The Effect of Species on Frequency of

Surfacing in the NY Aquarium’s Sea

Turtle PopulationA demo UA exit project at the NY Aquarium, conducted by Fred Feraco, Rachel Volke, Maria Maldonado, and Lucas

Walker

2. QUESTIONHow does species affect frequency of surfacing in the NY Aquarium’s sea

turtle population?

3. HYPOTHESISThe research team in this study predicted that

the hawksbill turtles would surface to breathe more frequently than the loggerhead turtles.

The New York Aquarium has two types of sea turtles: Hawksbill (Eretmochelys imbrecata) and loggerhead (Caretta caretta)

According to the Sea Turtle fact sheets at the U.S. Fish and Wildlife service, hawksbill turtles generally reach a size between 95 and 165 lbs, whereas loggerhead turtles average about 200 lbs at their adult weight.

In fact, the three loggerhead turtles at the NY Aquarium are noticeably larger than the single hawksbill. We thought the smaller hawksbill turtle might have to work harder to move around the tank, which would seem bigger to her. She would therefore need more oxygen, and breathe more often.

4. BACKGROUND INFO.Sea turtles like the hawksbill and loggerhead are uniquely adapted

to their maritime environment. Marinebio.org describes their breathing style as “a single explosive exhalation and rapid inhalation” that lets them quickly cycle air through their lungs with a minimum of time actually spent at the surface. Turtles’ lungs allow them to continually absorb oxygen from the air they have inhaled, even at the higher pressures to which they are subjected during their dives.

Thus, we decided to define a “surfacing event” as the breaking of the water’s surface by the turtle’s nostrils. Sometimes, a turtle would come close to the surface and move its body such that a flipper would break the surface, but not its nose. We didn’t count this as a “surfacing event”. Other times, the turtles would break the surface with its nostrils, submerge its head, and then very shortly afterwards break the surface with its nostrils again. We counted these as two separate “surfacing events”. Over the long period during which we observed the turtles, it became increasingly easy for us to see that characteristic “explosive exhalation” when the turtle surfaced, and it was clear that our choice in defining “surfacing event” really did seem to reflect discrete breaths taken by the turtles.

4. BACKGROUND INFO.Marinebio.org also shares details about how often sea turtles breathe,

saying that “during routine activity”, surfacing every 4-5 minutes is normal. This helped us choose a sampling time of 30 minutes, thinking we would get to see 5-7 “surfacing events” for each trial.

Loggerhead (is that you, Yellow?) Hawksbill (note darker spots & serrated shell)

Investigation Design Diagram (ID)

Loggerhead Turtles Hawksbill Turtles

2x 30 minute observation periods 2x 30 minute observation periods

Title: The Effect of Species on Frequency of Surfacing in the NY Aquarium’s Sea Turtle Population

Question: How does species affect frequency of surfacing in the NY Aquarium’s sea turtle population?

Hypothesis: Hawksbill turtles will surface more frequently.

IV: Species of Turtle

DV: Number of surfacing events (see background research and procedure for definition)

Constants: Tank/habitat (location), time of day observed (that is, we observed both types of turtles at the same time for each trial), individuals (same turtles were observed both times), method of measuring surfacing

*

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The four female turtles were identified as follows:

Turtle Identifying marks

Loggerhead 1 Red tag in back right foot

Loggerhead 2 Algae-free shell

Loggerhead 3 No red tag, algae on shell

Hawksbill 1 Smallest turtle, more pointed snout

Procedures- OverviewEach of the 4 researchers was assigned a

different turtle to observe throughout the entire investigation. The turtles were distinguished based on their unique identification markings listed in the preceding table.

Two data collection trials of 30 minutes each were run. Both trials occurred on the same day, one from 12pm-12:30pm, and the other from 3pm-3:30pm.

Data was collected at the Coney Island Aquarium’s Sea Turtle Exhibit on November 20, 2010.

Procedures- Data Collection

The number of times each turtle surfaced during the 30 minute trial was recorded. Surfacing events were defined as instances when the turtle’s head broke the surface of the water and the turtle took a breath.

The data was collected using an all events focal animal ethogram.

Procedures- ExplanationThe all events focal animal ethogram was

selected as the most appropriate sampling method because we were recording the frequency of the occurrence of one event (surfacing) for four unique animals. This sampling method made it possible for us to focus solely on the occurrence of one event for each animal and then compare the frequency of that event between the two different species.

We watched four female turtles because they were the only turtles available. Three of the turtles were Loggerhead turtles and one was a Hawksbill turtle.

Loggerhead Turtle Vs Hawksbill Turtle Their Frequencies to Surfacing on the Water ( Breathing)

Types of Turtle

Species

Trial I 30

minutes(Number

of surfacin

g events)

Trial II30

minutes(Numbe

r of surfacin

g events)

Average

Loggerhead L2 (Maria)

9 5 7

Hawksbill H1 (Rachel)

2 3 2.5

Loggerhead L3 (Fred)

3 11 7

Loggerhead L1 (Lucas)

3 16 9.5

Species of Turtle

Average (Breathings)

Loggerhead Turtle

7.8

Hawksbill Turtle

2.5

Focal Animal Scan Sampling Data

Average Number of Breaths Taken by Species

Number of breaths

Dark Blue – LoggerheadLight blue - Hawksbill

8. RESULTSOur data shows that the loggerhead turtle on

average of both trials took five and a half more breaths than the hawksbill turtle. The loggerhead averaged 7.8 surfacing events and the hawksbill turtle averaged 2.5 surfacing events.

9. CONCLUSION

We thought the hawksbill would surface more often because it's smaller.  The hawksbill actually ended up breathing far less overall in both trials, so you could say our hypothesis was not supported.

There are also reasons to say the data is inconclusive, because there were many things we did not take into account. First, there were only 3 individual turtles that were loggerhead turtles and one individual that was a hawksbill. So the sample size was probably not big enough to claim we have a fair representation of each species. We also noticed that the turtles that breathed more seemed to be more active, swimming all around the tank during the 30 minute trial, while the turtles taking fewer breaths spent their time in one corner of the bottom of the tank not moving. One turtle breathed 3 times in the first trial and a whopping 16 in the second, suggesting that activity level matters more than species.

10. (Further Study) NEXT STEPS

One member of our team thought we could try timing the actual length in seconds of each surfacing event, which might give us a better idea of each individual’s lung capacity.

We are also interested to see the relationship between activity level and breathing frequency. This could be important because it gives us more information about how long turtles DO actually stay underwater than just their average, calculated surfacing frequency… conservation applications?

11. Literature Cited“Hawksbill Sea Turtle, Eretmochelys imbricata at MarineBio.org". MarineBio.org. 26

November 2010 <http://marinebio.org/species.asp?id=164>. Last updated: 11/8/2010 5:14:34 PM

“Hawksbill Sea Turtle (Eretmochelys imbricata)”. U.S. Fish & Wildlife Service, North Florida Field Office. 26 November 2010. <http://www.fws.gov/northflorida/SeaTurtles/Turtle%20Factsheets/hawksbill-sea-turtle.htm>. Last Updated: 1/16/2009

“Loggerhead Sea Turtle (Caretta caretta)”. U.S. Fish & Wildlife Service, North Florida Field Office. 26 November 2010. <http://www.fws.gov/northflorida/seaturtles/turtle%20factsheets/loggerhead-sea-turtle.htm>. Last Updated: 11/12/2010

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