In late July, experts were scratching their heads after a clutch of turtle eggs were laid on a Sunshine Coast beach, four months out of season.
In what’s believed to be a first for the South-East Queensland shoreline, the unexpected winter nesting occurred at Mudjimba Beach, 110km north of Brisbane.
The eggs were found to belong to an endangered loggerhead turtle; this confirmed after the hatchlings emerged from their eggs.
Why is winter nesting so unusual?
Taking nine to ten months to produce functional sperm, male loggerhead turtles usually do not produce viable sperm earlier in the year.
As they are known to only mate once a month, the males habitually mate during the months of October, November and December.
The Sunshine Coast Council TurtleCare Coordinator was alerted to the out-of-season nesting and joined Coolum & North Shore Coast Care volunteers and, together, they painstakingly retrieved 93 eggs.
Since, any rotation could have caused an embryo to rupture and die, the task of extracting the eggs was done with great care.
Each egg was gently weighed and measured before being placed into containers of moist sand, along with a compass on top to lessen the risk of unnecessary movement.
The eggs were then transferred to a Council depot where they were inspected to check for viability before being placed in an incubator.
There was elation all round when 87 of the eggs proved to be viable.
Temperature changes could lead to skewed sex ratios, as warmer sands tend to produce more female hatchlings.
More extreme weather events can lead to storm surges that inundate turtle nests and destroy nesting beaches.
Rising sea levels will steal vital beach nesting habitats while rising temperatures could also lead to complex changes in ocean currents, which could see hatchlings end up in unsuitable areas for survival and growth.
Sea temperature and acidity rises may limited the growth of sea grasses and other fodder for turtles.
Increasing air humidity could make eggs more susceptible to disease, resulting in higher mortality.
Had the eggs been left in the cold sand overnight, local turtle experts say, it’s doubtful that any would have survived to hatch.
In September, the hatchlings were released back at Mudjimba beach after staying in a climate-controlled incubator for 66 days.