Reference |
Haines, B. G. and T. Modde. 1996. Evaluation of marking techniques to estimate population size and first year survival of Colorado squawfish. North American Journal of Fisheries Management 16:905-912. |
Abstract |
Three marking methods – tattoo ink injected with dental inoculator, an elastic polymer injected by syringes, and fin clipping – were tested to determine a suitable technique for estimating population size, survival and movement of age-0 Colorado squawfish Ptchocheilus lucius. Laboratory tests indicated that all three marks were retained at sufficient rates (>97%) to make population estimates over a 21 d period. However, fish marked with tattoo ink had higher mortality (10%) than fish marked with elastic polymer (<1%) or with a fin clip (0%). Fish marked with elastic polymer had higher retention (85%) than those marked with fin clips (34%) or tattoo ink (26%) after 142 d. No differences in vulnerability to predation were observed among fish with the three marks or between marked and unmarked fish. A field test of the elastic polymer showed that it was easy to use, caused low mortality (5% for fish held overnight in live-cages), and produced marks that were readily visible. Mark-recapture data were more accurate and precise than those from catch-per-unit-effort data, at least for short-term studies in river reaches less than 50 km long. Simulations showed that doubling the size of the study section and increasing the probability of capture by 33% would reduce possible bias from 14.5% and the coefficient of variation (SE/mean) from 0.25 to 0/06. |
Tag |
Visible Implant Elastomer (VIE) |
Objective |
Population estimates Evaluate tags |
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