SEA TURTLE MOVEMENT AND HABITAT USE IN THE NORTHERN GULF OF MEXICO Kristen M. Hart, Ph.D., Research Ecologist, USGS Wetland and Aquatic Research Center, Davie, FL Margaret M. Lamont, Ph.D., Biologist, USGS Wetland and Aquatic Research Center, Gainesville, FL
Acknowledgements BOEM Marine Minerals Program, Jessica Mallindine and Mike Miner Trish Bargo and crew, Miss Adrienne Chris Slay and crew, Bosarge Boats, Santa Rosa Island Authority Mike Cherkiss, Andrew Crowder, Devon Nemire-Pepe NMFS permit 17304 (issued to K. Hart)
SWOT: http://seaturtlestatus.org/learn/lifecycle
Gulf Sea Turtles Loggerheads (Caretta caretta) Kemp s ridleys (Lepidochelys kempii) Green turtles (Chelonia mydas) Leatherbacks (Dermochelys coriacea) Hawksbills (Eretmochelys imbricata) All threatened or endangered Several subpopulations, various regional management units
Turtle nesting NMFS and USFWS (2008) Recovery plan for the Northwest Atlantic population of loggerhead sea turtle (Caretta caretta), second revision. National Marine Fisheries Service, Silver Spring, MD National Marine Fisheries Service, U.S. Fish & Wildlife Service and SEMARNAT (2011) Bi-national recovery plan for the Kemp s ridley sea turtle (Lepidochelys kempii), 2 nd revision. NMFS. Silver Spring, MD. Loggerheads: eastern Gulf Kemp s ridleys: western Gulf
Loggerheads in the Gulf Hart KM, Lamont MM, Sartain AR, Fujisaki I (2014) Residency and foraging patterns of Northern Gulf loggerheads: Implications of local threats and international movements. PLoS One 9(7): e103453. doi:10.1371/journal.pone.0103453
Loggerhead foraging areas: International component Tucker et al. 2014 Foley et al. 2013 Hardy et al. 2014 Hart et al. 2014
Kemp s ridleys in the Gulf, foraging areas: Shaver & Rubio 2008 Seney & Landry 2008 Seney & Landry 2011 Shaver et al. 2013
Kemp s ridleys in the Gulf, foraging areas: International component Shaver et al. 2013
Kemp s ridley migratory corridor Shaver et al. 2016
OBJECTIVES Utilize hopper dredge relocation trawling operations to opportunistically tag sea turtles and collect biological samples to inform management decisions related to trawling and dredge operations Track movements post-relocation will provide data needed to validate the distance required for relocation (economic feasibility of project, prevent multiple handlings of the same turtle) Evaluation of dive times to understand turtle use of various depth zones, inform survey protocols re: decommissioning of oil rigs, and establish area-specific, species-specific availability correction factors (ACFs) for aerial surveys (data on time spent in upper 2 m of water column)
Caminada headlands project Hart et al. (In review) Density of post-nesting Kemp s ridleys satellite tracked from Padre Island NS, TX (Hart & Shaver et al., unpubl. data). Darker red and blue/purple colors indicate a larger number of turtles per grid cell.
GOALS Characterize turtle dive profiles using satellite-linked depth tags Determine seasonal movement patterns using satellite telemetry Assess population structure using genetic techniques Assess isotopic signatures using stable isotope techniques Determine vital rates using mark-recapture methods
METHODS Relocation trawling for captures; standard sea turtle workup Switching state-space modeling (area-restricted search vs. migration/directed movement) Home range tools (kernel density estimation, grid cell summaries) Dive profile characterizations and comparisons Population genetic structure (microsatellites and mtdna) Isotopic signatures (Stable istopes: 14 C, 15 N) Vital rates (capture-mark-recapture tools)
RESULTS, 25 days on trawlers in 2016
Ship Shoal: 10 individuals, Kemp s ridleys (n=9) and loggerheads (n=1) High site-fidelity Daily transmissions of location and depth profiles, www.seaturtle.org/tracking/?project_id=1205
Just off Pensacola, FL, 14 individuals, all loggerheads High site-fidelity Daily transmissions of location and depth profiles, www.seaturtle.org/tracking/?project_id=1205 Project: >2000 tracking days, mean displacement ~25 km from capture sites
Tag Type Number Deployed GPS 12 SDT 7 SDTl 15 SDTs 11 ST 30
CONCLUSIONS & FUTURE WORK: Deploy remaining tags (n=4) Order new tags for deployment in 2017/2018 Obtain winter tracking/dive profiles Add in fine-scale acceleration data logging tags (ADLs); popoff package necessary where recaptures are low/unknown Present initial results at International Sea Turtle Symposium (April 2017) Publish 1 st manuscript in FY17 Serve data into BOEM Sea turtle decision support tool (D. Piatkowski, sea turtle dredging entrainment risk) Analyze biological samples (genetics, isotopes) Increase sample size/expand study areas
Acknowledgements BOEM Marine Minerals Program, Jessica Mallindine and Mike Miner Trish Bargo and crew, Miss Adrienne Chris Slay and crew, Bosarge Boats, Santa Rosa Island Authority Mike Cherkiss, Andrew Crowder, Devon Nemire-Pepe NMFS permit 17304 (issued to K. Hart)