Retention of Coded Wire Tags in Juvenile Shortnose Sturgeon

Abstract

We injected 50 juvenile shortnose sturgeon Acipenser brevirostrum with sequentially numbered, standard-length, binary coded wire tags, 4 along each pectoral fin spinous ray, 1 in the base of each pectoral fin, and 1 in the base of the dorsal fin, for a total of 11 tags per fish. After 120 d, the fish were examined for tag retention at each location by means of X-rays. Retention was 98% in the dorsal fin base, 96% in the pectoral fin bases, and 78% in the pectoral fin spinous rays. However, a mean of 6.5 pectoral fin spinous ray tags per fish were retained and all fish retained at least 2 tags. Because individual tags may be recovered nonlethally by taking incremental segments of the spinous ray, the process can be repeated, thus allowing for multiple recaptures. This may be especially important for population studies on endangered species such as the shortnose sturgeon.