Species composition and bycatches of a new crustacean trawl in Chile

The species composition and bycatches of a new trawl for crustaceans (Heterocarpus reedi, Cervimunida johni and Pleuroncodes monodon) was studied in central Chile between 2007 and 2009. The spatial and temporal variations of the catch composition were analyzed using univariate and multivariate comparison techniques. In 289 trawl hauls, 72 taxa were recorded, with target species accounting for most of the catch, while the bycatch consisted mainly of Merluccius gayi, Hippoglossina macrops, Coelorinchus aconcagua, Epigonus crassicaudus and Platymera gaudichaudii. 14 species of elasmobranchs were identified, and at least one of these species was present in 50% of the hauls made. The classification and ordination methods showed the existence of three groups, each one associated with a target species, with no significant spatial and temporal effects. The information obtained in this study represents the basis for setting targets in order to reduce the bycatch captured by this trawl. The focused strategy on the most recurring and sensitive species for these fisheries is also discussed. (C) 2011 Elsevier B.V. All rights reserved

Effect of hook size and seasonality on the artisanal long-line fishery of southern hake (Merluccius australis Hutton, 1872) in Chile

The effect of hook size and seasonality on the artisanal long-line fishery of southern hake (Merluccius australis) in Chile was studied. We analyzed the effect of four hook sizes on the size-at-catch and catch rates of southern hake (Merluccius australis) caught with mixed long-lines between Seno de Reloncaví and Golfo de Ancud (41º42�S-42º48�S). Sixty fishing hauls were done in four periods (March, May, July, September); a total of 59,294 hooks were set and 14,358 specimens (26,165 kg) were caught. The analysis showed overlapping retention sizes for each hook size in the months studied, indicating no significant effects in either catch size composition or in catch rates between hooks of different size. Nevertheless, significant differences were observed between periods in the catch rates, fluctuating between 31.75 and 16.17 individuals per 100 hooks from March to September. The above results suggest that it is necessary to analyze alternative fishing gear and management measures for the fishery.Se estudió el efecto del tamaño de anzuelo y la estacionalidad en la pesquería artesanal con espinel de merluza del sur (Merluccius australis) en Chile. Se analizó el efecto de cuatro tamaños de anzuelos sobre las tallas y tasas de captura de merluza del sur (Merluccius australis) capturada con espinel mixto entre el Seno de Reloncaví y el Golfo de Ancud (41º42¿S a 42º48¿S). Se realizaron 60 lances de pesca en cuatro períodos (marzo, mayo, julio y septiembre), virándose un total de 59.294 anzuelos, capturándose 14.358 ejemplares equivalentes a 26.165 kg. El análisis demostró la superposición de tallas de retención para cada tamaño de anzuelo en los meses de estudio, determinándose que no existen efectos significativos del anzuelo en la composición por tallas ni en las tasas de captura. Sin embargo, se observaron diferencias significativas en la tasa de captura entre períodos, fluctuando entre 31,75 y 16,17 individuos por 100 anzuelos entre marzo y septiembre, respectivamente. Lo anterior sugiere un análisis de alternativas de artes de pesca y de medidas de administración en la pesquería

Experimental study of ghost fishing by gillnets in Laguna Verde Valparaíso, Chile

In 2010, two experiments were carried out in order to study ghost fishing generated by lost or abandoned gillnets. The first experiment was aimed to identify and quantify the number of captured specimens in intentionally abandoned gillnet between 45 and 86 m depth, which were periodically checked up to 156 days after being abandoned. In this experiment, 912 specimens of 12 taxa were caught, mostly invertebrates such as Cancer porteri (81.6%) and Platymera gaudichaudii (9%). After the abandonment, the fish caught were only registered until day 63, while benthic species were captured during all the experiment. The second experiment consisted of checking and registering periodically the loss of height of an abandoned gillnet at 34 m depth in order to determine the reduction of the fishing capacity of the net. After 19 days of abandonment, the functional area of the net was reduced to 40% of the original area, reaching nearly zero after 155 days of abandonment. In order to estimate the potential effect of lost or abandoned gillnets in Chilean hake fisheries (Merluccius gayi gayi), an additional information-collecting process must be carried out, mainly in terms of frequency of gillnets losses

Explotación de peces asociada a la pesquería artesanal de langosta de Juan Fernández (Jasus frontalis)

Para contribuir al conocimiento de la explotación de peces asociada a la pesquería de langosta de Juan Fernández, se monitorearon 157 salidas de pesca durante la temporada 2010-2011. Se capturaron 10.462 ejemplares correspondientes a 19 especies de peces, tres de las cuales concentraron el 94% de la captura en número: jurel de Juan Fernández (Pseudocaranx chilensis) (45%), breca (Nemadactylus gayi) (41%) y anguila morena (Gymnothoraxporphyreus) (8%). Las capturas totales estimadas fueron 40, 24 y 13 ton de breca, jurel de Juan Fernández y anguila morena, respectivamente. El 97% de los ejemplares de peces capturados fueron utilizados como carnada de peces o langosta

Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring

Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring Latin American Journal of Aquatic Research, vol. 43, núm. 2, mayo, 2015, pp. 309-314 Pontificia Universidad Católica de Valparaíso Valparaíso, Chile ). It was found that under the most severe condition, that is, the highest current speed and the lowest linear weight of the sinker ring (0.75 m s -1 and 25 kg m -1 , respectively), the volume loss with respect to initial undeformed net pen volume reached a maximum value of 53%. This occurred in the net pen firstly exposed to currents. Based on modeling results, a relationship between net pen volume loss due to the combined effects of both water current speed and linear weights of the sinker rings is proposed. Key words: net pen deformation, current speed, sinker ring, Chile. Pérdida de volumen de una jaula de cultivo por efecto de la velocidad de la corriente y del uso de anillo cortacorriente RESUMEN. El volumen interno de las jaulas es una variable relevante para el bienestar de los peces durante el proceso de engorda. En este trabajo se modeló un tren de balsas jaulas usando el programa de elementos finitos AquaSim®. Se analizó la influencia de tres velocidades de corriente con flujo uniform

Spatial structure and morphometric relationships of the deep-sea shrimp Solenocera acuminata (Decapoda, Solenoceridae) in the Colombian Caribbean

Given the potential interest in targeting Solenocera acuminata in a new deep-sea fishery in the Colombian Caribbean, biological information is needed to support the management of this species. The objective of this study is to provide biological information about size structure, size at sexual maturity, morphometric relationships, abundances and spatial and bathymetric distribution of S. acuminata in the Colombian Caribbean. Specimens of S. acuminata were collected during four deep-sea prospecting surveys in the Colombian Caribbean Sea, which were conducted between Punta Gallinas and the Gulf of Uraba. A total of 87 exploratory fishing trawls were made between 100 and 550 m depth. Sexual dimorphism was evident, with males being smaller than females. The size at sexual maturity of the females was 95.2 mm total length (23.82 mm CL). Relatively high biomass values were found in the northern zone of the Colombian Caribbean, between Santa Marta and Riohacha. In the southern zone, higher biomass was found between Cartagena and Morrosquillo Gulf. The biomass of S. acuminata was higher at night (mean 1.82 kg/km2) than during daylight (mean 0.15 kg/km2). This species was distributed between 150 and 400 m depth and the highest biomass was associated with depths between 330 and 380 m. Before starting a new fishery, more research is needed to understand the life cycle parameters of deep-sea resources, such as growth, reproduction, recruitment, mortality, spawning areas and times, nursery areas and associated biodiversity