Tag location and retention in black rockfish: Feasibility of using PIT tags in a wild marine species

Tag and recovery programs can provide valuable information on population size and exploitation rates in fishes. Passive integrated transponder (PIT) tags are ideal for use in such programs because they provide identification of individual fish and are invisible to anglers, circumventing problems with nonreporting of tags. Our objective was to determine whether PIT tags could be used successfully to tag black rockfish Sebastes melanops. We tested tag placement and tag retention using intramuscularly injected PIT tags (12 x 2.1 mm) in 227 black rockfish (25-47 cm); three tag placement sites located outside of the area normally filleted were evaluated. Tag retention for all tag sites was 100% after 49 weeks however, two fish retained inoperative tags, which possibly sustained damage during the tagging procedure. The results indicated that the best tagging site is ventral and anterior to the Origin of the pectoral fin. At this site. tag retention is excellent, risk of infection is low. tag movement is minimal, and little or no tissue damage results from the tagging procedure.