Trends In Size Class Distribution, Recaptures, And Abundance Of Juvenile Green Turtles (Chelonia Mydas) Utilizing A Rock Riprap Lined Embayment At Port Canaveral, Florida, Usa, As Developmental Habitat

Despite great advances in the understanding of marine turtle biology over the past 60 yrs, there is still a paucity of demographic data on the juvenile stage of their life history. These data are required to adequately predict population trends for these long-lived marine turtle species. In the early 1990s, juvenile green turtles (Chelonia mydas) were observed in the Trident Turning Basin at Port Canaveral, Brevard County, Florida. We began a study in 1993 to assess the species composition, size class distribution, and degree of residency of the marine turtles utilizing this man-made embayment as developmental habitat. The results of the first 18 yrs of that study are related here. Juvenile green turtles constituted 99.4% of the marine turtle captures. Straight carapace lengths (SCL) of turtles ranged from 20.0 to 52.0 cm with a mean of 31.7 cm, smaller than those observed in other known green turtle developmental habitats in Florida. The mean SCL of the green turtles in the basin has declined over the course of the study. Although initially there was a high recapture rate of turtles tagged in the basin, that rate declined significantly along with the size of the turtles at their most recent recapture and the interval of time between their first capture and most recent recapture. We attribute these declines to the increase in the number of juvenile green turtles recruiting to developmental habitats along Florida\u27s east coast and to the limited forage available in the basin. Population surveys over the past 13 yrs of the study yielded estimates that ranged from 27 to 224 green turtles in the basin, with a mean estimate of 61±10 turtles. The results of this study illustrate the value of long-term monitoring projects in understanding both juvenile green turtle habitat preferences and sea turtle population dynamics. © Chelonian Research Foundation

Long-Term Trends In Loggerhead (Caretta Caretta) Nesting And Reproductive Success At An Important Western Atlantic Rookery

The Archie Carr National Wildlife Refuge (ACNWR), located along the central east coast of Florida (USA) in the western North Atlantic, hosts one of the largest loggerhead (Caretta caretta) nesting assemblages in the western Hemisphere. Sea turtle nesting activity has been continuously monitored on this beach for \u3e 31 yrs, representing one of the longest sea turtle reproductive data sets in the world. Between 1982 and 2012, an estimated 358,243 nests were deposited on the ACNWR with an estimated annual mean plus 95% confidence interval of 11,556 ± 1,129 nests. This constitutes 25.4% ± 0.8% of the mean annual Florida Index Nesting Beach Survey loggerhead complement. Mean annual clutch size was 113.9 ± 1.4, resulting in a 55.1% ± 4.0% mean annual hatching success rate and a mean emerging success rate of 53.3% ± 3.7%. The only egg-fate that was statistically correlated with emerging success were eggs washed out by erosion. The loss of eggs by erosion was significantly greater during storm and poststorm years, compared with nonstorm years. Among individual first-time nesting females that were measured, mean straight carapace length was 91.2 ± 0.15 cm and mean curved carapace length was 98.2 ± 0.15 cm. These data suggest that the ACNWR supports the greatest loggerhead nest density per kilometer in Florida, underscoring the importance of the ACNWR as one of the most important nesting habitats for loggerhead turtles in the Western Hemisphere

Behavioral Response Of Reef Fish And Green Sea Turtles To Midfrequency Sonar

There is growing concern over the potential effects of high-intensity sonar on wild fish populations and commercial fisheries. Acoustic telemetry was employed to measure the movements of free-ranging reef fish and sea turtles in Port Canaveral, FL, in response to routine submarine sonar testing. Twenty-five sheepshead (Archosargus probatocephalus), 28 gray snapper (Lutjanus griseus), and 29 green sea turtles (Chelonia mydas) were tagged, with movements monitored for a period of up to 4 months using an array of passive acoustic receivers. Baseline residency was examined for fish and sea turtles before, during, and after the test event. No mortality of tagged fish or sea turtles was evident from the sonar test event. There was a significant increase in the daily residency index for both sheepshead and gray snapper at the testing wharf subsequent to the event. No broad-scale movement from the study site was observed during or immediately after the test

Long-Term Trends in Loggerhead ( Caretta caretta

The Archie Carr National Wildlife Refuge (ACNWR), located along the central east coast of Florida (USA) in the western North Atlantic, hosts one of the largest loggerhead (Caretta caretta) nesting assemblages in the western Hemisphere. Sea turtle nesting activity has been continuously monitored on this beach for \u3e 31 yrs, representing one of the longest sea turtle reproductive data sets in the world. Between 1982 and 2012, an estimated 358,243 nests were deposited on the ACNWR with an estimated annual mean plus 95% confidence interval of 11,556 ± 1,129 nests. This constitutes 25.4% ± 0.8% of the mean annual Florida Index Nesting Beach Survey loggerhead complement. Mean annual clutch size was 113.9 ± 1.4, resulting in a 55.1% ± 4.0% mean annual hatching success rate and a mean emerging success rate of 53.3% ± 3.7%. The only egg-fate that was statistically correlated with emerging success were eggs washed out by erosion. The loss of eggs by erosion was significantly greater during storm and poststorm years, compared with nonstorm years. Among individual first-time nesting females that were measured, mean straight carapace length was 91.2 ± 0.15 cm and mean curved carapace length was 98.2 ± 0.15 cm. These data suggest that the ACNWR supports the greatest loggerhead nest density per kilometer in Florida, underscoring the importance of the ACNWR as one of the most important nesting habitats for loggerhead turtles in the Western Hemisphere

Trends in Size Class Distribution, Recaptures, and Abundance of Juvenile Green Turtles ( Chelonia mydas

Despite great advances in the understanding of marine turtle biology over the past 60 yrs, there is still a paucity of demographic data on the juvenile stage of their life history. These data are required to adequately predict population trends for these long-lived marine turtle species. In the early 1990s, juvenile green turtles (Chelonia mydas) were observed in the Trident Turning Basin at Port Canaveral, Brevard County, Florida. We began a study in 1993 to assess the species composition, size class distribution, and degree of residency of the marine turtles utilizing this man-made embayment as developmental habitat. The results of the first 18 yrs of that study are related here. Juvenile green turtles constituted 99.4% of the marine turtle captures. Straight carapace lengths (SCL) of turtles ranged from 20.0 to 52.0 cm with a mean of 31.7 cm, smaller than those observed in other known green turtle developmental habitats in Florida. The mean SCL of the green turtles in the basin has declined over the course of the study. Although initially there was a high recapture rate of turtles tagged in the basin, that rate declined significantly along with the size of the turtles at their most recent recapture and the interval of time between their first capture and most recent recapture. We attribute these declines to the increase in the number of juvenile green turtles recruiting to developmental habitats along Florida\u27s east coast and to the limited forage available in the basin. Population surveys over the past 13 yrs of the study yielded estimates that ranged from 27 to 224 green turtles in the basin, with a mean estimate of 61±10 turtles. The results of this study illustrate the value of long-term monitoring projects in understanding both juvenile green turtle habitat preferences and sea turtle population dynamics. © Chelonian Research Foundation