Abundance, composition and sources of marine debris trawled-up in the fishing grounds along the north-east Arabian coast.

The pollution due to marine debris is a serious environmental threat in many parts of the world. The abundance of marine debris, composition and its distribution over the seafloor along north-east coast of Arabian coast was studied through trawl based swept method. Experimental fishing was conducted fortnightly using shrimp bottom trawl and collected debris was categorized as per standard protocols. A total of 1077 pieces of debris (11.7 kg dry weight) were collected from 25 hauls. The average number and weight of debris were 943 items/km2 and 10.2 kg/km2 respectively. The estimated total marine debris along this coast was 379 t (dry weight). Plastic-based debris contributed maximum (87.1%) to the total debris collected in numbers and among this, plastic bags and food wrappers were dominant. Debris produced by shoreline/recreational activities comprised the major source of debris (88.6%) along this coast. This study provides the evidence that the effective use of available fishing trawlers and co-management practices ("Make fishers friend") can help to remove the seabed debris. The base data generated through this study would facilitate region-based effective control and management of plastic debris pollution.

Diversidad y distribución de peces y su relación con variables ambientales, en el sur del Golfo de México / Fish diversity, distribution and their relationship with environmental variables in Southern Gulf of Mexico

Resumen La sonda de Campeche posee gran diversidad de especies, heterogeneidad de hábitats y fuerte incidencia de las industrias petrolera y pesquera. El objetivo de este trabajo fue obtener la distribución espacial de la ictiofauna y su relación con elementos del ambiente, así como implementar una línea base que sirva como referente para futuras contingencias que puedan ocasionar estas industrias. Se empleó una base de datos obtenida en 2010, con 54 localidades en la Sonda de Campeche que fueron muestreadas mediante arrastres camaroneros. Se colectaron 2 502 438 kg de material biológico y 33 315 peces de 2 clases (Chondrichthyes y Actinopterygii) con un total de 193 especies. De ellas, 17 fueron dominantes, asociadas a fondos arenosos y lodosos, aunque también hubo especies de ambientes estuarinos, de arrecife y de hábitos pelágicos. La diversidad (H') promedio fue de 3.2 bits/individuos. Las familias más comunes fueron los Perciformes (84 species), Pleuronectiformes (23), Scorpaeniformes (15) and Tetraodontiformes (14); las riquezas de especies más altas fueron: Sciaenidae (15 especies), Paralichthyidae (12), Carangidae (10), y Triglidae y Synodontidae (7). Los géneros más comunes fueron: Prionotus (6 especies), Citharichthys and Sphoeroides (4 cada uno). Por cada localidad, la riqueza fluctuó entre 3 y 6 especies con un promedio de 46 kg. La composición de especies fue diferente entre hábitats y áreas. La ordenación comunitaria presenta una concordancia al identificar espacialmente cada zona. El análisis paisajístico define nódulos de alta densidad y diversidad que corresponden con áreas de desembocaduras de ríos, lagunas y de zonas arrecifales. De las relaciones entre las variables y los descriptores comunitarios, sólo el Carbono Orgánico fue significativo, tanto para la abundancia como para la biomasa, el REDOX para la riqueza de especies y las otras variables no fueron importantes.

Abstract: The Campeche Sound has a high heterogeneity of habitats, great fish species diversity, and a strong presence of oil and fishing industries. Our objective was to obtain updated information on a complete local fish species spatial distribution and their relationship with environmental elements, this will improve the baseline to evaluate the potential impact of future oil and fishing developments. For this, our approach used a database obtained in 2010, with a capture made in 54 sites with standard shrimp fishing trawls in the Campeche Sound. We collected a total of 33 315 fish, of 80 families, 138 genera and 193 species, that corresponded to 2 502 438 kg. The fish classes Chondrichthyes and Actinopterygii predominated. A total of 17 were dominant, associated to sandy and muddy bottoms, although were species of estuarine environments, reef and pelagic habitats. Averaged diversity (H') was of 3.2 bits/individuals. In decreasing diversity order, the common fish belong to Perciformes (84 species), Pleuronectiformes (23), Scorpaeniformes (15) and Tetraodontiformes (14); in the same way, the higher richness families were Sciaenidae (15 species), Paralichthyidae (12), Carangidae (10), and Triglidae and Synodontidae (7). Most common genuses were Prionotus (6 species), Citharichthys and Sphoeroides (4 each). Per each station, richness varied between 3 and 56 species, with an average weight of 46 kg. Fish assemblage composition was different among habitats and areas, with divergent management strategies. Landscape analysis defines nodules of high density and diversity that corresponded to river mouths, lagoons and reef areas fish assemblages. Of the relation between variables and community descriptors, only the organic carbon was significant for both abundance and biomass, the REDOX for the species richness and the other variables were not important. Rev. Biol. Trop. 66(1): 438-456. Epub 2018 March 01.

Investigations on juvenile fish excluder cum shrimp sorting device (JFE-SSD).

Penaeid shrimp is a major resource in India contributing about 7.4% of the total marine fish landings. They are mostly landed by small mechanized trawlers. Shrimp trawling generates large quantities of bycatch mostly consisting of juvenile fishes, due to use of small mesh size in codends of trawl nets. Juvenile Fish Excluder cum Shrimp Sorting Device (JFE-SSD) is a bycatch reduction device with an in situ sorting mechanism, which replaces the conventional codend in a trawl. The device was designed to catch shrimps and commercially important fish species using a specially designed oval sorting grid with appropriate bar spacing and dual codends. Shrimp sorting efficiency and bycatch exclusion characteristics of JFE-SSD attached to a 29.6 m shrimp trawl, was tested by experimental fishing along the coastal waters off Cochin, India. Out of a total of 317.07 kg of catch encountered in the JFE-SSD installed trawl, 58.22% was retained in lower codend, 17.53% in upper codend and 24.25%, mostly consisting of juveniles and sub-adults of finfishes and shellfishes, was excluded from upper codend. The mean CPUE registered for upper and lower codend were 7.23±1.04 SE and 5.84±0.96 SE kg h(-1) respectively. The CPUE of shrimps retained in upper and lower codends were significantly different (Kruskal-Wallis test (1,62), P<0.001), but the mean CPUE for fishes did not vary significantly. The average escapement of shrimps and juvenile fishes from upper codend were 0.06±0.02 SE kg h(-1) and 2.40±0.44 SE kg h(-1) respectively. Significant differences in the length composition between upper and lower codends were noticed for Megalaspis cordyla, Stolephorus waitei, Metapenaeus dobsoni and Parapenaeopsis stylifera. The experiments demonstrated in situ sorting ability of the device and its potential to reduce the bycatch of juveniles and sub-adults in shrimp trawls.

Distribución latitudinal y batimétrica de las especies más abundantes y frecuentes en la fauna acompañante del camarón del Golfo de California, México

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.

El Golfo de California es una de las regiones más mega diversas en el mundo, del cual poca información pesquera está disponible. Aquí se presenta la distribución latitudinal y batimétrica de las especies más abundantes y frecuentes en la fauna acompañante del camarón del Golfo de California. Las muestras fueron obtenidas de un total de 111 lances provenientes de siete cruceros en época de veda del camarón (2002-2005- 2007) y prospecciones realizadas a profundidades mayores a los 90m. Debido al gran número de especies en esta fauna asociada al camarón, se eligieron las que presentaron el índice de valor biológico (IVB) más alto. Las 15 especies con IVB más alto representaron el 60% de la abundancia total. Un total de 16 508 organismos fueron analizados representando 243 especies entre peces, crustáceos, moluscos y equinodermos. El grupo de los peces fue el más abundante, siendo las más abundantes y frecuentes: Urobatis halleri, Synodus scituliceps, Diplectrum pacificum, Haemulopsis nitidus y Eucinostomus argenteus. Se observó una amplia distribución latitudinal de estas especies a lo largo del área de estudio y una distribución batimétrica desde los 9 hasta los 67m de profundidad. Dos de ellas se distribuyeron hasta los 325m. Debido a esta amplia distribución batimétrica, se hace necesario determinar las abundancias totales y tallas por estrato de profundidad para cada especie, ya que a profundidades mayores de 25m la captura de éstas puede ser más baja y pueden servir como áreas de repoblación natural para las profundidades donde son capturadas principalmente por la flota camaronera comercial.

Tiburones y rayss (subclase elasmobranchii) desartados por la flota de arrastrre camaronero en el caribe de Colombia / Sharks and Rays (Subclass Elasmobranchii) Discarded from Commercial Shrimp Trawlers at the Caribbean Sea of Colombia

Con el fin de obtener una aproximación a la estructura del ensamblaje de peces cartilaginosos extraídos por la flota de arrastre camaronero en la costa norte de Colombia, se evaluó la composición y abundancia de tiburones y rayas descartados en dos sectores del Caribe colombiano, entre agosto y noviembre de 2004. Mensualmente se analizaron lances de la flota de arrastre camaronero al interior de cada sector (norte: La Virgen y Portete; sur: Barú, cabo Tiburón, Cascajal, Cispatá, Morrosquillo, Ceycén, Mestizo, río Cedro, Tigua y Tortuguilla). Observadores a bordo de la flota comercial de arrastre camaronero muestrearon 1/5 de la captura previamente homogenizada, tomada al azar de una de las cuatro redes de la embarcación. En 30 lances se registró la presencia de 47 peces cartilaginosos, correspondientes a seis familias y ocho especies. La mayor Captura por Unidad de Esfuerzo (CPUE) en términos de biomasa se registró en ambas zonas durante septiembre, la menor en noviembre en la zona sur; el mayor valor del número de individuos se presentó en septiembre en la zona sur y el menor en noviembre, lo cual puede atribuirse a la mayor disponibilidad del recurso objetivo que está asociado al periodo de mayores lluvias que enriquece las aguas de los ambientes costeros y son usados como hábitat y zonas de alimentación por los peces cartilaginosos.

In order to have an approximation to the cartilaginous fishes assemblage structure exploited by commercial shrimp trawlers from the north coast of Colombia, composition and abundance of the discarded sharks and rays on two zones of the Colombian Caribbean, between August and November of 2004 were evaluated. Each month, a number of trawls were analyzed in each zone (north: La Virgen and Portete; south: Barú, Cabo Tiburón, Cascajal, Cispatá, Morrosquillo, Ceycén, Mestizo, Cedro river, Tigua and Tortuguilla). Observers were placed on board commercial shrimp trawlers, sampling 1/5 from the total capture, previously homogenized, which was randomly taken from one of the four nets of the vessel. Within 30 trawls, there were 47 cartilaginous fishes registered, belonging to six families and eight species. The largest capture per effort unit (CPUE) in biomass was registered on September in both zones, whereas the smallest happened on November in the south one. The greatest value in number of units was in September within the south zone and the opposite occurred in November, registering the smallest values. This could explain the great availability of the objective resource, directly associated with the heavier rainy season that enriches the waters of the coastal environment and characterizes the region, probably used as habitat and feeding grounds for the cartilaginous fishes.