Pesca exploratoria con trampas alrededor de las islas Robinson Crusoe y Santa Clara, archipiélago de Juan Fernández, Chile

ABSTRACT. Golden crab (Chaceon chilensis) specimens were analyzed after being caught with traps by artisanal fishermen off Robinson Crusoe Island, Juan Fernández Archipelago, Chile. Of the 13,027 individuals caught between 300 and 1,000 m depth, 97.9% were male (12,754) and the rest female (273). The carapace length (CL) of the sampled crabs was measured and, on average, the males (CL: 118.9 mm) were larger than the females (CL: 94.3 mm). On the north side of the island, the specimens presented lower average sizes (112.2 mm) whereas, in the remaining zones, the average carapace lengths were similar (CL: 117.1-119.5 mm). In bathymetric terms, an increasing trend was seen between average size and depth, with sizes over 123 mm CL found beginning at 750 m depth. A comparison of linear regressions between the carapace length and chela length of males revealed physical maturity at 100 mm CL, whereas a numerical analysis showed the size at first sexual maturity (SSM 50% ) to be 109 mm CL.

Section: Introductionmentioning

confidence: 99%

Size structure and sexual maturity of the golden crab (Chaceon chilensis) exploited off Robinson Crusoe Island, Chile

Guerrero¹,

Arana²

2009

“…Capturas por trampa (unidades) de cangrejo dorado, por sexo y condición de los ejemplares, durante el experimento de separación de trampas en líneas de pesca (M: macho, HO: hembra ovígera, H: hembra). (Arana, 2000a). A la fecha, esta actividad ha sido desarrollada únicamente por algunas embarcaciones, de manera complementaria a la extracción del principal recurso objetivo, la langosta de Juan Fernández (Jasus frontalis).…”

Section: Discussionunclassified

“…Este hecho es coincidente con lo indicado por Arana (2000a), quien en faenas de Tabla 4. Parámetros de la función ajustada entre CPUE y separación entre trampas, para obtener el radio de atracción de las trampas.…”

Section: Discussionunclassified

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Pesca artesanal de cangrejo dorado (Chaceon chilensis) en el archipielago de Juan Fernandez, Chile. Artisanal fishing for golden crab (Chaceon chilensis)

Ahumada¹,

Arana²

2009

RESUMEN.Se describe la pesca artesanal de cangrejo dorado (Chaceon chilensis) en las islas Robinson Crusoe y Santa Clara, en el archipiélago de Juan Fernández (Chile), desarrollada entre julio de 2005 y mayo de 2006. Se dan a conocer aspectos biológico-pesqueros relativos a esfuerzo y rendimientos de pesca, proporción sexual, así como los resultados de una evaluación directa de biomasa vulnerable mediante el método de área de influencia de las trampas. La extracción se efectuó fundamentalmente en el cuadrante NE de ambas islas, mediante botes de madera de 9,0 m de eslora. Se monitorearon 157 salidas de pesca y se capturaron 13.903 ejemplares, los cuales mayoritariamente fueron machos (97,5%). La CPUE promedio fue 16,7 ejemplares por trampa y de 13,5 ejemplares comerciales por trampa. A partir del muestreo sistemático, se detectó al recurso entre 300 y 1000 m de profundidad, con mayores rendimientos entre 400 y 500 m de profundidad (19,8 y 15,9 ejemplares por trampa). Se consideran y discuten dos escenarios de evaluación de stock para ejemplares de talla comercial en el área actualmente explotada (45,8 km 2 ), el primero estimó un radio efectivo para las trampas de 13,4 m (área de 564,1 m 2 ), con una biomasa vulnerable de 1.002 ton, equivalentes a 832.983 ejemplares, mientras que el segundo consideró un radio de 30,0 m con una biomasa vulnerable de 203 ton equivalente a 168.587 ejemplares.Palabras clave: pesca artesanal, Chaceon chilensis, cangrejo dorado, aguas profundas, archipiélago de Juan Fernández, Chile. Artisanal fishing for golden crab (Chaceon chilensis) off the Juan Fernández archipelago, ChileABSTRACT. This work describes the artisanal golden crab (Chaceon chilensis) fishery off Robinson Crusoe and Santa Clara islands in the Juan Fernández archipelago (Chile) developed between July 2005 and May 2006. We report biological fishery aspects related to the fishing efforts and yields, the sexual proportion of the catch, and the results of a direct evaluation of the vulnerable biomass done using the trap area of influence method. The extraction was done mainly in the NE quadrant of both islands from wooden boats (9.0 m length). Monitoring was done during 157 fishing trips, in which 13,903 specimens were caught; most were males (97.5%). The average CPUEs were 16.7 specimens per trap and 13.5 commercial specimens per trap. Systematic sampling revealed the resource between 300 and 1000 m depth, with the greatest yields between 400 and 500 m depth (19.8 and 15.9 specimens per trap). Two stock assessment scenarios were considered and discussed for commercial-sized specimens in the currently exploited area (45.8 km 2 ). The first scenario estimated an effective radius for the traps of 13.4 m (564.1 m 2 in area), obtaining a vulnerable biomass of 1002 tons, equivalent to 832,983 specimens. The second scenario considered a radius of 30.0 m, giving a vulnerable biomass of 203 tons, or 168,587 specimens.

“…The golden crab is generally distributed between 200 m and 2,000 m of depth (Dawson & Webber, 1991). It was found at depths of 400 and 800 m along the undersea Nazca Ridge (Parin et al, 1997) and was caught at 100 and 1,000 m around Robinson Crusoe and Santa Clara islands, with a greater abundance at 300 m and between 500 and 600 m (Arana, 2000).…”

Section: Discussionmentioning

confidence: 99%

Seamounts in the southeastern Pacific Ocean and biodiversity on Juan Fernandez seamounts, Chile

Yáñez¹,

Silva²,

Vega³

et al. 2009

ABSTRACT. Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems is quite scarce; thus, a compilation of information on their geographical distribution and biodiversity is presented herein. A total of 118 seamounts distributed in the Chilean EEZ are identified and characterized. Additionally, an in situ assessment was carried out on the Juan Fernandez seamounts 1 and 2 (JF1 and JF2), which were also oceanographically characterized. Phytoplankton, zooplankton, and marine invertebrate samples were collected and an exploratory fishing survey was executed using different gears. According to the bibliographical review, a total of 82 species have been collected on the JF1 and JF2 seamounts, highlighting findings of black coral species caught in lobster traps at the Juan Fernandez Archipelago. Submarine images of the marine substrate at JF1 and JF2 reveal characteristics attributable to the impact of bottom dredges, coinciding with the information obtained from the trawling fleet. The fishing activity was carried out primarily at JF2 (4,667 km of trawling). The monthly fishing effort increased considerably in 2002, 2003, and 2005, reaching values above 500 km of trawling and, thus, modifying the spatial structure of the resource aggregates on the JF2 seamount.