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ABSTRACT: A type of dredge was introduced as fishing gear along the extractive bank of Mangue Seco - PE from which the largest annual catch of Anomalocardia flexuosa in the world is extracted. This study was carried out with the objective of estimating the selectivity of the new fishing gear and quantitatively evaluating the length classes most compromised by the catches, especially considering 20 mm as the reference value. Specimens larger than this size are most likely to be mature. For the selectivity estimation, the methodology using codends (16 or 20 mm) and small meshed cover (2 mm) was used. To estimate the selectivity parameters, a logistic regression and the Bayesian approach were used. The transition between the state in which the specimen is invulnerable to the fishing gear and vulnerable occurs between 10 and 18 mm, using a 16 mm mesh, and using a 20 mm mesh, this transition is between 14 and 20 mm. Dredgers with 16 mm and 20 mm mesh compromise a large proportion of specimens smaller than 20 mm. If the intention is to protect this part of the population, measures such as total restriction of the 16 mm mesh and use of the 20 mm mesh should be necessary only in the months of less catching incidences, or increasing the mesh to 25 mm.

ABSTRACT: Anomalocardia brasiliana post-larvae were cultured for 28 days to evaluate the effect of stocking density on their growth and survival rate. Three stocking densities were tested 40, 80 and 160 post-larvae cm-2, in experimental units (2-L) with static cultivation system and total water renewal at each 48 hours. The experimental design was completely randomized with three treatments and three repetitions each. Stocking density of 40 post-larvae cm-2 reached 1 mm length within 24 days, while only 18% of the post-larvae at density of 80 post-larvae cm-2 reached 1 mm length in the same time. The density of 40 post-larvae cm-2 had the highest specific growth rate, 4.98±0.08% day-1. The survival rates of post-larvae at lower densities were significantly higher (53.24±4.60% and 52.95±3.32%, on 40 and 80 post-larvae cm-2, respectively) compared to higher stocking density (31.54±0.70%). In the cultivation of A. brasiliana post-larvae, stocking density must be managed during growth. The density of 160 post-larvae cm-2 can only be used until the post-larvae reach 600μm in length, then they should be at 40 post-larvae cm-2 density to keep the maximum daily growth rate.

ABSTRACT: The purpose of this study was to determine the moment of the year for the oyster recruitment and define the type of collector and environmental conditions that maximize recruitment. Collections were conducted, during 12 months, on Amazon Macrotidal Mangrove at two different sites: raft (point I) and mangrove (point II). In each location three types of collectors were used (1) transparent PET bottles, (2) green PET bottles, and (3) PVC sheets, each with three replicates. Spats were counted and measured at 45-day intervals, while the environmental data were measured every two weeks. Identification of oyster species occurred by genetic testing (multiplex PCR) by randomly selecting individuals by sampling. Results indicated spat capturing was significantly influenced by the collector type, location and period of collection (P

Fluctuations in world harvests of Artemia sp cysts have increased prices sharply in the past years. Several organisms have been tested as alternative sources for a total or partial replacement of Artemia sp, among which the microcrustacean (Anostraca) Dendrocephalus brasiliensis stands out. The objective of this study was to investigate the reproductive strategy of D. brasiliensis by means of AFLP markers. The distinction between sexual and parthenogenetic reproduction was conducted using 7 EcoRI and MseI primer combinations in a full-sib family composed of 13 progenies. Forty polymorphic markers were obtained, of these, 35% were from paternal origin and 65% were maternally inherited. Results showed mendelian segregation in all markers through the chi-square at P≤0.05. Sex changes were observed after 72 hours of grouping individuals of the same sex in a container, suggesting a possible sex density-dependent behavior. Paternal inheritance revealed that this species adopts sexual reproduction under experimental conditions.Há vários anos que a produção de cistos de Artemia sp. apresenta flutuações, o que aumenta consideravelmente o seu valor. Vários organismos têm sido testados para a substituição total ou parcial da Artemia, dentre os quais se destaca o microcrustáceo (Anostraca) Dendrocephalus brasiliensis. O objetivo do presente trabalho foi investigar a estratégia reprodutiva de D. brasiliensis por meio de marcadores de AFLP. A distinção entre uma reprodução sexuada e partenogenética foi feita a partir da genotipagem de sete combinações de primers de AFLP em uma família composta de 13 progênies. Quarenta marcadores polimórficos foram obtidos, dos quais 35% foram de origem paterna e 65%, materna. Os resultados mostraram a segregação mendeliana de todos os marcadores através do teste de qui-quadrado a P≤0.05. Mudanças de sexo foram observadas após 72 horas do agrupamento de indivíduos de mesmo sexo em um recipiente, sugerindo uma possível razão sexual populacional densidade-dependente. A herança paterna mostrou que a reprodução sexual é adotada por essa espécie sob condições experimentais.