Tag placement, mark retention, survival and growth of juvenile white shrimp (Litopenaeus setiferus Perez Farfante, 1969) injected with coded wire tags

We tested binary-coded wire tags (CWT) (Northwest Marine Technology, NMT) f or effects of tag placement on growth, survival and mark retention in juven ile (30-90 mm in total length) white shrimp, Litopenaeus setiferus Perez Fa rfante,[Fish. Bull. 67 (1969) 461]. Tags were injected into shrimp at four locations: (a) base of the uropod, (b) telson, (c) coxa of the fifth leg an d (d) dorso-lateral musculature of the first abdominal segment. A control g roup received no tag. Each of the three separate 28-day experiments include d 240 shrimp distributed evenly among 24 tanks of 761 each. Individual dail y specific growth rates ranged from 0.0009 to 0.0096, equivalent to linear or absolute growth rates in total length of 0.05-0.46 min day(-1). Tag plac ement resulted in a significant effect on growth (test for differences in g rowth adjusted for initial length: ANCOVA F-4,F-231 = 7.25, P < 0.001) only in one experiment during which shrimp tagged in the abdominal musculature grew ca. 20% faster than the untagged control group and groups tagged in th e telson or uropod. Overall shrimp survival ranged from 69.6% in the first experiment to > 97% in others. The proportion of surviving shrimp was only marginally affected (Pearson x(4df)(2) = 9.12, P = 0.058) by tag location i n the first experiment, in which groups of shrimp with tags in the first ab dominal segment had the highest survival (81.2%) followed by the untagged c ontrol group (77.1%). Tag retention was unaffected by shrimp size in all ex periments but differed significantly (Pearson X-3df(2), P < 0.001) among ta g locations in all experiments. The base of the uropod and telson had relat ively poor and variable tag retention rates ranging from 35.4% to 66.7% and from 37.5% to 89.6%, respectively. The best retention (95.8-100%) was achi eved in the abdominal musculature, the same tagging location that yielded t he greatest survival rates (81.2-100%). (C) 2001 Published by Elsevier Scie nce B.V.