939 resultados para Marine pollution.
Resumo:
The recent establishment of a marine park in Vietnam offers lessons for future marine reserves in the country as well as for other countries considering their establishment. These lessons are contained in this brief article.
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The marine fisheries of Trinidad and Tobago are mainly artisanal and involve about 8,000 fishers. The main fishing gear used are the gillnets, the troll, the shrimp trawl, the fishpot and the industrial longline. Landings total approximately 14,000 t annually with Scomberomorus brasiliensis, shrimps and sharks being the most abundant in the landings. Assessment studies indicate overfishing and inferior marketing is an important issue. Underexploited resources include clupeiods, deep shell and slope resources, and lobsters. The shrimp trawl and longline by-catch are not fully utilized. Fishery legislation is mostly uotdated and a fisheries policy, including new legislation, is being developed to help solve the problems and effectively manage the fisheries.
Resumo:
A study of chemoreception in relation to feeding and other factors involved showed that feeding behavior in shrimps can be triggered by chemical stimuli. However, Penaeus indicus and Metapenaeus dobsoni differ significantly in their chemotactic response to different stimuli.
Resumo:
Parameters of the length-weight relationship are presented for 85 fish species from the marine and estuarine regions of the central Brazilian coast (latitude 13° to 23° S). Three different methods were used. A non-linear iterative process using the quasi-Newton algorithm yielded a better fit for all data sets analyzed. The length-weight allometry coefficient b estimated from standard length data tended to be lower than from total length data. The difference between these estimates was significant for some species.
Resumo:
A total of 140 sets of parameters (a and b) of the length-weight relationships (LWR) of the form W=aL super(b) are presented for fishes caught in Cuban waters. These parameters cover 94 species of fish belonging to 43 families. Most of the parameters were compiled from 107 sets of published and unpublished studies. Twenty-five sets of parameters were from personal communications through colleagues in Cuba, while the remaining eight sets were estimated by the authors from unpublished data.
Resumo:
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
Resumo:
This paper discusses the status, direction and management issues in the marine protected areas (MPAs) of the Bohol (Mindanao) Sea, Philippines. The MPAs in the study area have increased through the years. Many of them were established and managed by the local government units (LGUs) in collaboration with national government agencies (NGAs), academic institutions, people’s and non-governmental organizations (NGOs). Several management issues and problems were cited by the MPA managers such as insuffi cient funds and facilities, lack of support from NGAs/NGOs and lack of education among the people. Nevertheless, lessons for sustainability can be learned from the experience of some wellmanaged MPAs in the Bohol Sea. These include strong support from the political leadership, community participation and networking among the concerned sectors. Although the best practices are being followed in a number of MPAs in the Bohol Sea, success is still fragmented. The MPAs are currently managed independently although there are ongoing initiatives to network their efforts. However, it can be observed that, as a management tool, MPAs are gaining popularity and support, not only among the fisherfolk but also among local communities and LGUs in the Bohol Sea area.