Project Title: Using steroid hormone analysis, ultrasonography and telemetry as non-invasive tools for examining reproduction in tiger sharks
Determining the reproductive strategies and mating behaviors of animals is crucial for management and conservation. For example, identifying gestating, mating or pupping grounds could be use to implement reserves or reduce exploitation in these areas critical to the survival of threatened species. The goal of this project is to determine the mating, gestation and pupping grounds of tiger sharks in the western Atlantic.
Historically, the reproductive biology of sharks has been studied by sacrificing the animals; however, in this study, we will be performing ultrasounds on tiger sharks as well as taking blood samples for hormone analysis to determine reproductive status of these large predators. Coupling these techniques (ultrasonography imaging and blood hormone analysis) will allow us to examine the reproductive state (e.g. pregnancy), cycle and length of gestation of sharks during our ongoing research. After their “pregnancy check-ups,” the sharks will also be tagged with satellite transmitters to track their movements and evaluate behavioral patterns that may reveal locations where mating, gestation, or giving birth is occurring. The ultimate goal is to use these data to establish effective marine protection in these areas critical to the reproduction of these large sharks.
The major outreach component of this project is through the participation of conservation enthusiasts. Six people were able to share in the research experience by helping to catch the sharks, collect fin and muscle samples, measure the sharks, and learn about some of the ultrasound and blood analysis techniques. Moreover, the conservation enthusiasts were given the opportunity to dive with these charismatic megafauna, one of which was a female tiger shark tagged during the trip, in an effort to further ecological understanding, and promote the dissemination of conservation awareness.
Hammerschlag N, Sulikowski J. 2011. Killing for Conservation: The Need for Alternatives to Lethal Sampling of Apex Predatory Sharks. Endangered Species Research 14: 135–140