Care For Hedland Environmental Association’s turtle monitoring program has entered its 7th week of its 22nd season of data collection of Flatback Turtle nesting activity along local Port Hedland beaches. Past the half-way mark, in the scientific Mark and Recapture program. The team has processed 195 turtles and 82 individuals, many of them being sighted and recorded 2-3 times. To date this season a total of 184 new successful nests, 227 false crawls and 6 hatched nests with an estimate of 144 hatchlings have been recorded at Cemetery Beach.
Compared to last season, with 384 nests and 355 false crawls recorded. We can see that this year we have had an increase in false crawls and a decrease in overall activity. The increase in false crawls could potentially be from drier sand this season. False crawls can occur for many different reasons. It can be caused by natural factors, such as sand conditions being too dry, the presence of predators, and unsuitable nest conditions, such as physical obstructions like vegetation or rocks. There are also anthropogenic (human-induced) factors, such as artificial light or noise, that can disturb them and result in the turtles leaving without nesting. If people get too close or in the direct eyesight of the turtle, she can get spooked and leave. Tourists can be excited to see a large marine reptile up on the town beach but must remember why she has taken such an effort to crawl up onto the land in the first place.
Track counts are an essential long-term consistent source of population data, but to interpret the tracks, we initially need to follow individual turtles in some detail. If the track count data found that there were 500 nests for the season, that is excellent data, but it would not tell us how many turtles were in the local population. To know that, we need to know how many clutches of eggs each individual turtle lays during a season, how many days she takes to make the next clutch, and how many years she spends in her feeding grounds before returning for another season. There are many things that tagging individuals can tell us about what’s going on biologically in the population that we can’t know from tracks alone.
This is the twelfth year of tagging on Cemetery Beach, with each turtle receiving 2 pit tags and 1 flipper tag. Last year, 15 turtles sighted were newly-tagged. This year, there have currently been 2 newcomers to the rookery, which mostly appear to be first-time breeders.
Flatbacks migrate for a nesting season, on average, every two years. Now twelve years into the tagging program at Cemetery Beach, even most of the turtles with longer remigration intervals have been recorded. It is an exciting time for tagging, as all the time we are discovering the biological parameters of the Port Hedland flatbacks.
Many of the turtles seem to be homebodies, with several tag recaptures showing 35 turtles this season nested in 2024, making them annual nesters.
As well as the Mark and Recapture program, our turtle coordinators and volunteers have deployed 24 temperature data loggers in nests evenly distributed across Cemetery beach. There would ideally be up to 40 data loggers deployed, however with lower nesting numbers this season it was more difficult to reach that number. Nest marking is used to determine the average temperature of the nest over the 45-50 days the eggs take to develop as well as determining nest success. In January once these 40 nests have hatched the team will dig the nests up to see how many eggs have hatched and how many are under-developed. This is crucial to help understand the nests hatching success. Volunteers are welcome to help with nest excavations; it is a smelly but rewarding process!
Not only have the turtles been out in force, but also the people of Hedland. The first half of the tagging season has seen 85 local volunteers and 4 out of town volunteers patrolling the beach as part of the nightly tagging program. “The volunteers are so greatly appreciated by the coordinators, we couldn’t do what we do without them. It’s incredible to see so many people of different ages, lifestyles and experiences coming together to help a species. It is inspiring to see the dedication of both our long-term and new volunteers”, said Morning Coordinator Haylee. Volunteers have varied duties, including recording the data in the clipboard, helping to process the turtles, restraining any turtles that are speeding down the beach so their tag numbers can be read, GPS-ing the turtle activities and most importantly, protecting the turtles from being disturbed by beachgoers. Another big part of our work is educating the community, as we all want to encourage positive human interactions with these beautiful turtles.
The Program is made possible through the generous support of principal partner BHP, sponsors Northern Star Resources and the Town of Port Hedland, and technical support and assistance from the Department of Biodiversity, Conservation and Attractions (DBCA). This program also wouldn’t have the success it has today without the steady band of dedicated local volunteers who join in to patrol the beach at all hours of the night.
If you have been wanting to volunteer, please reach out to Morning Coordinator Haylee, turtle@careforhedland.org.au for more information. The Mark and Recapture program normally goes for four to six hours over the night-time high tide. This year Care for Hedland is tagging for 50 consecutive nights over the peak of the season, so tagging will continue every night up to and including 7th December. After this date, the turtle monitoring program will continue with evening monitoring, tour guiding, people management, outreach events, and track counting of nesters and hatchlings each morning for the next couple of months.
Story and images supplied by Care for Hedland