Tag placement, mark
retention, survival and growth of juvenile white shrimp (Litopenaeus
setiferus Pérez Farfante, 1969) injected with coded wire tags
R.T. Kneib, M.C. Huggler-2001
Journal of Experimental Marine Biology and Ecology,
266(1): 109-120
Abstract:
We tested binary-coded wire tags (CWT) (Northwest
Marine Technology, NMT) for effects of tag placement on growth, survival and
mark retention in juvenile (30-90 mm in total length) white shrimp, Litopenaeus
setiferus Pérez Farfante,[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 and (d) dorso-lateral musculature of the first
abdominal segment. A control group received no tag. Each of the three
separate 28-day experiments included 240 shrimp distributed evenly among 24
tanks of 76 l each. Individual daily 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 mm day-1. Tag placement resulted in a
significant effect on growth (test for differences in growth adjusted for
initial length: ANCOVA F4,231=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 the 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
4
df2=9.12, P=0.058) by tag location in the
first experiment, in which groups of shrimp with tags in the first abdominal
segment had the highest survival (81.2%) followed by the untagged control
group (77.1%). Tag retention was unaffected by shrimp size in all
experiments but differed significantly (Pearson
3
df2, P<0.001) among tag locations in all
experiments. The base of the uropod and telson had relatively 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 achieved in the
abdominal musculature, the same tagging location that yielded the greatest
survival rates (81.2-100%).
(University of Georgia Marine Institute, Sapelo
Island, GA 31327, USA, Tel.: +1-912-485-2297; fax: +1-912-485-2133, e-mail: rtkneib@arches.uga.edu)
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