Semah predominantly populates Upper Baleh River
Kuching: An indigenous fish in Sarawak, Semah, is found thriving well in the headwaters of Baleh River, deep in the Heart of Borneo (HoB). The yellowish-gold coloured fish dominates the upper Baleh River more than other freshwater fish species from the loach family.
According to Nur Ezaimah Idris, a researcher from University Malaysia Sarawak (UNIMAS), Semah dominates most of the riverine system in upper Baleh, followed by Lelekat, which is also known as the Bornean sucker fish.
“Semah is more easily found in Kian River, a tributary to Baleh River, compared to other tributaries,’’ she said at the recent Heart of Borneo (HoB) Seminar on Scientific Expedition to Upper Baleh.
In Ezaimah’s presentation entitled ‘Fish Fauna of Tributaries of Upper Baleh River, Kapit, Sarawak,’ she said Semah, Tor douronensis accounts for 27.4% of fish individuals sampled, out of 15 species recorded in the study area. Bekut, Parhomaloptera microstoma accounts for 18.4% while Lelekat, Neogastromyzon chini accounts for 10.4% of the sample size.
Ezaimah was one of the 17 researchers from different disciplines who took part in the first scientific expedition to the proposed Upper Baleh National Park in November 2015, and presented the findings at the seminar in Kuching in November 2016.
The scientific expedition was conducted by Forest Department Sarawak (FDS), Sarawak Energy Berhad (SEB), UNIMAS and WWF-Malaysia. Findings from the expedition will be documented in a proceeding book entitled ‘Conserving the Gems of Upper Baleh.’
WWF-Malaysia Freshwater Management and Conservation Officer, Mohd Khairulazman Sulaiman who studied on genetic diversity of Semah in that area, found that the fish has unique genetic trait variation. “Genetic variation is important for species survival as it enables species to react and adapt to any changes in the environment,” he said.
Apart from that, he noticed that Upper Baleh has high level of dissolved oxygen which is important for the growth of Semah fish. He added, “Semah especially in their juvenile period, need at least 7-8 milligram per litre of dissolved oxygen for their metabolic activity,” Only pristine rivers in good forested areas contains high dissolved oxygen concentration, which is ideal for the growth of Semah.
Both researchers agreed that Semah fish is abundant in Kian river compared to other rivers. The Semah documented in the river is also one of the most genetically diverse compared to other tributaries surveyed such as in Ukit, Irak, Penganen, Selentang, Jambu, Tor and Entakun rivers. Kian River is situated south of the Upper Baleh River and is one of the tributaries with the highest fish species found during the expedition.
In the seminar, all researchers expressed that more studies are needed There is little information about the forest conditions prior to logging activities.The first logging activity in Upper Baleh was recorded in the early 1970s and the area has been logged over at least twice in the past.
WWF-Malaysia is working with Forest Department Sarawak and other stakeholders to gather biological data for the proposed Upper Baleh National Park. According to Belinda Lip, WWF-Malaysia, Freshwater and Water Security Manager, findings from the expedition provide important baseline information for the gazettement process and to eventually come up with a good catchment and protected area management plan.
Upper Baleh is also a priority conservation area for WWF-Malaysia as it forms part of a pilot study, which aims at developing a green economy management concept that promotes environmentally-friendly resource use and production within the transboundary HoB Corridor for West Kalimantan and Sarawak.
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