index the index was used to show the most important species in the catch which uses a relative mea sure of each species for the abundance of individuals biomass kg and frequency of samples RIT N P F 1 Where N is the relative abundance of each specie P is the relative biomass and F is the relative frequency in the samples De la Cruz Ag ero 1994 Dominance dominance patterns were analyzed using several kinds of curves like dominance plot k dominance curves and geo metric class curves which enable to extract information about the species relative abun dance without reducing that information to a simple index Clarke and Warwick 1994 Catch per unit of effort analysis CPUE to analyze the variation of the CPUE the unit of effort used was a fishing day where the same number and type of gillnets were used giving number of fish and kilograms per fish ing day The monthly abundance or biomass values are given in all cases as the cumulative catch of the five fishin
6. of southwestern Taiwan Fish Res 28 71 83 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 151 Tsai C F P Y Chuen C P Chen M A Lee G Y Shiah amp K T Lee 1997 Fluctuations in abundance of larval anchovy and environmental conditions on coastal waters off South western Taiwan as associated with the El Ni o Southern Oscillation Fish Oceanogr 6 238 249 Vanderklift M A amp C A Jacoby 2003 Patterns in fish 152 assemblages 25 years after major seagrass loss Mar Ecol Prog Ser 247 225 235 Zar J H 1999 Biostatistical analysis Prentice Hall Englewood Cliffs New Jersey USA INTERNET REFERENCE Duffy D amp P J Bryant 1998 The 1997 98 El Ni o Southern Oscillation ENSO 97 98 One of the most severe ENSO events in history Electronic page University of California in Irving darwin bio uci edu sustain ENSO html Downloaded 21 April 2007 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008
7. y octubre de 1998 250 peces y 100 kg por d a de pesca y el m nimo se registr durante septiembre y noviembre de 1994 25 organismos y 10 kg por d a de pesca La abundancia y biomasa total fue menor durante el periodo 1994 1995 F 6 16 8 32 P lt 0 05 Se encontraron dife rencias estad sticamente significativas entre la captura Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 149 anual de las diferentes redes Los cambios ambientales provocados por el evento ENOS tuvo efectos que pudieran considerarse de moderados a severos tanto ecol gicos como econ micos Palabras clave M xico Jalisco composici n espec fica de peces pesquer a artesanal El Ni o Oscilaci n del Sur captura por unidad de esfuerzo REFERENCES Abitia C rdenas L A J Rodriguez Romero F Galv n Maga a J De La Cruz Ag ero amp H Ch vez Ramos 1994 Lista sistem tica de la ictiofauna de Bah a de la Paz South Baja California Mexico Cienc Mar 20 159 181 Aguilar Palomino B C P rez Reyes F Galv n Maga a amp L A Abitia C rdenas 2001 Ictiofauna de la Bahia de Navidad Jalisco Mexico Rev Biol Trop 49 173 190 Allen G R amp D R Robertson 1994 Fishes of the tropical eastern pacific Univ of Hawaii Honolulu Hawaii USA Arntz W E 1984 El Ni o and Peru positive aspects Oceanus 27 36 39 Arntz W E amp E Fahrbach 1996 El Ni o Experimento clim tico de l
8. 15 36 02 PERIOD 1998 Microlepidotus brevipinnis 2015 28 98 603 91 18 66 12 100 00 147 65 Caranx caninus 1333 19 17 543 73 16 80 12 100 00 135 98 Caranx caballus 440 6 33 217 70 6 73 12 100 00 113 06 Caranx sexfasciatus 237 3 41 116 21 3 59 12 100 00 107 00 Scomberomorus sierra 202 2 91 172 04 5 32 12 100 00 108 22 Kyphosus analogus 303 4 36 140 85 4 35 12 100 00 108 71 Kyphosus elegans 140 2 01 120 74 3 73 12 100 00 105 74 Lutjanus argentiventris 85 1 22 42 41 1 31 12 100 00 102 53 Elops affinis 174 2 50 61 99 1 92 12 100 00 104 42 Haemulon flaviguttatum 92 1 32 34 76 1 07 12 100 00 102 40 118 species 1927 27 78 1179 57 36 52 PERIOD 1999 Microlepidotus brevipinnis 1587 17 89 512 07 13 42 12 100 00 131 32 Caranx caballus 546 6 16 229 16 6 01 12 100 00 112 16 Scomberomorus sierra 185 2 09 134 92 3 54 12 100 00 105 62 Caranx sexfasciatus 120 1 35 78 07 2 05 12 100 00 103 40 Haemulon flaviguttatum 452 5 10 186 77 4 90 11 91 67 101 66 Haemulon scudderi 79 0 89 24 88 0 65 12 100 00 101 54 Lutjanus guttatus 343 3 87 188 29 4 94 11 91 67 100 47 Kyphosus analogus 277 3 12 153 60 4 03 11 91 67 98 82 Lutjanus argentiventris 252 2 84 129 00 3 38 11 91 67 97 89 Anisotremus interruptus 112 1 26 60 94 1 60 11 91 67 94 53 131 species 4916 55 43 2117 13 55 49 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 139 Kbundanse Relative Biomass Relative Esque y Relative Relative importance importance importance importance
9. 2 53 1 62 1 34 4 46 1 43 0 83 0 86 2 56 0 55 0 90 1 00 1 18 0 19 0 51 0 42 1 01 0 59 0 80 2 80 1 51 0 23 0 27 0 87 18 08 Biomass kg 1825 17 873 59 504 66 589 55 940 56 279 69 629 46 326 45 227 30 155 89 312 05 134 30 99 70 93 67 347 41 29 23 276 91 307 57 281 73 115 00 27 62 35 22 146 15 50 08 216 03 219 90 42 43 58 70 6 40 74 86 2452 82 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 Relative importance 15 63 7 48 4 32 5 05 8 05 2 39 5 39 2 79 1 95 1 33 2 67 1 15 0 85 0 80 2 97 0 25 2 37 2 63 2 41 0 98 0 24 0 30 1 25 0 43 1 85 1 88 0 36 0 50 0 05 0 64 21 00 Frequency months 47 47 45 46 42 47 43 45 44 44 39 41 41 40 37 36 31 30 30 30 30 29 28 27 26 25 26 26 24 23 Relative Relative importance importance Index 100 00 138 31 100 00 114 48 95 74 105 74 97 87 105 67 89 36 105 50 100 00 104 34 91 49 102 23 95 74 101 07 93 62 97 18 93 62 96 29 82 98 90 11 87 23 89 82 87 23 88 92 85 11 86 77 78 72 84 26 76 60 77 39 65 96 69 22 63 83 67 47 63 83 67 42 63 83 65 01 63 83 64 57 61 70 62 42 59 57 61 83 57 45 58 46 55 32 57 96 53 19 57 87 55 32 57 19 55 32 56 06 51 06 51 39 48 94 50 44 137 100 g 80 Abundance S A 60 8 e 5 40 oe E y e 5 20 Biomass 0 4 4 1 10 100 1000 Species rank Abundance 100 2 y
10. 3 00 and 5 00 US kg involving the greater losses ACKNOWLEDGMENTS The authors thank Daniel and Gerardo Kosonoy for designing the gillnet and for fishing operations Jorge Rojo was supported by the CONACYT and PROMEP Doctorate Scholarship The English version was reviewed by Cristina Ber nardez Univ Corufia Spain Casimiro Quifiones is member of COFAA and EDI RESUMEN Se llevaron a cabo 219 dias de pesca experimental en la Bah a de Navidad Jalisco M xico Se utilizaron cuatro redes de enmalle de diferente luz de malla 76 2 88 9 101 6 and 114 3 mm de luz de malla de abril de 1994 a marzo de 1995 y de enero de 1998 a diciembre de 2000 En total se capturaron 26126 organismos que pesaron 11680 kg Fueron identificadas 183 especies pertenecientes a 57 familias y 19 rdenes Diez especies acumularon m s del 60 de la abundancia y biomasa total el resto de las espe cies 173 individualmente aportaron menos del 2 de la abundancia y biomasa total Las especies m s importantes en la captura fueron Microlepidotus brevipinnis Caranx caballus Haemulon flaviguttatum Scomberomorus sierra C caninus C sexfasciatus Lutjanus guttatus y L argen tiventris La captura por unidad de esfuerzo mostr una gran variaci n durante todo el periodo de estudio tanto en n mero de organismos como en biomasa En promedio se capturaron 110 organismos d a de pesca 48 5 kg d a de pesca Los valores m ximos se registraron durante enero
11. 8 50 Abundance s Biomass Caranx caballus amp 5 D El 2 a Y 8 E E 2 amp a OO OO WD CO OO OO OX OO OY OO OOOO gt 5 EX eoe iQ 3 C DE 0 20 3 E DE woo C Oi Ea s a o o o o 92 5 gt Pes 200A eszsZ20ALeZZ206 e Abundance we Biomass 150 50 Caranx caninus 40 2 100 5 gt p a 2 20 z 50 a m g 10 0 NUN t 0 sr st Y sb A LN QAO OQ OQ OO O O c OO OO HW CO OO OO OO OO Oc c 73 EL E Q gt c tH o E S ad Y a Es c o Hn fo oa Y oa Q o 5 lt lt lt amp e Abundance Biomass 20 Haemulon fluviguttatum gt 15 E 5 5 S 2 10 a s 2 2 e gt 2 e C 0 st sto sb NN QOO OO ON ON c c OO OO O OO OV OO OO OO OO O OOOO gt gt C x ore UD tj UV a Ss Ot V x c ot uv os 5 o 325929582 CTFSZSZSOALKTSZZS6OAHLZFSZZ2684 Fig 6 Variation of the CPUE abundance biomass for the most important species when a considerable increase in its abundance with respect to the other months took place while 1t practically disappeared during the sum mer months C caninus was the
12. 80 a 1994 95 S t F 60 uut 1998 o e o o e s S 40 a S an 1999 5 8 5 20 2000 0 ji 1 1 10 100 1000 Species rank Biomass 100 BE 1994 95 E e zt 45 60 e 1998 o g on gt gfe 2 40 A a t f n 1999 5 h as o 20 g 2000 0 1 10 100 1000 Species rank Fig 2 Total and yearly k dominance abundance and biomass curves for the catch of the gillnet fishery from Jalisco Mexico 138 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 TABLE 2 Values of the Relative Importance Index for the most important species of each year Abundance Relative Bins lt Relative Relative Relative importance importance importance importance PERIOD 1994 95 org kg months Index Microlepidotus brevipinnis 1195 28 51 338 61 19 51 12 100 00 148 02 Caranx caballus 336 8 02 178 20 10 27 12 100 00 118 28 Haemulon flaviguttatum 401 9 57 122 45 7 05 11 91 67 108 29 Anisotremus interruptus 94 2 24 53 89 3 10 12 100 00 105 35 Caranx sexfasciatus 72 1 72 42 72 2 46 12 100 00 104 18 Pomadasys branickii 96 2 29 28 55 1 64 12 100 00 103 94 Lutjanus guttatus 475 11 33 154 21 8 88 10 83 33 103 55 Scomberomorus sierra 138 3 29 118 46 6 82 11 91 67 101 78 Lutjanus inermis 27 0 64 5 06 0 29 12 100 00 100 94 Lutjanus argentiventris 149 3 56 68 53 3 95 11 91 67 99 17 65 species 1208 28 82 625
13. 88 9 mm net that caught 8 808 organisms 3496 with 33 org fish ing day on average the 101 6 mm net caught 3 458 organisms 13 and 20 fishes fishing day and finally the 114 3 mm gillnet that caught 2 464 organisms 996 and 11 org fishing day In relation to the biomass the 88 9 mm gillnet caught 3 706 kg 32 with 17 kg fishing day followed by the 76 2 mm net that caught 3 614 kg 31 16 kg fishing the 101 6 mm gillnet caught 2 067 kg 18 and finally the 114 3 mm caught 2 294 kg 20 with 10 kg fishing day on average The variation of the CPUE in number showed significant difference between the 76 2 mm gillnet mesh size and the other nets however such difference was smaller in terms of biomass Fig 4 There were significant statistic variations within the annual catch from each gillnet The main differences were observed for the catch of the 88 9 mm mesh size from 1994 95 respect to 1998 and 1999 and between the catch of the 114 3 mm mesh size from 1998 respect 1999 Table 3 CPUE of the most important species six species were selected to analyze their CPUE variations finding a great similarity in their abundance and biomass pattern for all the species selected However each species showed some seasonal pattern in the different years and some of them like Caranx caninus 140 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 207 species
14. Ni o Limnol Oceanogr 44 466 469 De la Cruz Ag ero G 1994 ANACOM Sistema para el an lisis de Comunidades Manual del usuario La Paz B C S Mexico De la Cruz Ag ero J F Galv n Maga a L A Abitia C rdenas J Rodr guez Romero amp FJ Guti rrez 1994 Lista sistem tica de los peces marinos de Bah a Magdalena B C S Mexico Cienc Mar 20 17 31 Francis R C amp S R Hare 1994 Decadal scale regime shifts in the large marine ecosystems of the Northeast Pacific a case for historical science Fish Oceanogr 3 279 291 Gaston K J 2000 Global patterns in biodiversity Nature 405 220 227 Gobert B 2000 Comparative assessment of multispecies reef fish resources in the Lesser Antilles Fish Res 44 247 260 God nez Dom nguez E J A Rojo V zquez V H Galv n Pi a amp B Aguilar Palomino 2000 Changes in the structure of a coastal fish assemblage exploited by a small scale gillnet fishery during an El Ni o La Ni a event Estuar Coast Shelf Sci 51 773 787 Gonz lez J A J I Santana V Rico V M Tuset amp M M Garc a D az 1995 Descripci n de la pesquer a de enmalle en el sector Norte Noreste de Gran Canaria Inf Tec Inst Cienc Mar No 1 Telde Gran Canaria Spain Harris A N amp LR Poiner 1991 Changes in species com position of demersal fish fauna of Southeast Gulf of Carpentaria after 20 years of fishing Mar Biol 111 503 519 150 Rev Biol Tr
15. The fish species composition and variation of catch from the small scale gillnet fishery before during and after the 1997 1998 ENSO event central Mexican Pacific J A Rojo V zquez C Qui onez Vel zquez3 H A Echavarria Heras Lucano Ramirez 1 E Godinez Dominguez S Ruiz Ram rez V H Galv n Pi a amp O Sosa Nishizaki 1 Departamento de Estudios el Desarrollo Sustentable de Zonas Costeras Universidad de Guadalajara G mez Farias 82 San Patricio Melaque Jalisco M xico jrojo costera melaque udg mx Phone 315 355 6330 Fax 315 355 6331 2 CICESE Departamento de Ecolog a Km 107 Carr Tijuana Ensenada Ensenada B C M xico hechavar cicese mx 3 CICIMAR Departamento de Pesquer as Av Instituto Polit cnico Nacional s n Col Playa Palo de Santa Rita La Paz B C S M xico cquinone ipn mx Received 06 VII 2006 Corrected 15 II 2007 Accepted 22 VIII 2007 Abstract In the tropical and subtropical coastal zone were highly diverse fish communities occur it is important to study the small scale fisheries exploiting these communities For this study 219 fishing days were carried out in Bahia de Navidad Jalisco Mexico Four gillnets with different mesh sizes 76 2 88 9 101 6 and 114 3 mm were used for the fishing operations from April 1994 to March 1995 and from January 1998 to December 2000 A total of 26126 organisms weighting 11680 kg were caught One hundred and eighty three s
16. a naturaleza Secci n de Obras de Ciencia y Tecnolog a Fondo de Cultura Econ mica Mexico Mexico Auster P J 1988 A review of present state of understand ing of marine fish communities J Northwest Atl Fish Sci 8 67 75 Brander K 1988 Multispecies fisheries of the Irish Sea p 303 328 In J Gulland Ed Fish Populations Dynamics 2 Ed Wiley New York New York USA Brodeur R D amp D M Ware 1995 Interdecadal variability in distribution and catch rates of epipelagic nekton in the Northeast Pacific Ocean p 329 356 In R J Beamish Ed Climate change and northern fish populations Can Spec Publ Fish Aquat Sci 121 Changnon S A 2000 What made El Ni o 1997 1998 famous p 3 27 In S A Changnon Ed El Ni o 1997 1998 The climate event of the century Oxford University Oxford England Ch vez F P P G Strutton G E Friederich R A Feely G C Feldman D G Foley amp M J McPhaden 1999 Biological and chemical responses of the Equatorial Pacific Ocean to the 1997 98 El Ni o Science 286 2126 2131 Clarke K R amp R M Warwick 1994 Change in Marine Communities An approach to Statistical Analysis and Interpretation Plymouth Marine Laboratory Plymouth England Connell J H 1978 Diversity in tropical rainforests and coral reefs Science 199 1302 1310 Connolly S R amp J Roughgarden 1999 Increased recruit ment of northeast Pacific barnacles during the 1997 El
17. aphic changes have happened in the Pacific Ocean which have affected the marine ecosystem Brodeur and Ware 1995 Francis and Hare 1994 Hollowed and Wooster 1995 As a result one of the most important changes observed in the system is in the catch composition from several fisheries The environment from the tropical Eastern Pacific shows seasonal and interannual changes and at higher scales decadal and climatic change The interannual variability of the oceanographic conditions is relatively strong in the Equatorial Eastern Pacific due to the natural cycle of the ocean atmosphere system called El Ni o Southern Oscillation ENSO which occurs at irregular time intervals 2 to 7 years and lasting 12 18 months The ENSO is an irregular fluctuation that involves all the Tropical Pacific Ocean and the global atmo sphere Philander 1999 During the last 50 years there have been 12 El Ni o events being the most intense events during 1982 83 and 1997 98 Trenberth 1997 the latest called the climatic event of the cen tury McPhaden 1999 because it was consid ered the largest and hottest from the latest 100 years Changnon 2000 In contrast during the period 1980 1998 there were only three La Ni a episodes during 1988 89 1995 96 and 1998 99 Maga a and Morales 1999 A gen eralization about the ENSO effects on higher organisms was made by Sharp 1992 examin ing the facts closely it has been shown that the effects
18. at of the most conspicuous characteristics of the fish commu nities from coastal areas that is the abundance of juvenile fishes and for this reason these areas have been considered as nursery areas Lindeman and Snyder 1999 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 The effect of impoverishment of the habitat during El Ni o event is well known Chavez et al 1999 and many changes in the recruitment of some populations have been attributed to this event Arntz 1984 Lee et al 1995 Tsai et al 1996 1997 Connolly and Roughgarden 1999 By this reason the unusual abundances in K pelamis and O libertate during El Ni o both pelagic species and predator prey it could represent the best example in the displacement toward coastal waters during the warm period to pursuit food sources Godinez Dominguez et al 2000 Finally all these environmental changes caused by the ENSO event had effects that could be considered from moderate to severe both ecological and economically From the ecological point of view the changes in the composition can have effect in the food chains mainly due to the intrusion of a bigger number of species and in the case of the coastal fish the considerable increase in the abundance of some species of the family Carangidae which has been identified as extremely voracious and whose feeding is based on juvenile and adults of many fish species From the econ
19. d by different organisms like pelagic fishes and organisms associated to the bottom or shelters like demersal fishes Allen and Robertson 1994 involving complex and unstable interrelations between fish fauna of the environment Auster 1988 It is important to study the small scale fisheries exploiting these communities in the central Mexican Pacific these fisheries are characterized by the use of several fishing gears and the exploitation of several species Gillnets are the most commonly used fishing gears in these fisheries The nets are frequently used on soft bottom and the fishing effort is focused on demersal and benthic fishes The Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 133 gillnets are constructed with meshes of a wide range of sizes giving rise to catches of high species richness and causing a complex pattern of differential fishing mortality in exploited stocks Rojo Vazquez et al 1999 2001 The reliable management of the multispe cies fisheries requires understanding the struc ture and dynamics of the fish community from which 1 ecological and fishery implications of the exploitation strategies could be foreseen Brander 1988 Sainsbury 1982 and 2 the undesirable changes in the specific composi tion could be prevented while the desirable ones are shown Pauly and Murphy 1982 Sherman and Alexander 1986 Since the end of the 70 s great climatic and oceanogr
20. ent they became important due to its higher abundance and biomass in the area appearing practically during the whole period Lehodey et al 1997 reported that K pelamis is characterized to inhabit areas of low rate primary production as found in the warm est Western Pacific observing that during the formation of the hot reservoir characteristic of the ENSO event this provides a habitat that can sustain the population of this species resulting in an apparent spatial change in the population of K pelamis that is bound to the great displacement of the warm water that hap pens during the ENSO events Also Seckel and Waldron 1960 report ed that K pelamis from Hawaiian waters had bigger captures when influence of waters associated to the current of California existed characterized by low salinities 34 7960 while when there is influence of waters from Northwestern Pacific with more salinity 35 0960 the captures fell notably Variation of the abundance variations in the abundance and biomass of coastal fishes show significant differences among the dif ferent years as well as specifically among the months of 1998 Fig 6 Table 3 Finding that very few species had influence on this variation of the total catch Great deviations are observed in the catch being the main ones those observed during the first and latest months of 1998 due to the presence of some species that were favored with the climatic changes obs
21. erved in the area The El Ni o period January to May of 1998 produced a heating in the normal cold season while the period La Ni a June to December of 1998 caused the intrusion of cold water during the normal warm season which allowed the occurrence of the species before mentioned in a non normal season Godinez Dominguez et al 2000 That is why the habitat variability has been considered as one of the factors that most severely affect the species composition of the capture Connell 1978 Seasonal changes in the catch can be more related with the California Current Madrid Vera and S nchez 1997 besides the event ENSO that was presented in the area during 1997 98 Specifically for some of the most important species the catch per unit effort data showed that the fluctuations in abundance can be related to the climatic periods and the characteristics of the life cycle of each species For example M brevipinnis was the most important spe cies in the fishery being present in 10096 of the samples this species shows two peaks of abundance one during the summer months and another during the winter months In summer according to size most are Juvenile fishes while during winter they are mostly mature individuals that come to the coast to spawn The only anomaly in the capture of this species was during the first months of 1998 146 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 200
22. esent and that a great number of species up to 75 could be con sidered as rare or occasional because of the low numbers caught less then 30 organisms Fig 2 Period 1994 1995 during this year 4 191 organisms weighting 1 735 kg were caught belonging to 75 fish species According to RII values the most important species were M brevipinnis 148 C caballus 118 H fla viguttatum 108 A interruptus 105 C sexfasciatus 104 Pomadasys branickii and Lutjanus guttatus 103 and Scomberomorus sierra 101 Table 2 The ten most impor tant species accumulated 75 of the total abun dance and 70 of the total biomass Only six species 8 were caught during 12 months and 40 species 53 were caught during three months or less Fig 2 Period 1998 during this period 6 844 organisms weighting 3 231 kg and belong ing to 130 fish species were caught Only ten species 7 5 accumulated almost 75 of the total abundance and biomass Fig 2 In this case two species show a high dominance M brevipinnis and C caninus only 1096 of the species 14 were caught during 10 to 12 months while 57 74 species were caught Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 135 Bah a Tenacatita Bah a Manzanilla Punta Las Iguanas Chubasco Carrizalillo Punta Cuastecomatito aleta Isla El Estrecho y almi Punta Punta Isla Iglesias f El Estrecho El Cenicero Cal
23. eta Cuastecomate Bah a de Navidad Punta El Viejo Oc ano Pac fico 1 L San Patricio Punta Melaque Melaque Fig 1 Study area Bah a de Navidad Jalisco M xico during three or less months The most impor tant species according to the RII values were M brevipinnis 147 C caninus 135 C caballus 113 Kyphosus analogus y S sierra 108 C sexfasciatus 107 and K elegans 105 Table 2 Period 1999 during this year 8 869 organ isms and 3 814 8 kg were caught belonging to 141 fish species Ten species accumulated almost 55 of the total abundance and 50 of biomass Fig 2 Only 20 species 14 were caught during 10 to 12 months and 5196 72 species were caught during three months or less The most important species were M brevipinnis 131 C caballus 112 S sierra 105 C sexfasciatus 103 H flav iguttatum y H scudderi 101 and L guttatus 100 Table 2 Barra de Navidad Punta Graham Punta El Coco o Period 2000 in this year 6 120 organisms weighting 2 895 5 kg and belonging to 128 fish species were caught The ten most important species accumulated 65 of the total abundance and 60 of the biomass Fig 2 Only 19 spe cies 14 were caught during 10 or 11 months while 69 species 53 were caught during three months or less The most important spe cies were M brevipinnis 131 C caballus 116 H flaviguttatum y L guttatus 114 U
24. from individual El Ni o events can be devastating but in a short time period most of the effects disappear This paper analyses the changes in the fish species composition and the changes in the catch per unit of effort from the artisanal gillnet fishery in the Mexican central Pacific compar ing results before during and after the 1997 98 ENSO event in order to test the hypothesis that these anomalous events promote changes in the fish species composition of the catches in tropi cal fish communities MATERIALS AND METHODS Study site the study area is located in Bahia de Navidad Jalisco Mexico in the coastal zone of the Mexican central Pacific 19 10 30 and 19 12 50 N and 104 42 45 and 104 41 30 W The coastline of the bay is characterized by sandy beaches alternat ing with rocky shores and cliffs with different kinds of substratum like e g rocky bottom Caleta Cuastecomatito and Punta Corrales soft bottom Bahia de Cuastecomates and Bahia de Melaque and soft bottom with small rocks The last is the most frequently used by fishermen in gillnet fishing operations Fishing operations during 47 months five consecutive days each month in average experimental fishing operations were made from April 1994 through March 1995 and from January 1998 through December 2000 Four gillnets with different mesh size 76 2 88 9 101 6 and 114 3 mm were used except during 1994 95 when the 101 6 mm
25. g days Differences in CPUE among years for the total catch in num ber and kilograms the catch of each kind of gillnet and the catch for the five most important species were tested using a one way ANOVA Abundance and biomass data were transformed to log x 1 When significant differences were found Tukey s test Zar 1999 was used to conduct multiples comparisons Prior to each analysis data were checked for homogeneity of variances using Cochran s test Zar 1999 RESULTS Fish species composition during this study 219 fishing days were carried out A total of 26 126 organisms and 11 680 kg were caught One hundred and eighty three species belonging to 57 families and 19 orders were identified The families with the largest number of species were Carangidae 25 Haemulidae 17 Sciaenidae 16 and Serranidae 10 From the 183 species caught ten spe cies accumulated more than 60 of the total abundance and biomass the remaining spe cies 173 individually contributed with less than 296 of the total abundance and biomass Fig 1 The most important species in the catch according to the RII were Microlepidotus brevipinnis 138 Caranx caballus 114 Haemulon flaviguttatum and Scomberomorus sierra 105 C caninus 104 C sexfas ciatus 104 Lutjanus guttatus 102 and L argentiventris 101 Table 1 The geometric classes curves show that both totally and within years a marked domi nance pattern was pr
26. mbrina xanti 111 S sierra 108 and L argentiventris 105 Table 2 Abundance and Biomass variation the Catch Per Unit of Effort CPUE organisms and kg per fishing day showed great variation during the study both in number and in bio mass although both patterns were very simi lar On average 110 organisms and 48 5 kg 136 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 TABLE 1 Values of the Relative Importance Index for the 30 most important species of fishes during all the period of study 183 species Microlepidotus brevipinnis Caranx caballus Haemulon flaviguttatum Scomberomorus sierra Caranx caninus Caranx sexfasciatus Lutjanus guttatus Lutjanus argentiventris Anisotremus interruptus Elops affinis Trachinothus rhodopus Mulloidichthys dentatus Epinephelus labriformes Haemulon sexphasciatus Kyphosus analogus Lutjanus inermis Sectator ocyurus Katsuwomus pelamis Kyphosus elegans Tylosurus acus pacificus Haemulon maculicauda Gerres cinereus Haemulopsis elongatus Haemulon scudderi Nematistius pectoralis Umbrina xanti Selene peruviana Lutjanus novenfasciatus Myripristris leiognathus Caranx vinctus 153 species Abundance org 5926 1830 1483 718 2112 507 1398 660 423 350 1165 374 218 224 669 143 234 262 308 50 132 110 263 153 208 731 394 61 71 226 4723 Relative importance 22 68 7 00 5 68 2 15 8 08 1 94 5 35
27. mp LC Potter 1999 Factors influencing community structure and distribution of different life cycle categories of fishes in shallow waters of a large Australian estuary Mar Biol 106 25 37 Longhurst A R amp D Pauly 1987 Ecology of tropical oceans Academic London England Madrid Vera J amp P Sanchez 1997 Patterns in marine fish communities as shown by artisanal fisheries data on the shelf off Nexpa River Michoacan Mexico Fish Res 33 149 158 Maga a V amp C Morales 1999 El clima y la sociedad p 1 21 In V O Maga a ed Los impactos de El Ni o en M xico Sep Conacyt IAI Mexico Mexico McPhaden M J 1999 The child prodigy of 1997 98 Nature 398 559 562 Parrish J D 1989 Fish communities of interacting shal low water habitats in tropical oceanic regions Mar Ecol Prog Ser 58 143 160 Pauly D amp G Murphy 1982 Theory and management of tropical Fisheries Manila ICLARM Conference Proceedings 9 Philander S G H 1999 A review of tropical ocean atmo sphere interactions Tellus 51 71 90 Rojo Vazquez J A amp M E Ramirez Rodriguez 1997 Composici n espec fica de la captura de redes de enmalle en Bah a de Navidad Jalisco M xico Oce nides 12 121 126 Rojo V zquez JA F Arreguin Sanchez E God nez Dom nguez amp M E Ram rez Rodr guez 1999 Selectividad de redes de enmalle para el pargo Lunarejo Lutjanus guttatus y el pargo amaril lo Lu
28. omic point of view fishing is one of the economic activities most severely affected by the El Ni o event The prelimi nary estimates of the Food and Agriculture Organizations of the United Nations FAO show that the world production of food reg istered a decrease from 2 to 4 during 1997 being expected an increase for 1998 Lluch Cota et al 1999 The East Pacific fisheries including Mexican fisheries are significantly impacted during El Ni o event because they are in the area of direct influence So Peru suffered a decrease during 1997 that almost reached 60 with similar values during 1998 Duffy and Bryant 1998 For the case of Mexico official reports still do not exist although it is known that the impacts were severe mainly in the Pacific The changes in the Pacific mean serious losses for our country since these coasts are the biggest contribution to the national production in terms of volume and production value About the species that showed some increase during the ENSO event as C caninus C sexfasciatus K pelamis E affinis all these are species that has little economic value in the area that do not reach higher prices than 1 00 US kg They are considered as third quality and generally used as bait on the other hand the species that could be in turn worst affected as H flaviguttatum L guttatus L argentiven tris are considered as species of second and first quality and they can reach prices of
29. op Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 Hollowed A B amp W S Wooster 1995 Decadal scale vari ations in the eastern Subarctic Pacific II Response of Northeasr Pacific fish stocks p 373 385 In R J Beamish Ed Climate change and northern fish pop ulations Can Spec Publ Fish Aquat Sci No 121 Hyndes G A M E Platell 1 C Potter amp R C I Lenanton 1999 Does the composition of the demersal fish assemblages in temperate coastal waters change with depth and undergo consistent seasonal changes Mar Biol 134 335 352 Lee M A K T Lee amp G Y Shiah 1995 Environmental factors associated with the formation of larval ancho vy fishing ground in coastal waters of southwestern Taiwan Mar Biol 121 621 625 Lehodey P M Bertignac J Hampton A Lewis amp J Picaut 1997 El Nifio Southern Oscillation and tuna in the western Pacific Nature 389 715 718 Lindeman K C amp D B Snyder 1999 Nearshore hardbot tom fishes of southeast Florida and effects of habitat burial caused by dredging Fish Bull 97 508 525 Lluch Cota D D Lluch Belda S Lluch Cota J L pez Mart nez M Nev rez Mart nez G Ponce D az G Salinas Zavala A Vega Vel zquez J R Lara Lara G Hammann amp J Morales 1999 Las pesquer as y El Ni o p 137 178 In V O Maga a ed Los impactos de El Ni o en M xico Sep Conacyt IAI M xico D F Mexico Loneragan N R a
30. ough the ENSO event had a certain effect on the community of fish exploited by the artisanal or small scale fishery causing the migration of some important species for the fishery this effect was compensated in turn by the occurrence of other species which may be of less commercial interest A similar effect 1s reported for the same period for some fisher les in the north of the country where some species show considerable increases in their catches while others diminish its abundance being substituted by new species that enlarged their distribution Lluch Cota et al 1999 On the other hand it has been observed that the changes in the patterns of presence absence abundance distribution composition and repro duction in the populations of fish due to the El Ni o event are remarkable causing consider able displacements in these populations as well as an alterations in the communities Arntz and Fahrbach 1996 These authors mention this effect for the Peruvian central coast Chile and the Gal pagos pointing out that most of the autochthonous species disappeared of the shallow area up to 30 m of depth which is exploited by the artisanal fishery Madrid Vera and Sanchez 1997 report a similar behavior in the fish communities exploited by the artisanal fishery from Michoacan Mexico This seasonal change in the fish species composition of the capture from multispecies fisheries has been observed both in tropical and tempe
31. pecies belonging to 57 families and 19 orders were identified Ten species accumulated more than 60 of the total abundance and biomass the remaining species 173 individually contributed with less than 296 of the total abundance and biomass The most important species in the catch were Microlepidotus brevipinnis Caranx caballus Haemulon flaviguttatum Scomberomorus sierra C caninus C sexfasciatus Lutjanus guttatus and L argentiventris The catch per unit of effort showed a large variation during the study both in number and biomass On aver age 110 fishes and 48 5 kg fishing day were caught The maximum values were recorded during January and October 1998 250 fishes and 100 kg fishing day and the minimum values were recorded during September and November 1994 25 org and 10 kg fishing day The total abundance and biomass was lower during the 1994 95 period F 6 16 8 32 P lt 0 05 There were statistically significant differences among the annual catch from each gillnet All the environmental changes caused by the ENSO event had ecological and economic effects that can be rated from moderate to severe Rev Biol Trop 56 1 133 152 Epub 2008 March 31 Key words Mexico Jalisco fish species composition small scale fisheries El Ni o southern oscillation catch per unit of effort In the tropical and subtropical coastal zone highly diverse fish communities occur Longhurst and Pauly 1987 Such communi ties are integrate
32. rate areas Harris and Poiner 1991 Fishing effort Harris and Poiner 1991 habitat stability Vanderklift and Jacoby 2003 chang es in the recruitment Gobert 2000 and some interannual global processes Madrid Vera and Sanchez 1997 have been mentioned as some of the main causes of the alteration of the fish community Differences in the fish assemblage among sites that are separated by short dis tances also have been reported even though the differences can vary from year to year Parrish 1989 Loneragan and Potter 1999 Although the number and the type of species were different during the four years analyzed there is a coincidence when finding a very similar pattern in their composition where some species appear throughout the year 20 species and they could be considered as resi dents in the area other species appear in a sea sonal way and are captured during five to eight months around 30 species and many species that can be considered as rare or eventual up to 80 species which appear in the catch during three months or less However it is important to remark that from the 20 most important species of each year considered as residents around 60 coincide in every year Considering that any extreme perturbation present in the system would affect in principle the resident species some changes are observed in this group of species Table 2 finding that some species like C caninus C sexfasciatus Rev Biol T
33. rop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 145 K pelamis E affinis even M brevipinnis seemed positively affected for the conditions that prevailed during the period 1998 during which the biggest anomalies caused by the El Ni o La Ni a event occurred when these species increased its presence considerably in the catch during that period compared the previous normal period 1994 95 On the other hand in some species a reverse effect was observed as H flaviguttatum L guttatus L argentiventris T rhodopus which diminished in the captures specifically during 1998 and were more abundant in the catch before and after this year finally there were some species that didn t show considerable changes during the ENSO event as C caballus S mountain A interruptus H sexfasciatus Some species of the family Carangidae and Scombridae like K pelamis have been known that live far from the coast under nor mal conditions but during the El Ni o condi tions they migrate with the masses of water towards the coast becoming more vulnerable to the fishery Arntz and Fahrbach 1996 In the present study it was found that some spe cies of the family Carangidae as well as K pelamis presented a similar behavior since during a normal period prior to the event Rojo Vazquez 1997 and Aguilar Palomino et al 2001 registered a low relative importance and low frequency however during the ENSO ev
34. s less than 10 of the total caught contribute with more than 50 to the total catch being this characteristic pattern of the tropical and subtropical systems Gaston 2000 Also the composition of the fish fauna in the coastal areas typically suffers marked seasonal changes which are attributed to the sequential patterns of immigration and emigra tion of the same species Hyndes et al 1999 The analysis of the relative importance of the fish catch obtained with gillnets from Bahia de Navidad Jalisco Mexico allow us to deter mine that a reduced number of species contrib utes in an important way to the capture The most important species for their contribution in abundance and biomass were M brevipinnis C caninus and C caballus whose contribution rises to more than 50 of the total abundance and of 42 in biomass In general the exis tence of a great number of species with low biomasses per species is characteristic of the fishing resources in the tropical and subtropi cal areas Gonz lez et al 1995 This pattern 1s maintained along the study a high number of species were caught but only a few dominate in the community due to their abundance bio mass and frequency in the catches these few species sustain the effort of the fishery appear ing a great quantity of species with very low abundances and with little frequency and could be considered as rare or eventual According to our results we could verify that alth
35. second more abundant species in the capture present in 42 of 47 months this species was characterized by some abundance peaks during September and October benefitting in a notorious way during those same months of 1998 This behavior for C caninus had already been observed by Madrid Vera and Sanchez Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 Continue on next page 1997 in whose study this species was the sixth most important and 1t was related to the influence of the Current of California L gut tatus occupies the fifth place in abundance and it appeared in 43 of 47 months it was the most important species in the artisanal fishery from the Coast of Michoacan Madrid Vera and Sanchez 1997 and practically it disap peared during the period 1998 For the species H flaviguttatum the most notorious change was present in its abundance disappearing 147 Abundance Biomass 80 25 Lutjanus guttatus S 5 2 E E E 65 a 3 a m 5 ES o v st sb Y Y CO QOO O OO cc o o 0 DO Md HD HW OQ OO OY OO OO OO CTD Oo o 2 7a gt c E a oe coy Yo nd o 3 a Y o 0 2 42 sS Les 2S 2 OD xxu 200 gt amp 150 o 5 5 gt o 4 100 3 un 8 S amp ea 50 o E 0 gt sr st Y SY A D COO QOO
36. ted to the 1997 98 ENSO events that was particularly intense In some cases the relation between the El Ni o and some of these natural disasters is nonexistent or at least debat able However it is clear that this event pointed out the vulnerability of some sectors and activi ties focused on climatic variability The variation in catch composition of gillnet depends among other factors on the availability accessibility and vulnerability of the organisms in relation to the fishing gears Gonz lez et al 1995 However it has been proven that these fishing gears are very effi cient in showing the changes in the catch composition De la Cruz Aguero et al 1994 Abitia C rdenas ef al 1994 Gonz lez et al 1995 Madrid Vera and S nchez 1997 The results reported by Madrid Vera and S nchez 1997 show a great similarity with the present study as for the compositional pattern That is because from their 26 most important species around 90 appear within the first 50 species of the present work Also with that same work there are some differ ences in the catch seasonality between Bahia de Navidad Jalisco and Michoacan Madrid Vera and S nchez 1997 due partly to the use of a greater diversity of fishing gears However in general terms both fisheries present a very sim ilar pattern in the catch finding that a reduced 144 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 number of specie
37. tjanus argentiventris en Bahia de Navidad Jalisco M xico Cienc Mar 25 145 152 Rojo Vazquez JA F Arreguin Sanchez amp E God nez Dom nguez 2001 Fishing power efficien cy and selection of gillnets for the shrtfin grunt Microlepidotus brevipinnis Steindachner 1869 in the southern coast of Jalisco Mexico Rev Biol Mar Oceanog 36 9 14 Sainsbury K 1982 The ecological basis of tropical fisheries management p 167 188 Jn Pauly D amp G Murphy Eds Theory and management of tropical Fisheries Manila ICLARM Conference Proceedings 9 Manila Phillipines Seckel G amp K D Waldron 1960 Oceanography and the hawaian skipjack fishery Pacific Fisherman 2 1 18 Sharp G D 1992 Fishery catch records ENSO and Longer Term Climate Change as Inferred from Fish Remains From Marine Sediments p 379 417 In H Diaz amp V Markgraf eds Paleoclimatology of El Nifio Southern Oscillation Cambridge University Cambridge England Sherman K amp L Alexander 1986 Variability and Management of Large Marine Ecosystems American Society for the Advancement of Science selected Symposium Series No 99 Blackwell Publishing Boston Massachusetts USA Trenberth K E 1997 The definition of El Ni o Bull Am Meteorol Soc 78 2 771 2 777 Tsai C F Chen P Y Lee M A Shiah G Y amp K T Lee 1996 Effects of fishing effort on stock size and catch of larval anchovy in coastal waters
38. vipinnis 2 32 0 297 0 74 Scomberomorus sierra 2 32 0 206 0 81 shows statistic significance differences Abundance 4 Biomass 300 120 250 100 200 80 150 60 100 40 50 20 0 0 Y AY OO OOo 0O0000000000000570005075 gt Opntcto0pco9ostsoeouy ponmsaseovldg 325828582 za320 8 Z23208 453Z2048 Fig 4 Variation of the catch per unit effort of the abundance number of organisms fishing day and biomass kg fishing day from the gillnet fishery from Jalisco Mexico Solid lines is the CPUE using three gillnets 3 0 3 5 and 4 5 mesh size Dashed lines is the CPUE using the 4 0 gillnet 1998 2000 Rev Biol Trop Int J Trop Biol ISSN 0034 7744 Vol 56 1 133 152 March 2008 143 ttt tN So gt gt Dm 235 gt gt XI3 lt Oct 98 o O00 0 uU 029055797097925229059 Qiu 5 gxo0niuiu 4gxooo Fig 5 Variation of the CPUE by kind of gillnet for abundance number of organisms fishing and biomass kg fishing day from the catch of the gillnet fishery from Jalisco Mexico precipitations the presence of hurricanes or storms were repeatedly signaled as catastro phes associa
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