What happened
Researchers from James Cook University and Charles Darwin University have re-examined dugong numbers in the Gulf of Carpentaria, Australia. The assessment indicates a population of about 5,000 animals in 2025. A 2007 estimate placed the population at approximately 10,000.
The figures point to a substantial reduction across the 18 years separating the two assessments. However, the information available from those two points does not establish when the change took place, or whether it occurred steadily or during a shorter period. Researcher Chris Cleguer said further examination is continuing.
The assessment concerns dugongs in their natural habitat in the Gulf of Carpentaria. Readers tracking marine biodiversity in northern Australia should follow the continuing work, as the current evidence does not provide a timetable for additional findings or population-recovery measures.
Why it matters
Dugongs are marine mammals in the sea-cow family and feed entirely on plants. They are long-lived, mature relatively late and breed slowly. Marine scientist Rachel Groom said those characteristics mean that rebuilding a reduced population could take years.
The species is listed as vulnerable by international conservation organisations. Its dependence on seagrass makes the condition of those habitats important to its population. Scientists cited in the report say losses of seagrass may be one possible contributor to the lower estimate, because it is the animals’ main food source.
Seagrass can be affected by higher seawater temperatures, flooding, intense rainfall and cyclones associated with climate change. These pressures may therefore affect both habitat availability and the food base on which dugongs rely.
Commercial gillnet fishing is also identified as a possible source of mortality in the region. Dugongs can become entangled in nets and drown. The evidence does not quantify the contribution of either seagrass change or gillnet entanglement to the difference between the 2007 and 2025 estimates.
What to watch next
Further investigation is under way into the population and the factors that may be behind the reduction. For now, the comparison should be read as two estimates separated by 18 years, rather than evidence pinpointing the timing or precise causes of the decline.
Source: EkoIQ.
