Participatory management of a reservoir fishery in northeastern Brazil

Consensus, compromise and cooperation. That was how more than 100 fishers reached agreement on how they would manage their own fishery in a small reservoir in northeastern Brazil. The long hard road that led to the agreement, the final congress in which fishers made minor history and the lessons that others may draw from the experience are described in this article. The fishers agreed on a nonfishing period of protected areas and a seasonal ban on certain nets in the face of a government department that told them the measures were non-building and essentially illegal.

Population parameters of 'corvina' (Plagioscion squamosissimus) in the Barra Bonita Reservoir, Brazil

Estimates for the growth parameters (L sub( infinity ) and K) mortality coefficients (Z,M and F) and exploitation rate (E) for the sciaenid Plagioscion squamosissimus are presented. The following results were obtained: 1) for male: L sub( arrow right )=44.2 cm, K=0.30 yr super(1), Z=0.82 yr super(1), M=0.66 yr super(1), F=0.16 yr super(1), and E=0.20; and 2) for females: L sub( arrow right )=68.4, K=0.22 yr super(1), Z=0.91 yr super(1), M=0.47 yr super(1), F=0.44 yr super(1) and E=0.49. Females are more heavily fished than males. Artisanal fishing carried out with gillnets, is mainly directed toward the young section of the population and individuals reproducing for the first time.

A list of commercial fish species from Santarem, state of Para, Brazil

A list, comprising 129 species in 23 families, is presented of the fish commonly caught in 1992/93 in the commercial fisheries around Santarem, Para State, Brazil. The most important families were the Pimelodidae (22 spp.), Cichildae (20) and Serrasalmidae (15), and six species contribute over 50% of the catch in weight.

Length-weight relationship of marine fishes from southern Brazil

The relationship between length (L) and weight (W) was estimated for 80 species belonging to 50 families of marine fishes from the shelf and upper slope of southern Brazil (lat. 28°S - 34°S). Sample sizes (n) for different species ranged from 11 to 14 741 specimens collected from commercial landings and research surveys. The fit of the equations (W=aLb) with a and b parameters estimated from regular and functional regression (of log-transformed weight and length data) as well as from a non-linear iterative process using the quasi-Newton algorithm were compared. The non-linear method gave the most accurate estimates in terms of residual sum of squares. Differences were less than 2.3% for n>500 compared with predictive regressions and 1.5% compared with functional regressions. No difference was observed between both predictive and functional regressions. Determination coefficients (r2) increased with sample size, and the highest r2 were obtained for 50

Can the age of the tropical species be determined by otolith measurement?: a study using Pristipomoides filamentosus (Pisces: Lutjanidae) from the Mahe Plateau, Seychelles

The sagittal otoliths of bluespot jobfish (Pristipomoides flamentosus) from the Mahe Plateau, Seychelles, were examined for growth rings using light microscopy. Banding with putative annual and monthly frequency were observed. Consistent age estimates were derived from each of the two patterns. The resulting length-at-age data were use t estimate the parameters K and t sub(0), viz: K=0.33, t sub(0) = 0.16 for males and K = 0.36, t sub(0) = 0.06 for females (using von Bertalanffy plots). Possible causes of the banding are discussed.

A traditional floodplain fishery of the lower Amazon River, Brazil

This paper describes fishing activities of households in four communities located in a floodplain lake system of the lower Amazon river. An average of 42 households were interviewed about their fishing activity on a monthly basis. The fishery is a typical multi-gear, multi-specific artisanal fishery. Approximately ten types of fishing gear are utilized, of which the three main types of gillnets account for 51% of the total catch. The catch per trip averaged 15 kg, for an annual total of 2,295 kg per household. Some 40 species or groups of species are caught, although four species account for 50% of the total. There is a strong seasonal pattern to the fishery, with catch per trip and catch per unit effort (CPUE) highest in the low water season (September-November). While there are marked differences between subsistence and commercially oriented fishing strategies, these differences are more in degree than in type, since fishers use the same types of gear and most fishers regularly sell part of their catch.

Length-weight relationship of marine fish species off Sao Sebastiao system, Sao Paulo, Southeastern Brazil

The parameters a and b of the length-weight relationship of the form W = a . L super(b) were estimated for 57 fish species sampled in Sao Sebastiao Channel and shelf system in 1997, Sao Paulo, Brazil. The b values ranged from 2.746 to 3.617. The Student's t-test revealed that mot (44) species had b values significantly different from 3. A normal distribution of the calculated LWR exponents (b) was obtained.

Preliminary Analysis of the Feasibility of Transferring New Longline Technology to Small Artisanal Vessels off Northeastern Brazil

The catches of three longliners, including two recently converted small artisanal vessels and one large leased foreign longliner, were compared to provide some indication of the feasibility of transferring new longline technology to small vessels in the northeastern Brazilian pelagic longline fishery. Comparisons of catches between the two recently converted vessels operating across the same spatial and temporal scales showed no significant differences for the main target species, providing evidence to suggest that adoption of the technology was rapid and straightforward. A comparison of relative catch rates between one of the recently converted small longliners and the leased longliner across the same temporal scale, but in different areas, showed that while there were significant differences detected for some species, contributing to a significant reduction in total CPUE, the relative abundance of commercially important species within the operational range of the smaller vessels was sufficient for economically viable catches. The results showed that the net financial profit from the artisanal longliner was almost 10 times greater than that derived from existing fishing methods. The inclusion of some artisanal vessels in this fishery may help address the social and economic problems currently faced by fi

Review of a Small-scale Pelagic Longline Fishery off Northeastern Brazil

The annual catches of four small longliners operating off northeast Brazil from 1983 to 1997 were examined across different areas and locations. The total catch comprised tunas (30%), sharks (54%), billfishes (12%), and other fish species (4%). Fishing strategy and annual composition of catches showed large spatial and temporal variabilities with the dominant catches alternating among yellowfin tuna, Thunnus albacares; gray sharks, Carcharhinus spp.; and blue shark, Prionace glauca. Catches of blue and gray sharks showed a significant interaction among seamounts, with gray sharks occurring in maximum abundance around those seamounts that had relatively deep summits and low-sloping depth profiles. Results are discussed in terms of the various factors that may have influenced distribution of effort.