Originally Posted By: Carcassman
The tags broadcast as long as the battery lasts. They have been recorded in Great Blue Heron, for example. A smolt is "dead" when it does not pass the next downstream line of receivers. In some cases, they can get by one line and are recorded at the next. Plus, a smolt may decide to remain in FW for another year. Battery dies, it survives and smolts, but would likely be considered a mort from the year before.

As with all stuff biological, you need years of data, consistently collected, to detect trends. This "one year of data and we have what we need" does save money but is stupid.


No doubt that more data using the same processes provides for better analysis over time. That said, even first year data has some value in evaluating a hypothesis such as in this case - huge early mortality.

The real questions will be what are the primary causes and what, if anything, can/will be done to mitigate them (biologically and socially/politically)?
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