Mid-Atlantic Sea Turtles:
Possible Causes for Declines in Population
and Potential Mitigation Strategies
Francesca Fusaro
Emily Knaus
Barbara Madden
Background
Five species of sea turtles have been recorded in the
Mid-Atlantic region including1:
Hawksbill
(eretmochelys
imbricata)
Green
(chelonia
mydas)
Kemp’s ridley
(lepidochelys
kempii)
Loggerhead
(caretta
caretta)
Leatherback
(dermochelys
coriacea)
Significance of Sea Turtles
Sea Turtle Impacts on Ecosystem2
Marine Ecosystem
Beach/Dune Ecosystem
The Problem
Habitat alteration and degradation has
led to a decrease in sea turtle
populations in the mid-Atlantic region.
Evidence of Sea Turtle Population
Declines3
Proximate Causes4
1.
Beach Habitat Alteration
2.
Lounge Chairs on the Beach
3.
Strong Storms
4.
Increasing Sea Level
5.
Pollution
6.
Artificial Lights
7.
Commercial Fishing
8.
Egg Predation
9.
Modification of the Oceanic Currents
10. Increase Sand Temperature
Ultimate Causes
1.
2.
3.
4.
Urbanization
Increased Recreational use of Coastlines
Unmanaged Trash Disposal
Global Warming
Major Cause
5. Increased Recreational use of Coastlines
Case
Proximate causes
Evaluate
causes
Beach habitat
alteration
Artificial lights
Ultimate cause
(source)
Urbanization
positive
Unmanaged
trash disposal
Pollution
Decrease of
sea turtle
populations
in Mid-Atlantic
region
Increased
recreational
use of
coastlines
Modification of
oceanic currents
Increase of
sea level
positive
Increase of sand
temperature
Strong storms
Commercial fishing
Egg predation
Positive /
negative
Positive but
natural
phenomenon
Global warming
Commercial
fishing
Food chain
Options for Mitigating Impacts of Increased
Recreational use of Coastlines5
1. Reduce Lighting within the Range of the Beach
2. Designate Critical Habitat for Turtle Nesting Only
3. Place More Trash Cans on the Beach
4. Remove Lounge Chairs from the Beach at Night
and Reduce Lighting
5. Use Beach Signs to Promote Public Awareness
Evaluation Criteria
1. Maintain Recreational Use of Beaches
2. Increase Turtle Population from Current Levels
3. Preserve Critical Habitat
4. Remove Significant Barriers to Nesting
5. Costs Should Not Outweigh Benefits
Options
Criteria
Reduce
Designate
lighting within critical habitat
the range of
as turtle
the beach
nesting only
Maintain
recreational
use of
beaches
Increase in
turtle
population
from current
levels
Preserve
critical habitat
√
Costs should
not outweigh
benefits
√
√
√
√
√
Remove
significant
barriers to
nesting
Place more
trash cans on
beach
√
√
√
√
√
√
Remove
Use beach
lounge chairs
signs to
at night &
promote public
reduce lighting
awareness
√
√
√
√
√
Best Option
Remove Lounge Chairs from Beach at Night
and Reduce Lighting
Sources
1.
Meylan, A. Long-Term Monitoring Program Reveals a Continuing Loggerhead Decline, Increases in
Green Turtle and Leatherback Nesting. Florida Fish and Wildlife Conservation Committee
2.
Caribbean Conservation Corporation and Sea Turtle Survival League, “Why Care About Sea Turtles?”,
http://www.cccturtle.org/sea-turtle-information.php?page=whycareaboutseaturtles; University Of
Florida “New Research Shows Loggerhead Sea Turtles Sustain Delicate Dunes”, 1998; Frazier, Jack.
“Community Based Conservation: Research and Management Techniques for the Conservation of Sea
Turtles”, 1999.
3.
Godfrey, D., “Loggerhead Sea Turtle Nesting In Steep Decline”. http://www.worldwire.com/news/0611090001.html
4.
Carrillo-Rubio, L. “On the path of a hatchling: sea turtles and their survival on the warming planet.”
Climate Institute, 2007; Committee on Sea Turtle Conservation, National Research Council, “Decline of
the Sea Turtles: Causes and Prevention”, 1990; Endangered and Threatened Species Group. “An
Overview.” Florida Fish and Wildlife Conservation Committee,
http://floridamarine.org/features/view_article.asp?id=2156; McCauley, S.J and Bjorndal, K.A.
“Conservation Implications of Dietary Dilution from Debris Ingestion: Sublethal Effects in PostHatchling Loggerhead Sea Turtles.” Conservation Biology, 1999; Meylan, A. “Long-Term Monitoring
Program Reveals a Continuing Loggerhead Decline, Increases in Green Turtle and Leatherback
Nesting.” Florida Fish and Wildlife Conservation Committee,
http://floridamarine.org/features/view_article.asp?id=27537; Mosier, A., “Impacts of Coastal Armoring
on Sea Turtle Nesting Behavior.” Florida Fish and Wildlife Conservation Committee,
http://floridamarine.org/features/view_article.asp?id=2190; Murray, K.T. “Bycatch of sea turtles in the
Mid-Atlantic sea scallop (Placopecten magellanicus) dredge fishery during 2003. U.S. Dep. Commer.,
Northeast Fish. Sci. Cent. 2004; National Marine Fisheries Service. “Endangered Species Act Section 7
Consultation on the Atlantic Sea Scallop Fishery Management Plan.” NMFS, Northeast Regional
Office. 2006; Patrick, B. “By disturbing a massive ocean current, melting Arctic sea ice might trigger
colder weather in Europe and North America.” Science.nasa.gov, 2006; Richard, B., “Only 50 years
left' for sea fish.” BBC NEWS/Science & Environment, 2006; "Critical danger' warning on fish " 2006
BBC NEWS/Science & Environment; WWF, September 2008. Sea turtle threatened by rising seas.
Sources Continued
5.
Johnson, S.A., Bjorndal, K.A., & Bolten, A.B., “Effects of Organized Turtle Watches on Loggerhead
(Caretta caretta) Nesting Behavior and Hatchling Production in Florida.” Conservation Biology, 1996;
Lewison, R.L., Crowder, L.C. and Shaver, D. J. “The Impact of Turtle Excluder Devices and Fisheries
Closures on Loggerhead and Kemp's Ridley Strandings in the Western Gulf of Mexico.” Conservation
Biology, 2003; Pfaller, J.B., Limpus, C.J., and Bjorndal, K. A., “Nest-Site Selection in Individual
Loggerhead Turtles and Consequences for Doomed-Egg Relocation.” Conservation Biology, 2008;
Reece, J.S., Ehrhart, L.M., & Parkinson, C.L., “Mixed stock analysis of juvenile loggerheads (Caretta
caretta) in Indian River Lagoon, Florida: implications for conservation planning.” Conservation
Genetics, 2006.