In April this year, a small but significant window opened for Torres Strait Islanders to harvest Black teatfish (Holothuria whitmaei), a sea cucumber species that is making a comeback from overfishing.
In preparation for the trial, fishers had worked with scientists and fishery managers to set a maximum harvest of 20 tonnes, and procedures for reporting their daily landings. After four days of fishing, the combined catch reached 17 tonnes. Everyone was alerted that ‘the opening was closed’, and the trial was believed to be successful.
The Black teatfish trial was part of a new management system, or ‘harvest strategy’, adopted by the fishery in January 2020. Scientists, fishery managers, fishers and islander communities developed the strategy together, in meetings and workshops on Thursday, Erub and Ugar islands.
The strategy sets agreed rules for making decisions about the amount of sea cucumbers that can be collected each season, and what data are needed to decide whether fishing can be expanded. It offers a pathway to a steady and reliable livelihood, founded on a shared approach to sustainable management. This includes acknowledgement of cultural laws for individual nation groups from different islands.
Opportunity and challenge
Sea cucumbers can be a vital resource for remote, island communities because they are relatively easy to collect, and simple to process and store. The dried sea cucumber product, called bêche-de-mer, is a luxury food and medicine in several Asian countries.
The commercial Torres Strait Beche-de-mer Fishery has been operating for more than a century and is concentrated around the eastern islands of Mer, Ugar, Erub, Poruma and Masig. Only Torres Strait Traditional Inhabitants can participate, and some 170 licence holders share the challenge of safeguarding the harvest.
As well as being slow moving, sea cucumbers are slow to grow and reproduce, so their populations can be easily overfished. High-value species are in trouble throughout the Pacific, and several are subject to international conservation measures. The Black teatfish is categorised as Endangered on the International Union for Conservation of Nature Red List, and Black teatfish and White teatfish are listed under the Convention on the International Trade of Endangered Species (CITES). The CITES listing means these species can be legally exported only by fisheries that can demonstrate sustainable management.
Fishing for Black teatfish was prohibited in the Torres Strait in 2003, and CSIRO surveys have been monitoring their gradual recovery.
Partners in science and management
Traditional Inhabitant and fishery licence holder Mike Passi works with other Mer (Murray) Islanders in diving for and processing sea cucumbers, and distributing beche-de-mer to local seafood buyers. He is also a member of the Torres Strait Hand Collectables Working Group, which plays a role in fishery management.
“Our fisheries, whether they be crayfish, finfish or sea cucumber are our livelihood within the Torres Strait Islands,” Mr Passi says. “We depend on them as our main food source and for economic growth, and have traditional and cultural ties to them from generations past until today.
“We face challenges that include overfishing and climate change, so it is important that our fishing industry works in partnership with government agencies to develop sustainable management for future generations. Working with scientists is also important so we can combine local traditional knowledge with science in better management practices.”
CSIRO marine ecologist Nicole Murphy has been working with the fishery for 15 years. She says the harvest strategy and successful Black teatfish trial demonstrate how far working together on the fishery has come.
“The success of the trial was a very important outcome for Traditional Owners,” Dr Murphy says. “There are very few examples of sea cucumber species elsewhere in the world recovering from being overfished. Previous trial openings in the Torres Strait had failed due to reporting problems, and managers and fishers had postponed another attempt until the fishery had improved its capacity for data collection.
“This time everything worked perfectly. After five years of development, all the systems were in place to ensure effective reporting of quality data. This has involved developing forms and filling in the right information including total catches and correct species identification, alongside real-time electronic monitoring.”
Building skills and understanding
To build their skills in fishery and environmental data collection, Traditional Owners from Thursday, Erub, Yam and Poruma islands have joined CSIRO scientists for hands on training workshops, field surveys and experimental fishing trials at Warrior Reef.
“We talk about survey methods, swim transects together, collect, measure and weigh sea cucumbers and work through data sheets.” Dr Murphy says.
“Our 2019/20 survey indicated Black teatfish numbers were rising, which is also what the Islanders were seeing. This meant that under the harvest strategy the fishery could be opened."
The survey also made use of a remotely controlled underwater video camera that offered a first look at the sea cucumbers in deeper waters, beyond the reach of survey scuba divers.
“It was so exciting to see species such as the high value White teatfish in deeper waters,” Dr Murphy says. “We also saw lots of seagrass and coral deeper than expected. This deeper habitat is important as it provides natural protection for sea cucumbers from free-diving (the fishers free-dive to 20 m). It may also provide important refuge from climate change and other environmental pressures in the future.”
Learning the same language
Dr Murphy says that learning how to communicate effectively has been a steep learning curve for her. Working with fishers to develop a species identification guide as the basis for accurate catch reporting held plenty of challenges.
“Sea cucumber species can be hard to tell apart,’ she says. “Some Blackfish you can only identify by the shape of their anal teeth! I’ve had to put myself in the seat of the fisher and keep changing tack, to find the best ways of exchanging information.
“I was really proud that we were able to include Erub-Mer language alongside English for each species in the ID guide, and there have been other great instances of weaving together our different perspectives.
“I was also asked to include ecological information, and ‘spawning season wheels’ for each species. The Islanders agreed not to collect Prickly redfish during the breeding season, and to avoid sea country where they know the young ones are. This approach can follow a rotational pattern that rests fishing areas that have ‘baby grounds’.
“The Islanders have a phenomenal understanding of their fisheries and what they fish, and it’s really great to see how that is being incorporated into their fishing.”
Future collaboration
Dr Murphy says there is a real trust now between the scientists and fishers, and this has become a foundation for expanding the collaboration.
“After attending our workshops, a group of Torres Strait Islanders came to Brisbane where we spent time talking through the science. We also toured and discussed the CSIRO aquaculture facility at Bribie Island.
“A Traditional Owner from Ugar was inspired to develop a sea cucumber aquaculture project. We are working closely on this, and there is support from Queensland Fisheries. There is potential to bring the concept and innovation to the rest of the Torres Strait. It’s been a really nice outcome, on top of getting the harvest strategy endorsed.
“Another group of Islanders just completed a visit to our lab in May. We’re also trying to organise for some of the Islanders to present at a fisheries conference, a first for Torres Strait. This will have terrific flow on benefits for communities.
“Working one on one in this way helps the Islanders to see that we want the best for the fishery. We want to help them make sure the fishery will still be there in 20 years’ time, for the next generation of fishers.”
Fast facts
- Sea cucumbers 'clean' vast amounts of sand, filtering organic material, recycling nutrients and delivering oxygen deep into the sediments.
- There are more than 1000 sea cucumber species and they range in length from 1 cm to 5 m.
- Sea cucumbers are found in all oceans of the world, to depths of 2000 m.
- When present in healthy numbers, sea cucumbers potentially buffer coral reef ecosystems against the effects of climate change, including ocean acidification.
- Some sea cucumbers need to be harvested carefully or they will become stressed and expel their intestines.
- Nine species of fish are known to find refuge inside a sea cucumber, mainly in the digestive tract. Some even use this space as part of their life-cycle.
This research is co-funded by CSIRO and the Australian Fisheries Management Authority, with surveys co-funded by the Torres Strait Regional Authority.