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Terrapin trends in Jamaica Bay-fall 2018 Task Force Presentation

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analysis on population trends of turtles in Jamaica Bay.

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Terrapin trends in Jamaica Bay-fall 2018 Task Force Presentation

  1. 1. Diamondback Terrapin Population Changes and GPS Tracking Presented by: Alexandra Kanonik & Maria Roe
  2. 2. Malaclemys terrapin ● Only species of the family Emydidae specialized to estuarine habitats ● Sexually dimorphic ○ Females from 15 to 23 cm, Males 10 to 14 cm ● Keystone species in Jamaica Bay ○ Curbs invertebrate populations and maintains nutrient pathways “your friendly neighborhood turtle”
  3. 3. Celebrating our 20th year of research! • Aim was to study nesting behavior and ecology of terrapins by catching and uniquely marking individuals. • Research • Education • Citizen Science Dr. Russell Burke and graduate student Adriana
  4. 4. Many partners and volunteers throughout the years:
  5. 5. 2018 was the year for two new regulations giving terrapins more protections: ● On May 1, 2018 the NYS DEC announced “the closure of the commercial harvest of terrapins and added the species to the list of native turtles with no open season”. ● On March 28, 2018 DEC added regulations to “put forth a requirement for diamondback terrapin excluder devices on commercial and recreational crab pots set in near shore harbors, creeks, coves, rivers and tributaries in New York's Marine and Coastal Districts”. Terrapin Excluder Device (TED) on crab pot
  6. 6. “How are terrapins doing”? What we learned about the Jamaica Bay population after 20 years of mark-recapture work
  7. 7. Jamaica Bay Nesting Sites
  8. 8. Jamaica Bay Nesting Sites Ruler’s Bar JFK
  9. 9. Current Threats in Jamaica Bay Habitat destruction Marsh Loss Coastal Storms Predation Recreational boats Derelict fishing gear Pollution
  10. 10. Captures & Recaptures Females are PIT tagged, measured, examined for abnormalities, and released at point of capture. 1,078 individual female terrapins marked in Ruler’s Bar (2003-2018) ● 686 total recaptures 3,130 individuals marked in JFK (2011-2018) • 1,015 total recaptures
  11. 11. Adult Female Survival Ruler’s Bar Best Supported Models: • Resident survival decreasing from 0.92 • Female survival declined for 2 years post-Hurricane Sandy JFK Best Supported Model: • Resident survival constant over time at 0.92
  12. 12. Major Injuries- Ruler’s Bar Major Injuries • Damage to 2 or more adjacent costal or vertebral scutes • Damage to 3 or more adjacent marginal scutes • Missing limbs • Dislocated limb bones 2.9% 15.6% 17% 17.8% of females in Ruler’s Bar exhibited major injuries (2009-2018) • Predominantly shell damage
  13. 13. Major Injuries- Ruler’s Bar 17% of females in Ruler’s Bar exhibited major injuries (2009-2018) • Predominantly shell damage Survival is lower after major injuries • Persistent infection • Increased vulnerability to predators • Survival of females with little to no injuries: 0.92 • Survival of females with major injuries: 0.88
  14. 14. Female Terrapin first found in 2011 Same exact female found again in 2018! But...Major Injuries can heal!
  15. 15. Ruler’s Bar Population
  16. 16. JFK Population
  17. 17. Population Movement Diamondback terrapins exhibit site fidelity • Minimal interchange between populations • 11 individuals found in both locations Evidence of transient individuals found in both Ruler’s Bar and JFK • 17% of newly tagged terrapins in RB • 27% of newly tagged terrapins in JFK Temporary emigrants? What are their movement patterns?
  18. 18. Next Steps: Tracking turtles in real-time using GPS transmitters ● Deployed 9 total units this past August Charging up via solar power. Relay tower installed at Littoral Society HeadquartersTerrapin model tests fit on to shell
  19. 19. Questions? Thank You! Link to our website at: http://jbtr.org/ Link to our Facebook Page at: Jamaica Bay Terrapin Research and Conservation https://www.facebook.com/groups/92834779554/Photo credits: Don Riepe, Peter Hyung Yoon & Dexter Raphael jbtr.org website was created by:nexxite.com

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