CLEVELAND BAY FIELD RESEARCH

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1 The Rivers to Reef to Turtles Project CLEVELAND BAY FIELD RESEARCH UPDATE #4 We all met again at our reference site in Cleveland Bay to sample the environment and turtles for the Rivers to Reef to Turtles (RRT) project. This marks the fourth field trip of the project and the second sampling event at Cleveland Bay to detect differences between pre- and post- wet seasons. The first step in the RRT project is to characterise and quantify the environmental (water, sediment and seagrass) and bio-accumulated contaminant exposure of green turtle populations in the study sites. The first year of this project is a non-targeted screening phase, meaning we are not targeting any pollutant in particular. The results of these analyses will guide the future targeted monitoring program. Over the life of the project, the data will be used to determine if environmental pollutants exist and if so, whether exposure can be correlated to turtle health at both the individual and population level. This knowledge will help us understand whether exposure to land-based pollutants may be adversely affecting coastal green turtle populations of the Great Barrier Reef. The Field Trip 29 May to 7 June 2015 Study site #2 the reference site at the southern end of Cleveland Bay. Contaminant exposure to green turtles at this site will be compared to Upstart Bay where the mass turtle stranding event occurred in page 1

2 The research team consisted of volunteers and scientists from all over Queensland including turtle biologists, water quality scientists, Traditional Owners, rangers, government representatives and WWF working together to deliver the objectives of the trip! With so much to achieve, we started with the briefing on all things boating and safety. Unfortunately the weather wasn t the best for the majority of the field trip with turbid waters, dense cloud cover, and wet windy conditions. The environmental sampling team hit the water on 29 May, focussed on collecting the environmental samples. Representatives from the Great Barrier Reef Marine Park Authority (GBRMPA) guided by scientists from TropWATER astutely deployed passive samplers (which accumulate a range of environmental pollutants) and grabbed water, sediment and seagrass for chemical analysis. Additional samples around these sites were collected this trip, including a new site at Cockle Bay in an attempt to reduce variability and provide more certainty in the results. The rest of the research team hit the water on the morning of 1 June. With the sun trying to shine through the many clouds above, we worked the three previously surveyed foraging sites and along the length of southern Cleveland Bay looking for any signs of bow waves or bobbing turtle heads in an attempt to catch them. We worked long days from sunup to sundown and at night entered data until late. After seven days in the field, challenged by the conditions, motivation levels and uncooperative turtles, we slowly worked towards collecting the required data. A lot less turtles captured than last year, but more environmental samples, so a successful trip. The Science: Due to limited rain at the study and reference sites this wet season, the first flush sampling event in Cleveland and Upstart Bays was cancelled. Although no significant discharge event occurred, this trip s focus was to detect pollutant changes in type and concentrations in pre- and post- wet season environmental samples and recaptured turtles, and to refine the environmental sampling methodology. The trip s objective was to also tag, weigh and measure as many turtles as possible to increase turtle numbers for mark/recapture population studies. Other complimentary project data was collected, including turtle photo identification and a future turtle health project to investigate the effects of contaminant exposure on green turtle physiology, but still too soon to tell all! page 2

3 Turtle Stats: 58 TURTLES CAUGHT 6 adults 2 sub-adults 50 juveniles 58 green turtles caught, tagged and measured 49 primary (first time) turtles caught 4 within-season recaptures 5 inter-season recaptures Smallest was 43.0 cm and largest cm 7 blood and scute turtle samples from recaptured and sub-adult age class was taken for toxicological (metal and organic) and health analysis 7 turtles of all age classes lavaged (to determine diet composition and for toxicological analysis) Environment Stats: 3 passive samplers deployed for assessment of metal contamination 3 passive samplers deployed for assessment of organic contaminants 4 different foraging areas sampled for water, sediment and seagrass with multiple grab sub-samples collected With limited recaptures to date, there seems to be some mixing of turtles between the foraging areas we sampled but not in other areas of Cleveland Bay (e.g. Cockle Bay or Cape Pallarenda). Of the 58 turtles caught, 6 were adults (6 females; 0 males), 2 sub-adults, and 50 juveniles. The sex ratios of females to males for adults was approximately 1:0 (meaning no adult males were captured). The lavage samples showed that the turtles were feeding primarily on seagrass with limited evidence of algae and mangrove fruits. There seemed to be two species of seagrass flourishing in each of the foraging areas. One turtle caught was emaciated but showed signs of a healed fibropapilloma, and one turtle presented with significant boat strikes. Other samples were taken for complementary or other projects including: 24 photos of turtles post-ocular scutes were taken to add to the new Turtle Photo ID database. The remaining samples and data collected will be taken back to our RRT collaborative partners for the screening analysis and future comparison to the other study sites as part of the RRT project. page 3

4 Highlights from the trip: We saw a single dugong and some pied oystercatchers- yes, Chris s favourites Working in murky waters all knowing there had been a crocodile sighting and EHP in the midst of searching for it Of course, the gourmet snacks of crackers, spam, and bottled cheese! Our turtle catching machine Hector and his unstoppable singing! Stephen Menzies special wetsuit always a hit Night time adventures spinning blood, making friends, and sharing daily adventures The field trip was primarily led by WWF, the GBRMPA, and the Queensland Government s Department of Environment and Heritage Protection (EHP). A big thanks to Dr Ian Bell for all the logistical support and role as principal investigator for the trip. Without the assistance of government departments and their support this trip could not have occurred. A special thanks to Gudjuda Aboriginal Reference Group and Girringun Aboriginal Corporation for their star turtle catchers, skippers and field assistance. Hats off to Stephen Menzies from Reef HQ Aquarium also for his skippering expertise, and all our volunteers! WWF-Australia and its partners are leading this pioneering research to protect the Great Barrier Reef and the turtles that call it home. Collaborative project partners of the RRT project include the National Research Centre for Environmental Toxicology at the University of Queensland, the Centre for Tropical Water & Aquatic Research at James Cook University, Vet-MARTI School of Veterinary Science at the University of Queensland, state and Commonwealth Government agencies, local Traditional Owner and natural resource management groups and other supporters and volunteers in the local community. The next field research trip will be conducted in Upstart Bay, as we continue to sample our way towards unravelling how much a turtle can take Until then, I m signing off Chris Hof. Rivers to Reef to Turtles investigation is made possible with the help of Banrock Station wines page 4

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