Patrones de desove de peces de arrecife comercialmente importantes (Lutjanidae y Serranidae) en el Atlántico tropical suroccidental

Although information on the spawning seasons of commercially important snappers (Lutjanidae) and groupers (Serranidae, subfamily Epinephelinae) is available for the north and central west Atlantic, there is little information for the tropical western South Atlantic (Brazil). As a consequence, there are few fishery regulations in this entire region that take into consideration such information. In this study, we characterized the reproductive cycles of three Epinephelinae serranids (Epinephelus morio, Mycteroperca bonaci and Cephalopholis fulva) and five lutjanids (Lutjanus synagris, L. jocu, L. analis, Ocyurus chrysurus and Rhomboplites aurorubens) that occur in the Abrolhos Bank, Brazil, the largest reef complex in the tropical western South Atlantic. A total of 3528 gonads were collected from May 2005 to October 2007. Temporal variability in spawning patterns was evaluated using the Gonadosomatic Index (GSI) and macroscopic analyses. The peak of reproductive activity for the three grouper species occurred between July and August. Snappers exhibited two peaks of reproductive activity, the more intense of which occurred between September and October. The other peak occurred between February and March, with the exception of the deep-dwelling species R. aurorubens, which only reproduced between February and March. Seasonal patterns were consistent over the two consecutive years that we studied, and these patterns are equivalent to those observed for the Northern Hemisphere, as are the sizes at maturity and at the time of sexual change (for the three protogynous hermaphrodite groupers). Fisheries management in this region could be significantly improved by a combination of catch and effort limitations being imposed during spawning seasons and by overall size limitations, particularly considering that most of the fish caught are generally below size at maturity. The proposed buffer zones for the marine areas that are presently protected in Abrolhos represent an opportunity for implementing both spatial (e.g. setting no-take zones that cover spawning sites) and temporal (e.g. seasonal closures during spawning peaks) management tools, using a participatory approach at the regional scale.A pesar de que se tiene un buen conocimiento sobre la época de freza de los pargos (Lutjanidae) y los meros (Serranidae, subfamilia Epinephelinae) en las zonas norte y central del Atlántico occidental, la información disponible del Atlántico suroccidental es escasa. Como consecuencia, en esta zona aún existen pocas regulaciones pesqueras que tengan en cuenta esta información. En este estudio se caracterizan los ciclos reproductores de tres serránidos Epinephelinae (Epinephelus morio, Mycteroperca bonaci and Cephalopholis fulva) y cinco pargos (Lutjanus synagris, L. jocu, L. analis, Ocyurus chrysurus and Rhomboplites aurorubens) en el Banco de Abrolhos, el mayor complejo de arrecifes del Atlántico suroccidental. Se examinaron un total de 3528 gónadas entre mayo de 2005 y octubre de 2007. La variabilidad temporal de las pautas de puesta se evaluó mediante el Índice Gonadosomático (GSI) y análisis microscópicos. Para los tres meros el máximo en la actividad reproductora se produce entre julio y agosto. Los lutjánidos presentan dos picos de actividad bien diferenciados, siendo el más intenso el que tiene lugar entre septiembre y octubre, mientras que el menor se produce entre febrero y marzo, con la excepción de R. aurorubens, una especie de profundidad, que sólo se reproduce entre febrero y marzo. Las pautas estacionales en la reproducción son consistentes en los dos años consecutivos y, junto a la edad de primera madurez y la edad de inversión sexual (los tres meros son hermafroditas proterogínicos), son equivalentes a las que se producen en el hemisferio septentrional. La gestión pesquera en esta región podría mejorar significativamente mediante una combinación de limitaciones en las capturas y en el esfuerzo durante las épocas de puesta, así como limitando la talla mínima de captura, considerando que la mayoría de individuos capturados actualmente son inmaduros. Las zonas de amortiguación de las áreas marinas actualmente protegidas en Abrolhos representan una buena oportunidad para implementar herramientas de gestión tanto espaciales (e.g. estableciendo zonas de exclusión pesquera en los lugares de freza) como temporales (e.g. prohibiendo la pesca durante la época de reproducción), utilizando una aproximación participativa a una escala regional

A pesca artesanal no reservatorio Billings (São Paulo)

Orientador: Miguel Petrere JuniorDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O Reservatório Billings é o maior corpo d'água da Região Metropolitana de São Paulo (RMSP). Sua construção, iniciada em 1925, foi motivada pela demanda de energia elétrica da cidade de São Paulo. Durante muitos anos apresentou baixa qualidade ambiental devido à recepção dos efluentes orgânicos da RMSP através de bombeamento do Rio Pinheiros. Atualmente, é utilizado como sistema regularizador da vazão do Alto Tietê, como manancial de abastecimento, como receptor de efluentes e como área de lazer. Neste reservatório desenvolveu-se uma atividade intensa de pesca artesanal, com 101 pescadores ativos. Este estudo tem como objetivo descrever a atividade de pesca, avaliar a composição da captura em peso, avaliar o esforço de pesca com diferentes artes de pesca e verificar com que fatores está relacionada a captura. Para tal, estabeleceu-se um sistema de coleta diária de dados de desembarque pesqueiro na localidade de Colônia (município de São Paulo), onde se acompanhou a atividade de fevereiro de 1996 a janeiro de 1997. No período de estudo foram desembarcados 147.593 kg de pescado em 3515 viagens de pesca, com rendimento médio de 42 kg/viagem e 572 kg/pescador/mês. As espécies comerciais capturadas são a tilápia do Nilo Oreochromis niloticus (81,4% do desembarque em peso), o lambari Astyanax eigenmanniorum (13,0%), a carpa Cyprinus carpio (2,4%), a traíra Hoplias malabaricus (2,1%), o sagüiru Cyphocarax modestus (1,1%) e o bagre Rhamdia sp (0,1%). As artes de pesca utilizadas são redes de espera, redes de batida e tarrafas. Através do ajuste de um modelo linear de covariância às capturas mensais de tilápia do Nilo constatou-se que a área de pesca é o único fator importante na determinação das capturas descontando o efeito da covariável esforço de pesca. Os fatores mês e arte de pesca não explicam porções significativas da variabilidade. No modelo final, 91,14% da variabilidade total é explicada pelo esforço de pesca e 3,27% pelo fator área de pesca. As áreas de pesca com capturas mais altas são as de Pedreira e Alvarenga, próxima à estação elevatória do rio Pinheiros. Para explicar estes resultados três hipóteses são discutidas: alta capturabilidade, alta produtividade e estratégia dos pescadores. A baixa riqueza e alta dominância das espécies presentes nas capturas é um indicativo de comunidades submetidas a estresse que neste caso são: transformação do ecossistema lótico em lêntico, eutrofização, contaminação e introdução de espécies. A dominância da tilápia do Nllo no reservatório pode ser atribuída a uma combinação de fatores como alta resistência a baixas concentrações de oxigênio dissolvido, tolerância a poluentes, capacidade de aproveitar o zooplâncton dos reservatórios e existência de litoral bem desenvolvido onde pode construir seus ninhosAbstract: Billings reservoir is the largest water body in the Metropolitan Region of São Paulo. Its building started in 1925 in order to supply the city of São Paulo with electricity. During many years it presented low environmental quality due to the reception of organic sewage from the Metropolitan Region. Nowadays, it is used also as an outlet regulatory system from High Tietê Basin, as water source and as leisure area. An intense artisanal fishery activity is developed. with 101 active fishermen. The objectives of this study are to describe the fishery, to evaluate the catch composition in weight, to evaluate the effort with different gears and to examinate the factors that could explain the catches. Landings were recorded daily from February 1996 to January 1997, at Colônia (São Paulo city). During this period 147.593 kg of fish were caught in 3.515 fishing trips by 21.5 fisherman/month in average, with mean yield of 42 kg/trip and 572 kg/fishermen/month. The main commercial species caught were Nile tilapia Oreochromis niloticus (81.4% of landings in weight). "lambari" Astyanax eigenmanniorum (13.0%), common carp Cyprinus carpio (2.4%), "traíra" Hoplias malabaricus (2.1 %), "sagüiru" Cyphocarax modestus (1.1 %) and catfish Rhamdia sp (0.1 %). The fishing gears used were gillnets, cast nets and gillnets used in an active way ("redes de batida"). Nile tilapia are caught with cast nets and gillnets "redes de batida". The other species are caught with gillnets. The fit of a linear covariance model on Nile tilapia catch and effort data showed that the effect of the fishing ground was the only important factor to explain the catches discounting the effect of the covariate fishing effort. Neither the month nor the fishing gear explained a significant portion of the variability. In the final model, effort explained 91.14% of the total variability and fishing ground explained only 3.27 %. The fishing grounds with highest catches were Pedreira and Alvarenga, near Pinheiros river pumping station. To explain this result three hypotheses are discussed: high capturability, high productivity, and fishermen strategies. The low richness and high dominance of few species on landings are indicative of communities under stressing conditions, which in the Billings case are: transformation of a lotic ecosystem in a lentic one, eutrophication, contamination and introduction of exotic species. The dominance of Nile tilapia is attributable to a combination of factors such as high resistance to low dissolved oxygen contents, tolerance to chemical stressors, ability to consume plankton and existence of a developed littoral zone enabling Nile titapia's nestingMestradoEcologiaMestre em Ciências Biológica

Padrões de dominância e raridade da assembléia de peixes ao longo de gradientes espaciais no reservatório de Itaipu, Estado do Paraná, Brasil - DOI: 10.4025/actascibiolsci.v25i1.2085

Patterns of dominance and rarity of fish assemblage in the Itaipu Reservoir were evaluated and related to a longitudinal or river-dam gradient (composed of riverine, transitional and lacustrine zones) and to a transversal or upstream-downstream gradients of the tributaries (composed of lotic and lentic stretches of tributaries and reservoir shores). Thirteen sampling stations were sampled quarterly during 2 years. Patterns of species dominance were investigated using Whittaker plots and patterns of rarity using analysis of variance. A total of 85 fish species were caught. In the reservoir shores of riverine zone, the dominant species was the migratory Prochilodontidae curimba Prochilodus lineatus that uses the upstream floodplain as a spawning and nursery area. In the reservoir shores of transitional and lacustrine zones (i.e. close to the dam) the dominant species was the introduced Sciaenidae curvina Plagioscion squamosissimus. Loricarids dominated the tributaries. The proportion of rare species presented significant differences along longitudinal gradient. Lowest proportion of rare species was found close to the dam indicating a loss of ecological integrity in this zonePadrões de dominância e raridade da assembléia de peixes no reservatório de Itaipu foram avaliados e relacionados com os gradientes longitudinal (dividido nas zonas fluvial, intermediária e lacustre) e transversal (dividido em trechos lóticos e lênticos dos tributários e margem do reservatório). As coletas foram realizadas trimestralmente em treze estações durante dois anos. Padrões de dominância e raridade foram investigados utilizando curva de espécie-abundância e análise de variância, respectivamente. Foram capturadas 85 espécies. Na zona fluvial, a espécie dominante na margem do reservatório foi o curimba Prochilodus lineatus, que utiliza a planície de inundação a montante como área de reprodução e crescimento. A curvina Plagioscion squamosissimus, espécie introduzida, foi dominante nas margens do reservatório das zonas intermediária e lacustre. Loricarídeos dominaram nos tributários. A proporção de espécies raras apresentou diferenças significativas ao longo do gradiente longitudinal. Na zona lacustre, próximo à barragem, foi registrada a menor proporção de espécies raras, indicando perda de integridade ecológica nessa zon

Dispersal of Amazonian trees: Hydrochory in Swartzia polyphylla

Hydrochory was investigated in the seeds of the Amazonian floodplain tree, Swartzia polyphylla, in which pods open on the tree to release one large seed. Seeds collected from beach drift along the Rio Negro showed a high percentage of floaters (82%). Yet most seeds sank following collection from: adult trees (89%), unflooded ground under adults (96%), and flooded ground under adults (86%). The specific gravity of the seeds was near that of water, 1.04 ± 0.03 for sinkers and 0.98 ± 0.02 for floaters. The ability to float was correlated directly with the volume of the air pocket between the two cotyledons, which varied from 5.6 to 20.5 percent of the total seed volume. In a long-term floatation test lasting 81 days, 45 percent of the seeds never floated, 33 percent always floated, and 22 percent first sank for one week and then floated for at least one month. Seeds that never floated eventually rotted, but not until days 6373. Seeds that were floating at day 81, regardless of how long they had been floating, were placed on moistened filter paper for 18 days during which time 36 percent germinated, 45 percent rotted, and 19 percent did neither but remained viable. These results suggest that S. polyphylla achieves dimorphism in flotation of its seeds, some sinking and some floating, by producing seeds of continuous variation in specific gravity around a mean close to 1.00. Seeds that float can be dispersed long distances along river margins, while those that sink may be moved only marginally from the parent tree

Estimativa da captura total: desenhos amostrais para pesca artesanal

Estimating total landings of artisanal fisheries in managed areas is essential for the development of programs aimed at the establishment of sustainable production systems. However, few experiences addressed the constraints of assessments targeted at multispecific and small scale fisheries with pulverized landings. Total annual production (fish, lobsters and octopus) at the Marine Extractive Reserve of Corumbau, Bahia, Brazil, in 2006, was estimated through yields recorded by fisherfolks, in the scope of a participatory fisheries monitoring program. Three designs were employed: 1) simple random sampling, 2) stratified random sampling by month and fishing frequency, 3) stratified random sampling by community, fishing frequency and months, resulting in estimates of 349t (95% confidence interval = 305-393), 330t (289-372) and 315t (279-351), respectively. This kind of information can help design strategies for aggregation of value to small scale fisheries production, and also for the dimensioning of the corresponding infrastructure. However, these estimates shall not be used to support fishing effort increase, as there is high uncertainty regarding the state of the stocks, as well as limitations related to the asymmetry in monthly landings per fisherfolk and to the sampling coverage in the different strata

Spatial patterns of benthic megahabitats and conservation planning in the Abrolhos Bank

Application of sidescan sonar at the regional scale of the Abrolhos Bank, with ground-truthing by remotely operated vehicles and mixed-gas diving operations, revealed a much more complex habitat mosaic than previously recognized. The regional benthic habitat map indicates 8844 km2 of reefs (earlier estimates from remote sensing were around 500 km2) and 20,904 km² of rhodolith habitat—the world's largest continuous bed. Integration of the regional megahabitat map with spatially explicit data on the distribution of marine protected areas (<0.2% of each benthic megahabitat area) and economic activities with the highest potential of environmental impact (fishing, mining, oil and gas exploitation and dredging) reveals the need of a regional scale spatial planning process engaging conflicting sectors