Using a partial sum method and GPS tracking data to identify area restricted search by artisanal fishers at moored fish aggregating devices in the Commonwealth of Dominica.

Foragers must often travel from a central place to exploit aggregations of prey. These patches can be identified behaviorally when a forager shifts from travel to area restricted search, identified by a decrease in speed and an increase in sinuosity of movement. Faster, more directed movement is associated with travel. Differentiating foraging behavior at patches from travel to patches is important for a variety of research questions and has now been made easier by the advent of small, GPS devices that can track forager movement with high resolution. In the summer and fall of 2012, movement data were collected from GPS devices placed on foraging trips originating in the artisanal fishing village of Desa Ikan (pseudonym), on the east coast of the Caribbean island nation of the Commonwealth Dominica. Moored FADs are human-made structures anchored to the ocean floor with fish attraction material on or near the surface designed to effectively create a resource patch. The ultimate goal of the research is to understand how property rights are emerging after the introduction of fish aggregating device (FAD) technology at the site in 1999. This paper reports on research to identify area-restricted search foraging behavior at FAD patches. For 22 foraging trips simultaneous behavioral observations were made to ground-truth the GPS movement data. Using a cumulative sum method, area restricted search was identified as negative deviations from the mean travel speed and the method was able to correctly identify FAD patches in every case.

Reproductive biology of Cetengraulis edentulus (Cuvier, 1829), the major fishery resource in Guanabara Bay, Brazil

Cetengraulis edentulus is a broadely distributed engraulid in Southwest Atlantic, currently accounting for the main fish species commercially exploited at Guanabara Bay, Brazil. This study aimed to extend the knowledge on reproduction of C. edentulus at Guanabara Bay and to test whether some descriptors of reproductive activity, especially the gonadosomatic index (GSI), and the index of reproductive activity (IRA) changed among seasons. A total of 978 C. edentulus specimens were retrieved from purse seine commercial landings at Conservas Rubi S.A. company, in São Gonçalo city, RJ. Subsamples of 90-120 individuals were collected from bimonthly yields between July 2010 (winter) and June 2011 (autumn). Most fish were adults (120-170 mm TL), in response to the high selectivity of commercial fisheries. All descriptors indicated a broad spawning period (late winter to spring), peaking in November, suggesting this is the critical period to protect C. edentulus stocks from overfishing at Guanabara Bay. Fecundity averaged 12,720 oocytes and was positively related to fish size, GSI and fullness index, indicating that preserving larger individuals (TL > 160 mm) could contribute significantly to the reproductive success of C. edentulus, since they produce more oocytes. Cetengraulis edentulus é um engraulídeo amplamente distribuído no Atlântico Sudoeste, sendo um importante recurso comercialmente explorado na baía de Guanabara, Brasil. O presente estudo teve como objetivo ampliar o conhecimento sobre a reprodução de C. edentulus na baía de Guanabara e testar quais descritores da atividade reprodutiva, especialmente o índice gonadossomático (IGS) e o índice de atividade reprodutiva (IAR) se modificaram ao longo das estações do ano. Um total de 978 indivíduos de C. edentulus foram capturados pelo método de rede de cerco da frota comercial no cais da empresa Conservas Rubi S.A., na cidade de São Gonçalo, RJ. Subamostras de 90-120 indivíduos de C. edentulus foram coletados bimestralmente durante o período de julho de 2010 (inverno) e junho de 2011 (outono). A maioria dos indivíduos foram adultos (120-170 mm CT), em resposta a alta seletividade das capturas comerciais. Todos os índices indicaram um amplo período reprodutivo (final do inverno e primavera), com pico em novembro, sugerindo que este seria um período crítico para preservar os estoques de C. edentulus da sobrepesca na baía de Guanabara. A fecundidade média foi de 12720 ovócitos e foi positivamente relacionada com tamanho do peixe, IGS e índice de repleção, indicando que preservar maiores indivíduos (CT > 160 mm) poderia contribuir significativamente para o sucesso reprodutivo de C. edentulus na área, visto que esses indivíduos produzem um maior número de ovócitos.

Reproductive biology of Cetengraulis edentulus (Cuvier, 1829), the major fishery resource in Guanabara Bay, Brazil

Cetengraulis edentulus is a broadely distributed engraulid in Southwest Atlantic, currently accounting for the main fish species commercially exploited at Guanabara Bay, Brazil. This study aimed to extend the knowledge on reproduction of C. edentulus at Guanabara Bay and to test whether some descriptors of reproductive activity, especially the gonadosomatic index (GSI), and the index of reproductive activity (IRA) changed among seasons. A total of 978 C. edentulus specimens were retrieved from purse seine commercial landings at Conservas Rubi S.A. company, in São Gonçalo city, RJ. Subsamples of 90-120 individuals were collected from bimonthly yields between July 2010 (winter) and June 2011 (autumn). Most fish were adults (120-170 mm TL), in response to the high selectivity of commercial fisheries. All descriptors indicated a broad spawning period (late winter to spring), peaking in November, suggesting this is the critical period to protect C. edentulus stocks from overfishing at Guanabara Bay. Fecundity averaged 12,720 oocytes and was positively related to fish size, GSI and fullness index, indicating that preserving larger individuals (TL > 160 mm) could contribute significantly to the reproductive success of C. edentulus, since they produce more oocytes. Cetengraulis edentulus é um engraulídeo amplamente distribuído no Atlântico Sudoeste, sendo um importante recurso comercialmente explorado na baía de Guanabara, Brasil. O presente estudo teve como objetivo ampliar o conhecimento sobre a reprodução de C. edentulus na baía de Guanabara e testar quais descritores da atividade reprodutiva, especialmente o índice gonadossomático (IGS) e o índice de atividade reprodutiva (IAR) se modificaram ao longo das estações do ano. Um total de 978 indivíduos de C. edentulus foram capturados pelo método de rede de cerco da frota comercial no cais da empresa Conservas Rubi S.A., na cidade de São Gonçalo, RJ. Subamostras de 90-120 indivíduos de C. edentulus foram coletados bimestralmente durante o período de julho de 2010 (inverno) e junho de 2011 (outono). A maioria dos indivíduos foram adultos (120-170 mm CT), em resposta a alta seletividade das capturas comerciais. Todos os índices indicaram um amplo período reprodutivo (final do inverno e primavera), com pico em novembro, sugerindo que este seria um período crítico para preservar os estoques de C. edentulus da sobrepesca na baía de Guanabara. A fecundidade média foi de 12720 ovócitos e foi positivamente relacionada com tamanho do peixe, IGS e índice de repleção, indicando que preservar maiores indivíduos (CT > 160 mm) poderia contribuir significativamente para o sucesso reprodutivo de C. edentulus na área, visto que esses indivíduos produzem um maior número de ovócitos.(AU)

Management of gillnet fisheries in the south coast of the state of São Paulo, Brazil.

Gillnetting is one of the most practiced fishing methods adopted in the South of Brazil and has been increasingly expanding over the last years. This paper presents the characterization of the activity and discusses its management, in accordance to results from the discussions on the development of regulations on net fisheries in the South Coast Marine Protected Area (APAMLS) in the state of São Paulo. Gillnet fleets are formed by small-scale boats, with low autonomy, and lower fishing capacity, when compared to boats from other ports in the South and Southeast. However, the number of fishing units is high, reaching 1,709 units operating in the South coast of São Paulo in 2010. This kind of fleet uses several types of gillnets, and the activity may be classified according to the fishery type (industrial, coastal artisanal and estuarine artisanal). The activity was discussed in the APAMLS and the fishing industry, with the participation of all segments, and a proposal for gillnetting regulation was reached. The results suggested that gillnet length for industrial fisheries should be reduced by 30%. It must be emphasized that without effective inspection measures leading the fishing industry to believe in the enforcement of the proposal, private interests of the most influential political sectors may cause the process to retrocede.

Fishing strategies among prehistoric populations at Saquarema Lagoonal Complex, Rio de Janeiro, Brazil.

Two distinct fishing technologies were identified among the shellmound builders of the Saquarema Lagoonal Complex, in the Brazilian state of Rio de Janeiro: bone point technology and worked fish spines. These technologies were related to the acquisition of specific fish resources; Worked fish spines were used in the capture of Micropogonias furnieri (Desmarest), and bone points used for fishing specimens of the Ariidae family. Worked spines technology was predominant between 6,726 cal. years BP and 3,699 cal. years BP, while the bone point technology was dominant after 3,699 cal. years BP. It is believed these different strategies for obtaining fishing resources before 3,699 years cal. BP was related to environmental. Notably the gradual regression of relative sea level occurred during the mid- and late Holocene.

Behaviour of fish by-catch in the mouth of a crustacean trawl.

The behaviour of fish by-catch was recorded and characterized by in situ observations in the mouth of a crustacean trawl using an underwater camera system with artificial light, at depths between 106 and 461 m, along the central coast of Chile. The groups or species studied were rattails (family Macrouridae), Chilean hake Merluccius gayi gayi, sharks (orders Carcharhiniformes and Squaliformes), skates (family Rajidae), flatfishes (genus Hippoglossina) and small benthopelagic and demersal fishes (orders Osmeriformes, Stomiiformes, Gadiformes, Ophidiiformes and Perciformes). The fish behaviour was categorized in terms of (1) position in the water column, (2) initial orientation with respect to the trawl, (3) locomotion and (4) swimming speed with respect to the trawl. Rattails, sharks, skates and flatfishes were passive in response to the trawl and showed similar behavioural patterns, with most fishes observed sitting or touching the bottom with no swimming or other activity. Merluccius gayi gayi was the most active species, displaying a wide combination of behavioural responses when the trawl approached. This species showed several behavioural patterns, mainly characterized by swimming forward at variable speed. A fraction of small bentho-pelagic and demersal fishes also showed an active behaviour but always at lower speed than the trawl. The species-specific differences in behaviour in the mouth of the trawl suggest that improvements at the level of the footrope can be made to reduce by-catch, especially of passive species.

Physical demands during the hauling of fishing nets for artisan fishing using rafts in beach of Ponta Negra, Natal--Brasil.

The current article aims to analyse the activity and the repercussions in the health of the artisan fishermen who use rafts in the urban Beach of Ponta Negra in Natal - RN, with emphasis on the physical demands at the step of hauling the nets from the ocean. It has been taken as a reference the methodology of Work Ergonomic Analysis-WEA. 21 fishermen participated in the study (50% of the population). It was used applying observational techniques and methodologies (open and sistematic observations and simulations) interactional ( social and economic questionnaire, conversational actions, verbalizations, self confrontations and collective analysis) and health assessment (static postural assessment, movement flexibility of flexo extension of the shoulder and the ischiotibial muscle, lumbar region and hang grip. Applying the diagram of painful areas and the Nordic Questionnaire of mucleskeletal symptoms). The results were submeted to restitutions and validations with the raftmen. The hauling of the nets represents a high muscleskeletal risk, joining physical effort, adopting forced postures with the rotation of the spine and movement repetition, mainly flexo extension of vertebral spine, aggravated by the demand of strength fo the stabilizing muscles of the human body to keep the poise. The impacts of the activity of the fisherman of Ponta Negra, related to postures and strength demand were observed in the postural assessment and are related to the activity.

Gillnet fisheries as a major mortality factor of Magellanic penguins in wintering areas.

The incidental capture in fisheries is probably the main conservation problem affecting seabirds. While the capture of albatrosses and petrels on longline hooks is well-known worldwide, the bycatch of diving seabirds in gillnets is an overlooked conservation problem. During a winter coastal fishing trip, the capture of Magellanic penguins (Spheniscus magellanicus) was recorded in driftnet and bottom setnet fisheries for the first time in southern Brazil. The highest captures rates were found in driftnets, from 146.5 to 545.5 penguins/km² of net and a total of 56 dead penguins were recorded. In the bottom gillnet, a total of 12 birds were killed and the capture rates varied from 41.7 to 125.0 penguins/km² of net. Although preliminary, the results presented in this paper were consistent between sets. If we consider the magnitude of driftnet and setnet fishing fleets, and that most dead penguins were adults, the impact upon Magellanic penguin populations is probably significant.

Ethnobotany and ecological perspectives on the management and use of plant species for a traditional fishing trap, southern coast of São Paulo, Brazil.

The cerco-fixo is an artisanal fishing trap widely used by traditional communities in the estuarine region of the southern coast of the state of São Paulo, Brazil. The primary goal of the study was to investigate, through ethnobotanical and ecological approaches, the use of plant species by traditional fishermen to build the cerco-fixo at Cardoso Island State Park and Cananéia Island. Ethnobotanical data were collected through interviews, direct observation, plant collection and identification, and document analysis. An ecological evaluation was also done comparing five 20 × 20 m plots in a managed area to five 20 × 20 m plots in an unmanaged area, both within arboreal sandy soil vegetation called restinga arbórea, found within the Brazilian Atlantic Forest domain. This study involved 34 fishermen living at Cardoso and Cananéia Islands. The fishermen know more than 90 Atlantic Forest plant species that can be used to build the cerco-fixo. Tree species from the family Myrtaceae were the most quoted in the interviews. With respect to the ecological evaluation, the cluster analyses showed greater heterogeneity in terms of floristic composition (i.e. greater floristic dissimilarity) within the plots of the managed area. The analyses of diversity showed a slightly higher species richness and slightly lower values for Shannon, Simpson, Hurlbert's PIE and Evenness indices in the managed area (59 species; H' = 3.28; 1/D = 10.77; E = 0.80; Hurlbert's PIE = 0.91) compared to the unmanaged area (54 species; H' = 3.39; 1/D = 20.21; E = 0.85; Hurlbert's PIE = 0.95). The Hutcheson's t test showed no significant difference between both areas' Shannon diversity indices (t: -1.04; p: 0.30). These results are attributed to the greater dominance of the palm species Euterpe edulis Mart. in the managed area (28.2% of the trees sampled at this area; n = 118), which equals twice the percentage of individuals of the same species found for the unmanaged area (14.6% of the sampled trees; n = 48). We discuss the impact of the fishermen's harvesting practices in the managed area with an emphasis on three main points: (1) the harvesting practices are likely not contributing to a decrease in diversity in the managed area; (2) the greater heterogeneity in terms of floristic composition found for the managed area may reflect a mosaic pattern created by the opening of small tree-gaps distributed across this area over the course of more than 50 years; (3) the disturbance promoted by the fishermen's harvesting practices can be compared to natural disturbances of low impact that create mosaic patterns in tropical forests. This study emphasizes the prominence of the human dimension in ecological processes and the importance of considering the perspectives of local people when discussing the conservation of the natural environments in which these people live.

Small-scale marine fisheries in the municipal district of Florianópolis, Santa Catarina, Brazil.

The objective of this paper is to describe the main characteristics of small-scale marine fisheries in the municipal district of Florianópolis (SC), the capital city of the state of Santa Catarina. We give information about the most captured species, the fishing fleet and fishing gear used. The dynamics of the activity is described, considering the kind of operation of the boats, alongside post-capture procedures. The analyses were accomplished in two types of fishing communities: the one composed of fishers that fish in bays (North and South) and those who fish in the open sea. Numeric differences were observed among these two fishing areas, indicating the existence of two different fleets operating in the area. Differences between the two fishing areas were detected, considering the species caught, the harvest time and the fishing gear used. The open sea fishers have boats with dimensions, engine power, number of crew and fuel consumption numerically higher than those working in bays, indicating the existence of two distinct fleets operating in the region.

Small-scale marine fisheries in the municipal district of Florianópolis, Santa Catarina, Brazil / Pescarias marinhas de pequena escala no município de Florianópolis, Santa Catarina, Brasil

The objective of this paper is to describe the main characteristics of small-scale marine fisheries in the municipal district of Florianópolis (SC), the capital city of the state of Santa Catarina. We give information about the most captured species, the fishing fleet and fishing gear used. The dynamics of the activity is described, considering the kind of operation of the boats, alongside post-capture procedures. The analyses were accomplished in two types of fishing communities: the one composed of fishers that fish in bays (North and South) and those who fish in the open sea. Numeric differences were observed among these two fishing areas, indicating the existence of two different fleets operating in the area. Differences between the two fishing areas were detected, considering the species caught, the harvest time and the fishing gear used. The open sea fishers have boats with dimensions, engine power, number of crew and fuel consumption numerically higher than those working in bays, indicating the existence of two distinct fleets operating in the region.

Este trabalho teve como objetivo caracterizar a pesca de pequena escala no município de Florianópolis (SC). São apresentadas informações sobre as principais espécies capturadas, sobre a frota e artes de pesca utilizadas, sobre a dinâmica da atividade, considerando a forma de operação das unidades produtivas, e sobre os procedimentos pós-captura adotados. As análises foram realizadas em dois tipos de comunidades pesqueiras: as compostas por pescadores que atuam em baías e aquelas cujos integrantes pescam em mar aberto. Foram detectadas diferenças entre as duas áreas de pesca considerando as espécies capturadas, as épocas de captura e as artes de pesca utilizadas. Os pescadores de mar aberto possuem embarcações com dimensões, potência dos motores, número de tripulantes e consumo de combustível numericamente superiores aos que atuam nas baías, indicando a existência de duas frotas distintas operando na região.

Estructura de tallas, selectividad y composición específica de las capturas en trampas para peces marinos en el Golfo de California

Size structure, selectivity and specific composition of the catch in traps for marine fish in the Gulf of California. We analyzed the performance of three traps for marine fish between October 2005 and August 2006 in the Gulf of California, Mexico. The performance was measured as difference in selectivity, fish diversity, size structure and yield. The samples were collected with quadrangular traps 90 cm wide, 120 cm long and 50 cm high. Trap type 1 had a 5 x 5 cm mesh (type 2: 5 x 5 cm including a rear panel of 5 x 10 cm; trap 3: 5 x 10 cm). Most abundant in our traps were: Goldspotted sand bass (Paralabrax auroguttatus), Ocean whitefish (Caulolatilus princeps), Spotted sand bass (P. maculatofaciatus) and Bighead tilefish (C. affinis); there was no bycatch. The number of fish per trap per haul decreased when mesh size was increased. We also observed a direct relationship between mesh size and average fish length. By comparing our traps with the authorized fishing gear (hooks-and-line) we found that the size structure is larger in traps. Traps with larger mesh size were more selective. Consequently, we recommend adding traps to hooks-and-line as authorized fishing gear in the small scale fisheries of the Sonora coast, Mexico. Rev. Biol. Trop. 56 (3): 1403-1417. Epub 2008 September 30.

Se realizó un estudio orientado a evaluar tres tipos de trampas (eficiencia de captura, estructura de tallas, selectividad y composición de especies) para la captura de peces marinos en el Golfo de California. La recolecta de muestras se efectuó con trampas de 90 cm de ancho, 120 cm de largo y 50 cm de alto, con malla galvanizada cuadrangular en tres tamaños: una trampa completamente construida con abertura de malla de 5 x 5 cm (trampa 1); otra con malla de 5 x 5 cm, pero con el panel trasero de 5 x 10 cm (trampa 2) y la tercera con malla de 5 x 10 cm (trampa 3). Los experimentos se llevaron a cabo entre octubre del 2005 y agosto del 2006. Las especies que presentaron mayor incidencia de captura en cuanto a proporción del volumen total fueron el extranjero (Paralabrax auroguttatus), pierna (Caulolatilus princeps), cabrilla arenera (P. maculatofaciatus) y conejo (C. affinis) y prácticamente todas las capturas tuvieron valor comercial. El número de organismos por trampa por lance decreció al aumentar el tamaño de malla, mientras que la talla media se incrementó con el tamaño de malla de las trampas. Además las tallas son más grandes en cualquiera de las trampas que las obtenidas con piola de mano con anzuelos (el arte de pesca autorizado). Los resultados de la selectividad de tallas indicaron que las trampas de malla grande fueron más selectivas que las de malla más pequeña. En consecuencia, la captura con tram-pas es mejor que con los anzuelos y línea de mano, por lo que las trampas serían una muy útil adición al conjunto de artes de pesca usados en la pesca artesanal de la costa de Sonora, México.

[Size structure, selectivity and specific composition of the catch in traps for marine fish in the Gulf of California]. / Estructura de tallas, selectividad y composición específica de las capturas en trampas para peces marinos en el Golfo de California.

We analyzed the performance of three traps for marine fish between October 2005 and August 2006 in the Gulf of California, Mexico. The performance was measured as difference in selectivity, fish diversity, size structure and yield. The samples were collected with quadrangular traps 90 cm wide, 120 cm long and 50 cm high. Trap type 1 had a 5 x 5 cm mesh (type 2: 5 x 5 cm including a rear panel of 5 x 10 cm; trap 3: 5 x 10 cm). Most abundant in our traps were: Goldspotted sand bass (Paralabrax auroguttatus), Ocean whitefish (Caulolatilus princeps), Spotted sand bass (P. maculatofaciatus) and Bighead tilefish (C. affinis); there was no bycatch. The number offish per trap per haul decreased when mesh size was increased. We also observed a direct relationship between mesh size and average fish length. By comparing our traps with the authorized fishing gear (hooks-and-line) we found that the size structure is larger in traps. Traps with larger mesh size were more selective. Consequently, we recommend adding traps to hooks-and-line as authorized fishing gear in the small scale fisheries of the Sonora coast, Mexico.

Shrimp by-catch reduction using a short funnel net, in the Gulf of Tehuantepec, South Pacific, Mexico

Reduction of the by-catch in shrimp fishery is an important goal worldwide. In order to compare by-catch using the conventional trawling net and a newly designed short funnel net, nine cruises were carried out by the commercial fleet operating in the Gulf of Tehuantepec, Mexico. A total of 480 trawls were done (mean duration: 85 min). The experimental trawls using the modified net produced a 21.13-28.86 % by-catch reduction (confidence interval 95 %), a 3 % increase of shrimp catch, and a significant reduction on net recovery time. Rev. Biol. Trop. 55 (3-4): 889-897. Epub 2007 December, 28.

La reducción de la fauna de acompañamiento del camarón (FAC) es uno de los temas de discusión más importantes en la pesca mundial. Con la finalidad de contribuir en este tópico, se diseñó y utilizó una red de arrastre variando la longitud del túnel, y se comparó su efecto con el de una red tradicional; durante 9 cruceros de la flota comercial en el Golfo de Tehuantepec, México. Se realizó un total de 480 lances con promedio de 85 min cada uno. Los arrastres de la red modificada mostraron mejores resultados, con variación entre 21.13 a 28.86 %, con un 95 % de confianza de reducción de FAC, un incremento de 3 % en la captura de camarón, y una disminución del tiempo de recuperación, lo que sugiere un incremento en la eficiencia gracias al nuevo diseño.

Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil.

The Pacu Piaractus mesopotamicus is the most captured fish species in the Pantanal, Mato Grosso do Sul State, and since 1994, its maximum sustainable yield had already been exceeded. Its capture is carried out only by hooks, as mesh gears are forbidden either for professional or for recreational fishing. The aim of this study was to determine selectivity for different hook sizes used in P. mesopotamicus fishing and to verify which sizes capture only adults. Data were collected in the rivers Miranda, Aquidauana, and Vermelho, in January, March, and April 2002. Six longlines with eight hook sizes were used and we adopted the hook opening as a measure related to selectivity. Different hooks captured individuals of the same length and their medians were similar, evidencing the great overlap among sizes. Regression results showed no significant relationship between ln[c2(l)/c1(l)] and total length of captured individuals. In addition, the Kolmogorov-Smirnov test also did not detect significant differences in the size of captured fish. Several hypotheses, such as the selectivity models, shape of selection curves, scarcity of large fishes, and behavior are used in order to explain the absence of hook selectivity for this species. Size of recruitment for this gear was 28 cm of total length, when individuals are still immature.

Hook selectivity of the pacu Piaractus mesopotamicus (Holmberg, 1887) in the Pantanal, the state of Mato Grosso do Sul, Brazil

The Pacu Piaractus mesopotamicus is the most captured fish species in the Pantanal, Mato Grosso do Sul State, and since 1994, its maximum sustainable yield had already been exceeded. Its capture is carried out only by hooks, as mesh gears are forbidden either for professional or for recreational fishing. The aim of this study was to determine selectivity for different hook sizes used in P. mesopotamicus fishing and to verify which sizes capture only adults. Data were collected in the rivers Miranda, Aquidauana, and Vermelho, in January, March, and April 2002. Six longlines with eight hook sizes were used and we adopted the hook opening as a measure related to selectivity. Different hooks captured individuals of the same length and their medians were similar, evidencing the great overlap among sizes. Regression results showed no significant relationship between ln[c2 (l)/c1 (l)] and total length of captured individuals. In addition, the Kolmogorov-Smirnov test also did not detect significant differences in the size of captured fish. Several hypotheses, such as the selectivity models, shape of selection curves, scarcity of large fishes, and behavior are used in order to explain the absence of hook selectivity for this species. Size of recruitment for this gear was 28 cm of total length, when individuals are still immature.

Desde 1994, o pacu Piaractus mesopotamicus, é a principal espécie nas capturas comerciais e esportivas no Pantanal sul-matogrossense, e seu rendimento máximo sustentável já foi ultrapassado. Sua captura só é permitida por anzóis, para as duas pescarias acima, visto que as artes de emalhe são proibidas na região. O objetivo deste estudo foi o de determinar a seletividade para diferentes tamanhos de anzóis usados na captura do pacu e verificar a partir de qual tamanho de anzol somente os adultos são capturados. Para tal, foram realizadas pescarias nos rios Miranda, Aquidauana e Vermelho, nos meses de janeiro, março e abril de 2002. Seis espinhéis contendo 8 tamanhos diferentes de anzóis foram empregados. A abertura do anzol foi adotada para expressar sua seletividade. Diferentes anzóis capturaram indivíduos de mesmo comprimento, e suas medianas foram similares, evidenciando a grande sobreposição dos tamanhos capturados. As regressões entre ln[c2 (l)/c1 (l)] e l não foram significativas. O teste de Kolmogorov-Smirnov também não detectou diferenças significativas nos tamanhos dos peixes capturados por diferentes anzóis. Várias hipóteses são levantadas para explicar a ausência de seletividade dessa amplitude de tamanhos de anzóis para a espécie. O recrutamento para a pesca, porém ocorre aos 28 cm de comprimento total, quando os indivíduos ainda estão imaturos.

Shrimp by-catch reduction using a short funnel net, in the Gulf of Tehuantepec, South Pacific, Mexico.

Reduction of the by-catch in shrimp fishery is an important goal worldwide. In order to compare by-catch using the conventional trawling net and a newly designed short funnel net, nine cruises were carried out by the commercial fleet operating in the Gulf of Tehuantepec, Mexico. A total of 480 trawls were done (mean duration: 85 min). The experimental trawls using the modified net produced a 21.13-28.86% by-catch reduction (confidence interval 95%), a 3% increase of shrimp catch, and a significant reduction on net recovery time.

Reduction of the impact produced by sea lions on the fisheries in Mexico.

Activities of fishermen in the Bay of La Paz, B. C. S. are focused to satisfy the local demand of fish and shellfish by using approximately 300 small outboard crafts equipped with gillnets. Sea lions in this Bay attack the fishes captured damaging both product and gear. We did experimental gillnet throws to determine the frequency and preferences of sea lions in fishing areas. 52 experimental gillnet throws with time averages of 2 hr were performed, rending an average of 30 kg of fish captured and less than 10% of damages to the net.. Traditional fishermen in this Bay usually left the net the whole night, (approximately 7.50 hr, obtaining an average of 50 kg of captured fish, but the damages to the nets is in average of 40%. The cost-benefit balance comparing our alternative fishing method, which includes the use of the gillnets during the afternoon, watching for sea lions and retiring the nets at their arrival, it is more sustainable and profitable than the traditional fishing method currently used by the local fishermen. This paper suggests how to minimize the harmful effects of the sea lions on the fishermen productivity and gear, maximizing the production and reducing the damage. Our alternative method is applicable to other regions where this harmful interaction is taking place. We conclude that the coexistence of sea lions-fisheries is feasible, by applying the simple measures that we propose.

Financial comparisons of the artisanal fisheries in Urubupungá Complex in the middle Paraná River (Brazil).

The main objective of this study was a bio-economic survey of artisanal fishing so as to compare average profit of the fishermen, in two different environments (reservoirs and river) and seasons (dry and rainy). To carry out financial comparisons of artisanal fisheries in Urubupungá Complex in the middle Paraná River (Brazil), three habitats were considered: I) Ilha Solteira and Jupiá reservoirs; II) the Paraná River between the Jupiá and Primavera dams; III) the Paraná River downstream from the Primavera dam. Data collection was done through questionnaires addressed to a total of 187 fishersmen; just 164 of the resulting interviews were considered valid. They were held in July 1998 (dry season) and February 1999 (rainy season). The daily average profit of the resevoir fisherman was R$ 13.19 during the dry and R$ 19.54 during the rainy season; R$ 4.10 and R$ 12.92 for fishermen located on the Paraná River between Jupiá and Primavera dam; and R$ 1.48 and R$ 23.01 for those located on the Paraná River below Primavera dam (R$ 1.00 = US$ 0.86 during the dry season; R$ 1.00 = US$ 0.52 during the rainy season). A linear model had been tried to explain the profit variable, in relation to those variables directly linked to fishing (e.g., as habitats; seasons, dry or rainy; gear used; days spent fishing) as well as several sociological variables (age, marital states, number of dependents, and education). However, due to large variability in profits, the proposed model only explained 48.4% of variability, and the only significant factors were education, type of gear, and covariant fishing days.