No abstract

. 2017. Length-weight relation for eleven demersal fish species in the artisanal shrimp fishery areas from the Bahia MagdalenaAlmejas lagoon system, Mexico. Acta Ichthyol. Piscat. 47 (3): 303-305.Abstract. The length-weight relations (L-W) for 11 demersal fish species from a lagoon system in south-western coast of the Baja California Peninsula, Mexico were estimated. The following species were studied: Occidentarius platypogon (Günther, 1864) . These species were caught in the artisanal shrimp fishery areas from the Bahia MagdalenaAlmejas lagoon system; thus the specimens were obtained with the shrimp trawl net. A total of 3824 specimens were used to estimate parameters of the relations. The slope (b) fell within 2.7 to 3.4 and the growth pattern was isometric in most cases (10 species), whereas for one species the growth was allometric. The L-W relation parameters for Occidentarius platypogon and Eucinostomus peruvianus, are not available in FishBase.

Latitudinal and bathymetric distribution of the most abundant and frequent species in the shrimp bycatch from the Gulf of California, Mexico. The Gulf of California is one of the most mega-diverse regions in the world, for which few fishery information is available. We present here latitudinal and bathymetric distribution of the most abundant and frequent bycatch species from the Gulf of California. The samples were obtained from a total of 111 hauls taken during seven research cruises of the closed shrimp season (2002-2005-2007), and also, from research cruises made at depths up to 90m. Due to the high variety species in this experimental shrimp bycatch, only those with highest biological value index (BVI) were selected. A total of fifteen species had the highest BVI and represented about 60% of the total abundance. A total of 16 508 organisms were analyzed, representing 243 fish, crustacean, mollusk and echinoderm species. Fish were the most abundant, being the most frequent species: Urobatis halleri, Synodus scituliceps, Diplectrum pacificum, Haemulopsis nitidus and Eucinostomus argenteus. A wide latitudinal distribution of these species along the study area, as well as a bathymetric distribution from 9 to 67m depth, was observed. Two of these species were found at 325m depth. Due to the wide bathymetric distribution obtained, total abundances and sizes for each species by depth strata should be determined, and one can assume that deeper than 25m, the capture of these species decreases, and these areas can be used as natural repopulation areas, for depths where they are mainly captured by the commercial shrimp fishery. Rev. Biol. Trop. 59 (1): 255-267. Epub 2011 March 01.

Resumen.-Algunas especies de lenguados son capturadas incidentalmente con redes de arrastre y algunas de éstas son especies objetivo de una pesquería artesanal en el Golfo de California, México. Con el propósito de conocer cuántos individuos de la población están siendo capturados y cuáles son los efectos de estas capturas, el objetivo de este estudio fue estimar la abundancia de los lenguados capturados incidentalmente con redes de arrastre y en una pesquería artesanal o de pequeña escala en el Golfo de California, y determinar la posible competencia entre flotas (con redes de arrastre y la flota artesanal con redes agalleras) por el mismo recurso. Las muestras fueron recolectadas durante 2002 y 2003 de 3 diferentes fuentes: prospecciones de 2 barcos de la flota camaronera comercial, prospecciones en 2 cruceros de investigación y de una flota artesanal la cual opera a lo largo de la costa del estado de Sonora, México. La abundancia de los lenguados capturados en las redes de arrastre fue estimada usando el método de área barrida y a través de análisis de cohortes por talla fue estimada la abundancia para los lenguados capturados por la flota artesanal. Catorce especies de lenguados fueron identificados en las capturas incidentales con redes de arrastre, destacando Paralichthys woolmani, Etropus crossotus, Citharichthys fragilis, Citharichthys gilberti, Achirus mazatlanus y Syacium ovale. Seis de las 14 especies de lenguados capturados incidentalmente fueron también capturados por la flota artesanal, de la cual el 70% corresponde a P. woolmani. Se demostró que cada flota opera sobre diferentes fracciones de la población, individuos de 25 a 90 cm en longitud total fueron capturados por la flota artesanal y los valores de mortalidad por pesca y tasa de explotación fueron < 0,01, mientras que en las capturas incidentales (flota camaronera) los individuos presentaron tallas entre 4 y 20 cm, demostrando presión de pesca en los individuos juveniles cuya captura podría tener efectos negativos, debido a éstos pueden ser reclutas para la pesca artesanal.Palabras clave: Abundancia, estructura de talla, lenguados, Golfo de California, captura incidental Abstract.-Some flatfish's species are caught incidentally in bottom-trawls and some of them are the target of an artisanal fishery in the Gulf of California, Mexico. To know the number of individuals removed from a population and the effects of their removal, the aim in this study was to estimate the abundance of flatfishes caught as bycatch in bottom-trawls and by artisanal or small-scale fishery in the Gulf of California and determinate the possible competiti on between fleets (bottom-trawl and artisanal with gillnets) for the same resource. During 2002 and 2003, samples were collected from 3 sources: (1) surveys of 2 vessels from the shrimp trawl fleet; (2) surveys in 2 research cruisers; and (3) from an artisanal fleet operating in the coast of the state of Sonora, Mexico. Abundance of flatfishes caught in bottom-trawls was estimated using the swept area method, and thr...

The assemblage of the fish species obtained as bycatch in trawl nets on the Gulf of California in 2004, 2005 and 2007 was studied. Sampling was carried out during July and August at a series of stations along the coast of Sonora. The criteria for the most important fish species caught were drawn from abundance and frequency of occurrence and weight, using various ecological indices (index of relative abundance, biological value index and index of relative importance). After identification, these species and their abundances were used to define study groups based on similarity matrices and Ward's clustering method. We analysed 125 fish hauls containing 19,000 organisms, representing 243 species (fish, crustaceans, molluscs and echinoderms). There were 28 dominant species, most notably Urobatis halleri, Synodus scituliceps, Eucinostomus argenteus, Diplectrum pacificum and Haemulopsis nitidus. Cluster analysis, based on latitude, and bathymetry showed three station groupings. The first was characterized by species from the northern region of the Gulf with a bathymetric distribution 25 m. The second was dominated by species from the central to southern region from depthsB25 m. The third was a transitional group with species found between the central and southern Gulf from depths of 10 to 45 m. Most fish assemblages consist of species with wide distribution within distinct biogeographic provinces, which showed a major change in the association, frequency and absence of species from north to south, indicating a variety of habitats in the Gulf of California.