An assessment of the sustainability of the hake Merluccius hubbsi artisanal fishery in San Matías Gulf, Patagonia, Argentina

N American J Fish Manag

Reinaldo

2010

Self Cite

The performance of management measures adopted to reduce the catch of small-size fish in trawl fisheries requires a proper evaluation taking into account that different factors (e.g., the behavior of fishermen, gear efficiency, market forces, and weak controls) may affect the results. The high bycatch of juvenile Argentine hake Merluccius hubbsi recorded in the trawl fishery of San Matías Gulf, Argentina, could be an indication of a suboptimal harvesting pattern that should be addressed. Regulations to mitigate this problem (i.e., a minimum mesh size and the seasonal closure of a nursery area) were imposed in 1997-1998. The purpose of this study was to assess the efficacy of the size-selectivity measure 10 years after its implementation based on two key indicators: the presence of juvenile Argentine hake in catches and discard rates. Our results show that this measure was ineffective in reducing the catch and discard of juveniles and that both indicator values increased during the period analyzed. This failure could be the result of the limited scientific advice available when the measure was designed or poor implementation, monitoring, and control strategies.

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

When Conventional Fisheries Management Fails to Reduce the Catch and Discard of Juvenile Fish: A Case Study of the Argentine Hake Trawl Fishery in San Matías Gulf

N American J Fish Manag

Reinaldo

2010

Self Cite

“…Desde hace más de tres décadas se desarrolla una pesquería dirigida al complejo de especies demersales y demersal-pelágicas. De acuerdo a sus propiedades oceanográficas y biológicas, se ha sugerido que algunas de las especies forman unidades demográficas diferentes a las existentes en la Plataforma Continental Argentina, como es el caso de la merluza común Merluccius hubbsi, principal especie blanco de la pesquería (Di Giácomo et al, 1993;Sardella & Timi, 2004;González et al, 2007). Esta condición de sistema semi-cerrado del golfo San Matías podría generar escenarios particulares para la interacción entre la flota pesquera de arrastre demersal que opera en el golfo y algunos predadores tope del ecosistema.…”

Section: Introductionunclassified

Solapamiento trofico entre el lobo marino de un pelo Otaria flavescens y la pesqueria de arrastre demersal del golfo San Matias, Patagonia, Argentina

Dans²,

et al. 2011

lajar

RESUMEN.A nivel internacional, paralelo a la declinación y al colapso de pesquerías de gran escala, surgió un interés creciente por el estudio de las interacciones entre mamíferos marinos y pesquerías. El golfo San Matías (Patagonia, Argentina) es considerado un ecosistema pesquero independiente de las aguas de la Plataforma Continental Argentina, con condiciones oceanográficas y biológicas particulares. La condición de sistema semi-cerrado podría generar escenarios particulares para la interacción entre la flota pesquera de arrastre de fondo y la población de lobos marinos de un pelo Otaria flavescens. En el presente trabajo se caracterizó la dieta del predador y la composición de las capturas pesqueras a fin de evaluar el solapamiento trófico entre ambos componentes. A partir de este análisis y la comparación de las tallas de las presas consumidas, se encontró que la posibilidad de una interacción competitiva entre la flota pesquera y los lobos marinos, a partir de la utilización de recursos similares, sería baja en el ecosistema del golfo San Matías. Palabras clave: Otaria flavescens, lobo marino, golfo San Matías, pesquería de arrastre, solapamiento trófico, Patagonia argentina.Trophic overlap between the South American sea lion Otaria flavescens and the demersal trawl fishery in San Matías Gulf, Patagonia, Argentina ABSTRACT. As world fisheries began to decline and massive collapses were observed, the competition between marine mammals and fisheries became an issue of growing concern. San Matías Gulf (Patagonia, Argentina) is considered to be a fishery ecosystem independent of the Argentine Continental Shelf waters, with particular oceanographic and biological properties. As a semi-enclosed ecosystem, this gulf may generate particular scenarios for interactions between the demersal trawl fishery fleet and the population of South American sea lions Otaria flavescens. In this paper, the diet of the top predator and the composition of fishery catches were characterized in order to assess the trophic overlap between these two components. This analysis and a comparison of the sizes of prey consumed revealed a low probability of competition for similar resources between the fishing fleet and the marine mammals in the San Matías Gulf ecosystem.

“…A third stock located within the San Matías Gulf (SMG; Fig. 1) is fished by both industrial bottom trawl and artisanal semi‐pelagic near‐bottom longline fleets, and several studies have shown that this stock completes its life cycle within SMG, constituting an independent demographic unit with its own spawning season in October to November (Di Giácomo et al, 1993; Sardella & Timi, 2004; González et al , 2007; Ocampo Reinaldo, 2010; Machado Schiaffino et al, 2011). The population structure of the stock of SMG seems to be well preserved since the beginning of the trawl fishery in 1971 (Ocampo Reinaldo, 2010; Romero et al , 2010).…”

Section: Introductionmentioning

confidence: 99%

Feeding strategy and cannibalism of the Argentine hake Merluccius hubbsi

Reinaldo

Journal of Fish Biology

2011

The diet composition and feeding strategy of the Argentine hake Merluccius hubbsi in the San Matías Gulf were analysed in order to use this information for the sustainable management of the fishery. Merluccius hubbsi behaved as an opportunistic predator. Small M. hubbsi consumed planktonic crustaceans, whereas medium and large fish ate numerous prey taxa with low frequency of occurrence and variable specific abundance. Intra- and intercohort cannibalism were detected in all size groups and were particularly significant in large M. hubbsi. Medium-sized M. hubbsi consumed small conspecifics and large-sized M. hubbsi consumed both small and medium M. hubbsi. These results indicate that the removal of large M. hubbsi by fishing may increase the risk of overfishing by two combined effects: a direct effect of recruitment-overfishing and an indirect effect of growth-overfishing through an enhanced cannibalism of medium M. hubbsi on small M. hubbsi. Intra- and intercohort cannibalism and other trophic relationships in the M. hubbsi should therefore be considered explicitly in stock assessment models.