ISSN: 0363-2415 (Print) 1548-8446 (Online) Journal homepage: http://www.tandfonline.com/loi/ufsh20

Fishing Down Coastal Food Webs in the Gulf of

Enric Sala , Octavio Aburto-Oropeza , Miriam Reza , Gustavo Paredes & Luis G. López-Lemus

To cite this article: Enric Sala , Octavio Aburto-Oropeza , Miriam Reza , Gustavo Paredes & Luis G. López-Lemus (2004) Fishing Down Coastal Food Webs in the , Fisheries, 29:3, 19-25, DOI: 10.1577/1548-8446(2004)29[19:FDCFWI]2.0.CO;2

To link to this article: http://dx.doi.org/10.1577/1548-8446(2004)29[19:FDCFWI]2.0.CO;2

Published online: 09 Jan 2011.

Submit your article to this journal

Article views: 361

View related articles

Citing articles: 53 View citing articles

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ufsh20

Download by: [The University of British Columbia] Date: 09 May 2016, At: 08:31 Fishing down coastal food webs in the Gulf of California

We usedinformation from interviewswith fishers,fisheries statistics, and field surveysto doc- ument changesin fisheriesand assemblagesin shallowcoastal habitats in the Gulf of California, . Coastal food webs in the Gulf of California have been "fished down" dur- ing the last 30 years--fisheriesshifted from large, long-livedspecies belonging to high trophic levelsto smallshort-lived from lower trophic levels.In addition,the maximum individuallength of the landingshas decreased about 45 cm in only 20 years.Although some catchesare stagnantor stillincreasing for somespecies groups, catch-per-unit-effort declined for mostspecies groups after 1980.These declines were associatedto a dramatic increasein fishingeffort in the region in the late 1970s-early1980s, mostly in the numberof gillnets. Fishingnot only impactedtarget species,but alsocaused community-wide changes. These resultssuggest that coastalfisheries in the Gulf of Californiaare unsustainableand their managementneeds to be reevaluatedwith soundregulatory measures to preventfurther degradationof coastalfood webs,and the concurrentinefficiency of artisanalfishing.

Introduction 2002). The totalnumber of localcommercial fishers in the studyregion is 10,600(SEMARNAP, 1990-2000), Fisheriescatches worldwide have gradually shifted althoughthese shores are also used by hundreds of fish- ftom long-lived,high-trophic level species to short- ersbased on mainlandMexico, fromSonora to asfar lived, low-trophiclevel speciesin what has been southas Chiapas.The fisherytargets coastal called"fishing down marine food webs" (Pauly et al. belongingto 25 families 1998a;Baum et al. 2003; Myers and Worm 2003; (Table 1). The most Wormet al. 2003).This patternis consistentamong commonlyused fishing Enric Sala marineand fteshwaterecosystems at both regional gearis a motoredfiber- andlocal scales (Pauly et al. 1998a,1998b, 2001). The glassskiff with hand Octavio Aburto-Oropeza consequencesof fishingdown food websextend linesand gillnets. Miriam Reza beyondthe directeffects on the targetspecies became Fisheries in Baja Gustavo Paredes the removalof large predatorscan came changes California Sur showed affectingentire ecosystems (Estes et al. 1998;Jackson a general pattern of LuisG. Lbpez-Lemus et al. 2001). In Mexico,82% of the fisheriesfully increasingcatch since exploitor over-exploittheir target species (Hernandez 1950 but decreasing Sala is associatedirector, Center for Marine andKempton 2003), but thereare no publishedanal- catch-per-unit-effort Biodiversityand Conservation,and assistant ysesof fisheriesshifts and their ecosystem effects. Here (CPUE) after 1980 professor,Scripps Institution of Oceanography,La Jolla, CA. He can be reached at [email protected]. wepresent evidence of fishing down marine food webs (Figure1, Secretariade Aburto-Oropezais a researcher,Universidad in the Gulf of California,a tropicalmarine biodiver- Marina 1950-1960; sity hotspot(Roberts et al. 2002), and addressthe Secretaria de Pesca Autbnomade BajaCalifornia Sur (UABCS),La Paz, BajaCalifornia Sur, Mexico. Reza is conservation needfor rigorousfisheries management in the region. 1970-1980; Ramirez scientist,Gulf of CaliforniaProgram-World Wildlife In spiteof its low humanpopulation density, the 1988; SEMARNAP Gulf of Californiais subjectedto intensefishing. Fund, Hermosillo,Sonora, Mexico. Paredesis a 1990-2000). The only graduatestudent, Scripps Institution of

Downloaded by [The University of British Columbia] at 08:31 09 May 2016 Presently,six species of marinefishes ( and exception of CPUE Oceanography,La Jolla,California. Lbpez-Lemus is Sciaenidae)are threatened or at riskof extinctionin decrease after 1980 the Gulf of California(Musick et al. 2000). Sinceno adjunctprofessor at UABCS,La Paz,Baja California wasfor a multi-species Sur, Mexico. publishedanalyses of the ecosystemimpacts of coastal fishingin the Gulf of Californiaexist, we describe changesover time in fishcatches and mean trophic BONY FISHES SHARKS RAYS levelof the coastalfishery in the southernGulf of Table 1. Major fish California.In addition,we attempted to determinethe Serranidae Alopiidae Rhinobatidae familiestargeted by changesin the structureof coastalfish assemblages Lutjanidae Carcharhinidae Mobulidae the artisanalfishery Lamnidae in the southern Gulf associatedwith documentedfishing pressure, and Myliobatidae Haemulidae Echinorhinidae Dasyatididae of California. changesin thespatial distribution of theartisanal fleet. Balistidae Squalidae Baja California Sur Fisheries Scaridae Heterodontidae Labridae Ginglymostomatidae We studiedthe coastalartisanal in Baja Mullidae Odontaspidae CaliforniaSur. This fishery operates from a largetown Kyphosidae Scyliorhinidae (La Paz,154,314 inhabitants) and severalsmall fish- Malacanthidae Triakidae Sphyrnidae ing villagesranging from 13 to 177 people(INEGI

March 2004 I www.fisheries.org I Fisheries 19 Figure1. Annualfish catch (solid circles) and catch categoryof medium- and small-sizedgroupers (Figure h per uniteffort (CPUE; metric tons/boat) (open "other ").The catches of the goliath squares)in the southernGulf of California. (Epinephelusitajara) and snappers(except red snapper)also 5harksinclude: 37 speciesfrom 11 families(Table showed declines in catch after 1980. Because CPUE declined 1)caught in nearshoreand offshore fisheries. over time, the fluctuations and increase of catch in multi- Jacks:green jack ( caballus), speciesgroups may be due to the shift in targetspecies over Pacificcrevalle jack (C caninus), bigeye(•evalle jack (C sexfasciatus), time (see Results).These changeswere associatedwith a rainbowrunner (Elagatis bipinnula•a), strikingincrease in the numberof motoredfishing boats and Padticmoonfish (Selene peruviana), and gillnets in the region since 1980 (Figure 2) (Secretariade gafftopsailpompano (Trachinotus rhodopus) Redsnapper: Lutjanus . Marina 1950-1960; Secretaria de Pesca 1970-1980; Othersnappers include: SEMARNAP 1990-2000). This patternis similarto that of yellowsnapper (Lutjanus argentiven•), all Mexican fisheries•in the late 1970snational policies dogsnapper (L novemfasciatus), mulletsnapper (L aratus), induceda significantmigration of unemployedfield workers spottedsnapper (L. guttatus), towardscoastal states, then landingspeaked in 1981, and coloradosnapper (L. colorado), and catchesdeclined afterwards in spite of a huge increasein barredpargo (Hoplopagrus gunther/). fishingeffort (Hernandezand Kempton 2003). Goliathgrouper: itajara Othergroupers include: Methods leopardgrouper ( rosacea), spottedsandbass (Paralabrax maculatofasciatus), Becausethe catchis pooledinto coarsetaxonomic groups Panamagraysby (Epinephelus panamensis), flagcabrilla (E. labriformis), and in the Gulf of California, fisheriesstatistics do not allow cal- Pacificcreolefish ( colonus). culationof the meantrophic level (Paulyet al. 2000). Catch

5000 8 1000 - 1.5 Sharks Jacks 4000] 800 - 6 - 1.0 600

3000] 4

400 2000i - 0.5 2 200

10000 0 0.0

600 0.5300 [ 0.3 • 400 2001

Downloaded by [The University of British Columbia] at 08:31 09 May 2016 200 100 • 0 0.0 0+ 0.0• 1000 , - 1.5 6000I 2.0 ' Goliathgrouper 800 • 5ooo] groupers - 1.5 I 1.04000 1/ 3000,,2' 6001 /Other 7 1.0 400 ß

- 0.5 200 -0.5 800•/

0•-• 0.0 0 0.0 1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000 Year Year

20 Fisheries I www.fisheries.org I vol 29 no 3 Figure 2. Temporalchanges in the numberof fishers,fishing boats, and gillnetsin the length of each speciestimes its relativecontribu- southern Gulf of California. tion to the total catch. To assessthe temporalshifts in the spatialdis- tribution of the artisanal fleet we interviewed 4000; F 12000 fishersfrom the fishingcamp of E1 Parditoabout the locationof fishingsites and their useover time. 3000/ Fishers / / / F 10000 For everyfishing site used since 1970 we estimated a numberof fishingdays per year. We then entered 8000 the locationand use of everyfishing site for every time periodinto a geographicinformation system (ESRI Arc View 3.2a). Maps of fishingintensity wereobtained interpolating the dataon a matrixof 4000 72 points(on a 1:150,000scale map). 1000 The firsteffects of fishingare a reductionin the 2000 abundanceand averagesize of target species (Daytonet al. 2002). To determinethe impactsof O• the fisheryon the sizestructure of selectedtarget 1950 1960 1970 1980 1990 2000 specieswe used data obtained during visual censuses conductedfrom 1998 to 2001 in 21 rocky reefs data setsfor pelagicspecies such as dolphinfish (Coryphaena hip- betweenLa Pazand Loreto(Sala et al. 2002). Fish purus)and billfish (Istiophoridae),exclusively reserved for the censusesincluded 140 non-crypticspecies. These reefs could be sport fishery,are misreported(Ramirez 1988). Furthermore, rankedalong a gradientin fishingpressure. Fishing pressure was becausenot all fishersbelong to organizedfishing cooperatives, quantified as density of fishingboats (Haro et al. 2001;Sala et al. their catchis under reported. Here we turnedtraditional ecologi- 2002). Coastalfishing boats carry 3-4 fisherseach and carry out cal knowledgeobtained from interviewswith fishersinto dailyfishing trips, so we assumedthat effortper boat is constant. quantitativeinformation to assessfishing down and spatialeffort Fishingdown the foodweb haseffects on the entire coastal allocation. fishassemblage beyond the directeffect on the targetspecies. We To estimatethe relativecontribution of fish speciesto the investigatedthe changesin the structure(species composition and abundance)of the fishcommunity using a principalcompo- catchwe interviewed63 fishersbelonging to 4 fishingvillages nent analysis,which shows latitudinal differences in the structure locatedin the southernGulf, betweenCabo Pulmo and San Jose of the assemblages(Sala et al. 2002).To preventthese differences Island(El Pardito,El Sargento,La Ribera,Cabo Pulmo). All fish- from confoundingeffects we usedonly datafrom the 11 sitesin erson thesevillages were commercial fishers, and sold their catch the southernregion of study.The first principalcomponent in the town of La Paz.We selectedthe mostknowledgeable fish- (PC1, which accountsfor asmuch of the variabilityin the data erson the basisof previousinterviews. Fishers ranged from 25 to aspossible) explained 86% of the variance,therefore the scores 67 yearsold, and they provideddata only for the time periods of samplingsites on PC1 wereconsidered good proxies of the when they wereactive. Interviews with individualfishers were structureof fish assemblages.We then performeda nonlinear conductedover a periodof oneyear. Fishers were asked about the regressionbetween fishing pressure and the scoresof eachsam- relativeimportance of eachspecies in the catchin the 1970s, plingsite on PC1. 1980s,1990s, and 2000. We useda categoricalindex of fishing importancefrom 0 to 5, where0 meansthat the specieswas absent Results fromthe catch,and 5 that it wasthe mostimportant (by weight). There wasa markedshift in the compositionof the catchin We then estimatedthe changesover time in the meantrophic the coastalfishery in the southernGulf of California(Fig. 3; Chi- level of the catch (Paulyet al. 1998a). Mean trophiclevel in square= 95.65, df = 16, P < 0.001). Largepredatory fishes such Downloaded by [The University of British Columbia] at 08:31 09 May 2016 marineecosystems ranges from 1 (primaryproducers) to 5 (top as sharks,gulf grouper (Mycteropercajordani), gulf coney predators,e.g., killer whale, humans,Pauly et al. 2000). We (Epinephelusacanthistius), goliath grouper, and broomtail grouper obtainedthe maximumreported size and trophic level of the (M. xenarcha)were among the mostimportant fisheries in the speciesin this studyfrom Fishbase(Froese and Pauly2002). We 1970s,but becamerare by 2000. Althoughtotal sharkcatches estimatedmean trophic level (TLi) for time period i by multiply- have steadilyincreased in the southernGulf of California,these ing the fishingimportance index (I, seeabove) times the trophic includeboth coastaland pelagic fisheries (Figure 1). Our results level of the individualspecies j, then takinga weightedmean indicatethat the nearshorefishery collapsed and wassubstituted (modifiedfrom Pauly et al. 1998): by an offshorefishery. Catch of other speciessuch as leopard groupers(Mycteroperca rosacea), snappers, and jacks also • T•Iij decreased,but theyare still commonlycaught. In contrast,some TLi - speciesthat werenot appreciatedor not targetedin the 1970s, •Iij suchas parrotfishes(Scarus spp.), whitefish (Caulolatilus prin- ceps),spotted snapper (Lutjanus guttams), tilefish (Caulolatilus When fisherscould not provide information for individual affinis),and creolefish(Paranthias colonus), have now become specieswithin a group,we usedthe averagetrophic level for the commontargets. Because the largerspecies of groupershave speciesin that group.We alsoestimated the meanmaximum size becomeincreasingly rare in the catch, most of the growth in of the catchas the summationof the productof the maximum grouperfishing has been related to the leopardgrouper (Figure 3).

March 2004 I www. fisheries.org I Fisheries 21 Maximum fish size in the catch decreased45 cm Discussion and recommendations from 1970 to 2000, and 33 cm in the 1980salone (Figure4). The mean trophic level of the catch in Baja The results of the interviews showed that the CaliforniaSur in the 1970swas 4.2, significantly depletionof fishstocks near fishing villages forced higherthan any other fisheryin the worldat that fishersto moveto fishingsites located farther away. In time (Paulyet al. 1998a).This meansthat themost El Pardito,while most of the fishingactivities in the importantorganisms caught were largepredators 1970swere conducted near the fishing camp (< 10km suchas sharks and largegroupers, while todaythe radiusin average),fishing now occursmostly 50 km most importanttargets are medium-sizebenthic- fromit (Figure5). We assumethat thisis representa- feedingfishes. The declinein meantrophic level of tiveof otherfishing grounds in theGulf of California. fishlanded in onlyone decade (1980s) was greater Meantrophic level decreased from 4.2 in the 1970s than that of the globalmarine fisheries since 1950, to 3.8 in 2000, the greatestreduction being in the andcomparable to the largestregional declines in 1980s.The averagesize of four abundantspecies Canada, northwestand western central Atlantic, decreasedalong a gradientin fishingfor both car- and southPacific (Pauly et al. 1998a,2001). These nivorous(leopard grouper, yellow snapper, Lutjanus estimates are, however, conservative. The first argentiventris; greybar grunt Haemulon sexfasciatum ) impactsof a fisheryare reduction in abtn•danceand and herbivorousfishes (bluechin parrotfish Scarus sizeof the targetspecies. Because small individuals ghobban)(Figure 6). We foundsimilar patterns for tendto havelower trophic levels than largeadults most commercial fishes. (Paulyet al. 1998a,b), the declinein meantrophic The structureof fishassemblages changed along level of the catch must have been greaterthan the gradientin fishingpressure (Figure 7). These reportedhere. These resultsindicate that the results indicate the existence of a threshold coastal fisheries in the Gulf of California have had (around7 fishingboats/km) beyond which average comparativelystronger impacts in the short term fishsize is significantly reduced and the structureof than mostother fisheries in the world.Although the fishassemblage significantly changed. there were no rigorousfisheries statistics at the specieslevel for the Gulf of California,the low variancein the data obtainedfrom independent interviews(Figure 3) allowsus to believethat the patternsdescribed in thisstudy are consistent. Figure3. Shiftsin fishcatches in the southernGulf of Californiacoastal fishery. Bars Sharkswere among the mostimportant species represent•ndex of fishingimportance (mean + S.E.)(see text for details).Leopard in the catch in the 1970s, but now have been grouper(Mycteroperca rosacea); gulf grouper(M. jordanl);jacks (Caranx caballus, C caninusand C sexfasciatus);gulf coney(Epinephelus acanthistius); goliath grouper replacedby smallerspecies of bony fishes.The (Epinephelusitajara); barred pargo (Hoplopagrus gunthen); broomtail (M. xenarcha); declinein nearshoreshark catches may be related to yellowsnapper (Lutjanus argentiventris); dog snapper(L. novemfasciatus); triggerfish an offshoreshark fishery and to the fact that the (Balistespolylepis); red snapper(L. peru);parrotfish (Scarus ghobban, S. compressus, fishedcoastal sites may harbornursery areas. The and S. perrico); whitefish (Caulolatilus princes); spotted snapper (L. guttatus); possibleinteractinns between the coastalartisanal Pacifictilefish ( Caulolatilusaffinis); creolefish (Paranthias colonus).

1970s 1980s 1990s 2000

Sharks Leopard grouper Gulf grouper Downloaded by [The University of British Columbia] at 08:31 09 May 2016 Jacks Gulf coney Goliath grouper Barred pargo Broomtail Yellow snapper Dog snapper Triggerfish Red snapper Parrotfish Ocean whitefish Spotted snapper Tilefish Creolefish

0 1 2 3 4 50 1 2 3 4 50 1 2 3 4 50 1 2 3 4 5

Index of fishing importance

22 Fisheries I www.fisheries.org I vol 29 no 3 fishery,and the sportand offshore fisheries targeting 4.3 150 pelagicspecies are not clearand cannot be explored at presentbecause data for the latter is yet unavail- 4.2 140 able.Nonetheless, the existingdata indicatethat sharkswereabundant inshallow rockyhabitats in 1970,where they now have been depleted. 130 The decreaseof the mean trophiclevel of the catch is alsoassociated with the disappearanceof 4.0 - 120 some spawningaggregations of large predatory fishes(such as the goliathgrouper) in the southern 3.9 11o E Gulf of Californiadue to fishing(Sala et al. 2003). The eliminationof theseaggregations accelerates 3.8 -100 the declinein meantrophic level at a rate higher than that causedby a fisherytargeting non-repro- 3.7 90 ductive individuals.In to prevent further 1970s 1980s 1990s 2000 declines,fisheries management in the Gulf of Californianeeds to incorporatethe spatio-tempo- ral patternsof fishspawning. Figure4. Temporalchanges in meantrophic level and The removalof largepredators from marine ecosystems has cascade effects on maximumfish sizeof coastalfisheries landings in the foodwebs (Estes et al. 1998;Jackson et al. 2001).Our resultsclearly indicate that southern Gulf of California. increasingfishing pressure causes significant changes in the structureof the fish assemblagesbeyond the direct effects on target species. This supports at local scales Figure 5. Smallscale changes in fishinggrounds over Paulyet al.'s(1998) hypothesis that landing data can be used as ecosystem indica- time aroundEl Parditofishing village. Values are tors,that is, changesin meantrophic level of the catchreflect changes in the deviationsfrom meanfishing use. ecosystem.The resultsof thisstudy suggest that reducingthe potential density of

1970s : 1980s

-1 Mean

10Km

hrdito ito Downloaded by [The University of British Columbia] at 08:31 09 May 2016

• E! Pardito

March 2004 I www.fisheries.org I Fisheries 23 boatsbelow 7boats/km 2 could -prevent marked reduc- sound ecosystem-based fisheries management, while tionsin averagefish size and the degradationof fish theuse of certain types of fishing gear (mainly gfilnets) assemblages.This meansthat fisheriesmanagement is revised.Protecting those species at risk of local shouldbe spatially-explicit and regulate effort as a func- extinction(Musick et al. 2000) and the spawning tionof 1) numberof boats per fishing camp and 2) the aggregationsof commercialspecies (Sala et al. 2002, densityof boatson fishinggrounds at anytime. 2003) isalso necessary. The overallpatterns of speciesshifts, and dedine of Acknowledgements CPUE and meantrophic level indicate that coastal fisheriesin the southernGulf of California are unsus- We aregrateful to fishersfrom the fishing commu- tainable.Food web collapses might not haveoccurred nitiesof E1 Pardito, La Paz,E1 Sargento, La Ribera,and yetbecause the dedinein meantrophic level has not Cabo Pulmo who providedinformation on fish beenassociated with overall&dining catches(Pauly catches.Preliminary catch, effort, and gear analysis at et al. 2001),although most species showed stagnant la Riberawas provided by A. Klett of the Centro catches.Although coastal fisheries regulations for Regionalde InvestigacionesPesqueras in La Paz. sharksand finfish in theGulf of California theoretically Several individuals and institutions provided help and limitfishing effort, they do not mentionhow it isto be advice:G. Anaya,J.C. Barrera,L. Findley,I. Parra, reached,beyond restricting fishing zones and gear spec- ReservaIslas del Golfo, Parque Marino Nacional Cabo ifications(DOF 2000).There are no fishingquotas, Pulmo,and World Wildlife Fund--Gulf of California and enforcementis virtuallynon-existant. Urgent Program.Thanks to J. Curriss,L. Fichman, G. measuresneed to be takento developand implement Thompson,and A. Tombafor their help with our div- ing operations.We are also grateful to three anonymous reviewers Figure6. Meansize (+ S.E.) of four abundant reef fishes 35 40 , who greatly improved • Lutjanusargentnventrls i the manuscript. This in 21 sitesalong a gradientin N = 1646 ß N = 1485 30 fishingpressure in the 30 • study was funded by southern Gulf of California. the Moore N= number of individuals for Foundation,The Tinker which size was estimated 20 • Foundation, the Robins duringvisual censuses. '• 20 Family Foundation,and t the World Wildlife Figure7. Changesin the '• 15 - 45 Fund•ulf of California structure of fish communities Haemulon sexfascialurn Scarusghobban Program. We are on rockyreefs along a ,e ß N = 977 40 N = 759 gradientin fishing pressure. i •0i indebtedto P. Dayton Communitystructure is 35 I and M. del Enebro for expressedas the scoreon the continuous help and 30 firstaxis of a principal encouragementthrough- componentanalysis, 25 outthe study.This article providinga quantitative is dedicated to the descnptionof species • 20 abundancesimilarity at 0 2 4 6 8 10 12 14 o 2 4 6 8 10 12 14 memory of B. Montes differents•tes. Fishing who helpedus in many pressureexplains 99% of the Fishingboats /km 2 ways throughout the variance in the data. study.•

Downloaded by [The University of British Columbia] at 08:31 09 May 2016 Literature cited Baum,J. K., R. A. Myers, D. G. Kehler,B. Worm, S. J. Harley, and P. A. Doherty. 2003. Collapseand conservationof shark populationsin the NorthwestAtlantic. Science299: 389-392. Dayton,P. K., S. Thrush, andF. C. Coleman.2002. Ecological effectsof fishingin marineecosystems of the . PewOceans Commission, Arlington, Virginia. DOF--Federal Gazette.2000. Acuerdo por el quese da a conocer la cartanacional pesquem 2000. PoderEjecutivo--Secretarfa de Medio Ambiente, RecursosNaturales y Pesca.Diario Oficial de la Federaci6n(Mexico), Mexico D.E, 28 August 2000. Estes, J. A., M. T. Tinker, T. M. Williams, and D. F. Doak. 1998.Killer whalepredation on seaotters linking oceanic and nearshoreecosystems. Science 282:473-476. 6 7 8 9 10 11 12 13 Froese,R., and D. Pauly. Editors. 2002. FishBase.World Wide Fishingboats km -2 Webelectronic publication. www. .org, 19 July2002. Haro, A., I. Parra, and H. Lie6n. 2001. Metodologfapara el reconocimientode amenazaspotenciales en el Golfo de

24 Fisheries I www.fisheries.org I vol 29 no 3 California. Technical Report World Wildlife Fund PP22, Pauly, D., M. L. Palomares,R. Froese,P. Sa-a, M. Vakily, D. Hermosillo, Mexico (2001). Preikshot, and S. Wallace. 2001. Fishing down Canadian Hernandez, A., and W. Kempton. 2003. Changesin fisheries aquaticfood webs.Canadian Journal of Fisheriesand Aquatic managementin Mexico: effectsof increasingscientific input Sciences 58:51-62. and public participation. Ocean and Coastal Management Ramirez, R. M. 1988. La pescaen Baja California Sur: capturas 46:507-526. de 1952 a 1985. Pages31-37 in VII SimposioInternacional de INEGI (Instituto Nacional de Estadistica, Geografia e BiologlaMarina. La Paz, B.C.S., M•xico. Informfitica). 2002. Anuario estadisticode BajaCalifornia Sur. Roberts, C. M., C. J. McClean, J. E. N. Veron, J.P. Hawkins, Instituto Nacional de Estadistica,Geografla e Informfitica.La G. R. Allen, D. E. McAllister, C. G. Mittermeier, F. W. Paz,Baja California Sur. Schueler, M. Spalding, E Wells, C. Vynne, and T. B. Jackson,J. B.C., M. X. Kirby, W. H. Berger, K. A. Bjorndal, Werner. 2002. Marine biodiversityhotspots and conservation L. W. Botsford,B. J. Bourque,R. Bradbury,R. Cooke, J. A. prioritiesfor tropicalreefs. Science 295: 1280-1284. Estes, T. P. Hughes, S. Kidwell, C. B. Lange, H. S. Lenihan, Sala, E., O. Aburto-Oropeza, G. Paredes, I. Parra, J. C. J. M. Pandolfi, C. H. Peterson, R. S. Steneck, M. J. Tegner, Barrera, and P. K. Dayton. 2002. A general model for and R. W. Warner. 2001. Historicaloverfishing and the recent designingnetworks of marine reserves.Science 298: 1991- collapseof coastalecosystems. Science 293:629-638 1993. Musick, J. A., M. M. Harbin, S. A. Berkeley,G. H. Burgess,A. Sala, E., O. Aburto-Oropeza, G. Paredes,and G. Thompson. M. Eklund, L. Findley, R. G. Gilmore, J. T. Golden, D. S. 2003. Spawningaggregations and reproductivebehavior of Ha, G. R. Huntsman, J. C. McGovern, S. J. Parker, S. G. reef fishes in the Gulf of California. Bulletin of Marine Poss,E. Sala, T. W. Schmidt,G. R. Sedberry,H. Weeks, and Science 72: 103-121. S. G. Wright. 2000. Marine, estuarineand diadromusfish Secretarla de Marina. 1950-1960. Anuario estadlstico de stocks at risck of extinction in North America (exclusive of actividades pesquerasen aguas territoriales Mexicanas. Pacific salmonids).Fisheries 25 (11 ):6-30. Gobierno de los Estados Unidos Mexicanos, Mexico D.E Myers, R. A., and B. Worm. 2003. Rapidworldwide depletion of Secretaria de Pesca. 1970-1980. Anuario estadfsticopesquero. predatoryfish communities.Nature 423:280-283. Gobierno de los EstadosUnidos Mexicanos, Mexico D.E Pauly, D., V. Christensen, J. Dalsgaard, R. Froese, and F. SEMARNAP (Secretarla del Medio Ambiente, Recursos Torres. 1998a. Fishing down marine food webs. Science Naturales y Pesca). 1990-2000. Anuarios estad[sticosde 279:860-863. pesca.Secretaria del Medio Ambiente, RecursosNaturales y Pauly, D., R. Froese,and V. Christensen.1998b. How pervasive Pesca. M•xico D.E is "Fishingdown marinefood webs?" Science 282:1383. Worm, B., H. K. Lotze, R. A. Myers. 2003. Predatordiversity Pauly, D., V. Christensen,R. Froese, and M. L. Palomares. hotspots in the blue ocean. Proceedingsof the National 2000. Fishing down aquatic food webs. American Scientist Academyof Sciencesof the United Statesof America 100: 88:46-51. 9884-9888. Downloaded by [The University of British Columbia] at 08:31 09 May 2016

March 2004 I www.fisheries.org I Fisheries 25