Hutchinson Island Hardbottom Surveys

General Information

Project Type(s):sighting

Site Name:Hutchinson Island Hardbottom Surveys

Site Reference Number:22

Region(s):Southeast, Southeast

Counties:Martin, St. Lucie

Approximate Latitude: 27.32 Approximate Longitude: -80.21

View ArcGIS map of study area

Principal Investigator(s):Bagley, Dean; Bresette, Michael; Gorham, Jonathan; Herren, Richard; Witherington, Blair E

Point(s) of Contact:Bresette, Michael - Phone Number: (772) 467-7726, Email: mbresette@inwater.org

Organizations Involved:Inwater Research Group, Inc.

Organization Type(s):non-profit

Project Status: Inactive

Start Date: 6/2004

End Date: 4/2005

Equipment and Methods

General Method(s) Used:boat survey

Sampling and Effort

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

Bottom Type(s):coral, hardbottom, worm rock

Water Type Zone: neritic Water Type Environment: marine

Min. Depth (m): 0 Max. Depth (m): 14.9

Mean Depth (m): 8.4

Captures and Sightings Information

Species	No. of Captures	No. of Sightings	Min Size* (cm)	Max Size* (cm)	Mean Size* (cm)	FP Observed	Life Stages**
Green Turtle (Cm)	n/a	198	n/a	n/a	n/a	n/a	n/a
Loggerhead (Cc)	n/a	49	n/a	n/a	n/a	n/a	n/a
Kemp's Ridley (Lk)	n/a	0	n/a	n/a	n/a	n/a	n/a
Hawksbill (Ei)	n/a	0	n/a	n/a	n/a	n/a	n/a
Leatherback (Dc)	n/a	1	n/a	n/a	n/a	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.

This report adheres to the following size ranges for life stage classification for these species:

	Green turtle	Loggerhead	Kemp's ridley	Hawksbill
Oceanic-stage juvenile	< 25 cm SCL	< 30 cm SCL	< 25 cm SCL	< 25 cm SCL
Neritic-stage juvenile	25-69 cm SCL	30-69 cm SCL	25-39 cm SCL	25-64 cm SCL
Subadult	70-84 cm SCL	70-79 cm SCL	40-59 cm SCL	65-74 cm SCL
Adult	≥ 85 cm SCL	≥ 80 cm SCL	≥ 60 cm SCL	≥ 75 cm SCL

	Leatherback
Immature	< 135 cm OCL
Adult	≥ 135 cm OCL

Other Information Collected

Project Summary

This study investigated the distribution of marine turtles in the nearshore, hardbottom habitat off Hutchinson Island. Eight permanent 3-km visual transects were established parallel to the beach at six locations over and adjacent to the reefs. Turtles were located by observers atop a tower on a slow-moving vessel along these transects. Many more green turtles were observed than loggerheads in the study area, but their distribution was significantly more variable between transects, indicating that green turtle “hotspots” exist along the reef. Loggerheads were found in nearly equal abundances nearshore (200 m from shore) and offshore (1000 m from shore). Green turtles, however, were significantly more abundant closer to shore. Green turtles were present year-round, but loggerheads were much more common on summer transects than on those in the winter months.

Documents

No documents uploaded.

Literature/Reports Produced

Inwater Research Group, Inc. 2005. Abundance and distribution of marine turtles within nearshore hardbottom and associated habitats. Report submitted to FWC, 38 pp.