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Oak Ridge, NJ, United States

O'Connell C.P.,Coastal Carolina University | Abel D.C.,Coastal Carolina University | Rice P.H.,Florida College | Stroud E.M.,SharkDefense | Simuro N.C.,Clarkson College
Marine and Freshwater Behaviour and Physiology | Year: 2010

The behavioral responses of free-swimming, wild southern stingrays (Dasyatis americana) and nurse sharks (Ginglymostoma cirratum) to permanent magnets were evaluated in the Florida Keys, USA. Animals were attracted to a baited magnetic treatment board consisting of two 15 cm × 10 cm × 5 cm grade C8 Barium-Ferrite (empirically, BaFe12O19) permanent magnets producing a flux of 950 gauss at their surface and a baited procedural control board containing two smooth nonmagnetized clay bricks. In the presence of permanent magnets, D. americana and G. cirratum demonstrated a significantly greater number of avoidance behaviors away from the magnet side of the apparatus, while both species fed a significantly greater number of times from the non-magnetized procedural control side. Thus, D. americana and G. cirratum showed sensitivity to a magnetic field and were successfully repelled from baited areas containing magnets. The results from the current study suggest that the use of grade C8 Barium-Ferrite permanent magnets as an avoidance mechanism (e.g., repellent) to reduce elasmobranch mortalities associated with fishing operations and beach nets merits further investigation. © 2010 Taylor & Francis.

Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 166.81K | Year: 2010

This Small Business Innovation Research (SBIR) Phase 1 project addresses unintended shark catch in commercial fisheries by creating an advanced fishing hook material that is repellent to sharks and not repellent to market-valuable fish. In the commercial longline fishing industry, it is not uncommon to capture more sharks than target fish. Unintended shark catch, or "bycatch", results because a baited hook is equally attractive to both fish and sharks. If unwanted sharks can be selectively repelled, the target fish catch can be maximized, allowing the industry to remain sustainable, profitable, and eligible for incentives from fishery regulators. To address this selective fishing requirement, the proposed technology combines two known shark repellent technologies directly into a fishing hook: Magnetism and electropositivity. These repellents affect the shark's unique electrical sense and are not detectable by tuna and swordfish, which lack the electrical sense. The proposed technology is transparent to fishermen because it will not require external power and will not change the shape, function, or handling of a standard hook. The broader/commercial impacts of this research are the training of new scientists and increased understanding of shark behavior and shark repellent materials. By identifying compounds with selective shark repellent activity, marine biologists will have an enhanced understanding of the behavioral differences between sharks and fishes. Technological understanding will be advanced identifying surface treatment techniques for metals used in marine environments. These techniques will provide direction for future shark-repellent coatings for marine aquaculture and marine infrastructure.

SharkDefense | Entity website

Phone: (877) 571-2207 Address: PO Box 2593 Oak Ridge, NJ 07438 USADr. Patrick H ...

SharkDefense | Entity website

SharkDefense | Entity website

Several species of sharks have demonstrated the ability to sense magnetic fieldsThe ampullae of Lorenzini are small vesicles and pores that form part of a subcutaneous sensory network of sharks. These vesicles and pores are found around the head of the shark and are visible to the naked eye ...

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