Presented by: Khiem Phan

OUTLINE I. Introduction II. Materials and Methods III. Results IV. Conclusions

I. INTRODUCTION Temperature plays an important role in animal development. Oviparous animals: fish, and many reptiles: all crocodilians, tuataras, many turtles, and some lizards. Effects: the direction of sexual differentiation for several species. Grunion Fish, California

I. INTRODUCTION Temperature-dependent sex (TSD) determination has been found in many orders of fish and many reptiles. All sea turtles exhibit TSD: with higher temperatures producing more to all females, and cooler temperatures producing more to all males. Subtle temperature changes in the nest environment will influence the survivorship or fitness of both individuals and species.

I. INTRODUCTION Due to their slow growth and late maturity of sea turtles, they used phenotypic measures (crawling speed, self-righting time, and swimming performance) as a proxy for hatchling fitness. Incubation temperature affects: several factors in sea turtle egg incubation besides development time, size, mass, and amount of yolk content converted to hatchling tissues. locomotor performance for hatchling sea turtles.

I. INTRODUCTION Hatchlings incubated at 26°C (78.8 F): have lower flipper stroke rate frequency and force output than hatchlings incubated at 28°C- 30°C ( F). These results suggest that sea turtle hatchlings show optimal performance when incubated at mid-range temperatures (optimum).

I. INTRODUCTION The Atlantic loggerhead sea turtles are long-lived, slow growing, and late maturing animals, and in the past they have been able to adapt to a changing climate. There are concerns that rapid climate change will have negative impacts on the populations of this species. Hot beach temperatures could decrease overall hatchling survival. Hypothesis: to test for performance and survivorship differences between loggerhead hatchlings incubated at different controlled temperatures.

II. MATERIALS AND METHODS 1. Egg collection and incubation: collection on North Island, South Carolina. 68 loggerhead hatchlings in 2011, 31 in 2012, from three loggerhead clutches collected the morning. 5 incubators set to temperatures ranging from 27°C– 32.5°C ( F). surrounded by moist vermiculite. the temperature of each shelf was recorded daily. at days 15–17 and 38–40 of incubation, ∼ 65 mL of distilled water were added to the vermiculite around each egg.

II. MATERIALS AND METHODS 2. Hatching: Incubators: 29.5°C (85.1 F) to simulate the natural warm and dark environment. Hatchlings remained in the containers for a minimum of 72 hrs, a maximum of 96 hrs to simulate the actual course of hatching and emergence from a nest. Then, hatchlings were transported in their individual holding containers to the Marine Aquaculture Research Center (MARC) facility in Marshallburg, North Carolina, August– September, 2011, and from 15 June–3 August,

II. MATERIALS AND METHODS 3. Experiments: The facility was climate controlled between 24°C–26°C (75.2 – 78.8 F). 10 trials in 2011 and 8 trials in

II. MATERIALS AND METHODS 4. Righting Response and Crawl Test: Hatchlings crawl towards the brightest light source, 3 times, distance crawled of 7.32 meters 5. Swim Test: Hatchlings swim continuously for the first approximately 24 hours in the ocean.

III. RESULTS 2011, 62% hatch success rate (n = 88/143), and 41% survivorship (n = 59/143). % hatched and % survivorship: maximized at 29°C ( 84.2 F). The same overall patterns were seen in 2012.

III. RESULTS Mean Righting Response time ± S.E.M. in 2011, demonstrating that hatchlings incubated at 27°C and 31°C (80.6 – 90.5 F) take significantly longer to right themselves than hatchlings from the middle range of incubation temperatures

III. RESULTS Crawl speed for the third crawl in 2011, with hatchlings from 27°C (80.6 F) being significantly slower than all other hatchlings.

III. RESULTS On average, hatchlings from 27°C (80.6 F) slowed down while all other hatchlings sped up between crawls

III. RESULTS Hatchlings from 27°C and 28°C (82 – 82.4 F) were significantly less active than those from all other incubation temperatures

III. RESULTS The composite rank for each incubation temperature ± S.E.M., fit with a quadratic curve through the means. Incubation temperature maintained a significant effect on the composite rank of hatchlings from 27°C (80.6 F).

III. RESULTS Hatchlings incubated at °C ( F) were too weak to survive the first few days of life. Leading to the conclusion that if they had survived, they would have exhibited poor performance.

V. CONCLUSION Using a controlled laboratory experiment, they observed: an effect of incubation temperature on hatchling loggerhead performance, consistent with findings in previous hatchling sea turtle performance studies. turtles incubated at 27°C (80.6 F) showed decreased locomotor ability (took longer to right themselves, crawled slower, slowed down while crawling, and swam for a shorter amount of time).

V. CONCLUSION Using a controlled laboratory experiment, they observed: Turtles incubated at 31°C (87.8 F) took longer to right themselves but showed high locomotor ability in other tests. Turtles incubated at both 27°C and 31°C ( F) were also the smallest in curved carapace length. Hatchling turtles with decreased locomotor abilities have typically been interpreted to have a reduced chance of survival, and thus a lower overall fitness.

V. CONCLUSION For 2011 and 2012, both percent hatched and survivorship of hatchlings peaked around 29°C (84.2 F), in the middle of the incubation temperature range for loggerheads. The optimal range of hatchling loggerhead appears to be at incubation temperatures from approximately 28.5–31°C ( F).

V. CONCLUSION Future research: Similar performance testing should be done on hatchlings produced on real nesting beaches to test if there is geographic variation in performance ability. It is important to quantify hatching success and survivorship in the field.

WORKS CITED

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