Dugongs of Moreton Bay: Field Health Study and Seagrass Ecology

Summary

In this episode, ABC Science documents a week-long expedition off the coast of Queensland as researchers from the University of Queensland and the SeaWorld Foundation work with volunteers to study dugongs in Moreton Bay. The team aims to capture and examine a sample of dugongs to learn about their health, diet, stress levels, and reproductive status, using both invasive and non-invasive methods. The program highlights how seagrass beds underwrite the dugong population and how extreme weather events threaten both the seagrass ecosystem and calf recruitment. Through ultrasound and field sampling, the team builds a baseline for dugong health that can inform conservation efforts worldwide. The episode also demonstrates the challenges and excitement of field biology and ends with a call to stream more episodes in Dr. Anne’s Secret Lives series.

• Key insight: researchers combine direct sampling with non-invasive techniques to monitor health
• Key insight: seagrass meadows are a critical carbon store and food source for dugongs
• Key insight: climate extremes directly impact dugong calves and seagrass habitats
• Key insight: pregnancy can be confirmed in dugongs using ultrasound and poo hormone analyses

Overview

The video follows a major field operation in Moreton Bay, a 3400 square kilometer marine park near Brisbane, where around 1000 dugongs inhabit the area. It introduces the researchers from the University of Queensland and the SeaWorld Foundation who collaborate with volunteers to conduct a focused health survey of the local dugong population. The objective is to catch and sample a subset of dugongs during a week-long campaign, with the aim of collecting data from at least 20 individuals and more than 200 samples across a range of measurements. The narrative emphasizes that this is not mere spectacle; it is a structured effort to understand health, diet, reproductive status, and long-term population viability in a species facing global decline.

The Location and Team

Moreton Bay is described in detail, including its edge habitats and seagrass beds which form the backbone of the dugong diet. The team includes Dr. Janet Lanyon, a lead investigator with decades of dugong research, and a cohort of researchers and volunteers who bring a mix of veterinary, field biology, and logistics expertise. The show frames this as one of the world’s most studied dugong populations and situates the work within broader conservation science aimed at protecting seagrass habitats and the dugong’s future.

Field Methods and Sampling

The operation involves capturing dugongs using a coordinated team, with a focus on safety and minimizing stress. Data collection spans on-board sampling and in-water procedures. Blood sampling on the deck is paired with non-invasive approaches such as saliva, tears, and buccal swabs, as well as nasal and oral swabs. Frisbees are used as urine and fecal collectors to reduce water contamination and surgical-like sampling. The program discusses why water-only sampling is challenging due to seawater contamination, necessitating temporary out-of-water handling for certain samples.

Ultrasound is a central tool on SeaWorld’s clinic boat for assessing body condition and confirming pregnancy, while fecal and hormonal analyses from poo samples provide clues about gestation and health. The narrative emphasizes the balance between invasive sampling and animal welfare, highlighting ongoing efforts to develop non-invasive alternatives that still yield meaningful health indicators.

Seagrass Ecology and Dugong Diet

The documentary makes clear that seagrass meadows are a critical ecosystem service, acting as a carbon store and stabilizing coastlines. The dugongs rely on large quantities of seagrass, with estimates suggesting daily intake in the tens of kilograms per animal. The meadows have a complex structure with underground rhizomes, fragility to climate events, and rapid recovery potential when grazed. Observations of feeding trails reveal patterns of dugong movement and grazing strategies, ranging from pulling upright shoots to excavating smaller grasses. This section links the health of the dugong population to the health of the seagrass ecosystem and broader carbon-cycle considerations.

Health and Reproduction

Lead investigator Dr. Janet Lanyon outlines a robust, week-long sampling regime that includes both core diagnostics in haematology and hormones, and non-invasive markers such as tears and saliva. The team collects a suite of data including red and white blood cell counts, stress hormone markers, and contaminants like heavy metals and microplastics. The ultrasound reveals that at least one of the studied dugongs is pregnant, demonstrating the potential to learn about reproduction and calf viability in this population. This pregnancy assessment, in combination with hormonal data from fecal or other non-blood matrices, provides a critical baseline for understanding reproductive health and population trends in the face of environmental pressures.

Conservation Implications

The video emphasizes that the Moreton Bay dugong population is globally significant, both for research methods and for conservation results that can be applied elsewhere. It connects the dugong's future to seagrass health, noting that extreme weather events disrupt seagrass meadows and reduce calves, which in turn affects long-term population viability. The show closes by highlighting how the ongoing work will inform conservation strategies, not only in Australia but around the world, as researchers apply developed protocols to other dugong populations. The final message invites viewers to stream additional episodes in Dr. Anne’s Secret Lives series on ABC iView for more on dugongs and other species.

Takeaway and Context

Overall, this program blends field biology, veterinary sampling, and ecology to illustrate how scientists study and protect a secretive, keystone marine mammal. It underscores the interconnectedness of diet, habitat, health, and climate in shaping the future of dugongs and their seagrass ecosystem, while also showcasing the practicalities and ethics of wildlife research in the wild.