In this study data relative to the fishery in the freshwater area of the Patos Lagoon are analysed, and the dynamics, fishing gears used and catches evaluated. The results reveal the existence of two fishery strategies: forbidden mesh size gillnets (FMG; <35 mm; square measure) and allowed mesh size gillnets (AMG; ≥35 mm; square measure). In total, 31 species were caught (AMG = 27 and FMG = 24), but selectivity due to mesh size was significant (P < 0·001). The FMG may be very harmful since it captures individuals of most species below size at first maturity, including the target species, the armoured catfish Loricariichthys anus (61% of the total catch). In addition, this gear is used throughout the year, including the closed season (CS; November to January), when the target species is reproducing. Target species for the AMG are larger in size, comprising mainly the mullet Mugil liza, the marine catfish Genidens barbus and the whitemouth croaker Micropogonias furnieri. AMS gillnets were not used during the CS. The use of FMG reveals the need for effective fishery law enforcement and the need for additional studies to assess the status of populations of the exploited species.

No abstract

We analysed the ratios Sr:Ca and Ba:Ca in the otoliths of 55 adults of the southern population of Mugil liza in Brazil (Paraná to Rio Grande do Sul) to investigate its coastal zone use and migratory behaviour. All individual M. liza analysed had Sr:Ca and Ba:Ca values indicating that their birth was in the marine environment, which is consistent with the southern population migration to spawn in the ocean,. Juveniles exhibited at least three coastal use and recruitment strategies (contingents): the majority (89%) of M. liza juveniles migrated toward brackish water. They entered the estuary before completing the first year of life (64%) or after (25%) their first year of life. The remaining 11% did not appear to enter brackish or freshwater water as a nursery or at any point in their life cycle. Some adults returned to the estuary after spawning in the ocean but others (of both sexes) never returned to the estuary after spawning, remaining in the marine environment. The pattern of juvenile habitat use in the Brazilian southern population of M. liza seems to be recurrent throughout the extent of its distribution as a consequence of the reproductive spawning aggregation behaviour, which mixes all contingents (with marine or estuarine preferences).

This contribution records the reproductive periods of ten dominant freshwater fish species from the Patos Lagoon and Guaíba Lake (Astyanax fasciatus, Cyphocharax voga, Hoplias malabaricus, Oligosarcus jenynsii, Oligosarcus robustus, Hoplosternum littorale, Loricariichthys anus, Parapimelodus nigribarbis, Trachelyopterus lucenai, Pachyurus bonariensis). Data were derived from monthly samples in Casamento Lake (northern Patos Lagoon; Nov. 2002 to Apr. 2004) and Guaíba Lake (Jun. 2005 to May 2006). The reproductive period was determined according to the monthly variation of the gonadosomatic index (GSI). Fish reproduction was identified during all months of the year. Oligosarcus jenynsii started reproduction in winter, but extended spawning to spring (early warming-water reproduction). Three species also presented reproduction during warming water months, but beginning in spring and finishing in summer (late warm-water reproduction): P. nigribarbis, T. lucenai and P. bonariensis. Three species presented relatively short reproduction periods on summer (spotted warm-water reproduction): H. malabaricus, H. littorale and L. anus, and only one species reproduces almost continuously during warmer waters (long-season warm-water reproduction): A. fasciatus. Finally, two other species presented a very distinct reproductive pattern, starting reproduction on late summer but increasing GSI values along autumn and winter (long-season cooling-water reproducers): C. voga and O. robustus.

A zona costeira brasileira é singular por sua histórica importância socioeconômica e sua riqueza natural, onde atividades de elevado impacto poluidor coexistem com recursos ambientais de extrema importância. Na tentativa de agregar uma vertente participativa na política de gestão do território costeiro, o plano de gestão do governo federal denominado “Projeto Orla” apresenta-se como uma proposta de política pública descentralizadora e integrada. Nesse contexto, o presente trabalho buscou contribuir na avaliação deste instrumento de gestão ambiental, considerando como estudo de caso a implantação do Projeto Orla no município de Balneário Rincão (litoral sul de Santa Catarina, Brasil). A partir da metodologia de observação participante e da análise de documentos de fontes primárias, identificaram-se os seguintes aspectos: (1) a participação da comunidade no processo de gestão territorial é fundamental para garantir o atendimento das necessidades e peculiaridades de cada região; (2) a integração dos instrumentos de gestão é de extrema importância para diminuir os conflitos no uso e ocupação do território; e (3) a educação ambiental é o principal instrumento de sensibilização para a transição do modelo atual de consumo para o modelo ambientalmente sustentável.

A grande concentração populacional nas regiões costeiras do Brasil, resultado da falta de planejamento territorial, gera uma ocupação predatória que leva a graves desequilíbrios socioambientais. A degradação dos ecossistemas costeiros, com supressão da flora nativa, contaminação de solo e dos recursos hídricos, traz à tona a situação de insustentabilidade, acarretando significativos impactos às comunidades, notadamente às tradicionais. Nesse contexto, enquadra-se o estuário da Bacia do rio Urussanga, situado na interface entre a Área de Proteção Ambiental da Baleia Franca e a localidade de Barra do Torneiro (Jaguaruna/SC), litoral Sul de Santa Catarina. Área historicamente utilizada para as atividades da pesca artesanal, que ao longo do tempo recebeu impactos diretos de atividades econômicas de várias matrizes, sobretudo, aquelas oriundas da mineração de carvão. Esta degradação resultou dentre outros aspectos na contaminação e assoreamento do rio Urussanga, devido ao carreamento de sedimentos compostos por metais pesados, entre outros poluentes em suspensão ou dissolvidos. Nesse estudo foram investigados os impactos socioambientais no estuário em questão, a partir da percepção ambiental de lideranças e representantes dos pescadores locais, através de pesquisa documental e de diagnóstico participativo. Pôde-se constatar que os pescadores remanescentes se encontram com as suas atividades precarizadas e em processo de extinção, seja pela dimensão ambiental dos impactos, devido à poluição do estuário, seja pela falta de políticas públicas voltadas para a valorização das populações tradicionais. Ao mesmo tempo, ampliam-se os problemas no território, face à ocupação desordenada crescente, destoante dos princípios básicos assegurados no Plano Nacional de Gerenciamento Costeiro, que preconiza o planejamento e a gestão ambiental na perspectiva da sustentabilidade.

In this study, we examine how the Guri catfish Genidens genidens uses estuarine and freshwater habitats along the largest South American coastal lagoon, through the chemical analysis of otoliths and microscopic analysis of gonads. Chemical composition (Sr:Ca) of otolith edges allowed distinguishing between individuals who used the estuarine or freshwater compartments of the lagoon. The analysis of core-to-edge chemical profiles of each individual otolith revealed that the population may present two different patterns of habitat use along the lagoon. The ‘type 1’ pattern (89.5%) includes fish who appear to have been born in estuarine waters, whereas ‘type 2’ (9.5%) includes those fish born in fresh water. Nevertheless, juveniles from both patterns appear to migrate to estuarine waters. The gonad analysis shows G. genidens may reproduce in fresh water, as nearly 57% of all sampled fish were found to spawn in the freshwater portion of the lagoon. Also, the otolith core of many adult fish presented freshwater signatures, thus suggesting consistent fresh water use during early life. Our findings based on otolith and gonadal analyses challenge the previous classification of G. genidens as an estuarine resident. Rather, our results allow the suggestion that this species should be placed in the ‘estuarine and fresh water’ guild, which includes both fish completing their life cycles within the estuary and fish who consistently use freshwater habitats.