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An examination of recreational angling for sharks in Delaware waters

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dc.contributor.author Johnson, Symone
dc.date.accessioned 2018-09-03T13:49:57Z
dc.date.available 2018-09-03T13:49:57Z
dc.identifier.uri http://hdl.handle.net/20.500.12090/36
dc.description.abstract Recreational angling targeting prohibited shark species (e.g. Sand Tiger (Carcharias taurus) and Sandbar (Carcharhinus plumbeus) Sharks) has increased in Delaware, raising concerns about the population status of these species. In an attempt to help address these concerns, my thesis had two objectives: to better understand recreational anglers’ perceptions of and interactions with prohibited sharks; and to explore gear modifications that result in minimizing harm to shark species caught during recreational angling. To achieve my first objective, I developed an angler survey with the goals of: 1) improving our understanding of threats to sharks, 2) identifying potential solutions to threats of shark conservation, and 3) improving fisheries management of sharks through reduced injury or mortality. The survey highlighted the need for improved accuracy in species identification and compliancy with best angling practices and/or regulations as threats to shark conservation. My findings suggest that resource managers may modify their approaches to reduce injury or mortality of sharks through increased angler education and training, K-12 education, social media campaigns, and increased enforcement. Building upon this, I examined the efficacy of experimental (blocker) longline gangions compared to control gangions for reducing damage to individual Sand Tiger and Sandbar Sharks during capture events. Over a three year period (2012-2014) comprising of 153 longline sets, I landed 493 Sand Tiger and 240 Sandbar Sharks. Overall catch rates of Sand Tigers (p = 0.024) and Sandbar Sharks (p = 0.013) were reduced on the experimental gangions. Gear type had a marked impact on hooking location (p = 0.003) for Sand Tigers as the overwhelming majority (96.3%) of gut hooked Sand Tiger individuals were encountered on control gangions. The use of blocker gangions shows much promise in minimizing risk of injury for Sand Tigers captured during longline surveys. In the case of Sandbar Sharks, there were no incidents of gut hooking in the entire study suggesting that the risk of injury from gut hooking is minimal for the species. The marked decline in gut hooking rates with Sand Tigers noted with the use of the experimental gangions underscores its potential use as a tool to reduce injury risk and to improve post-release survival prospects. It is well understood that a healthy marine environment provides direct and indirect economic awards and healthy shark populations are a key point in these environments. I hope my efforts to provide insights on angling preferences and practices in Delaware, as well as a potential tool for use in the angling community, will help foster increased recovery prospects for these important species.
dc.title An examination of recreational angling for sharks in Delaware waters
dc.date.updated 2018-05-29T19:14:52Z
dc.language.rfc3066 en


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