BAYLIE FADOOL
MASTERS STUDENT - University of Nebraska-Lincoln
I first came to the Shark Lab in January of 2021 as an intern and stayed on as the Media Manager and Outreach Coordinator until October of 2023. I began my master’s degree at the University of Nebraska-Lincoln in August 2024 in Natural Resource Sciences with an emphasis in Applied Ecology. I am in the LAMP Lab with Dr. Rene Martin as my advisor. My research focuses on the population structure and connectivity of nurse sharks throughout The Bahamas using genetic techniques and acoustic telemetry.
PROJECT DETAILS
A shark species that presents an ideal study system for expanding our understanding of population structure, movement, and reproductive behavior, are the nurse sharks (Ginglymostoma cirratum). Nurse sharks are one of the most abundant shark species around Bimini, The Bahamas (Hansell et al., 2018). In this area, they are slow-growing and long-lived, estimated to reach sexual maturity around 20 years of age and with longevities of up to 43 years (Fadool et al., 2024). Unlike the difficulties of observing mating in many other shark species, nurse sharks have been seen mating in the shallow coastal waters of The Bahamas and Florida, making them an accessible species to observe reproductive behaviors. Nurse sharks also display mating site fidelity in Florida, with some individuals observed visiting specific sites spanning three decades (Pratt et al., 2022). Additionally, captures and observations of nurse sharks in Bimini potentially also indicate them having specific site fidelity and philopatry. The Bimini Biological Field Station Foundation (BBFSF) has been collecting data on nurse sharks for over 30 years, and most of this data has remained relatively underutilized.
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Nurse shark populations from Bimini and The Bahamas are an ideal study system to investigate population connectivity and structure since a large, long-term dataset from BBFSF exists and individuals are readily accessible to researchers. Additionally, a reassessment of their genetics is crucial for understanding the genetic diversity among this population. A previous population genetics study on nurse sharks throughout the Western North Atlantic Ocean was conducted more than a decade ago and performed a different method from the one we will be using (Karl et al., 2012). This project will investigate population structure and connectivity in nurse sharks by using genome-wide single nucleotide polymorphisms (SNPs) and a reduced representation sequencing protocol (ddRAD-seq). Additionally, this work will expand upon previously collected acoustic telemetry data from BBFSF to determine regional and seasonal movement patterns of individuals in the Bimini nurse shark population.
Research Objectives
The broad objectives of this work are to:
(1) use SNPs to examine fine-scale population structure of nurse sharks in Bimini,
(2) examine their regional movement patterns and philopatry, and
(3) determine their population connectivity throughout The Bahamas.
This research will aim to address the following questions:
(1) Are there any parent-offspring pairs in the population?
(2) Are nurse sharks born in Bimini contributing to the Bimini population at sexual maturity or do offspring emigrate?
(3) Is Bimini a pupping or nursery grounds for nurse sharks? and
(4) Do Bahamian nurse sharks comprise a single population or distinct populations?
Conservation Importance
Bimini provides essential habitat for numerous shark species, but coastal land development and habitat destruction are happening on Bimini at an increasingly fast pace. Since nurse sharks have been observed mating in shallow Bimini waters, future coastal development would likely disrupt the reproduction of this IUCN listed vulnerable species. Additionally, past captures have shown the importance of coastal habitat (such as mangroves and seagrass) for juvenile nurse sharks, which are the environments most impacted by development. Through this project, we will better define how crucial this area is for nurse shark reproduction. These results would be essential for ensuring their survival by better informing conservation biologists who can advocate for protecting this area from future development.
CITATIONS:
Fadool, B. A., Bostick, K. G., Brewster, L. R., Hansell, A. C., Carlson, J. K., and Smukall, M. J. (2024). Age and growth estimates for the nurse shark (Ginglymostoma cirratum) over 17 years in Bimini, The Bahamas. Frontiers in Marine Science. 11. doi: 10.3389/fmars.2024.1265150
Hansell, A. C., Kessel, S. T., Brewster, L. R., Cadrin, S. X., Gruber, S. H., Skomal, G. B., & Guttridge, T. L. (2018). Local indicators of abundance and demographics for the coastal shark assemblage of Bimini, Bahamas. Fisheries Research, 197, 34–44. doi: 10.1016/j.fishres.2017.09.016
Karl, S. A., Castro, A. L., and Garla, R. C. (2012). Population genetics of the nurse shark (Ginglymostoma cirratum) in the western Atlantic. Marine Biology, 159, 489–498. doi: 10.1007/s00227-011-1828-y
Pratt, J. H. L., Pratt, T. C., Knotek, R. J., Carrier, J. C., & Whitney, N. M. (2022). Long-term use of a shark breeding ground: Three decades of mating site fidelity in the nurse shark, Ginglymostoma cirratum. PLoS One, 17(10), e275323. doi: 10.1371/journal.pone.0275323