Electropositive shark repellent Atlantic longlining vessels in 2008. As expected, teleosts (bony fish) are not repelled by the electropositive metal’s cation liberation in seawater. This is because teleosts lack the ampullae of Lorenzini. Teleost response was confirmed using captive Cobia ("Rachycentron canadum") and Pacific halibut ("Hippoglossus stenolepis"). In July 2008 swordfish ("Xiphias gladius") catch was reported on experimental hooks treated with electropositive metal. As with all shark repellents, 100% effectiveness will not be achieved with electropositive metals. The metals are particularly effective when the shark is relying on its electrosense. It is likely that electropositive metals are ineffective for deliberately stimulated (chummed) sharks,
Peters' elephantnose fish Peters' elephantnose fish Peters' elephant-nose fish ("Gnathonemus petersii") is an African freshwater elephantfish in the genus "Gnathonemus". Other names in English include elephantnose fish, long-nosed elephant fish, and Ubangi mormyrid, after the Ubangi River. As the Latin name "petersii" confirms it is named after someone called "Peters" (probably Wilhelm Peters), although the apostrophe is often misplaced and the common name given as "Peter's elephantnose fish". It uses electrolocation to find prey, and has the largest brain-to-body oxygen use ratio of all known vertebrates (around 0.6). Peters' elephantnose fish are native to the rivers of West and Central Africa, in particular