Electrogenic metals for elasmobranch bycatch mitigation

• Other Authors: Smith, Kieran Thomas.
• Format: Others
• Language: English
• Published: Florida Atlantic University
• Subjects: Fishery conservation; Sharks > Conservation; Lanthanide shift reagents; Wildlife management
• Online Access: http://purl.flvc.org/fcla/dt/3361053

Commercial longline fishing results in large amounts of incidental bycatch of elasmobranch fishes (sharks, skates, and rays). Teleost species lack electrosensory systems and development of technologies which target the ampullary organs of sharks provides an avenue to selectively deter elasmobranchs without affecting the catch rate of target teleosts. Electric field measurements and a controlled scientific longline study were conducted testing whether the lanthanide metal neodymium or zinc/graphite might reduce elasmobranch catch per unit effort (CPUE). Baited longline hooks were treated with neodymium and zinc/graphite and catch rates were compared to that of controls. Shark CPUE decreased by 60% on neodymium treated hooks and 80% on zinc/graphite treated hooks. The effectiveness of both treatments varied among species with significant reductions shown for Atlantic sharpnose sharks (Rhizoprionodon terranovae) but less dramatic differences for others. Zinc/graphite is potentially a viable tool for reduction of shark bycatch in a commercial longline fishery. === by Kieran Thomas Smith. === Thesis (M.S.)--Florida Atlantic University, 2013. === Includes bibliography. === Mode of access: World Wide Web. === System requirements: Adobe Reader.