MODELS FOR TAGGING DATA THAT ALLOW FOR INCOMPLETE MIXING OF NEWLY TAGGED ANIMALS

The Brownie models for tagging data allow one to estimate age- and yea r-specific total survival rates as well as tag recovery rate parameter s. The latter can provide estimates of exploitation rates if the tag r eporting, tag shedding, and tag-induced mortality rates can be estimat ed. A limitation of the models is that they do not allow for newly tag ged animals to have different survival rates than previously tagged an imals because of lack of complete mixing. We develop a model that allo ws for the animals to be incompletely mixed, or not fully recruited, i nto the population during the entire year in which they are tagged. Th ere is a penalty in terms of precision associated with the use of this model. To increase the precision, we also developed a model for which it is assumed that animals become fully mixed (recruited) after a por tion of the year has elapsed. Sometimes, animals must be tagged after the fishing season has begun. In this case, newly tagged animals exper ience fishing and natural mortality for only a fraction of the year. T he partial-year non-mixing model can be modified to account for this s ituation.