Evaluation of the accuracy and precision of volunteered size data from tagged red drum returns.




Ferguson, M.O.
Green, A.W.
Matlock, G.C.

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The accuracy and precision of total lengths and weights from recaptured tagged red drum (Sciaenops ocellata) reported by Texas Parks and Wildlife Department (TPWD) biologists, anglers, and commercial fishermen were compared. No differences were found in the total length - weight regressions of data reported by sport and commercial fishermen, but there were significant differences found between data reported by fishermen and data collected by TPWD biologists (Fs = 6.312; P < 0.05). Fish lengths reported by fishermen were not biased but they were more variable than lengths reported by TPWD due to rounding to the nearest whole or partial English unit. Weights reported by fishermen were more variable than weights reported by TPWD biologists. A significant difference between regression coefficients was found and a comparison of confidence limits of the regression lines showed that fishermen overestimated the weight of small fish; therefore, growth estimates calculated from red drum weights provided by fishermen will be biased. TPWD total length data provided the most precise data for growth estimates.


p. 181-185.


evaluation, accuracy, size, length-weight relationships