What’s Happening?
New research has raised concerns about fishing pressure on endangered black teatfish. Scientists found the sea cucumbers can live for more than 100 years.
Researchers compared DNA samples from a Great Barrier Reef Marine Park no-take zone with samples from the same location 24 years later. The findings suggest black teatfish populations recover from harvesting much more slowly than previously thought.
Why It Matters
Australian Institute of Marine Science Senior Principal Research Scientist Dr Sven Uthicke said the findings could affect commercial fishery catch limits.
Current fisheries management approaches assume tropical sea cucumbers can replace harvested animals faster than the new research indicates.
“These findings suggest black teatfish populations recover much more slowly from fishing pressure than previously assumed.” Dr Uthicke said harvesting practices need to reflect the species’ slow recovery. “Harvesting needs to be a lot more conservative than it currently is if we are to avoid a possible extinction and preserve their important ecological functions.”
Local Impact
Black teatfish live throughout the Great Barrier Reef, and their distribution extends across to Western Australia.
Sea cucumbers play an important role in tropical marine ecosystems. They recycle nutrients on the ocean floor and mix sediment. Recent studies cited by AIMS also show healthy sea cucumber populations can enhance coral health.
By The Numbers
- 60% of the sampled animals, or 33 individuals, matched black teatfish sampled at the same location in 2000.
- More than 100 years is the estimated lifespan of some black teatfish, according to modelling used in the study.
- More than AU$400 per kg is the price black teatfish can fetch in Hong Kong.
Zoom In
Researchers took small biopsies from the animals and then returned them to their collection locations. They used modelling to estimate the animals’ lifespan.
Black teatfish were commonly thought to live for around 10 years. However, the study estimated their average lifespan at 24 to 27 years. Some can live for more than 100 years.
Many recaptured animals grew very little during the 24-year period, while some became smaller. Dr Uthicke said the results showed extreme longevity and very low natural death rates.
“We collected 55 animals to sample and thought if we find three that were the same individuals as 24 years ago, that would be amazing,” he said. “In fact, we found 60% (33) were the same as those sampled in 2000, and that really was a surprise.”
Zoom Out
Fishers harvest black teatfish commercially in Australia, the Pacific Islands and Southeast Asia. AIMS said overfishing has depleted wild stocks, and the animals are now seldom seen in Asian markets.
The IUCN Red List classifies black teatfish as Endangered. The species also appears on Appendix 2 of the Convention on International Trade in Endangered Species.
University of Sydney Professor of Marine Biology Dr Maria Byrne said black teatfish were in a perilous state of conservation globally.
“The results of this study are a wake-up call to urgently increase their protection,” she said. Southern Cross University Marine Science and Management Professor Steven Purcell also pointed to experiences elsewhere in the region.
“Pacific Island fishers say this species is now rarely seen on their reefs, and Australia should take heed to avoid overfishing this resource too,” he said.
What To Look For Next?
Researchers are calling for fisheries managers to reassess current approaches because of the species’ longevity and slow recovery.
The Australian Institute of Marine Science led the research with the University of Sydney and Southern Cross University. The findings support better harvest planning and more conservative fishing practices.
