Fishing Strategies and Niche Partitioning Among CoastalFishers in Southern Brazil

Daniela Marques Nunes & Sandra Maria Hartz &

Renato Azevedo Matias Silvano

Published online: 14 June 2011# Springer Science+Business Media, LLC 2011

Introduction

Interactions between potentially competing groups of fisherscan reduce chances of capture for a particular group, thereforeincreasing fishing related conflicts (Berkes 1984; Begossi1995; Castro and Begossi 1996; Sunye 2006; Peterson et al.2008; Rebouças 2008; Zeller et al. 2008). Furthermore,interactions among groups of fishers may lead to increasedpressure on fish stocks, for example if fishers spend moretime than expected in fishing grounds due to increasedcompetition (Begossi 1992). Moreover, fishing communitiesmay adopt local rules that include division of space (fishinggrounds) and access restrictions to fishing resources. Forexample, Vietnamese coastal fishing communities regulateaccess to fishing grounds through sea user rights, which areobtained by fishers through heritage, proximity of thefishers’ residence, sale, rent and sometimes following a ‘firstcomer user rule’ that confers user rights to the first fisherwho arrives at the fishing ground (Ruddle 1998). Theallocation of sea user rights in spatial and temporal scalesis a complex task, as fishing effort is allocated among severalunpredictable habitats on the basis of fishers’ perceptions ofthe quality of fishing grounds, which may be influenced byphysical, ecological and social variables (Ruddle andAkimichi 1989). The sea user rights in some Asiatic fishingcommunities have developed into local management systemsthat include several fishing rules, such as the control offishing grounds, restrictions on outsiders, besides the rights

and obligations of local fishers (Ruddle and Akimichi 1989;Ruddle 1998). These characteristics, which have beenrecognized as local forms of management, can reduceconflicts among fishers and control fishing effort (Acheson1975, 1987; Johannes 1978, 2002; Ruddle and Akimichi1989; Ruddle 1998). Indeed, these local managementsystems often include sanctions, both economic (destructionof fishing gear) and social (intimidation and ostracism), onthose who violate local rules (Ruddle 1989, 1996, 1998).Besides well-established and socially enforced local rules,other, more subtle fishers’ behaviors can promote resourceconservation, such as incipient territoriality, use of differentfishing strategies by distinct communities or individuals, andseasonal variations in fishing strategies (Begossi 1995, 1998;Castro and Begossi 1995, 1996; Silvano and Begossi 2001).

General concepts of ecology, such as the niche, havebeen useful to understand different fishing strategies andinteractions among different groups of resource users, whocan be considered as distinct ‘cultural species’ (Hardesty1975). Studies have analyzed three niche dimensions offishing strategies: temporal (period of fishing), spatial(fishing grounds used), and resources (species exploited),to better understand conflicts between local and recreationalfishers in Canada (Berkes 1984) and southeastern Brazil(Castro and Begossi 1995, 1996). An alternative approachto analyze spatial and temporal differences in fishingstrategies is the concept of ‘allocating the sea,’ which hasbeen used to investigate competition among small scaleJapanese fishers who catch similar species using similarfishing gear (Ruddle and Akimichi 1989).

One obstacle to resource conservation is that user rulesimposed by governmental agencies usually do not take intoaccount socioeconomic and ecological site specific differ-ences. Consequently it is not uncommon for rules imposed byoutside environmental agencies to be unacceptable to resource

D. M. Nunes : S. M. Hartz : R. A. M. Silvano (*)PPG-Dept. Ecology, Universidade Federal do Rio Grandedo Sul (UFRGS),91501–970, Porto Alegre, Brazile-mail: renato.silvano@ufrgs.br

Hum Ecol (2011) 39:535–545DOI 10.1007/s10745-011-9411-1

users, creating serious conflicts. In both Brazil and NewZealand, fishers have contested laws formulated by manage-ment agencies regarding administration of fishing areas andrestrictions on access to resources (Silva 2000; Bess andRallapudi 2007; Costa-Doria et al. 2008). If resourcemanagers are able to recognize differences in fishingstrategies adopted by fishers, conflicts with resource userscould be avoided and management could be improved.

For this study we adopted an ecological approach tounderstand the relationships between two distinct groups offishers who use coastal resources in a southern Brazilianconservation unit, addressing the central question of whichecological variables are linked to resource exploitation andfishing strategies of the two groups. We therefore aimed toanalyze the differences between the two groups of fishersalong four niche dimensions: fishing gear used, fish speciescaught (resources), fishing strategies (how fishers use theirgear), and fishing spots exploited (habitats). Fishingstrategies and fishing spots were also analyzed during theperiod of highest fishing activity, when conflicts would bemore evident.

Study Area and Ecological Context

This study was carried out in the coastal area of the Serra doTabuleiro State Park, in the estuary of the Guarda do Embaúbeach (27°54′ S″, 48°35′ W″) in the municipality of Palhoça,Santa Catarina state, southern Brazil (Fig. 1). This coastalregion, which has several estuaries and bays surrounded byrocky shores (Lago 1961, Diegues 1999), includes a fishingcommunity (Vila da praia Guarda do Embaú) that iseconomically dependent on local tourism. Although fishinghas been a culturally important as well as a subsistenceactivity in this community for more than 30 years, morerecently tourism-related activities, such as construction,provision of meals, and leisure activities, have increasedand have come to be the main source of income for localfamilies, while fishing has declined. Fish are caught forhome consumption, and for sharing with relatives or withcolleagues from the Fishing Association of Guarda doEmbaú, a local association of fishers who club together inorder to buy a boat and a seine net (known locally as ‘redede cerco’) (information given by fishers in informalconversations). Fish can be sold if there is a surplus catch.

During the autumn and winter (from May to July), shoalsof mullet of the family Mugilidae, Mugil platanus Günther(locally called tainha) and Mugil curema Valenciennes,(locally called parati) migrate along the Brazilian coast fromthe south in order that their larvae and juveniles to be carriedby ocean currents into the estuaries where they develop. Thismigratory pattern of mugilid fishes has been observed inBrazil, Mexico, and Africa (Vieira and Scalabrin 1991;

Ibáñez and Gutiérrez Benitéz 2004; Longhurst and Pauly2007). The seasonal demand for mugilid fish at Guarda doEmbaú Beach attracts outsider recreational fishers. TheBrazilian environmental agency (IBAMA) considers thetainha over-exploited and has forbidden exploitation of thisfish during its reproductive season (May–July), as well asbanning fishing with cast nets on sites less than 300 m fromrocky shores. These governmental fishing rules, which havebeen imposed to local fishers in a top down fashion, arecontested by southern Brazilian coastal fishers.

A fishing spot is a specific location where fishing iscarried out and that can become a fishing territorywhen access is restricted (Begossi 2004), either byactive defense against intruders (Acheson 1975) or by‘first-comer right’ rule, as observed in fishing communi-ties from Japan and Vietnam (Ruddle and Akimichi 1989;Ruddle 1998). In the study community, local fishers haveimpeded free access of recreational fishers from outsidethe community to specific fishing spots over the last15 years at least. Conflicts can occur between these twogroups of fishers when occasional fishers ignore the localrules of use (priority to local fishers) and try to occupyfishing spots. When this occurs, occasional fishers aresubjected to social sanctions from local fishers, such asbullying (D.M. Nunes, personal observation). Bullying,which generally involves ridicule, along with ostracismand prohibitions are social sanctions used by traditionalfishers in several regions, such as the Pacific islands,Japan and Southeast Asia (Alkimichi and Ruddle 1989;Ruddle 1989, 1994, 1996). However, those occasionalfishers who frequent the study community more oftenrecognize the ownership rights of local fishers to fishingspots and usually respect local rules of use (informationobtained from fishers in informal conversations).

Sampling Methods and Statistical Analysis

Prior to this survey, samples of fish species that are regularlycaught were collected with the help of local fishers. Collectedfish were initially preserved in 4% formalin, and after 30 dayswere washed, preserved in 70% ethanol, and identified tospecies level (Figueiredo and Menezes 1978, 1980; Menezesand Figueiredo 1980, 1985; Szpilman 1992, 2000; Carvalho-Filho 1999; Figueiredo et al. 2002).

Fishing activity was evaluated during the months ofFebruary, May, August, and November 2007, with a samplingeffort of 10 days per month. Data about fishers and aboutfishing activity were recorded for the full extent of both therocky shore and the sandy beach where fishing spots arelocated (Fig. 1). The following fishing variables wererecorded: number of active fishers, type of fishing gear used,fishing techniques employed, number of trials of fishing gear

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for each fishing technique (fishing effort), duration of thefishing activity (hours), fish biomass (kg) caught for eachfish species, and fishing grounds exploited. Failed fishingeffort when no fish were caught, were also included in thestatistical tests as having ‘zero’ fish biomass.

The fishers’ socioeconomic profiles were investigatedthrough interviews based on standardized questionnaires with163 fishers who agreed to participate in the research. Thesesocioeconomic data were recorded during the entire surveyperiod, together with sampling of fish catches. During theseinterviews, fishers were asked questions about their economicactivity and place of origin. Based on these data, the fisherswere separated for analysis into two groups: 38 local fishersand 125 occasional fishers (usually recreational fishers fromoutside the fishing community). Occasional fishers were so

defined based on comments by local fishers, who consideredany non-resident fisher occasional, including those fishersfrom other Brazilian regions and even those from theneighboring beach. Some of the interviewed fishers workedprofessionally in the industrial fishery or on large artisanalfishing boats, and thus fished in other regions (Table 1).

The total number of active fishers during the times ofpeak fishing activity (10:00 h and 16:00 h) was recordedthrough two counts (one in each time period) usingbinoculars and covering the entire fishing area. Fishingarea is defined here as the space used by several fishers,including several fishing spots (Begossi 2004). Thesecounts of fishers provided a daily mean of the number ofactive fishers, which was used to calculate the monthlymean (10 sampling days per month).

Fig. 1 Map of South America,showing the location of Brazil (a)and Guarda do Embaú Beach,Santa Catarina state (b, c), aswell as the location of the fishinggrounds mentioned in the text: a)rocky shore; b) sand-banks; c)river; d) observation site(location of the researcher whilerecording fishing activities)

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The fishing gear used and the fishing techniques adoptedwere reported by fishers during the interviews (see above).Fishing techniques were compared based on selectivity andsimilarity in composition of fish catch, in addition toproductivity and location in the fishing area. The twogroups of fishers were not analyzed separately, to avoidpseudo-replication, because fishers from both groups mayadopt any strategy or fishing gear.

The selectivity of the fishing strategies was analyzedthrough Simpson’s indexes of diversity and dominance andthe Shannon-Wiener (H’) diversity index (Margalef 1958) offish-catch composition. The Simpson index was used forcomparisons with other studies on resources (Castro andBegossi 1996) and the H’ index was used to allow statisticalcomparison of the differences of selectivity of fishingstrategies. The similarity (overlap) of fish-catch compositionamong fishing strategies was analyzed through Horn’s (0–1)similarity index (Horn 1966). All these indexes werecalculated using the biomass of fish species caught, and datawere grouped and analyzed separately for two seasons: warmseason (November and February, corresponding respectivelyto spring and summer) and cold season (May and August,corresponding respectively to autumn and winter).

The monthly productivity for each fishing strategywas measured based on catch per unit of effort (CPUE)(kg fish/h fishing). The significant positive relationshipobserved by simple linear regression between the biomass offish caught (kg, dependent variable) and the time spent fishing(hours, independent variable) (F1,390 = 29.8; p<0.001; r2=0.07; n=391) allowed CPUE to be considered as a measure offishing productivity, as long as changes in fishing effortaccounted for changes in amount of fish caught.

The fishing spots were indicated by fishers and mapped(Fig. 1). The sand bank is a fishing spot transition, which isformed by marine sediments deposited at the mouth of theriver and appropriate for fishing in the water. The river andthe sand-bank were grouped for analysis, because both were

part of the estuarine habitat (Fig. 1). The two fisher groups(local and occasional) were considered here as analogous totwo cultural species (Hardesty 1975). Their interaction wasanalyzed based on the use of fishing space: number of fishersfrom each group recorded on each fishing ground (river orrocky coast). The analyses of niche partitioning betweenlocal and occasional fishers regarding fishing strategies andfishing grounds were carried out for the period of peakfishing activity only, because conflicts over fishing space areusually density-dependent (Begossi 1995).

The variables number of fishers, CPUE, and number oftrials of fishing gear were log transformed for analysis, dueto unequal variances. The mean number of active fisherswas compared among months through One-way ANOVA(Gotelli and Ellison 2004) with the post-hoc multiplecomparison test of Newman-Keuls, to check for monthsshowing a higher fishing activity. The fishing gear mostoften used by each of the two groups of fishers (local andoccasional) was checked through chi-square tests (Gotelliand Ellison 2004). The mean differences in CPUE amongfishing strategies and months, the mean differences in thenumber of fishing gear trials among fishing strategies andfishing grounds (using months as control blocks, to checkfor the occurrence of specific fishing grounds for eachfishing strategy), and the mean differences in the number offishers from each group (local and occasional) that usedeach fishing ground (river or rocky coast) were allcompared through Two-way ANOVA (Gotelli and Ellison2004). Differences in the Shannon-Wiener (H’) diversityindex were analyzed through a t test, to identify differencesin fishing selectivity among fishing strategies.

Fishing Strategies

We recorded data on 391 trials of fishing gears by 163fishers, who caught a total of 700.1 kg of fish (Table 2). We

Table 1 Frequency (%) of active fishers by categories of place of origin and main economic activities at Guarda do Embaú Beach, southernBrazilian coast, during 2007

Economic activity Local fisher Occasional fisherb Total

Retired 15.8 21.6 20.3

Professional fisher (onboard) 34.2 15.2 19.6

Construction labourer 5.3 11.2 9.8

Public security 10.5 5.6 6.8

Tourism 21 1.6 6.1

Othersa 13.2 44.8 37.4

Total number 38 125 163

a Other economic activities mentioned by 1 to 8 fishers: farmer, student, butcher, manager, lawyer, free lance, secretary, bank attendant, truckdriver, businessman, cook, engineer, public employee, waiter, mechanic, auto driver, musician, teacher, taxi driverb Fishers from other regions, 2 to 400 km distant from Guarda do Embaú Beach (usually other Brazilian states)

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observed seasonal differences in the fishing activity (F3,36 =39.1; p<0.01): the highest mean number of active fishers(30.5±9.9 fishers) occurred in May (Fig. 2).

The fishing gears used by fishers were three kinds of fishingpoles (caniço, carretilha, and molinete) and the cast net. Thecast nets (n=34) and the caniço fishing pole (n=4) were thegear most used by local fishers, while cast nets (n=99) and themolinete (n=17), caniço (n=7), and carretilha (n=2) fishing-pole techniques were used by occasional fishers. The cast netwas the most used fishing gear by both local (χ2yates 0.05;1 =22.1; p<0.001) and occasional (χ20.05;3 = 199.6; p<0.001)fishers. The two groups of fishers thus overlapped in thefishing gear used.

The two fishing strategies adopted when fishing withcast nets were named by the fishers as espia and sarraio.When using the espia strategy, fishers observed fish in thewater before the trial (throw) of the cast net. When usingthe sarraio, fishers made several random and consecutivetrials of cast net. The three fishing-pole techniques weregrouped for analyses under the term ‘fishing pole’, becausethe data were insufficient to analyze them separately. Thestatistical analyses thus included three fishing strategies:espia, sarraio, and fishing pole.

Composition and Selectivity of Fish Caught

Twenty-two fish species were caught by the fishers duringthe study; eight were caught by espia, 13 by sarraio, and12 by fishing pole (Table 2). Fish from the familyMugilidae were regularly caught by fishers using the espiastrategy during the entire study period, but during themonth of May mainly by the sarraio strategy. During themonths of November (spring) and February (summer), themajority of the catch was mugilids with lower biomass,such as small-sized tainhas and paratis. During the monthsof May (autumn) and August (winter), the most caughtmugilid fish was the tainha, which was larger than parati

(D.M. Nunes personal observation). Other fish speciescaught by cast nets included the escrivão (Eucinostomusargenteus) and guaivira (Oligoplites saliens), which werealso caught by fishing poles, although in fewer numbers(Table 2).

The highest dominance values were observed for theespia and sarraio strategies during the cold season, whilethe highest values of diversity indexes were observed forthe fishing-pole strategy during the warm season (Table 3).The Shannon-Wiener (H’) diversity index did not differbetween the cast-net strategies of espia and sarraio(Table 4), but this index was higher for the fishing-polestrategy compared with these two cast-net strategies(Table 4). Therefore, the espia and sarraio strategies weremore specialized, while the fishing pole was a moregeneralist strategy in terms of the diversity of fish caught.The highest similarity regarding the composition of fishcatches was observed for the espia and sarraio strategiesduring the two seasons (warm and cold); the fishing-polestrategy differed from the two cast-net strategies andbetween the warm and cold seasons (Table 5). Therefore,the two groups of fishers showed an overlap on the nichedimension of fish species caught (resource), as both usedmainly cast nets and both caught mostly tainha during themonth of May (Table 2).

Fishing Productivity and Use of Fishing Spots

The mean fishing productivity (CPUE, kg/h) differedamong months (F3,108 = 8.9; p<0.01) and fishing strategies(F2,108 = 18.1; p<0.01), being highest for May and theespia strategy (Fig. 3). The interaction between month andfishing strategy was non-significant (p>0.3). No fish werecaught using fishing poles in November (Fig. 3).

Two major fishing spots were considered in the analyses:the rocky shore and the river banks (Fig. 1). There was asignificant interaction in the mean number of fishing trialsbetween fishing strategies and fishing grounds (F2,231 = 39.3;p<0.001) (Fig. 4). Over the duration of the study in 2007,the sarraio strategy was more intensively used in the river,whereas the espia strategy was used in both the river and therocky shore (Fig. 4). During May, which showed the highestfishing activity (number of fishers) and the highest fishingproductivity (CPUE), the more productive strategy of espiawas adopted mainly on the rocky shore, whereas the sarraiowas used only along the river (Fig. 4). The rocky shore wasthe preferred spot for fishers using the fishing pole,especially during February and August (Fig. 4).

There was a significant interaction between the groups offishers (local and occasional) and fishing grounds, based onthe number of fishers recorded during 10 sampling daysduring the month of highest fishing activity (May) (F1,40 =

Fig. 2 Mean and standard deviation (n=10 sampling days per month)of the number of active fishers in each sampling month on Guarda doEmbaú Beach, southern Brazilian coast, during 2007

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125.7; p<0.001) (Fig. 5). The two groups of fishers showedniche partitioning regarding fishing spots, as evidenced bythe observed differences in the use of fishing grounds(spatial segregation): local fishers frequented the rocky shore,whereas occasional fishers frequented the river (F4,40 = 200.4;

p<0.001) (Fig. 5). The two groups of fishers also showedniche partitioning regarding fishing strategies: during May,local fishers used the espia strategy on the rocky shore,whereas occasional fishers used the sarraio strategy alongthe river (Figs. 4 and 5).

Fishing strategies

Espia cast net Sarraio cast net Fishing pole

Seasons W C W C W C

Simpson’s dominance index 0.81 0.95 0.67 0.95 0.25 0.32

Simpson’s diversity index 1.23 1.05 1.49 1.05 4 3.12

Shannon-Wiener (H’) diversity index 0.45 0.13 0.76 0.15 1.62 1.26

Table 3 Diversity and domi-nance indexes of the fish catchcomposition for each fishingstrategy and for warm (W) andcold (C) seasons (see text) atGuarda do Embaú Beach,southern Brazilian coast, during2007

Table 2 Total biomass (kg) of all fish species caught by fishers at Guarda do Embaú Beach, southern Brazilian coast, during 2007 (n=40 days ofsampling, 391 trials of fishing gear), showing values by month and by fishing strategy (E = espia, S = sarraio, F = fishing pole)

Fish Family (bold) and speciesa February May August November Total

E S F E S F E S F E S F

Mugilidae

Mugil spp.b 42.3 4.4 – 188 338.6 – 13.6 – – 61.4 1.8 – 650.1

Pomatomidae

Pomatomus saltatrix (Linnaeus) – – – 3 – 4 – 1.1 – – – – 8.1

Sciaenidae

Menticirrhus americanus (Linnaeus) – – 2.5 – – 2 – – 1.9 – – – 6.4

Centropomidae

Centropomus parallelus Poey 5 0.3 0.2 – – – – 0.8 – – – – 6.3

Clupeidae

Brevoortia pectinata (Jenyns) – – – 2 0.6 – – 2.2 – 0.3 – – 5.1

Serranidae

Epinephelus sp. – – 4.5 – – – – – – – – – 4.5

Sparidae

Diplodus argenteus (Valenciennes) – – 4 – – – – 0.4 – – – – 4.4

Carangidae

Oligoplites saliens (Bloch) 3.2 0.2 – – – – – – – – – – 3.4

Gerreidae

Eucinostomus argenteus (Baird & Girard) – 0.2 0.9 – 1 – – – 0.2 0.6 – – 2.9

Othersc 0.3 0.7 2.0 – 0.1 2.1 – 1.9 – 1.8 – – 8.9

Total (kg) 50.8 5.8 14.1 193 340.3 8.1 13.6 6.4 2.1 64.1 1.8 0 700.1

Total number of fishing trials 25 11 25 45 135 10 15 28 31 59 4 3 391

a Local names of fish species studied, according to fishers (in Portuguese): Mugil spp. (tainha, parati), Pomatomus saltatrix (anchova),Menticirrhus americanus (papa-terra), Centropomus parallelus (robalo), Brevoortia pectinata (savelha), Epinephelus sp. (garoupa), Diplodusargenteus (marimbau), Oligoplites saliens (guaivira), Eucinostomus argenteus (escrivão)b Fishers did not distinguish between two species of this genus: Mugil platanus Günther, Mugil curema Valenciennes (February, November); Mugilplatanus (May, August)c “Others” refers to fish species caught that showed a total biomass less than 2 kg (including all months and types of fishing gear) (family in bold,local name in parentheses). Haemulidae: Anisotremus virginicus (Linnaeus) (salema), Pomadasys corvinaeformis (Steindachner) (corcoroca),Sciaenidae: Pogonias cromis (Linnaeus) (borriquete), Cynoscion sp. (pescada), Ariidae: Genidens genidens (Valenciennes) (bagre), Elopidae:Elops saurus Linnaeus (ubarana), Serranidae: Mycteroperca microleps (Goode & Bean) (badejo), Atherinidae: Odontesthes sp. (peixe rei),Carangidae: Trachinotus marginatus Cuvier (pampo), Trachinotus carolinus (Linnaeus) (pampo), Caranx latus Agassiz (xerelete), Balistidae:Balistes capriscus Gmelin (porquinho)

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Fishing Strategies and Fishing Productivity

The fishery of Guarda do Embaú Beach can be consideredrecreational because both local and occasional fishersderived their livelihoods from economic activities. Thesharp increase in the number of active fishers during themonth of May occurred because both local and occasionalfishers were targeting the tainhas during their seasonalmigration. An increase in fishing pressure during thisperiod has also been recorded in other southern Braziliancoastal regions where fishers also catch the tainha usingcast nets (Medeiros 2001; Peterson et al. 2008). Higherfishing productivity related to seasonal migration ofmugilids has been observed in several other coastal regions,such as Scotland (Beare et al. 2005), northeastern Mexico(Ibáñez and Gutiérrez Benitéz 2004), and along thesouthern and southeastern coasts of Brazil (Pina andChaves 2005; Seckendorff and Azevedo 2007; Mirandaand Carneiro 2007; Peterson et al. 2008). Since an increasein the number of individuals exploiting a given resourcecan lead to conflicts over the space used and resourcesexploited (Gotelli 2001), increased fishing activity duringMay in Guarda do Embaú may potentially lead tocompetition between local and occasional fishers.

During the entire study period, those fishers who usedthe espia strategy (either local or occasional) caught a largerbiomass of fish, even during the less-productive months(February, August, and November). The higher productivityof the espia strategy possibly resulted from the ability of

the fishers to observe and select the larger fish. The sarraiostrategy involved the largest fishing effort but was lessproductive (a lower CPUE) than espia. Furthermore, theespia strategy caught mugilids during all months of thestudy, because the fishers were able to locate these fish.Conversely, the sarraio strategy yielded the highest catchesof mugilids when these fish were more abundant (May).

Selectivity of Fishing Strategies

The dominance index of the catch composition was higherfor the espia and sarraio strategies during the cold perioddue to the tainha fishing season (May). These two cast-netstrategies, which were directed towards catching mugilids,were more selective compared to the more generalistfishing-pole strategy. A specialized cast net strategy and ageneralist fishing-pole strategy have also been observed forlocal and recreational fishers in a southeastern Brazilianriver (Castro and Begossi 1995). Indeed, the values of theSimpson diversity indexes for the cast net strategiesobserved in this study were very similar to those observedby Castro and Begossi (1995).The two cast-net strategiesused by the fishers of Guarda do Embaú Beach showed alsoa higher similarity in fish catch composition.

Use of Fishing Spots and Niche Partitioning

The two groups of fishers studied in Guarda do Embaúshowed niche overlap on the dimensions of resource use(overall fish species caught and specialization catchingtainha during May) and of fishing gear (cast nets).However, during the period of highest fishing activity andfishing productivity (May), the two groups of fishersshowed niche partitioning on the dimensions of fishingstrategies and fishing spots (Fig. 6). Local fishers used therocky shore and adopted the espia strategy, whereasoccasional fishers used the river and adopted the sarraiostrategy.

Table 5 Comparison of values of the Horn similarity index,which was based on the fish biomass caught, among fishingstrategies and seasons at Guarda do Embaú Beach, southern

Brazilian coast, during 2007. E (espia cast net), S (sarraio castnet), F (fishing pole), W (warm season, see text), C (cold season,see text)

Fishing strategy and season EW EC SW SC FW FC

EW 1

EC 0.98 1

SW 0.99 0.98 1

SC 0.99 0.99 0.98 1

FW 0.002 0 0.004 0.001 1

FC 0.0002 0.01 0.001 0.002 0.27 1

Table 4 Comparison of the Shannon-Wiener (H’) diversity indexesbetween pairs of fishing strategies at Guarda do Embaú Beach,southern Brazilian coast, during 2007

Comparison of the H’ between fishing strategies t-test pa df

Espia X Sarraio 1.7 NS 2

Espia X Fishing pole 4.8 <0.05 2

Sarraio X Fishing pole 3 <0.1 2

aNS non-significant

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Ecological interactions and conflicts among resourceusers have occurred in other coastal fishing communities insouthern Brazil, for example between recreational andprofessional fishers who use cast nets (Sunye 2006).Peterson et al. (2008) report that in another southernBrazilian coastal fishing community, occasional fishersinterfere with and disrupt the interaction between local fishersand dolphins (Tursiops truncatus) which cooperate with localfishers in the tainha fishery. However, these studies do notmention whether these conflicts were resolved. The fishers atGuarda do Embaú seem to avoid conflicts by means of theniche partitioning and spatial segregation using differentfishing spots and fishing strategies (Fig. 6). In another

southern Brazilian fishing community, Pântano do Sul,conflicts in the mugilid fishery have been mitigated by rulesbased on local fishers’ property rights (Medeiros 2001).

Which factors may have been influencing the observedniche partitioning between local and occasional fishers?The choice of the cast net strategies used (espia or sarraio)to fish for mullet is probably influenced by environmentalfactors (for example, water clarity), the skill of fishers orpersonal choices. During May, mullet are more easilysighted on the rocky shore where they enter the estuaryand fishers used the more productive espia strategy.Conversely, sarraio (the less productive strategy) was mostoften used in the river where water can vary in transparency

Fig. 5 Mean numbers of active fishers of the two cultural groups (localand occasional) on two fishing grounds on Guarda do Embaú Beach,southern Brazilian coast, during May 2007 (n=10 sampling days)

Fig. 3 Mean seasonal productivity, measured as the catch per unit ofeffort (CPUE), for each fishing strategy on Guarda do Embaú Beach,southern Brazilian coast, during 2007 (n=10 sampling days per month)

Fig. 4 Mean seasonal numberof fishing trials for eachfishing strategy and for eachfishing ground on Guarda doEmbaú Beach, southernBrazilian coast, during 2007(n=10 sampling days permonth). Numbers above bars arethe total number of trials ofeach fishing gear

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and flow, impeding fish observation and thus precluding theuse of espia.

In answer to the question of why occasional fisherswould voluntarily abdicate of the use of the mostproductive fishing gear, it seems, based on qualitativeevidence, that local fishers do have exclusive rights touse the rocky shore, which they defend through respectand social sanctions (intimidation) (D.M. Nunes, personalobservations), a form of territorial defense (Begossi1995, 1998). Similar behavior, known as “allocating thesea,” has been observed in Japan and Vietnam, where localfishers establish territories in sea space according toenvironmental and social factors (Ruddle and Akimichi1989; Ruddle 1998). The benefits gained by local fishers,in the form of exclusive use of a fishing spot, mayoutweigh the costs of territorial defense, which is acondition for the evolution of territorial behavior(Dyson-Hudson and Smith 1978). Therefore, the currentchoice of the less productive fishing strategy by occasionalfishers could have been influenced by past competitiveinteractions between local and occasional fishers, whichmay had been resolved by territorial defense (Fig. 6). Thisis analagous to the well-known ecological principle ofcompetitive exclusion (Gotelli 2001), according to whichtwo species with a very similar niche would segregate in atleast some niche dimensions due to the selective pressureof competition. However, in our study during the monthswhen territorial behavior was absent, the first fisher toarrive had user rights of the rocky shore fishing spot,similar to the ‘first-comer rule’ to allocate sea spaceobserved in fishing communities from Japan and Vietnam(Ruddle and Akimichi 1989; Ruddle 1998).

Human Ecology and Fisheries Management

The observed niche partitioning at Guarda do Embaúmay reduce the number of fishers in the most productivefishing spot (rocky shore) during the period of higherfish availability, thus possibly reducing fishing pressure.However, the behavior of local fishers seemed not to bemotivated by resource conservation, but rather to guaranteegood catches of mugilid fishes. Such absence of aconservation-driven purpose may be related to the fact thatnowadays fishing is more a leisure and culturally orientedactivity than a source of livelihood income in Guarda doEmbaú. The tainha fishery, besides being a widespreadeconomic activity among southern Brazilian fishing commu-nities (Chaves and Robert 2003; Pina and Chaves 2005;Peterson et al. 2008), may also be maintained mainly for itscultural value, as observed in this study and in other southernBrazilian coastal communities (Medeiros 2001; Rebouças2008).

Studies dealing with niche partitioning among fishershave addressed fishing related conflicts (Berkes 1984;Castro and Begossi 1996). For example, in a Canadianlake, recreational and commercial fishers show nichesegregation in three dimensions (fish caught, fishing spotsand activity period), but conflicts between them still occur,which may be due to cultural factors or some other non-analyzed ecological dimension (Berkes 1984). In a south-eastern Brazilian river, local and recreational fishers showoverall niche partitioning, but they do overlap in one nichedimension (fishing spots) during a specific season whenlocal fishers defend fishing territories that are not respectedby recreational fishers (Castro and Begossi 1996). In thestudied Guarda do Embaú fishing community, the observedniche partitioning (Fig. 6) help to reduce fishing pressureon mugilids, to avoid conflicts between the two groups offishers, and to maintain the mugilid fishery.

The conventional governmental top-down managementmeasures aimed at regulating catches of tainha on thesouthern Brazilian coast, such as prohibition of fishing withcast nets on the rocky shores, have caused conflicts withfishers and have not been effectively enforced. A feasiblealternative would be to consider the specific social andecological features of local fishing communities in theformulation of fishery management strategies. The so-calledecosystem approach to fisheries management, which hasbeen widely adopted by scientists in recent times, is basedon an integrated and interdisciplinary framework thatjointly embraces research, management and environmentalplanning (Ruddle and Hickey 2008). This ‘new’ approachclosely resembles long-standing traditional or local fisheriesmanagement systems, which recognize the ecologicalrelationships that affect fisheries (Ruddle and Hickey2008). Therefore, some of the conventional management

Fig. 6 Scheme of factors related to the niche partitioning andterritoriality between local and occasional fishers on Guarda doEmbaú Beach, southern Brazilian coast, during May 2007. a = nichedimensions

Hum Ecol (2011) 39:535–545 543

approaches, such as ecosystem management, adaptivemanagement and marine protected areas, could be mergedwith local management practices of traditional fishers andincorporate their local ecological knowledge (Johannes1998; Ruddle and Hickey 2008). For example, recreationalfisheries in Japan have been managed by exclusive privatelaws directed to each fishing area: both informal rules ofsea tenure and formal governmental rules could be appliedto reduce conflicts between recreational and commercialfishers (Ruddle and Segi 2006).

There is evidence that some form of spatial manage-ment and exclusive property rights assigned to localgroups of small-scale fishers may help them to achievesustainable resource use (Castilla and Defeo 2001), inaddition to contributing to resource protection through theexclusion of outsiders and reducing the risk and uncer-tainty that are usually related to fisheries (Ruddle andHickey 2008). The niche partitioning observed in theGuarda do Embaú fishing community can be considered aform of spatial management and could be a starting pointto reconcile local fishing practices with broader manage-ment goals, therefore facilitating the implementation ofmore efficient management measures.

Acknowledgments We thank the fishers of Guarda do Embaú for theircooperation essential to this research; Coordenação de Aperfeiçoamentode Pessoal de Nível Superior (CAPES) for a doctoral grant to D. M.Nunes; Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq) for research productivity grants to S.M. Hartz (304036/2007-2)and R.A.M. Silvano (304377/2010-4); Clarice B. Fialho, NelsonFontoura, Albano Schwarzbold, Alpina Begossi, Fernando G. Beckerand Kenneth Ruddle for useful comments on earlier versions of thismanuscript.

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