Delaware Bay and Sea Turtles
• Juvenile sea turtles in Bay June- October• Rich source of crabs and other invertebrates• Genetic studies
– loggerheads along northeastern states nest in Mexico, Florida, Georgia and South Carolina
• Satellite Telemetry– Wassaw Island Georgia to mouth of Delaware
Bay
Methods• Aerial Surveys June- August 1997
– Cessna 172• 100-224 mph• 300-500 ft above sea level
• In-Water Captures June- September 1997– Tangle nets
• 100 yd x 8 ft x 10 in mesh• 100 yd x 30 ft x 6 in mesh• Large bullet surface floats• Retrieved every 30 minutes• 25 ft Parker boat
• Sea Turtle Sighting Survey– Public users
Aerial SurveysFour transect linesTwo observersOne data recorder (+ pilot)Strip transect 300 m wideJune- August 1997
Locations of turtlesSpeciesTime
Strip transect estimates of density (Epperly et al 1995)
Aerial Surveys
• June – 10 loggerheads• July – 9 loggerheads• August- 14 loggerheads
• Density- 21-33 turtles/100 km2
In Water Captures
• 2 nets on 21 days• 103 hours• Observed 10 loggerheads (2 juveniles)• Captured 2 live male loggerheads
– 90 and 108.2 cm• Found ½ of dead loggerhead floating in
water
Public Sea Turtle Sightings• 60 postcard responses
– Most were recreational fishermen from lower Bay– A few sightings from Cape May- Lewes Ferry
• 65 turtles• 57 loggerheads• 4 hawksbills- probably small loggerheads or
Kemp’s Ridleys- spit out bait and hissed• 2 green turtles- probably loggerheads • 2 not identified to species• 12 of 65 turtles were caught by fishermen- 18.5%
Sea Turtle DensityLocation Density (turtles/100 km2)
• Delaware Bay- 21-33 • Lower Chesapeake Bay- 0-57 • Mid Chesapeake Bay- 0-8.5• Pamlico Sound- 0-6.5 • Core Sound- 0-30• Southern Georgia- 0-62
Conclusions1. Density of turtles is comparable or greater than in southeastern US2. Lower Delaware Bay provides important habitat for loggerheads3. Significant numbers of sea turtles are incidentally hooked
by recreational fishermen4. Many turtles swim in and around the shipping channel5.Collision with boats and propellers may be a threat to turtles6.Benthic trawling may be a significant threat to sea turtles in the Bay7.Decline of horseshoe crabs threatens the food supply for these turtles.
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