Alternate Title

A Comparison of Petersen Tags and Biological Stains Used With Internal Tags as Marks for Shrimp

Document Type



During May 20-31, 1968, 14,301 brown shrimp (Penaeus aztecus) were marked and released in Biloxi Bay, Mississippi. Of these 7,023 were marked by injection with a combination of Niagara Sky Blue 6B stain and polyvinyl chloride (PVC) internal tags and 7,278 were marked with Petersen tags. The objectives of this experiment were to compare the two methods as marks for shrimp and to obtain information on growth rates and migrations. Eighteen weeks after release, 1,942 (28%) of those marked with the biological stain-internal tag combination and 2,286 (31%) of those marked with Petersen tags had been recovered. The difference in proportions recaptured (significant at P <0.01) could have resulted from greater ease in recognition of the Petersen tag by commercial fishermen or from differential marking mortality, although no evidence was found that differential marking mortality occurred. Marking mortality was observed for both marks and appeared inversely related to size at time of marking. No significant differences were found between growth rates of shrimp marked with the biological stain-internal tag combination and those of shrimp marked with the Petersen tag, although most weekly average increments for stained shrimp were higher. Rates of return were similar in the vicinity of the release area, although a significantly higher proportion (P <0.01) of returns from waters outside of Biloxi Bay were marked with Petersen tags. Again, this was attributed primarily to greater ease in recognition by commercial fishermen. It was concluded that the Petersen tag was the more effective of the two marks as it appeared to be recognized more readily over longer periods of time than the biological stain.

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