Using DNA to identify bycatch species

Amount awarded £5,000

This project is identifying incidental bycatch species of the blue swimming crab fishery in the Java Sea using environmental DNA (eDNA) techniques. The fishery has been in a fishery improvement project (FIP) for several years led by APRI, with its progress now verified through the In-Transition to MSC Program.  

Surveys in 2016 and 2019 by APRI identified five crustacean species which could be vulnerable to bycatch from the fishery. They become accidentally caught in traps while fishing for blue swimming crab. Other species accidentally caught such as the Jones’ pony fish (Eubleekeria jonesi) are repurposed as bait so are not wasted. However, their use must be at a sustainable level. 

The fishery was also supported through the Fish for Good program; a four-year project that supported more than 25 fisheries across Indonesia, South Africa and Mexico to improve their fishing practices towards sustainability. 

Collecting environmental DNA samples for analysis

This Student Research Grant will support collection of eDNA samples from the local environment in the Java sea. These will be matched with DNA samples from non-target species interacting with the fishery to determine the level of risk they face from crab fishing.

Despite Covid cases in Indonesia leading to roads being closed, that prevented Anggini access to research sites for much of the year, she has successfully managed to collect a total of 825 blue swimming crabs for genetic sampling. She has also obtained seawater samples from 13 location points and is currently processing the DNA data at the Bogor Agricultural Institute laboratory. 

The results will help determine both the stock status and distribution of secondary bycatch species. A specific analysis has also been undertaken to understand growth patterns, mortality rates and distribution of stock units for the three-spot swimming crab (Portunus sanguinolentus). Anggini has also conducted face-to-face interviews with many crab fisherman in Madura, East Java province, staying in local homesteads in the communities to gain important insights for the project. 

The findings will contribute to the stock status for blue swimming crab and improve understanding of the impact of the fishery on the wider environment. This data will be a vital part of how the fishery’s sustainability is assessed against the MSC Fisheries Standard.