A microcontrolled fish tag which records post-tagging life span, was developed
and tested as a prototype. The method of making the tag and the results of
tank test trials on chinook salmon (Oncorhynchus tshawytscha) and field trials on chum salmon
(Oncorhynchus keta) are presented. This tag was specifically designed to measure survey life
(SL) but may have other applications. Survey life is an essential component
for area-under-the-curve (AUC) estimation of Pacific salmon (Oncorhynchus spp.) spawning
escapements. Accurate escapement estimates are critically important for
salmon fisheries management and science. However, AUC spawner estimates must
often employ average SL values from historic rather than year-specific
studies because direct estimates of SL can require extensive and costly
tag-recapture programs. Using assumed SL values can introduce serious bias
in population estimates, therefore alternative methods of determining annual
SL are important. In this study, the new tag estimated SL by measuring the
elapsed time from tagging until the fish came to rest permanently on its
lateral or dorsal surface. Details on how to construct the tag are provided
so that researchers will be able to make their own.