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The Negative Effects of Beach Renourishment on Sea Turtle Nesting. What is a Sea Turtle?. Sea turtle: A large air breathing reptile that spends most of it’s life in the water. It comes on land only if it is a nesting female, or if it is dead or dying. Mating/Nesting.
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The Negative Effects of Beach Renourishment on Sea Turtle Nesting
What is a Sea Turtle? Sea turtle: A large air breathing reptile that spends most of it’s life in the water. It comes on land only if it is a nesting female, or if it is dead or dying.
Mating/Nesting • What factors affect mating/nesting? • Time of year that mating occurs- late spring to late summer • Frequency of mating- most turtles mate every two to three years • Habitat that females choose to nest in
The Mating Process... • Male and female turtle meet offshore to mate • Female then returns to the same beach that she was born to lay her clutch (eggs)
Nesting cont’d... • Upon reaching the beach, the female drags her heavy body on shore • She crawls to a point above the high water mark where she will then dig a body pit
Nesting cont’d... • Once body pit is dug female lays a clutch of about 100 eggs • Female then covers the eggs and leaves them to incubate and hatch, never to return to the site
So What is the Problem? Beach Renourishment
Renourishment • Beach renourishment is a solution to dealing with the rapid erosion of beaches • Sediment from an alternative source is brought in and placed on the existing shoreline to make it larger • Renourishment is mostly done for economic reasons, such as attracting tourists to the beaches • In Miami Beach renourishment increased beach attendance from 8 million in 1978 to 21 million in 1983
Problems with Renourishment • If renourishment is done at the wrong time of the year (nesting season) it can cover nests • Equipment can compact the sand or make trenches that the turtles cannot breach to get high enough above the water line • Steep berms often form preventing females from nesting or causing them to nest below the high water mark
Problems with Renourishment • Replaced sand is often harder (more resistant to shear) than the natural sand and it is usually not the same material • Harder sand often results in a nest of inappropriate size or depth • More compact sand or sand of a different size can also results in insufficient gas exchange, change in nest temperature (important for determining turtles sex), and nest moisture
Regulate when renourishment is done • Require nest surveys, nest marking, and nest relocation • Modify methods to reduce compaction • Renourish with sediment of similar grain size and composition
Dealing with Renourishment- Nationally • Because so little is known about sea turtles and their nesting behaviors it is important to protect them • Federal Endangered Species Act • Section 7: Actions are not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of the critical habit • Section 9: prohibits the sale, import, export, or transport of any endangered species and most threatened species, and makes it unlawful to “take” them
Dealing with Renourishment- Locally • Most states have their own laws and agencies dealing with protecting sea turtles • Ex. Florida- FESA and Marine Turtle Protection Act • Beach and coastal acts • Often require permits to be obtained for renourishment which allows authorities to regulate when it is done
References cited www.law.fsu.edu/journals/landuse/Vol132/Butl.htm www.cccturtle.org/behav.htm www.brookdale.cc.nj.us/staff/sandyhook/dgrant/field/dollars.htm www.turtles.org Steinitz et al. 1998. Beach Renourishment and Loggerhead Turtle Reproduction: A Seven Year Study at Jupiter Island, Florida. Journal of Coastal Research, 14:3, 1000-1013 The Effect of Beach Nourishment with Aragonite Versus Silicate Sand on Beach Temperature and Loggerhead Sea Turtle nesting Success. Journal of Coastal Research. 13:3, 904-915