Red and Ziebell's handfish are small cryptic fish that don’t move much and are difficult to find. There are two known populations of Red handfish in south-eastern Tasmania, and Ziebell's handfish have not been seen for over ten years.
But how do we know there are no other populations out there?
While we can’t say for sure that more populations do not exist – there has been a considerable amount of data collected from Tasmania’s shallow marine reefs over the last 29 years. This information comes from the combined Reef Life Survey and Australian Temperate Reefs Collaboration surveys - much of which is coordinated through the Institute for Marine and Antarctic Studies at the University of Tasmania. Although the surveys were not all to look specifically/only for handfish - the survey methods include searches that would reveal any handfish that occur on shallow (less than 30m) rocky reef and seaweed covered reefs - the preferred habitat of Red and Ziebell's handfish.
In fact, there have been 7653 underwater surveys (each survey is a 50 m long transects) undertaken by scientific divers (University staff and trained volunteers) using systematic standardised methods.
No new Red or Ziebell's handfish populations have been recorded during these surveys.
Figure 1 shows the number of surveys conducted in particular areas around Tasmania and the Bass Strait islands from the combined survey work of the Reef Life Survey and Australian Temperate Reefs Collaboration from 1991-2019. Surveys were conducted along a 50 m transect line, and generally in less than 30 m depth (most between 5-10 m deep). These data are contained within the National Reef Monitoring Network of the Integrated Marine Observing System (imos.org.au).
References (data collection methods):
Edgar, G.J., Barrett, N.S., 2012. An assessment of population responses of common inshore fishes and invertebrates following declaration of five Australian marine protected areas. Environmental Conservation 39, 271-281.
Edgar, G.J., Stuart-Smith, R.D., 2014. Systematic global assessment of reef fish communities by the Reef Life Survey program, Scientific Data, 1. https://doi.org/10.1038/sdata.2014.7
If you see a Red or Ziebells handfish please report it here: RED ALERT
Header image: Ziebells handfish Credit: Andrew Green)