The shark-like rays of the family Rhinidae (wedgefishes) are one of the most threatened group of marine fishes globally. The poorly-known Clown Wedgefish Rhynchobatus cooki has historically only been recorded from fish markets in Singapore and Jakarta, Indonesia. Its natural geographic range has until now gone undocumented. Intentional searches of social media posts describing wedgefish catches in Indonesia and Malaysia revealed the first wild records of this Critically Endangered species. A total of six catch records from small-scale fisheries were located from Lingga and Singkep Islands in Indonesia (1 from 2015, 4 from 2019, 1 from 2020). It remains unknown if the species is a micro-endemic to this small area of the Malay Archipelago, or if it is wider ranging. These results demonstrate the utility of social media searches to identify biogeographic records of cryptic and data-poor species.

This final report covers conservation work for red and spotted handfishes during 2019-2020. For red handfish this includes monitoring of juveniles in the wild immediately after their release following captive-rearing. Juveniles were recorded on all three monitoring surveys post release, indicating initial success of this conservation strategy to bolster wild population numbers. This report includes investigation into sex-determination in adults using morphometrics and found a lack of clear separation between males and females, indicating that focus should be on other methods for non-destructive sex determination. 

For spotted handfish this report includes population dynamics from 22 years of monitoring and found that within the Derwent estuary, both genomics and population dynamics suggest a well-structured population, with local populations acting in isolation from each other, or small groups. There had been an overall decline in the Derwent estuary’s Spotted handfish population.

We have completed and analysed performance assessment surveys at nine local population sites for spotted handfish in the Derwent estuary from 2015-2019. To this time series we have also incorporated historic data for individual sites back to 1998. Local populations generally show stability of occurrence but with some difference in abundance (as measured by estimates of fish densities per habitat) by years.