If Electronic Tags Were Cheap- Designing for the Future

Electronic tags have enabled scientists to describe fish movements, habitat usage and migration patterns. However, the high cost of these tags limits the number that can be deployed. We consider what could be done if technological improvements and the production of tags with fewer features allowed large numbers of smaller tags with longer battery life to be sold at a low price. We envision routine application of tags that remain dormant until the programmed date of detachment and then simply report current location. Such tags could be used to determine the exchange rates of fish among management areas and mortality rates, as two examples. Use of pop-up tags can extend the usefulness of standard methods, like change-in-ratio and Brownie estimators. By having tag reporting rates (close to) 100%, additional parameters such as stock composition in mixed stock assemblages and fishing and natural mortality can be estimated. Significantly, an important class of models can utilize a single release of tags that are programmed to pop-off at different discrete times to estimate a variety of parameters.