The opal cling goby (Stiphodon semoni) is a critically endangered (EPBC) freshwater fish species found in rainforest streams of the Australian Wet Tropics.
These small, brightly coloured fish have only recently been discovered in the region, where they have only been recorded from a small number of streams. In addition to their stunning beauty (of the males at least!), these tiny fish lead an extraordinary life.
Although they spend their entire adult life in swift-flowing freshwater streams, much of their early life is spent with the plankton in the warm oceanic waters of the Indo-Pacific.
This pattern of migration, where the larvae are swept from freshwater streams into the ocean for several months before returning to freshwater, is quite common for freshwater fish species found on tropical Pacific islands, and is known as amphidromy.
Real travellers, amphidromous species are able to disperse across ocean basins and colonise freshwater systems on oceanic islands.
It is for this reason we think that many of the freshwater fish species found in the Wet Tropics are shared with places such as Vanuatu and French Polynesia.
Threats to the opal cling goby
- Over-extraction of water from short-steep-coastal streams
- Over collection for aquarium use
- Deforestation and sediment runoff into streams
- Barriers to migration including dams and culverts
- Competition and predation from pest species
- Inadequate knowledge of distribution or requirements to complete life cycle
Legislation protecting the opal cling goby
- Australia: Listed as 'critically endangered' under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.
What is Terrain doing to help?
Terrain is working with researchers from TropWATER at James Cook University and CSIRO to document the distribution of this species across the Wet Tropics, map their preferred habitat and incorporate the findings into regional planning documents.
- Donaldson, J. A., Ebner, B. C. & Fulton, C. J. (2013). Flow velocity underpins microhabitat selectivity in amphidromous gobies of the Australian Wet Tropics. Freshwater Biology 58, 1038–1051.
- Ebner, B. C., Donaldson, J. A., S. Fulton, C. & Schaffer J. (2015). Distinct habitat selection by freshwater morays in tropical rainforest streams. Ecology of Freshwater Fish (Early view)
- Ebner, B. C., Kroll,R., Godfrey, P., Thuesen, P.A., Vallance, T., Pusey, B., Allen,G., Rayner, T. S., Perna, C. N. (2011). Is the elusive Gymnothorax polyuranodon really a freshwater moray? Journal of Fish Biology 79, 70–79.
- Ebner, B. C., Thuesen, P. A., Larson, H. & Keith, P. (2011). A review of distribution, field observations and precautionary conservation requirements for sicydiine gobies in Australia. Cybium 35, 397–414.
- Thuesen P. A., Ebner, B. C., Larson, H., Keith, P., Silcock, R. M., Prince, J. & Russell, D. J. (2011). Amphidromy links a newly documented fish community of continental Australian streams, to oceanic islands of the West-Pacific. PLOS One 6, e26685.
- Wet Tropics Management Authority (2013). Annual Report and State of the Wet Tropics report 2012–2013. Cairns: Wet Tropics Management Authority. < http://www.wettropics.gov.au/site/user-assets/docs/b5-wtma-annual-report-2012-2013.pdf>
- Kroon F.J., Philip S., Donaldson J., Ebner B. (2014) Assessment of freshwater ecosystem condition, status and trends in the Wet Tropics region. Supporting study to the Wet Tropics Water Quality Improvement Plan. CSIRO, Australia.