By Kacey Deamer, Staff
Writer | July 7, 2016 07:08am ET
There may be such a thing as too
many turtles, according to scientists investigating why so few turtle eggs were
hatching on Raine Island, located on the tip of Australiaꞌs Great
Barrier Reef.
For more than 1,000 years, green sea
turtles have nested on Raine Island, where they dig pits to lay
and bury their developing eggs. Yet after a millennia of fruitful nesting
seasons, the island has recently had a drop in the rate of successful hatches —
now less than 30 percent, even in undisturbed nests.
With protective coral along the
broad sandy beaches, and no land-based predators, scientists were stumped as to
why an otherwise ideal nesting location would have so few baby turtles hatching
from eggs and scuttling down to the water.
Seawater was the first suspect.
Scientists thought flooding of the nests during high tides was killing newly
laid eggs, which cannot
survive underwater. Sand was added to a section of the beach in
2014, raising it by 3 to 5 feet (1 to 1.5 meters), but hatching rates were
still extremely low. Then in 2015, hatching success doubled, leaving scientists
to question what had changed.
A new theory from researcher
David Booth of the University of Queensland suggests that the island's
popularity for nesting is to blame for the plunge in hatching success.
Fewer turtles laid nests on the
island in 2015, Booth
said in a statement. That bit of information suggested that "a
density-depending effect was limiting hatching rates even in nests that
remained undisturbed throughout incubation, rather than the environmental
conditions."
Posts
