A method for the external attachment of miniature radio tags to pike Esox lucius

摘要

In pievious telemetry studies of pike Esox lucius L., radio and acoustic transmitters have been either implanted into the body cavity of the fish (e g Beaumont, Cresswell, Hodder, Masters & Welton 2002), implanted into the stomach (Diana et al. 1977), or mounted externally on the fish (Armstrong, Lucas, Piiede & De Vera 1989; Herke & Moring 1999). Implanted tags have several advantages over externally mounted ones in that the possibility of weed entanglement is lessened and swimming is less likely to be affected. The size of the tag however can preclude using internal tags on small fish, as, unless trailing external antennas are used, tag size is relatively large. This makes tagging of small fish a problem both with respect to minimum recommended tag size (Winter, Keuchle, Siniff & Tester 1978) and the physical space available for the tag in the fish's peritoneal cavity Whilst in some studies implanted tags have been ejected from the peritoneal cavity (Lucas 1989; Baras & Westerloppe 1999), implanted transmitters are designed to be permanently retained by the fish Intragastric tags maintain the benefits of an internal location, although tag loss through regurgitation can occur after a short period of time and, if the presence of the tag affects appetite, tracking data may be unrepresentative of normal behaviour (Lucas & Tohnstone J990). For short-teim studies and studies using smaller fish therefore, temporary, external attachment of transmitters may be a more suitable attachment method. This is a less severe procedure for the fish, and (in the case of implanted tags) has the added benefit of being simpler for the person performing the procedure.