Fisheries Journal Articles

Public engagement for the detection of the introduced marine species Charybdis japonica in Western Australia

Document Type


Publication Date


Journal Title

Management of Biological Invasions




marine biosecurity, alien, invasive species, non-indigenous, delimiting survey, citizen science


Aquaculture and Fisheries | Biosecurity | Marine Biology


The introduced crab, Charybdis japonica, was captured in the Swan River Estuary in Western Australia during October 2012. This constitutes the second documented report of this species in Western Australia after a single specimen was reported in 2010 from a nearby estuary. Given the invasive history of this species in locations such as New Zealand, a rapid-response delimiting survey was conducted to assess the prevalence of this crab within this estuary. A large public engagement campaign was run concurrently with the delimiting survey to inform and enlist the recreational crab fishers that use the Swan River and other nearby estuaries to report any more specimens that they caught. These activities yielded a total of three specimens, all handed in by recreational fishers as a result of the public engagement campaign. All three specimens were caught within a very limited area within the estuary, approximately 8 kilometres from the entrance. The two specimens that were able to be sexed were mature males, with carapace widths of 10.1 and 10.3 mm. The very small number of specimens caught, relative to the abundant native species indicates that C. japonica may be relatively scarce in the Swan River Estuary. This result highlights the importance of engaging members of the public to help detect introduced marine pest species in the early stages of incursions.