Endogenous Programs and the Endogenous Programs and the Development of Sea Finding Development of Sea Finding

Orientation of Loggerhead Sea Turtle Orientation of Loggerhead Sea Turtle Hatchlings (Hatchlings (Caretta carettaCaretta caretta L.) L.)

Christie BarrettChristie BarrettDepartment of Biological SciencesDepartment of Biological Sciences

Florida Atlantic UniversityFlorida Atlantic UniversityMaster’s Thesis Defense SeminarMaster’s Thesis Defense Seminar

ORDER OF CONTENTSORDER OF CONTENTSI.I. Migration and Endogenous Programs Migration and Endogenous Programs II.II. Endogenous Programs used by BirdsEndogenous Programs used by BirdsIII.III. Migration and Endogenous Programs Migration and Endogenous Programs

used by Sea Turtlesused by Sea TurtlesIV.IV. Research Objectives Research Objectives V.V. Methods and MaterialsMethods and MaterialsVI.VI. ResultsResultsVII.VII. Conclusions and Acknowledgements Conclusions and Acknowledgements

MIGRATION

Celestial and geomagnetic cues Celestial and geomagnetic cues used to maintain directionused to maintain direction

Endogenous programs control Endogenous programs control timingtiming

WHAT ARE ENDOGENOUS TIMING PROGRAMS?

► Internal mechanism in living organisms Internal mechanism in living organisms which controls timing of physiological which controls timing of physiological functions and behavioral activities.functions and behavioral activities.

PHYSIOLOGICAL CONTROL MIGRATION IN BIRDS

Berthold 1975Berthold 1975

Endogenous programs control the timing of Endogenous programs control the timing of physiological preparations for migrationphysiological preparations for migration

Fat storageFat storageFeather Feather moltingmolting

ORCHESTRATION OF MIGRATION IN BIRDS

Berthold 1975 Berthold 1975 ► Onset Zugunruhe = onset of migrationOnset Zugunruhe = onset of migration• Duration Zugunruhe = natural length of Duration Zugunruhe = natural length of

migrationmigration• Termination Zugunruhe = termination of Termination Zugunruhe = termination of

migrationmigration

Endogenous programs control when and Endogenous programs control when and how long to travelhow long to travel

MIGRATION IN BIRDS► Gwinner & Wiltschko 1978Gwinner & Wiltschko 1978 Endogenous programs enable first time Endogenous programs enable first time

migrants to make appropriate directional migrants to make appropriate directional shiftsshifts

HATCHLING SEA TURTLE HATCHLING SEA TURTLE MIGRATIONMIGRATION

Environmentally Environmentally Calibrated Calibrated

compasscompass

Innate Innate compacompassss

HOW DO HATCHLING HOW DO HATCHLING CALIBRATE THEIR MAGNETIC CALIBRATE THEIR MAGNETIC

COMPASS?COMPASS?I.I. Crawling in a fixed Crawling in a fixed

direction direction (Lohmann et al. 1995)(Lohmann et al. 1995)

II.II. Swimming in a fixed Swimming in a fixed directiondirection(Goff et al. 1998)(Goff et al. 1998)

IS TIMING IMPORTANT DURING IS TIMING IMPORTANT DURING HATCHLING MIGRATION?HATCHLING MIGRATION?

Wyneken & Salmon 1992 Wyneken & Salmon 1992 Frenzy period = 24 – 36 hours Frenzy period = 24 – 36 hours (similar to avian Zugunruhe)(similar to avian Zugunruhe)

IS TIMING IMPORTANT DURING IS TIMING IMPORTANT DURING HATCHLING MIGRATION?HATCHLING MIGRATION?

Study by M. Goff et al. Study by M. Goff et al. showed:showed:

15 min swimming into15 min swimming into waves waves ≠ ≠ calibratecalibrate

30 min swimming into 30 min swimming into waves waves == calibrate calibrate

MY STUDYIs the calibration process (vector transfer), which Is the calibration process (vector transfer), which

occurs during the crawl to the ocean, facilitated by occurs during the crawl to the ocean, facilitated by endogenous timing components?endogenous timing components?

OBJECTIVESOBJECTIVESI.I. How long, on average, does it take How long, on average, does it take

hatchlings to crawl from their nest to hatchlings to crawl from their nest to the ocean?the ocean?

II.II. Is the efficiency of vector transfer Is the efficiency of vector transfer related to a “typical” duration of related to a “typical” duration of crawling?crawling?

III.III. Is it the time spent crawling, or the Is it the time spent crawling, or the time spent in oriented crawling, that time spent in oriented crawling, that is most important for vector transfer?is most important for vector transfer?

CRAWLING TIME CRAWLING TIME MEASUREMENTMEASUREMENT

I.I. Measure the distance Measure the distance between 10 nests and between 10 nests and the surf zone at each the surf zone at each beach.beach.

II.II. Measurements Measurements occurred on 3 occurred on 3 nourished and 4 nourished and 4 natural beaches on natural beaches on the East Coast of the East Coast of FloridaFlorida

CRAWLING TIME CRAWLING TIME MEASUREMENTMEASUREMENT

Pompano Site 1 Pompano Site 2

CRAWLING TIME CRAWLING TIME MEASUREMENTMEASUREMENT

HatcheryHatchery

3 m3 m 6 m6 m 9 m9 m 12 12 mm

15 m15 m0 m0 m

STATISTICAL ANALYSIS STATISTICAL ANALYSIS NEST DISTANCESNEST DISTANCES

I. Kolmogorov-Smirnov testIf nourished and natural nests were normally distributed

II. Two tailed T-Test (p < 0.05)Differences between the nest distances at nourished and natural beaches

STATISTICAL ANALYSISSTATISTICAL ANALYSISCRAWL TIMESCRAWL TIMES

I. Kolmogorov-Smirnov normality testIf crawl times were normally distributed

II. One-way ANOVAIf crawl time differed between the 2 Pompano beach sites

II. General Linear RegressionIf crawl time and distance were If crawl time and distance were significantly relatedsignificantly related

LABORATORY EXPERIMENTSLABORATORY EXPERIMENTSCOLLECTION OF HATCHLINGSCOLLECTION OF HATCHLINGS

LABORATORY EXPERIMENTSLABORATORY EXPERIMENTS

CRAWLING EXPERIENCEVARY IN LENGTH

SWIMMING IN DARKNESSTEST FOR MAGNETIC COMPASS CALIBRATION (Vector Transfer)

CRAWLING ARENACRAWLING ARENA

SWIMMING POOLSWIMMING POOL

1 m

ARENA TRACKERARENA TRACKER

EXP. I: Is Crawl Duration Important EXP. I: Is Crawl Duration Important During the Calibration Process?During the Calibration Process?

Crawl Duration Crawl Duration (min)(min)

Oriented Oriented CrawlingCrawling

(min)(min)

Time Swimming Time Swimming (min)(min)

(i) 2 min(i) 2 min 2 min2 min 30 min30 min

(ii) 5 min(ii) 5 min 5 min5 min 30 min30 min

(iii) 10 min(iii) 10 min 10 min10 min 30 min30 min

EXP. II: IS CRAWL TIME OR ORIENTED EXP. II: IS CRAWL TIME OR ORIENTED CRAWLING TIME IMPORTANT FOR CRAWLING TIME IMPORTANT FOR

CALIBRATION?CALIBRATION?Crawl DurationCrawl Duration Dark (D)Dark (D) : Light : Light (L) (L) == (Total) (Total)

Oriented Oriented Crawling (min) Crawling (min)

Time SwimmingTime Swimming (min)(min)

(i) (i) 0D 0D : : 1L1L (1 (1 min)min)

1 min1 min 30 min30 min

EXP. II: IS CRAWL TIME OR ORIENTED EXP. II: IS CRAWL TIME OR ORIENTED CRAWLING TIME IMPORTANT FOR CRAWLING TIME IMPORTANT FOR

CALIBRATION?CALIBRATION?Crawl DurationCrawl Duration Dark (D)Dark (D) : Light : Light (L) (L) == (Total) (Total)

Oriented Oriented Crawling (min) Crawling (min)

Time SwimmingTime Swimming (min)(min)

(i) (i) 0D 0D : : 1L1L (1 (1 min)min)

1 min1 min 30 min30 min

(ii) (ii) 0D 0D : : 2L2L (2 (2 min)min)

2 min2 min 30 min30 min

EXP. II: IS CRAWL TIME OR ORIENTED EXP. II: IS CRAWL TIME OR ORIENTED CRAWLING TIME IMPORTANT FOR CRAWLING TIME IMPORTANT FOR

CALIBRATION?CALIBRATION?Crawl DurationCrawl Duration Dark (D)Dark (D) : Light : Light (L) (L) == (Total) (Total)

Oriented Oriented Crawling (min) Crawling (min)

Time SwimmingTime Swimming (min)(min)

(i) (i) 0D 0D : : 1L1L (1 (1 min)min)

1 min1 min 30 min30 min

(ii) (ii) 0D 0D : : 2L2L (2 (2 min)min)

2 min2 min 30 min30 min

(iii) (iii) 3D 3D : : 2L2L (5 (5 min)min)

2 min2 min 30 min30 min

EXP. II: IS CRAWL TIME OR ORIENTED EXP. II: IS CRAWL TIME OR ORIENTED CRAWLING TIME IMPORTANT FOR CRAWLING TIME IMPORTANT FOR

CALIBRATION?CALIBRATION?Crawl DurationCrawl Duration Dark (D)Dark (D) : Light : Light (L) (L) == (Total) (Total)

Oriented Oriented Crawling (min) Crawling (min)

Time SwimmingTime Swimming (min)(min)

(i) (i) 0D 0D : : 1L1L (1 (1 min)min)

1 min1 min 30 min30 min

(ii) (ii) 0D 0D : : 2L2L (2 (2 min)min)

2 min2 min 30 min30 min

(iii) (iii) 3D 3D : : 2L2L (5 (5 min)min)

2 min2 min 30 min30 min

(iv) (iv) 8D 8D : : 2L2L (10 (10 min)min)

2 min2 min 30 min30 min

STATISTICAL ANALYSISSTATISTICAL ANALYSISEXP I and IIEXP I and II

I. Second-order group mean angle and r- I. Second-order group mean angle and r- vectorvector

II. Rayleigh test (Zar 1999) to determine II. Rayleigh test (Zar 1999) to determine significant orientation (at p= 0.05) in thesignificant orientation (at p= 0.05) in the

biologically appropriate direction (east)biologically appropriate direction (east)

RESULTSRESULTS

•Nest Distance Nest Distance ComparisonComparison

•Crawl TimeCrawl Time

NEST DISTANCESNEST DISTANCES

CRAWL TIMESCRAWL TIMES

1.05 min1.05 min

1.95 min1.95 min

2.85 min2.85 min

3.76 min3.76 min4.66 min4.66 min

RESULTSRESULTS

Exp I: Is crawl time important Exp I: Is crawl time important for efficient calibration?for efficient calibration?

RESULTSRESULTS

Exp II: Crawl time or oriented Exp II: Crawl time or oriented crawl time important for crawl time important for

calibration?calibration?

DISCUSSIONDISCUSSIONNest Position and Crawl Nest Position and Crawl

TimeTime

NEST POSITIONNEST POSITION•Nests were further Nests were further

from the surf zone from the surf zone at natural beaches.at natural beaches.

Similar observations made by Ernest & Martin Similar observations made by Ernest & Martin 19991999

Hatchlings crawl further to reach the Hatchlings crawl further to reach the ocean on natural beachesocean on natural beaches

CRAWL TIMECRAWL TIME• Given my average crawl speed (3.2 m/min) Given my average crawl speed (3.2 m/min)

and range of nest distances: and range of nest distances: - 0.9 - 5.0 min nourished beach - 0.9 - 5.0 min nourished beach - 2.4 - 5.7 min natural beach- 2.4 - 5.7 min natural beach

Dial 1987 calculated crawl speed (6.5 m/min): Dial 1987 calculated crawl speed (6.5 m/min): - 0.5 – 2.5 min nourished beach - 0.5 – 2.5 min nourished beach - 1.2 – 2.9 min natural beach- 1.2 – 2.9 min natural beach

Takes < 5 min to reach the oceanTakes < 5 min to reach the ocean

DISCUSSIONDISCUSSION Calibration and its Timing Calibration and its Timing

• Crawl Duration is ImportantCrawl Duration is Important

Crawls too short (1 min) or too long (>5 min) not as Crawls too short (1 min) or too long (>5 min) not as effective as 2 min crawleffective as 2 min crawl

• Crawl Direction is ImportantCrawl Direction is Important

Prior period of non-directional crawl interferes with Prior period of non-directional crawl interferes with ability of 2 min directional crawl to promote calibrationability of 2 min directional crawl to promote calibration

CALIBRATIONCALIBRATION

DISCUSSIONDISCUSSION• Hatchlings emerge from nest with endogenous Hatchlings emerge from nest with endogenous

programs that specify they should crawl in 1 programs that specify they should crawl in 1 direction (offshore) for a period of time that direction (offshore) for a period of time that roughly matches the time it takes to reach the roughly matches the time it takes to reach the ocean from the nestocean from the nest

ACKNOWLEDGEMENTSACKNOWLEDGEMENTSDr. Mike SalmonDr. Mike SalmonDr. Alex Marsh Dr. Alex Marsh Dr. James Wetterer Dr. James Wetterer Bill IrwinBill IrwinDr. Sagristano Dr. Sagristano Dr. NashDr. NashKelly Purdy Kelly Purdy

THE ENDTHE END