Fernando D'Incao

The present status of artisanal fisheries of extreme Southern Brazil: an effort towards community-based management

Abstract The continental shelf of the extreme southern Brazil is one of the most productive fishing areas in Brazil. Great part of the commercial species is related to the estuary of Patos Lagoon. The estuary serves as spawning, nursery and feeding grounds for several species. The artisanal fishery in the estuarine area exists since the end of the last century but from 1982 onwards, catches have declined sharply. Nowadays, the estuarine fishery does not exist as an economic activity, except for pink shrimp (Farfantepenaeus paulensis) and mullet (Mugil platanus). The artisanal fishery involves about 3500 fishermen. Fisheries management in the Patos Lagoon and coastal area has been traditionally done in a top-down process: government decides and acts unilaterally. As a consequence, regulations exist only officially. In 1996 the Forum of Patos Lagoon, a multi-partner entity that includes political, economical and legal institutions, was established. This is the first initiative of the community to become part of the organization and regulation process of the fisheries in the area. The Forum activities initiatives range from evaluation of the present practices of fisheries management and enforcement, encouragement of co-operative and associated initiatives; to planning and development of activities that may lead to the possible recovery of the productive capacity of the Patos Lagoon. A new regulation for the area was produced considering, for the first time, the interest of the community. Although this represents a major step on fisheries management in the area, it resents the lack of a specific management for fisheries that exploit the same stocks in marine waters. The lack of a clear policy for the fishery sector in Brazil represents a major setback to achieve proposed goals in management.

Estágios de desenvolvimento gonadal de fêmeas do camarão-barba-ruça (Artemesia longinaris - Decapoda: Penaeidae)

The stages of gonadal development for the female of barba-ruca shrimp (Artemesia longinaris Bate, 1888) were characterized based on histological analysis. Four stages (immature, almost mature, ripe and spawned) were determined according to the structure and arrangement of cells in the ovary. Each stage corresponds macroscopically to a characteristic color, except stages I (immature) and IV (spawned), in which colors are very similar and can be distinguished only microscopically. The chromatic scale varies from white/translucent (stage I), neutral green (almost mature) to dark green (ripe). The mean size of cells was 56.9 µm (±3.5) (stage I), 127 µm (±2.6) (stage II) and 183 µm (±1.91) (stage III). The size frequency of cells was polimodal, and different cell stages were observed in ripe ovary, suggesting the occurrence of multiple spawning. The chromatic scale developed is an important tool for laboratory analysis, and can be easily used to identify the gonadal stages.

Growth and mortality of Hepatus pudibundus (Crustacea: Calappidae) in south-western Brazil

The predatory action of the pink shrimp {Farfantepenaeus brasiliensis and Farfantepenaeus paulensis) trawling fishery in south-western Brazil affects populations of some benthic species and Hepatus pudibundus is an abundant by-catch in this fishery. Individual growth and mortality of H. pudibundus were studied by taking monthly samples for a year from the by-catch of the pink shrimp fishery in the Ubatuba region. The von Bertalanffy growth model described growth of H. pudibundus (K=2.73 y -1 , CW ∞ =82.97 mm; K=2.62 y -1 , CW ∞ =66. 72 mm, for males and females respectively). Modal progression of the monthly average sizes was related to increasing values of relative condition index. The instantaneous coefficients of total, natural, and fishing mortality were: males, Z=7.62 y -1 ; M=1.80 y -1 ; F=5.83 y -1 ; females, Z=7.36 y -1 ; M=1.80 y -1 ; F=5.56 y -1 . Length composition and mortality analysis suggest that H. pudibundus in the Ubatuba region might be overfished.

Reproductive strategies of two sympatric swimming crabs Callinectes danae and Callinectes ornatus (Crustacea: Portunidae) in an estuarine system, south-eastern Brazil

The present study analysed the reproductive biology of Callinectes danae and Callinectes ornatus, which are captured as by-catch from pink-shrimp trawling in Guanabara Bay. The size atgonadal maturity was 79.9 mm and 67.4 mm respectively, for C. danae and C. ornatus. The pattern of reproduction was continuous for both species; however, the gonadosomatic index analyses showed seasonal and alternating reproductive peaks in the bay. While C. danae showed reproductive peaks in the autumn and in the winter, C. ornatus showed an apparent reproductive peak in the summer and probably another in the spring. The sex-ratio of C. danae was significantly skewed in favour of females (3.0:1). However, in C. ornatus, males predominated (1.2:1). This reproductive pattern indicated that possibly the females of C. danae return to the estuary after spawning where trawling takes place, while ovigerous females of C. ornatus migrate to adjacent coastal areas around the bay.

Effects of migration activity on the mortality rates of two Portunidae crabs in a tropical bay

*Universidade Federal do Rio de Janeiro, Instituto de Biologia, Depto. Biologia Marinha, Laboratorio de Biologia e Tecnologia Pesqueira, CCSBl.A, 21949-900, Cidade Universitaria, Ilha do Fundao, Rio de Janeiro, Brazil. †Universidade Federal de Sao Carlos, Depto. de Hidrobiologia, Laboratorio de Dinâmica de Populacoes de Peixes, Caixa Postal 676, 13565-905, Sao Carlos, Sao Paulo, Brazil. ‡Fundacao Universidade de Rio Grande, Depto. de Oceanografia, Laboratorio de Crustaceos Decapodes, Caixa Postal 474, 96201-900, Rio Grande, Rio Grande do Sul, Brazil. ∫Corresponding author, e-mail: keunecke@biologia.ufrj.br

Habitat selection of the pink shrimp Farfantepenaeus paulensis and the blue crab Callinectes sapidus in an estuary in southern Brazil: influence of salinity and submerged seagrass meadows

This study was conducted in two estuarine inlets (Saco da Mangueira and Saco do Arraial) at the Patos Lagoon estuary, southern Brazil. The changes in relative abundance and size of post-larvae and juvenile shrimp Farfantepenaeus paulensis and juvenile blue crab Callinectes sapidus were compared, considering the influence of salinity and the presence of submerged seagrass meadows. The analyses were performed using generalized linear models (GLM) for abundance variations and ANOVA for variations on the size of individuals. The pink shrimp was more abundant at Saco da Mangueira, in seagrass meadows and areas of higher salinity. The blue crab was more abundant at Saco do Arraial and in lower levels of salinity. The importance of submerged vegetation for the blue crab lies in a preference of smaller crabs of the species for the seagrass meadows. It has been shown that these species choose different habitats in the estuary, and both the salinity and the presence of submerged seagrass meadows influence the selection of habitat.

Growth of Ligia exotica (Isopoda: Oniscidea: Ligiidae) in two estuarine regions of Patos Lagoon, Rio Grande do Sul, Brazil

The aim of this study was to estimate growth parameters of two populations of Ligia exotica inhabiting discrete estuarine areas of Patos Lagoon, Rio Grande do Sul, Brazil. Sampling was performed fortnightly at two different estuarine zones, named Leonideo Island and West Breakwater, to detect different growth patterns for this species by using the von Bertalanffy growth model (VBGM). The VBGM estimated were as follows: TL mm = 34 . 57 ( 1 - e ―0.012(t ― 2.93) ) (males in Leonideo Island), TL mm = 35.61 (1 ― e ―0.009(t ― 5.87) ) (males in West Breakwater), TL mm = 30.11(1 ― e ―0.009(t ― 5.84) ) (females in Leonideo Island) and TL mm = 29.65(1 ― e ―0.01(t ― 4.87) ). Significant sexual dimorphism was observed, since males reach larger TL (mm) by higher k value (day) and consequently a faster growth pattern. Different growth patterns of males were also detected comparing both populations, in such a way that the West Breakwater individuals are larger than those from the Leonideo Island. One possible explanation is the higher food availability observed in the former site, as well as favourable environmental parameters, providing better conditions for individual growth. Briefly, two different populations of L. exotica were detected in the studied area, presenting discrete growth parameters highly influenced by environmental factors.

Crescimento de Callinectes sapidus (Crustacea, Decapoda, Portunidae) no estuário da laguna dos Patos, RS, Brasil

Utilizando o metodo de deslocamento modal para a identificacao das idades, estimou-se o crescimento do siri-azul Callinectes sapidus Rathbun, 1896 em duas areas de pesca no estuario da Lagoa dos Patos. Os individuos foram coletados entre fevereiro de 2005 e marco de 2006 no Saco da Mangueira e Saco do Arraial por meio de arrasto de rede de portas da pesca artesanal. Coletou-se um total de 2.609 animais, sendo 1.193 machos e 1.416 femeas. Para obtencao das curvas de crescimento utilizou-se o modelo de von Bertalanffy. As curvas foram validadas pela sua adequacao ao ciclo de vida e aspectos biologicos da especie. O tamanho maximo de largura de carapaca (LCmax) utilizado foi mantido fixo em todas as analises (LCmax=162,71mm; ± d.p.=3,10 para machos e LCmax=157,78mm; ± d.p.=5,45 para femeas), sendo esses valores medios das maiores medidas obtidas em mais de 20 anos de coletas no estuario. Os parâmetros de crescimento e longevidade foram estimados para machos (Saco da Mangueira, K=0,0039/dia; to=-6.07; 1.195 dias; Saco do Arraial, K=0,0041/dia; to=-5,84; 1.102 dias) e femeas (Saco da Mangueira, K=0,0040/dia; to=-6,22; 1.153 dias; Saco do Arraial, K=0,0039/dia; to=-5.91; 1.181 dias). As curvas de crescimento estimadas nesse trabalho denotam que a especie atinge o tamanho minimo de captura praticamente no primeiro ano de vida (120mm).

Range extension of the mud crab Eurypanopeus depressus (Smith, 1869) (Decapoda, Panopeidae): A new record for the coastal south of Brazil

The discovery of Eurypanopeus depressus (Decapoda: Panopeidae; Smith, 1869) on the coast of Rio Grande do Sul, Brazil suggests that the species was recently introduced, possibly due to different sources of introduction, such as the ballast water of ships. E. depressus were collected using otter-trawl net in the Patos Lagoon Estuary. Discussion focuses on the fact that the primary South American distribution derives from Uruguayan shores, and later expanded to nearby places (Brazil and Argentina). This work extends the Southern Hemisphere distribution for the species, as it was previously reported only from Argentina to Uruguay.