Recent Submissions

  • Identificación del patrón de distribución espacio-temporal del pez espada (Xiphias gladius) en el océano Pacífico suroriental.

    Espíndola, F.; Vega, R.; Yáñez, E. (2009)
    Se determinó el patrón de distribución espacio-temporal de los rendimientos de pesca (tasa de captura) de pez espada (Xiphias gladius) de la flota palangrera industrial chilena, mediante el uso de modelos aditivos generalizados, análisis de autocorrelación y análisis espectral de Fourier. La información base provino de bitácoras de pesca registradas por observadores científicos entre enero de 2001 y diciembre de 2005. En los modelos aditivos generalizados se incluyeron cinco variables físicas (latitud, longitud, fecha, temperatura superficial del mar (TSM) y el índice lunar), que afectarían la disponibilidad y vulnerabilidad del pez espada, y dos variables operacionales (largo del barco y tipo de palangre), que se asociarían directamente con la efectividad del sistema de pesca. Los efectos no lineales fueron establecidos significativamente (p < 0,01) para cada una de las variables independientes. Se observó un ciclo anual característico en la tasa de captura, con valores elevados de marzo a julio-agosto, y desplazamientos de la operación de pesca de sur a norte de 38~’ a 32~’S, en un rango de TSM de 17~’ a 19~’C. Posteriormente, los rendimientos disminuyeron en dirección norte desde los 32°S con TSM mayores a 20~’C. Este patrón espacio-temporal fue determinado con una alta coherencia cuadrada (79%) en las series temporales de las tasas de captura nominal y la componente latitudinal analizadas en el análisis espectral de Fourier. Además, para la serie temporal de la tasa de captura nominal se establecieron fluctuaciones de baja frecuencia con períodos de 28, 38 y 59 días. Esta variabilidad intraestacional en la tasa de captura coincide con las variaciones en las condiciones oceanográficas de mesoescala en la zona donde se desarrolla la pesquería frente a la costa de Chile.
  • An integrated conceptual approach to study the swordfish (Xiphias gladius Linnaeus, 1758) fishery in the eastern South Pacific

    Yáñez, E.; Vega, R.; Silva, C.; Letelier, J.; Barbieri, M.A.; Espíndola, F. (2008)
    The available environmental, biological, ecological, and fishery data associated with the exploitation of swordfish (Xiphias gladius) in the eastern South Pacific were analyzed and the literature on models aiming at an ecosystem approach to fisheries management was reviewed. The conceptual model set forth in this work incorporates three planes with processes defined on three spatial (Pacific Ocean, eastern South Pacific, fishing area) and three temporal (interannual, seasonal, intraseasonal) scales. Because of the swordfish’s geographic distribution, life history, and migratory activity, the model must consider several developmental states (eggs and larvae, juveniles, adults) inhabiting different grounds (spawning, breeding, adult feeding). The conceptual model presented herein, without detracting from current operational fisheries research, suggests what must be done to develop integrated fishery management.
  • Factores que afectan las tasas de captura de langostino amarillo (Cervimunida johni) en la zona norte de Chile

    Wiff, R.; Quiroz, J.C.; Montenegro, C. (Pontificia Universidad Católica de Valparaíso, 2005)
    An analysis was made of the factors affecting the catch rates of the yellow squat lobster (Cervimunida johni) in Chile’s northern region (26°03’-32°10’S) by reviewing commercial fishing logbooks from 1993 to 2003. Factors evaluated included years, months, depth stratum, fishing areas and fleet characteristics as linear predictors in a generalized linear model (GLM) in order to explain variability in the catch rate. In contrast with other fisheries, with this resource the technical characteristics of the fleet and its’ specialization poorly explain variations in catch rate; temporal factors and their interaction were, however, highly significant. The results of this study, together with the life history of the resource, allow the supposition that standardized catch rates are appropriate as an index of relative abundance in this fishery.
  • Estado de explotación del recurso besugo (Epigonus crassicaudus) en Chile

    Wiff, R.; Quiroz, J.C.; Tascheri, R. (Pontificia Universidad Católica de Valparaíso, 2005)
    The exploitation status of cardinalfish (Epigonus crassicaudus) yielded in Chile between 33° to 41°S was analyzed. An indirect assessment was performed between 1997 and 2003 through size-structured model with a transition matrix defining the changes among sizes. The model was calibrated using size structures, official landings, catch-per-unit of effort (CPUE) taken from commercial fishing logbooks and standardized by generalized linear models (GLM). After 7 years of an intense fishery activity, we concluded that the cardinalfish resource in Chile is on the recruitment overfishing limit. On 2003, the spawning biomass with respect to the virginal spawning biomass is close to 40%. The biological references points (BRP) based on spawning per recruit biomass (SPR) support this assesment because the fishing mortality level on 2003 (Fact) was very close to fishing mortality level of 40% of SRP at virginal value (F40%).
  • Modelo de optimización para el cálculo de la cuota de captura de langostino amarillo.

    Albornoz, V.; Canales, C.; Fazzi, R. (Pontificia Universidad Católica de Valparaíso, Escuela de Ciencias del Mar, 2006)
    This paper presents a nonlinear optimization model that use to establish an annual quota for the total allowable catch for managing the yellow squat lobster fishery. The proposed bioeconomic model maximizes the economic profits of the activity involved and, simultaneously, takes into account the long-term conservation of the resource by restricting catches and thereby assuring adequate biomass level in the future. The dynamic behavior of the population is incorporated through a single-specie logistic growth model. Parameters (e.g., growth rate, maximun population and ish eort) were estimated based on a sampling technique using historical biomass reports and fishing yields. The results obtained with this methodology are shown, as is their application in managing this particular fishery in the north of Chile.