Bathynomus vaderi, a newly discovered giant isopod in Vietnam, is now a popular delicacy and highlights the urgent need to study and sustainably manage deep-sea ecosystems.
Giant isopods of the genus Bathynomus, which can grow over 30 cm in length, are commonly known in Vietnam as bọ biển, or “sea bugs.” For the first time, a species from this genus has been identified in Vietnamese waters and named Bathynomus vaderi. The species name vaderi was inspired by the shape of its head, which closely resembles the iconic helmet of Darth Vader, the legendary Sith Lord from Star Wars.
Bathynomus vaderi is part of the “supergiant” group of isopods, reaching up to 32.5 cm in length and weighing more than a kilogram. Currently, this species has been found only near Vietnam’s Spratly Islands. However, ongoing research may reveal its presence in other areas of the South China Sea.
Giant isopods like Bathynomus vaderi have become an expensive delicacy in Vietnam. Until 2017, local fishermen only sold them as a bycatch product for low prices, but in recent years the media has drawn public attention to this unusual seafood. Some go as far as claiming it’s more delicious than lobster, the “king of seafood”.
These animals have been commercially fished by trawlers operating in various deep-water parts of Biển Đông ( East Sea, Vietnamese part of the South China Sea) and offshore of provinces in south-central coastal of Vietnam. Over the last five years, it has become common to see them sold alive in some seafood markets in Hanoi, Hồ Chí Minh City, and Đà Nẵng City.
Some outlets and restaurants even advertise the sale of these “sea bugs” online on various social media platforms, including how best to cook them!
Scientific Identification and Research
In March 2022, staff from Hanoi University purchased four giant isopod individuals from Quy Nhơn City and sent two of them to Peter Ng from the Lee Kong Chian Natural History Museum in the National University of Singapore for identification. Peter Ng has a very active crustacean laboratory in Singapore and has worked on the deep-sea fauna from many parts of Asia.
He subsequently co-opted Conni M. Sidabalok from the National Research and Innovation Agency Indonesia, who had described Bathynomus from southern Java with him. Together with Nguyen Thanh Son from the Vietnam National University, who is the resident crustacean researcher there, they studied the specimens. In early 2023, they realised they had specimens of a so far undescribed species. Now, they have published their findings in the open-access journal ZooKeys.
There is an urgent need to better understand our deep-sea biodiversity as humans increasingly endeavor to exploit this habitat for fisheries, oil and gas, and even minerals. The sustainable fishery of giant isopods just adds to the many challenges we face. And the first step is to know what lives there.
Reference: “A new species of supergiant Bathynomus A. Milne-Edwards, 1879 (Crustacea, Isopoda, Cirolanidae) from Vietnam, with notes on the taxonomy of Bathynomus jamesi Kou, Chen & Li, 2017” by Peter K. L. Ng, Conni M. Sidabalok and Thanh Son Nguyen, 14 January 2025, ZooKeys.
