| Popis: |
The advent of PlT-tags and establishment of decoders and slide-gate facilities at hydroelectric projects on the Columbia and Snake Rivers hold the promise of providing detailed information on capture histories and travel times of individual smolt. These data, along with measurements of pre-release attributes of smolt (e.g., length, weight, condition factor, BKD-indicators, ATP-ase level, rearing history, and degree of &scaling), traits and behavior of smolt after release (e.g., travel time, previous capture history), and ambient river conditions provide an important opportunity to determine those factors influencing survival over time and between individual smolt. To this end, new statistical methods for the analysis of tag-release data are being developed concurrently with implementation of PlT-tag facilities on the Snake and Columbia Rivers.The statistical theory and techniques of relating survival estimates from tag studies with environmental covariates is a recent development (Clobert 1985). Moreover, an ability to relate individual traits to the probable fate of individuals in a mark-recapture study was nonexistent prior to this study. The objectives of this investigation were therefore to determine the feasibility and develop new survival analyses for PIT-tag data that allowed interpretation of cohort-wise and individual covariates on smolt survival processes. The strategy of this research hasmore » been to develop increasingly sophisticated and flexible statistical models of the analysis of PIT-tag data. The research has demonstrated not only the feasibility of incorporating cohort-wise and individual covariates in tag analysis but also the ability to simultaneously analyze multiple tag release studies and the ability to allow capture probabilities (i.e., detection probabilities) to vary as a function of an individual’s release, capture history, and personal traits.« less |
