By: Azman Zakaria
SERDANG: A species of oyster, the only one found in the world and at the estuary of the Muar River in Johor, has been confirmed as a new species and named Crassostrea (Magallana) saidii.
The research collaboration between Universiti Putra Malaysia (UPM) and Queen's University Belfast confirmed that the species is not found in other parts of the world.
The species is known as the ‘white oyster’ among locals and fishermen because of its creamy white meat and high quality.
It is more popular with oyster enthusiasts than the Crasssotrea belcheri (Axe Oyster) species which can also be found at the estuary of the Muar River. The axe oyster species has a broad shell while the meat is grey, brown.
The researcher, Dr. Nur Leena Wong, from the International Institute of Aquaculture and Aquatic Sciences (I-AQUAS), Universiti Putra Malaysia (UPM), said the Crassostrea (Magallana) saidii specimen identified by the local fisherman was confirmed through DNA testing.
The species caught the attention of Dr. Nur Leena when a resident of Muar, Md Saidi Mohamed, contacted UPM in 2017 about the problem of the declining oyster population at the estuary of the Muar River.
She said that as a result of Md Saidi's efforts in preserving the natural heritage, the UPM team was able to understand the biology and ecology of the unique species in more depth.
“Although the oyster species are difficult to identify through external morphology, experienced local oyster divers can distinguish them.
“I am impressed with the accuracy of oyster divers in distinguishing the oyster species. The specimen identified by the local fishermen was confirmed through DNA testing, thus proving the importance of knowledge and expertise possessed by locals that lead to scientific findings," she said.
According to her, the unique method of ‘oyster diving’ to harvest oysters in the Muar River was recorded in the history and journals of a British Captain as early as 1858, and the method is still practised to this day. Bottom river oyster farming at the estuary of the Muar River is a famous heritage.
She said a 20 foot (6.1 meter) long mangrove wooden pole would be piled into the riverbed next to the boat, and divers would dive down adjacent to the wood and pick up oysters at the riverbed by hand.
According to her, white oysters or premium oysters were once used as a delicacy for the royal families as well as the senior officials, and then they were exported to the market in Singapore in the early 1990s.
Dr. Nur Leena, who is also Senior Lecturer at the Department of Aquaculture, Faculty of Agriculture, UPM, and Head of the Museum and Herbarium Unit, said the oyster was named Crassostrea (Magallana) saidii in recognition of Md Saidi's efforts to promote research and conservation of that oyster species.
She said the joint research by her (Dr. Nur Leena) and fellow researcher from Queen’s University Belfast, Dr Julia Sigwart, commenced with sample collection in 2017 before studying reproductive cycle biology in 2018 and 2019.
She said they collected and compared data with collections of oyster related data found in museums in the United Kingdom as well as species found in Asia and found no DNA records similar to white oysters at the estuary of the Muar River.
She said they were surprised that after more than 160 years of the oyster being known and harvested commercially at the estuary of the Muar River, it still had no scientific name.
Thus, they sent the research paper of the study’s findings last year to the German-based journal, Marine Biodiversity. On October 12, 2021, the scientific name Crassostrea (Magallana) saidii for the oyster was acknowledged.
Dr. Nur Leena said the focus of the research now is on the seeding of oysters through the aquaculture approach to reproduce them.
She said studies were also conducted to identify the most suitable water quality and salinity rate of the water for the breeding of Crassostrea (Magallana) saidii.
According to her, at present, it only lives in the estuary of Sungai Muar with a water salinity range of 8 to 25 PPT, and it cannot live in seawater.
"The conservation of this small population of oysters is essential to ensure its sustainability," she said. - UPM
Date of Input: 12/11/2021 | Updated: 12/11/2021 | hairul_nizam
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