Loss of Floy Anchor Tags from White Bass

Abstract

Tag-shedding rates were estimated for white bass Morone chrysops in the Brazos River and Whitney Reservoir, Texas, to estimate tag retention and to provide a correction for tag loss. Altogether, 487 white bass were double-tagged in 1989 and 215 in 1990 with Floy FD-68BC anchor tags. Mean total lengths of the fish were 342 mm (range, 230–429 mm) in 1989 and 312 mm (range, 123–553 mm) in 1990. Tagged fish were at liberty for up to 560 d, and tags were subsequently returned by anglers for cash rewards ranging from $5 to $100. One hundred three fish tagged in 1989 were recaught (85 in 1989 and 18 in 1990) and 62 fish tagged in 1990 were recaught (59 in 1990 and 3 in 1991). Sixteen percent of returns from the 1989 tagging and 13% of returns from the 1990 tagging consisted of single tags. Immediate posttagging loss resulting from mortality, improper tag placement, and nonreporting by anglers was negligible. Long-term shedding, estimated for up to 560 d, was 24.8% per year for one tag and 6.2% for both tags. This study demonstrated that failure to adjust for Floy FD-68BC tag loss could seriously bias estimates of white bass population parameters.