نتایج جستجو برای: catchability
تعداد نتایج: 207 فیلتر نتایج به سال:
Abstract Estimation of the unknown population size using capture-recapture techniques relies on key assumption that capture probabilities are homogeneous across individuals in population. This is usually accomplished via post-stratification by some covariates believed to influence individual catchability. Another issue arises estimation from data collected multiple sources list dependence, wher...
Due to the heavy exploitation of holothurians over the last few decades, it is necessary to implement fishing regulations aimed at reversing this situation. Holothurians require specific regulations that take into account their biology and ecology. Their behavior to group and form patches as a strategy for feeding, defense and reproduction, makes them vulnerable to overfishing. The higher the p...
The yellowfin tuna ( Thunnus albacares: YFT) is a widely distributed, migratory species that supports valuable commercial fisheries. Landings of YFT are seasonally and spatially variable, reflecting changes in their availability accessibility to different fleets metiers which, turn, has implications for sustainable management. Understanding the dynamics behaviour how it affected by biological e...
A 4exible method for modelling capture–recapture data with continuous covariates that describe heterogeneous catchability is developed. The well established generalized additive modelling framework is used. An estimator of population size is developed using this method. The performance of the method is demonstrated using neural tube defect capture–recapture data from the Netherlands, with the b...
Survival analysis was applied to fisheries catch at age data to develop maximum likelihood estimators for stock assessment. This new method estimated natural mortality, fishing mortality and catchability from typical catch at age matrices. Monte Carlo simulations suggested estimates were unbiased and provided a better fit than the traditional multinomial approach. Application to a dataset from ...
Eduardo P. Pérez E. Marine Biologist, Universidad Católica del Norte (UCN), Chile. M.Sc. and Ph.D., Centro de Investigación y Estudios Avanzados (CINVESTAV-IPN), Mexico. Professor, Department of Marine Biology, UCN, Chile and Researcher, Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile. Address: Casilla 117, Coquimbo, Chile, e-mail: [email protected] Omar Defeo. Ph.D., CINVESTAV-IPN, M...
We develop an economic model for a multi-species fishery that incorporates the spatial distribution of effort and fish stocks. Catchability coefficients and initial stocks are estimated from catch and effort data for each specific location. Vessels are allocated over space and time to locations of maximum profit which decline with harvest because of stock externalities. A supply function for la...
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