Design and Analysis of Salmonid Tagging Studies in the Columbia Basin, Volume XXI; A Summary of Methods for Conducting Salmonid Fry Mark-Recapture Studies for Estimating Survival in Tributaries, Technical Report 2005-2006.

Productivity and early fry survival can have a major influence on the dynamics of fish stocks. To investigate the early life history of fish, numerous methods have been developed or adapted to these much smaller fish. Some of the marking techniques provide individual identification; many others, only class identification. Some of the tagging techniques require destructive sampling to identify a mark; other methods permit benign examination and rerelease of captured fish. Sixteen alternative release-recapture designs for conducting fry survival investigations were examined. Eleven approaches were found capable of estimating survival parameters; five were not. Of those methods capable of estimating fry survival, five required unique marks, four required batch-specific marks, and two approaches required remarking and rereleasing captured fry. No approach based on a simple batch mark was capable of statistically estimating survival.