Central Indian River Lagoon

Project Type(s):capture, sighting

Site Name:Central Indian River Lagoon

Site Reference Number:27

Region(s):Southeast, Southeast

Counties:Brevard, Indian River

Approximate Latitude: 27.94 Approximate Longitude: -80.51

Principal Investigator(s):Bagley, Dean; Ehrhart, Llewellyn; Redfoot, William

Point(s) of Contact:Bagley, Dean - Phone Number: (407) 765-5250, Email: de315786@pegasus.cc.ucf.edu

Organizations Involved:University of Central Florida

Organization Type(s):university

Project Status: Active

Start Date: 5/1982

End Date: n/a

General Method(s) Used:set net

	Visual	Capture
Sampling regime:	annually	annually
Measure of effort:	unknown	cap/area

Bottom Type(s):drift algae, sand, seagrass

Water Type Zone: neritic Water Type Environment: estuarine

Min. Depth (m): 0 Max. Depth (m): 0.1

Mean Depth (m): 0.1

Species	No. of Captures	No. of Sightings	Min Size* (cm)	Max Size* (cm)	Mean Size* (cm)	FP Observed	Life Stages**	Comments
Green Turtle (Cm)	3290	n/a	22.0	99.5	44.4	No	n/r
Loggerhead (Cc)	1110	n/a	41.5	106.0	65.2	No	n/r
Kemp's Ridley (Lk)	3	n/a	35.1	48.5	40.0	No	n/r
Hawksbill (Ei)	1	n/a	67.6	0.0	67.6	No	n/r
Leatherback (Dc)	0	n/a	0.0	0.0	0.0	n/a	n/a

*All size measurements are SSCL unless otherwise indicated
** For Cm, Cc, Lk, & Ei: O - Oceanic-stage juvenile; N - Neritic-stage juvenile; S - Subadult; A - Adult. For Dc: I - Immature; A - Adult. n/a = not applicable; n/r = not reported.

blood chemistry

diet

growth rates

satellite tracking

This study has allowed for the assessment of trends in turtle populations over a long period of time. Since 1982, tangle nets have been deployed at nine locations in the central region of the IRL system between the town of Indialantic, Brevard County, and the town of Wabasso, Indian River County. The majority of netting effort has occurred in a large embayment 3 km south of Sebastian Inlet known locally as South Bay. The undisturbed areas of shoreline are made up of red mangroves; seagrass beds are composed of manatee grass and shoal grass in areas less than one meter deep. Halophila is found in deeper waters. Large areas of drift algae cover the lagoon and are found adjacent to the seagrass beds. Green turtles make up the majority of captures in the lagoon, followed respectively by subadult loggerheads, adult loggerheads (both male and female), and other species including Kemp’s ridley and hawksbill turtles. Male loggerheads measuring 63.5 to 72 cm are probably maturing males; those between 74.1 and 80.9 cm are classified as maturing males. The higher catch of green turtles may be misleading because this may be a result of the netting site and not necessarily representative of the entire lagoon. The netting site is amidst large mats of drift algae, where green turtles may be foraging. Aside from one adult male, all of the green turtles captured have been juveniles. Green turtle captures and CPUE in the lagoon have been increasing over the years. Green turtle relative abundance follows a cyclic pattern throughout the year, with higher abundances during the fall and winter than in the spring and summer. This cycle may be due to seasonal migration and changes in food supply. Green turtles in this area forage principally on drift algae that are more abundant during colder temperatures. The biomass of these algae undergoes a marked decrease during late spring and summer. In addition, this change in seasonal abundance may be due to southern and northern seasonal migrations that occur to areas with appropriate water temperatures along the east coast. A sharp drop in captures of green turtles over 70 cm may signal an ontogenic shift as maturing green turtles leave this area. Genetic samples show that green turtles in the lagoon come from rookeries in Florida, Mexico, Costa Rica, Aves Island, Brazil, Ascension Island, and Guinea Bissau. Genetic samples have also been taken from loggerheads. RIA techniques show that both greens and loggerheads in this habitat have a sex ratio bias towards females. The severity of green turtle FP varies greatly from individual to individual, as well as temporally. Overall there is 28.3 – 71.6% incidence of the condition.

File Name	Type	Description
Hirama_etal_2014.pdf	Journal Article
Kubis_etal_2009.pdf	Journal Article
Ng_etal_2009.pdf	Journal Article

* This document is available from FWC by request. Email SeaTurtleData@MyFWC.com if you would like a copy. Please include both the project name and file name in your email.
** This document has been provided to FWC but is unavailable for download. Please contact the project PI if you would like a copy.

Ehrhart, L.M., W.E. Redfoot and D.A. Bagley. 2007. Marine turtles of the central region of the Indian River Lagoon System, Florida. Florida Scientist 70(4): 415-434.

Hirama, Shigetomo and Llewellyn M. Ehrhart. 2007. Description, prevalence and severity of green turtle fibropapillomatosis in three developmental habitats of the east coast of Florida. Florida Scientist 70(4): 435-448.

Kubis, Stacy, Milani Chaloupka, Llewellyn Ehrhart, Michael Bresette. 2009. Growth rates of juvenile green turtles, Chelonia mydas from three ecologically distinct foraging habitats along the east central coast of Florida, USA. MEPS 389:257-269.

Ng, Terry Fei Fan, Charles Manire, Kelly Borrowman, Tammy Langer, Llewellyn Ehrhart, and Mya Breitbart. 2009. Discovery of a novel single-stranded DNA virus from a sea turtle fibropapilloma by using viral metagenomics. Journal of Virology p.2500-2509.

Hirama, S, L. Ehrhart, L Rea, R. Kiltie. 2014. Relating fibropapilloma tumor severity to blood parameters in green turtles Chelonia mydas. Dis. Aquat. Org. 111:61–68.