Tampa Bay Entrance Channel

Project Type(s):capture

Site Name:Tampa Bay Entrance Channel

Site Reference Number:10

Region(s):Southwest

Counties:Manatee, Pinellas

Approximate Latitude: 27.57 Approximate Longitude: -82.77

Principal Investigator(s):Nelson, David

Point(s) of Contact:Nelson, David - Phone Number: Not Provided, Email: drdavenelson@msn.com

Organizations Involved:United States Army Corps of Engineers - Vicksburg

Organization Type(s):federal agency

Project Status: Inactive

Start Date: 2/1997

End Date: 6/1998

General Method(s) Used:trawl

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

Bottom Type(s):channel

Water Type Zone: neritic Water Type Environment: marine

Min. Depth (m): Max. Depth (m): 28.5

Mean Depth (m): 6.5

Species	No. of Captures	No. of Sightings	Min Size* (cm)	Max Size* (cm)	Mean Size* (cm)	FP Observed	Life Stages**	Comments
Green Turtle (Cm)	1	n/a	83.7	n/r	n/r	No	S
Loggerhead (Cc)	5	n/a	62.0	99.3	86.6	No	N, S, A
Kemp's Ridley (Lk)	3	n/a	53.4	54.9	54.4	No	S
Hawksbill (Ei)	0	n/a	n/a	n/a	n/a	n/a	n/a
Leatherback (Dc)	0	n/a	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.

satellite tracking

This study included four seasonal trawl surveys within the Tampa Bay Entrance Channel in the spring, summer, and fall of 1997, and the spring of 1998. The Army Corps of Engineers conducted relative-abundance surveys for ten days each season by using trawl nets to assess sea turtle spatial occurrence relative to the channel bottom. There were only a small number of turtles captured at any time of the year, suggesting that the number of turtles in the channel throughout the year is low. Seasonal abundance was documented to be somewhat higher in the fall. USACE fit two adult male loggerheads, one adult female loggerhead, two subadult loggerheads, and two subadult Kemp’s ridleys with satellite transmitters during 1997 and 1998. Turtles were tracked for 13 to 376 days. Tracking revealed that sea turtles remained in the general study area for days or months at a time and eventually moved in response to changing water temperatures. Turtle densities were higher when water temperatures were above 15° C and lower when the temperature fell below that threshold. Turtles moved either offshore or southward as water temperatures decreased, and returned to their original location when water temperatures warmed. The researchers recommended that dredging activities in the Tampa Bay Entrance Channel be conducted during water-temperature extremes in either winter or summer. Cool winter temperatures force sea turtles offshore, and turtles move farther inshore and to the north of the channel when temperatures warm in the summer.

No documents uploaded.

Nelson, D.A. 1999. Sea turtle relative abundance and seasonal movements in Tampa Bay Entrance Channel. Report prepared for U.S. Army Corps of Engineers, Jacksonville District, 40 pp.

Nelson, D.A. 2000. Winter movements of sea turtles. In: Kalb, H., and T. Wibbels (comps.). Proc. 19th ISTS. NOAA Tech. Memo. NMFS-SEFSC-443, pp. 26.