Using Citizen Science And Laser Photogrammetry To Assess Monthly Maturity By Size And Sex Distributions Of Sand Tiger Sharks, Carcharias Taurus, Off Of The North Carolina Coast

Abstract

Sand tiger sharks, Carcharias taurus, are classified globally as vulnerable by the International Union for Conservation of Nature (IUCN) Red List. To better understand the sand tiger shark population on the US East Coast and especially off the North Carolina Coast, the Spot A Shark citizen science program was developed by North Carolina Aquariums. The program relies on citizen scientist scuba divers to take photographs of sand tiger sharks while diving recreationally. Divers may use a laser photogrammetry rig with their camera so that shark length measurements can be collected to determine the maturity status. This project examined the size class and sex of sharks present off the North Carolina coast throughout the year from images in the Spot A Shark USA database. The specific aims were to measure shark length using laser photogrammetry and images from the Spot A Shark USA database, assign maturity to sharks using previously established length at maturity data, determine sex for all sharks in the Spot A Shark USA database, and describe the seasonal trends in sex. Understanding maturity status and sex distributions will provide insight into life history characteristics for sand tiger sharks in North Carolina.