Despite the magnitude of domestic and industrial pollution, fishery yield registered in several landing points at
The invertebrate benthos, especially the micro-and mesofaunal components, of the Brazilian seas is still poorly known. Relatively few species have been recorded, reflecting the lack of research in this field. The intertidal zone, to depths of about 20 m, has been studied the most, and there the numbers of endemic species are relatively high. The diversity of demersal and pelagic fishes is similar among the major marine regions, and endemism is typically low (<5%) and restricted to reef species. Surveys in southeastern Brazil (depths of up to 2000 m) have recorded more than 1300 species of benthic animals, of which the Porifera, and Brachiopoda were the most abundant or frequent. Excepting the molluscs, decapods (brachiurans), cirripeds, and echinoderms, the faunas of salt marshes, coral reefs, and islands remain poorly known. Marine and estuarine demersal teleosts include 617 species in 26 orders and 118 families. Just over half the species (337) are Perciformes. Overexploitation, for food and by the aquarium fish trade, habitat degradation and destruction, alien species introductions, pernicious tourism, and pollution are the principal threats to Brazil's marine biodiversity. The Ministry of the Environment lists 34 threatened and 10 overexploited or at risk of being overexploited benthic species. Fishes officially listed as threatened include 15 species of sharks and rays and 7 teleosts. Another six elasmobranchs and 27 teleosts are currently or potentially being overexploited. Conservation of marine biodiversity in Brazil is still broadly inadequate despite existing legislation and several protected areas. The number and size of marine protected areas are insufficient, and some still lack management plans or have yet to receive the appropriate measures and infrastructure to make them effective. Fisheries administration and management is still precarious and in many areas lacks effective participation of local communities. Major conservation initiatives include the identification of keys areas for biodiversity conservation, surveys, intensified monitoring of fisheries, environmental education, and the creation and improved management of protected areas. Conservación de la Biodiversidad Marina y Costera en BrasilResumen: Los invertebrados bentónicos, especialmente los componentes micro y mesofaúnicos, de los mares brasileños son poco conocidos. Se han registrado pocas especies relativamente, lo que refleja la carencia de investigación en este campo. La zona intermareas hasta profundidades de casi 20 m es la más estudiada, y el número de especies endémicas es relativamente alto. La diversidad de peces demersales y pelágicos es similar en las regiones marinas principales, y el endemismo es típicamente bajo (<5%) y está restringido a especies arrecifales. En muestreos en el sureste de Brasil (profundidades hasta 2000 m) se han registrado más de 1300 especies de animales bentónicos, de las cuales fueron más abundantes y frecuentes Porifera, Cnidaria, Sipuncula, Gastropoda, Bivalvia, Scaphopoda, Polychaeta, Crustac...
In the recent past, the Sepetiba Bay watershed, located in the Rio de Janeiro State, Brazil has experienced rapid industrial development and population growth, as well as an increase in water pollution and environmental degradation. To analyze the complex interrelationships among the agents affecting the Sepetibza Bay environment, a system dynamics model was developed. The model builds on extensive studies conducted for the watershed, and simulates different hypotheses of economic growth and of demographic expansion. Thus, it can be used as a decision support tool for the identification of investment priorities and policy analyses under various scenarios. In order to provide a comprehensive approach to the environmental management of the Sepetiba Bay watershed, the model had to consider only the most relevant aspects of the behavior and the key interactions among agents operating in the watershed. In this article, the model's structure is presented together with some of its main results.
SUMMARY:The recruitment process for Brazilian sardine (Sardinella brasiliensis) from 1977 to 1993 was investigated by taking into account the effects of spawning stock biomass (SSB), the intensity of the wind and the sea surface temperature (SST). Nonparametric models were applied. Best fits resulted from relating recruitment to a combination of SSB and Ekman transport. Transformation of Ekman transport is nearly dome-shaped, with lower and upper limits of 520 and 700 kg s -1 m . SST transformations also follow an apparent dome-shaped curve optimising around 24.75 and 25.5ºC. Inclusion of SST as a third predictor variable led to the loss of the dome-shaped relationship, as shown by the transformations with two predictor variables. Biomass curves are almost logarithmic, their critical point oscillating around 200,000-250,000 t, below which value the stock becomes more dependent on recruitment. The biomass range is greater than previous estimates. [1977][1978][1979][1980][1981][1982][1983][1984][1985][1986][1987][1988][1989][1990][1991][1992][1993]. -El reclutamiento de la sardina brasileña (Sardinella brasiliensis) fue investigado, en el periodo de 1977 a 1993, teniendo en cuenta los efectos de la biomasa del stock frezante, la intensidad del viento y la temperatura de la superficie del mar (TSM). Se aplicaron modelos no parámetricos. Los mejores ajustes fueron obtenidos considerando las variables de biomasa frezante (SSB) y el transporte de Ekman. Para la transformada del transporte de Ekman fue observada una forma aproximada de "domo" con límites inferior y superior, respectivamente, de 520 y 700 kg s -1 m -1 . La fracción de la variabilidad del reclutamiento explicada por el ajuste fue de 94%. Fueron evidenciadas regiones de máximo con lími-tes, respectivamente, de 0,035 y 0,045 N m -2 para el "stress" del viento; y 30 y 45 m 3 s -3 para el índice de turbulencia. Esos valores corresponden a vientos con intensidad entre 3,0 y 4,5 m s -1 . Las transformadas para la TSM muestran, también, un efecto con forma de domo alrededor de 24,75 a 25,5ºC. La inclusión de la TSM como una tercera variable independiente llevó a la 'perdida' de la forma "domo", observada en las curvas de las transformadas para dos variables. Para la biomasa, se observan curvas próximas a la logarítmica, con un valor de cerca de 200 a 250 mil toneladas como límite por debajo del cual el stock pasa a depender mas estrictamente del suceso del reclutamiento. Ese intervalo es superior a las estimativas obtenidas en estimaciones anteriores.
Most of the oil and natural gas produced in Brazil derive from offshore fields, virtually concentrated in the Campos Basin off the coast of Rio de Janeiro State. The area is also of intense fisheries interest, involving participation of hand-liners artisanal boats and tuna boats due to the fish aggregating effect of the oil rigs. In order to avoid accidents with the platform "Stena Tay", in operation at Santos and Campos Basins, in 2001 e 2002, an awareness project was developed aiming at avoiding the presence of fishing boats in its 500 m exclusion zone. This paper summarizes the main observations concerning the extent of the fish aggregating effect and the behavior of the fishing boats in the vicinity of the platform.
Size compositions and total landings of skipjack tuna caught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length cohort analysis and virtual population analysis. From monthly size frequency data it is suggested that there is constant immigration and emigration of different modal groups in the fishing area with an interval of two to three months. The exploitation rate was very low for length class between 35-45 cm FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 cmFL. The estimate of the average number of fish attaining a size of 43 cm FL (recruit) was 11.0 x 10(6) fish for assumed values of M - 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes
Size eorrrpositions and total landings of skipjaek tuna eaught in the southeastern Brazilian waters by bait-boats are used as the basis of the assessment of the population for 1980-1983 period, employing the length eohort analysis and virtual population analysis. From monthly size frequeney data it is suggested that there is eonstant immigration and emigration of different modal groups in the fishing area with an ~nteY'Val of two to three months. The exploitation rate was very low for length elass between 35-45 em FL, then increased gradually. The weighted mean exploitation rates were 0.060 and 0.448, respectively for length classes smaller and larger than 55 em FL. The estima_te of the average number of fish attaining a size of 43 em FL (recruitJ was 11.0 x 10 6 fish for assumed values of M = 0.7 and K = 0.307. Increasing the fishing mortality rate by 30% and 50%, an estimated increment in yield is 8% and 12%, respectively. From virtual population analysis, we obtained the biomass estimate of skipjack population older than two years-old to be 70.3 thousand tonnes for assumed value of M = 0.7 and the estimated MSY was 24.6 thousand tonnes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.