Cape Canaveral (Henwood)

Project Type(s):capture

Site Name:Cape Canaveral (Henwood)

Site Reference Number:31

Region(s):Southeast

Counties:Brevard

Approximate Latitude: 28.41 Approximate Longitude: -80.44

Principal Investigator(s):Henwood, Tyrrell

Point(s) of Contact:Henwood, Tyrrell - Phone Number: Not Provided, Email: Not Provided

Organizations Involved:Auburn University, National Marine Fisheries Service - Pascagoula

Organization Type(s):university, federal agency

Project Status: Inactive

Start Date: 1/1978

End Date: 12/1984

General Method(s) Used:trawl

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

Bottom Type(s):channel

Water Type Zone: neritic Water Type Environment: marine

Min. Depth (m): 0 Max. Depth (m): 18.9

Mean Depth (m): 10

Species	No. of Captures	No. of Sightings	Min Size* (cm)	Max Size* (cm)	Mean Size* (cm)	FP Observed	Life Stages**	Comments
Green Turtle (Cm)	20	n/a	23.6 SCLmax	68.1 SCLmax	33.8 SCLmax	No	O, N
Loggerhead (Cc)	3710	n/a	45.0 SCLmax	110.0 SCLmax	73.2 SCLmax	No	N, S, A
Kemp's Ridley (Lk)	40	n/a	24.1 SCLmax	66.0 SCLmax	38.6 SCLmax	No	O, N, S, A
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.

Loggerheads: Size and sex composition of turtle aggregations in the Canaveral area changed seasonally. Migrations of breeding turtles occurred during the spring and summer months and were less common throughout the rest of the year, suggesting that adults were not resident in the area. Subadult turtle movements were not dependant on reproductive activities and so their distributions may have reflected changes in environmental conditions and foraging opportunities. CPUE and recapture data indicated that turtle aggregations are dynamic and that turtles move into and out of the area regularly. Adult males moved into the Canaveral area prior to adult females. Peak densities of males occurred during April and May, with adult males leaving by June. The same males were often present year after year for breeding activities. This suggested that males may breed annually and do not migrate with females. Adult females who nested in the Canaveral area did not overwinter there. Females that were encountered in the winter were either non-breeding or members of other nesting populations. Breeding females were dominant May to August. These were short-term migrants that emigrated from distant foraging areas. Subadult turtles were dominant in the ship channel from August to March. Subadults emigrated as far north as Chesapeake Bay in the spring. The majority of the long-distance recoveries of Canaveral turtles occurred north of Cape Canaveral, but these may portray a biased impression of dispersal patterns. Most of the recoveries came from shrimp trawlers. Higher levels of shrimping occur in the north while not much fishing effort takes place to the south. The greatest concentrations of subadults occurred from October to March. Many subadults were present year after year, depending on environmental conditions. This suggested a residential population of subadults which disperse locally during spring and summer and return to the channel each winter. Green Turtles: Green turtles were captured during all months except August and November. The infrequent nature of capture and lack of seasonal change in abundance when compared to loggerheads suggested that these animals may represent an itinerant population. No green turtles were ever recaptured. Greens in the Canaveral area may represent early developmental stages that precede the shift to herbivory and subsequent recruitment to feeding pastures since they were smaller than those observed by Ehrhart in Mosquito Lagoon. Offshore captures of green turtles may represent transients that are making their way to coastal developmental habitats where seagrasses are abundant. Kemp’s ridleys: All but one Kemp’s ridley capture were immature. The capture of this one adult-sized Kemp’s ridley outside the Gulf of Mexico suggested that mature Kemp’s ridleys occasionally forage along the east coast of Florida. Most Kemp’s ridley captures occurred from December through March, suggesting that the species is present primarily during winter months. Recaptures by shrimping vessels off Georgia and South Carolina confirmed that Kemp’s ridleys occur in waters north of Canaveral during the summer and fall months, but shrimping effort is biased towards that time of year. There was a southward movement of ridleys during periods of colder water temperatures. Kemp’s ridleys overwintered in Cape Canaveral and moved north along the Atlantic coastline with increasing sea temperatures, foraging as far north as Chesapeake Bay. These same turtles moved south when water temperatures began to fall. Seasonal movements up and down the coast may continue until they reach sexual maturity and then return to the Gulf of Mexico to breed.

File Name	Type	Description
Henwood_1987.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.

Henwood, TA. 1987. Movements and Seasonal Changes in Loggerhead Turtle Caretta caretta Aggregations in the Vicinity of Cape Canaveral, Florida (1978-84). Biological Conservation 40:191-202