ABSTRACT
Acoupa weakfish, Cynoscion acoupa, in Lake Maracaibo is subject to intense commercial fishing by an artisanal fleet, and a recent decrease in fish size observed from landings is of concern. This fishery has not yet been modeled, and its assessment and the establishment of management practices to overcome the current overfished condition are urgently needed. To address this, we used recent and past empirical growth estimates to model relative yield-per-recruit under different lengths at first capture. Our results from relative yield-perrecruit analysis showed evidence that growth and recruitment overfishing occur under current fishing practices in Lake Maracaibo. Particular attention was given to fishing practices in El Tablazo Bay where young, small fish predominate in the commercial catches (mean total length=33.7cm), well below the length at first sexual maturity (~40cm TL) for both sexes. As management strategies, we propose to set a mesh size limit at or above 8.89cm (3.5in), which will reduce fishing mortality of immature fish, increase yield-per-recruit, and will result in an increase of Acoupa weakfish recruitment for the long term in Lake Maracaibo.
La curvina, Cynoscion acoupa, en el Lago de Maracaibo se encuentra sometida a una intensa actividad pesquera comercial. No obstante, antes de este estudio no se había examinado el potencial efecto de la sobrepesca a través del modelado. Utilizamos estimados empíricos de crecimiento actuales y pasados para modelar el rendimiento-por-recluta relativo bajo diferentes longitudes de primera captura. Presentamos evidencia a partir de resultados de rendimiento-por-recluta relativo que indica que existe sobrepesca por crecimiento y reclutamiento bajo las prácticas pesqueras actuales en el Lago de Maracaibo. Se puso particular atención a las pesquerías en la Bahía El Tablazo donde predominan peces jóvenes pequeños en las capturas (longitud total promedio=33.7cm), muy por debajo de la longitud de primera madurez sexual (~40cm LT) para ambos sexos. Proponemos establecer un tamaño de malla igual o superior a 8.89cm (3.5in), el cual reduciría la mortalidad por pesca de peces inmaduros, aumentaría el rendimiento-por-recluta y a largo plazo aumentaría el reclutamiento de la curvina en el Lago de Maracaibo.
Subject(s)
Animals , Female , Male , Fisheries , Perciformes/growth & development , Conservation of Natural Resources , Lakes , Models, Biological , Population Dynamics , Perciformes/anatomy & histology , Time Factors , VenezuelaABSTRACT
No presente estudo foram identificadas as características microbiológicas da pescada amarela (Cynoscion acoupa) desembarcada em Cedral/MA e avaliada a qualidade do gelo utilizado na sua conservação. Foram coletadas 42 amostras de pescada e analisadas quanto à pesquisa de Salmonella spp, V. parahaemolyticus, Escherichia coli, Staphylococcus coagulase positivo, Aeromonas spp, contagem de bactérias aeróbias mesófilas e Número Mais Provável de coliformes a 35 °C e coliformes a 45 °C. Onze amostras de gelo foram analisadas quanto à contagem de coliformes a 35 °C e a 45 °C e de bactérias psicrotróficas. A pescada amarela mostrou contaminação por bactérias mesófilas, coliformes e A. hydrophila, e ausência de Salmonella, Staphylococcus coagulase positivo e V. parahaemolyticus. As amostras de gelo foram consideradas impróprias para uso na conservação do pescado.
Subject(s)
Food Preservation , Ice , Food Microbiology , Fishes , Food QualityABSTRACT
The acoupa weakfish (Cynoscion acoupa - Sciaenidae) is a marine species of croaker with estuarine-dependent behavior, found in the western Atlantic from Panama to Argentina. It is one of the most exploited food fish on the northern coast of Brazil. In this study, DNA sequences were determined from the entire control region (D-loop) of the mitochondrial genome of 297 individuals collected during seven different months between December 2003 and August 2005 on the northern coast of Brazil (Amapá and Pará). Genetic variability expressed by haplotype (h = 0,892) and nucleotide (pi = 0,003) diversities were low compared to other heavily exploited marine fish species from the western Atlantic and eastern Asia. AMOVA depicted a lack of genetic structuring among the samples from different years, indicating the presence of a single stock of C. acoupa within the sample area. The possible reasons for the low levels of genetic diversity are discussed. These results demonstrate a need for the monitoring of C. acoupa harvesting and the preservation of the estuaries within its geographic range, considering that this large fish depends on estuarine ecosystems during part of its life cycle.