Juvenile Green Sea Turtles Research Articles

Confronting the gauntlet: understanding incidental capture of green turtles through fine-scale movement studies

We conducted a 2 yr study of small juvenile green sea turtles Chelonia mydas in an estu- ary in North Carolina, USA, to examine how turtle behavior affected their vulnerability to incidental capture in an artisanal gill net fishery. We used sonic and satellite telemetry to track the movements and habitat use of 10 green turtles during the summers of 2005 and 2006. Individual turtles estab- lished summer foraging sites and showed very strong fidelity to particular tidal creeks and marsh islands. Turtles were strongly associated with seagrass habitat and were easily disturbed by natural and anthropogenic activity. We found that green turtles and gill net fishers exhibited similar habitat preferences, leading to the potential for entanglement, a finding corroborated by 8 yr of by-catch records. Individual turtles interacted with multiple gears during our study as a result of fishing activ- ity in their small home ranges.

Morbidity in a Juvenile Green Sea Turtle (Chelonia mydas) Due to Ocean-Borne Plastic

An emaciated 2.36-kg juvenile green sea turtle, Chelonia mydas, was found floating off of Melbourne Beach, Florida, USA (28 degrees 2'4"N, 80 degrees 32'32"W). The turtle exhibited signs of cachexia, positive buoyancy, lethargy, and obstipation; was covered with barnacles; and was anorexic at the time of presentation. Dorsal-ventral radiographs with positive contrast confirmed obstruction of the gastrointestinal tract. Serum chemistry abnormalities reflected metabolic/nutritional deficiencies. Gastrointestinal prokinetics and oral/enema mineral oil applications were effective in relieving gastrointestinal obstruction with the turtle defecating a total of 74 foreign objects over a period of a month. After the removal of the foreign material, the turtle quickly regained normal behavior and health. The lack of blood parameters demonstrating infection or inflammation; the failure to respond to antibiotic and antifungal treatment as well as the parallel improvement in behavior and health after incremental evacuation of the plastic is highly suggestive of a cause and effect association.

The Effect of Beach Nourishment on Juvenile Green Turtle Distribution Along the Nearshore of Broward County, Florida

Juvenile green sea turtles (Chelonia mydas L.) aggregate and develop to maturity in nearshore coastal habitats, putting them in close proximity to beach restoration projects. This study's objective was to determine if the Broward County Shore Protection Project negatively altered the distribution of green turtles along the County's shallow (� 8 m) reef systems. For five consecutive years, 'Shark Fishing' surveys were conducted to record abundance estimates and dis- tribution profiles before and after completion of the beach nourishment project. While pre-construction surveys revealed the natural fluctuation of sea turtle abundance within the nearshore waters, a universal decline in turtle sightings was re- corded for both the project area (25%) and the control site (12%) after beach construction activities. Even so, the distribu- tion of turtles was not adversely affected or skewed, as 89% of the turtles sighted during post-construction surveys within the project area were recorded along reef resources adjacent to the beach fill reaches.

Intake passage time, digesta composition and digestibility in East Pacific green turtles ( Chelonia mydas agassizii) at Gorgona National Park, Colombian Pacific

We investigated the food digestibility of East Pacific green turtles, Chelonia mydas agassizii, at tropical coral reefs of Gorgona National Park in the Colombian Pacific and calculated the intake passage time (IPT) of 3 different diets. We collected 150 faecal samples from turtles (mean straight carapace length 61.3 ± 4.12 cm and mean mass 32.3 ± 6.67 kg) to determine digesta composition and for measurement of neutral detergent fibre (NDF), acid detergent fibre (ADF), sulphuric acid lignin and protein. The mean (± S.D) IPT to recover at least 73% of external markers (plastic beads) in the faeces was 23.3 ± 6.6 days. The true NDF digestibility and dry matter digestibility were determined for high protein (fish), plant (fresh leaves of Araceae, Moraceae and Bombaceae) and mixed (combination of both high protein and plant) diets. NDF values obtained for digestibility of the protein, plant and mixed diets were 1%, 63% and 49% respectively. There was a large amount of undigested plant material in the faeces, dominated by fruits of red mangrove ( Rhizophora mangle). We considered the relationships between the type of food, IPT and apparent digestibility in the context of the nutritional contribution of an omnivorous diet. Our results suggest that for juvenile green sea turtles in the Eastern Pacific combined diets are an opportunistic strategy responding to habitat features and supply to maximise energy acquisition in transitional habitats such as Isla Gorgona.

Use of Human Granulocyte Colony-Stimulating Factor in a Green Sea Turtle, Chelonia mydas

ABSTRACT Trauma of undetermined cause resulted in the massive injury, infection, and subsequent stranding of a juvenile green sea turtle, Chelonia mydas. With an initial calculated total leukocyte count of zero cells/μl and no mature circulating heterophils on the differential, the turtle was treated with antibiotics and recombinant human granulocyte colony-stimulating factor, (hG-CSF, filgrastim), in an attempt to increase heterophil production and possibly activation. Three daily doses o f hG-CSF at 6.7 mcg/kg given subcutaneously resulted in a rapid increase in acidophilic progranulocytes, which subsequently declined over the next three days. A second regimen, consisting of a repeat of the first three-dose daily regimen followed by continued dosing every 48 hr for an additional nine days, maintained a white blood cell count of 11,600 – 24,700 cells/μl. Three weeks after initiating therapy, mature heterophils began to appear in the peripheral blood and the hG-CSF was discontinued. Finally, after the tur...

Estimates of age and growth in a population of green sea turtles (Chelonia mydas) from the Indian River lagoon system, Florida: a skeletochronological analysis

The Indian River lagoon system harbors a dynamic population of juvenile green sea turtles (Chelonia mydas). This foraging or developmental population occupies the lagoon year-round and periodically experiences cold-stunning events that kill a portion of the population. A sample of 59 C. mydas (28-74 cm straight carapace length) from the December 1989 cold-stunning event was aged by skeletochronology, yielding age estimates of 3-14 years. Mean growth-rate estimates range from 30 to 52 mm/year for most age and size classes, with means for the 6- to 11-year age classes (44-49 mm/year) not significantly different but greater than those of the youngest and oldest classes (3-5 and 12 years old, respectively) (32-38 mm/year). Because of the lack of adults and near-adults in the sample, growth models (e.g., Gompertz) do not yield biologically realistic asymptotes, hence they do not provide accurate estimates of age at sexual maturity. The age estimates suggest that the western Atlantic C. mydas change from a pelagic to a neritic life predominantly as 5- to 6-year-olds and, in central Florida, juveniles may live in a developmental habitat for 6 or more years.

Chemosensory imprinting in juvenile green sea turtles, Chelonia mydas

Chemosensory imprinting in juvenile green sea turtles, Chelonia mydas

Regulation of hemoglobin function and whole blood oxygen affinity by carbon dioxide and pH in the loggerhead (Caretta caretta) and green sea turtle (Chelonia mydas mydas).

The oxygen affinity of suspensions of erythrocytes from juvenile and adult loggerhead (Caretta caretta) and green sea (Chelonia mydas mydas) turtles decreased markedly with increasing concentrations of carbon dioxide (0 to near 15%) or hydrogen ion (pH 7.6 to pH 7.2). The P50's were higher with increases in pCO2, particularly at pH near 7.4, than were the P50's with increases in hydrogen ion concentration at any given CO2 concentration. Solutions of hemoglobins from the juvenile loggerhead (8-9 mos.) and green sea (10 mos.) turtles responded to 2, 3-DPG, ATP, or inositol-P5 when added at molar ratios of phosphate to hemoglobin of 4:1 and 20:1 in 0% and 6.29% CO2 but showed no decrease in oxygen affinity at these two CO2 levels in the green turtle when the molar ratio of phosphate to hemoglobin was 0.4. These compounds had little effect on the P50 of these hemoglobins in 14.6% CO2. The P50 of the adult loggerhead turtle hemoglobin did not increase in the presence of organic phosphates beyond the effect induced by CO2 alone. The P50 of hemoglobin from the adult green sea turtle increased only slightly when the molar ratio of phosphate to hemoglobin was 20:1 and at 0 and 6% CO2 concentration; little effect was observed at 14.6% CO2. These data demonstrate that blood oxygen affinities and hemoglobin function in these two species of marine turtles are altered significantly by CO2 and to a lesser degree by pH. It is suggested that such alterations may be of significance in vivo during prolonged diving when there are dramatic rises in blood pCO2 and [H+] and profound decreases in pO2.