Retention of visible implant tags in small rockpool fishes

Retention and associated fish mortality of visible implant alphanumeric (VIA) and fluorescent elastomer tags was assessed in 2 Australian intertidal rockpool fishes, Girella elevata (Girellidae) and Bathygobius cocosensis (Gobiidae). Mean retention of VIA and elastomer tags after 90 d was 32 ± 20% and 77 ± 19%, respectively. After 90 d the fish mean mortality from VIA tags (20 ± 5%) was significantly higher than from elastomer tags (7 ± 2%) and untagged control groups (11 ± 2%). Elastomer tags appear most suitable for marking batches of fish of various size, while VIA tags appear suitable for identification of larger individuals of species such as many gobies that have adequate transparent tissue for tag recognition.