Biodiversity Data Journal : Taxonomy & Inventories
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Taxonomy & Inventories
Freshwater fishes (Actinopterygii) of Kenyir Reservoir, Peninsular Malaysia: Updated checklist, taxonomic concerns and alien species
expand article infoMohamad Aqmal-Naser‡, Norsyafira Anis Ali§, Nur Ummiliani Azmi§, Muhammad Fahmi-Ahmad§, Syed Ahmad Rizal§, Amirrudin B. Ahmad§,‡
‡ Terrestrial Ecology, Biodiversity and Aquatic Research (TEBAR), Institute of Tropical Biodiversity and Sustainable Management, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
§ Biodiversity and Ecology Research (BERes), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
Corresponding author: Amirrudin B. Ahmad (amirrudin@umt.edu.my)
Academic editor: Tihomir Stefanov
Received: 10 Jan 2023 | Accepted: 21 Apr 2023 | Published: 03 Jul 2023
© 2023 Mohamad Aqmal-Naser, Norsyafira Ali, Nur Azmi, Muhammad Fahmi-Ahmad, Syed Rizal, Amirrudin Ahmad
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Aqmal-Naser M, Ali NA, Azmi NU, Fahmi-Ahmad M, Rizal SA, Ahmad AB (2023) Freshwater fishes (Actinopterygii) of Kenyir Reservoir, Peninsular Malaysia: Updated checklist, taxonomic concerns and alien species. Biodiversity Data Journal 11: e100337. https://doi.org/10.3897/BDJ.11.e100337
 Open Access

Abstract

Background

A total of 87 freshwater fish species from 30 families were recorded from the Kenyir Reservoir, Peninsular Malaysia, where 75 are native and 12 are introduced species. Few species still have unstable taxonomy identities which urge further studies. Most of the species were categorised as Least Concern (LC) and two were threatened species; Endangered and Critically Endangered (EN and CR). One introduced species, Gambusia affinis is widespread in the human-associated area, while other introduced fish species can be considered low in numbers.

New information

Twenty five fish species are recorded for the first time in the Kenyir Reservoir.

Keywords

biodiversity, conservation, impoundment, native species, Southeast Asia

Introduction

Reservoirs have generated high economic impact via inland fisheries, especially in the Asian region (Tessier et al. 2016). The number of reservoirs is also expected to increase due to economic development, climate change and human population (Zarfl et al. 2014). This has led to the fragmentation of the major rivers worldwide because of dam construction (Santos et al. 2013). The concern arises whether this fragmentation will be affecting the aquatic ecosystems at temporal and permanent spatial isolation.

Peninsular Malaysia has more than 70 reservoirs used for hydropower and agriculture purposes (Syuhada et al. 2018). One of them is Kenyir Reservoir, formed by damming the Terengganu River from 1978 until its maximum water capacity in 1985. Cramphorn (1983) had studied fish community of the Terengganu River, before the dam was wholly inundated in 1985. Since then, several researchers have conducted several studies to document the fish species recorded in this reservoir (post-inundation) (Ambak and Jalal 1998, Amirrudin et al. 2002, Kamaruddin et al. 2011). As the taxonomic revision and studies on fish advanced, many scientific names have been synonymised which need the latest update and additional information. Apart from that, some species are rarely been recorded and sometimes recorded only once or twice, for the last 40 years.

In this article, we gathered the previously-published data and our current data to review and improve the information on the fish species richness in the Kenyir Reservoir, coupled with some findings on the taxonomic ambiguity, alien invasive species (AIS) and some new records of the fish fauna. This study is essential and aligns with Malaysian Sustainable Development Goal 15 (SDG) which aims to conserve and restore the terrestrial and freshwater ecosystem, as well as to prevent invasive alien species in the water ecosystems.

Materials and methods

Study area

Kenyir is the largest freshwater reservoir in Peninsular Malaysia with approximately 260,000 hectares of catchment area (Ambak and Jalal 1998), located on the east coast of Peninsular Malaysia (5°05'20.1"N 102°43'26.5"E) in the Terengganu State (Fig. 1). There were numerous headwater streams with rocky and sandy habitats and more than ten large rivers flowing into Kenyir Reservoir (Ambak and Jalal 2006). The Reservoir comprises of 52.83% forest cover and the other 34.23% is a multitype land-use area (Kamarudin et al. 2018). It experiences northeast monsoon from November until February annually.

Figure 1.  

The location of Kenyir Reservoir on the eastern part of Peninsular Malaysia within the red square (left). Streams and rivers sampled haphazardly in 2008, 2013, 2017, 2018, 2019 and 2020 are represented by the red circles (primary data).

Historical data

The previous checklists on fishes in Kenyir Reservoir were reviewed and all the synonyms and misidentifications were corrected following Zakaria-Ismail et al. (2019) and Fricke et al. (2021). The list includes information on fish reported by Cramphorn (1983), the Department of Fisheries (1994), the Department of Fisheries (1995), Yusoff et al. (1995), Zakaria et al. (1997), Ambak and Jalal (1998), Amirrudin et al. (2002), Shahid et al. (2010) and Kamaruddin et al. (2011).

Sampling

All sampling events were carried out with the permission by the Department of Fisheries, Terengganu. An electrofishing technique using backpack electro-shocker model LR-24 (Smith Roots Inc.) was used following Aqmal-Naser et al. (in press). The ethical procedure for fish collection follows guideline by Bennett et al. (2016). The data including unpublished data are owned by the corresponding author, collected in 2008, 2013, 2017, 2018, 2019 and 2020. Three units of gill nets (mesh sizes of 1.0, 2.0 and 4.0 inches; 2.5, 5.1 and 10.2 centimeters) were used to collect pelagic fish species and scoop nets were also used to collect small fish-like loaches. Interviews with the boat operators and local fishermen have also been conducted regarding the species that can be found in Kenyir Reservoir (personal communication).

Species identification

The fish were identified in situ when possible based on Zakaria-Ismail et al. (2019). The voucher specimens were fixed in 10% formalin and left for two weeks before rinsing and transferred into 70% alcohol for long-term storage. The preserved specimens were kept in Universiti Malaysia Terengganu Zoological Collection (UMTZC). Species validity and the spelling of the scientific names follow the California Academy of Science’s Catalogue of Fishes (Fricke et al. 2021).

List of freshwater fish from Kenyir Reservoir

Scleropages formosus (Müller and Schlegel, 1840)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Cramphorn. J. (1983). Department of Fisheries (1994; 1995), Ambak. M.A., Jalal. K.C.A. (1998)
Native status: 

Native species.

Conservation status: 
EN

Chitala cf. lopis (Bleeker, 1851)

Material   Download as CSV 
  1. locality:
    Cacing River
    ; samplingProtocol:
    Gill net (specimen was not taken), Literature; Cramphorn. J. (1983). Department of Fisheries (1994), Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017
Native status: 

Native species

Conservation status: 
NE
Notes: 

The distribution of Chitala lopis is restricted to Java, Indonesia (Kottelat and Widjanarti 2005), which raises questions about the current taxonomic identity of other identified Chitala lopis outside its native distribution ranges. The species is declared extinct in Java (Ng 2020) as it was not recorded for the past 100 years. The individuals resembling Chitala borneensis were also recorded from Peninsular Malaysia in the Endau and Terengganu River (Mohd Ilham Norhakim Lokman, pers. comm.). The identity of Chitala spp. from Peninsular Malaysia needs further taxonomic clarification based on morphology and molecular works (Fig. 2).

Figure 2.  

Chitala cf. lopis from Kenyir Reservoir.

Notopterus notopterus (Pallas, 1769)

Material   Download as CSV 
  1. locality:
    Cacing River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1995), Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7738
Native status: 

Native species.

Conservation status: 

LC

Clupeichthys sp.

Material   Download as CSV 
  1. locality:
    Cacing River, Lepar River
    ; samplingProtocol:
    Literature; Department of Fisheries (1994), Aqmal-Naser et al. (2021), Scoop net
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7849
Native status: 

Native species

Conservation status: 

NE

Notes: 

Clupeichthys aesarnensis is restricted to the river systems in Cambodia, Laos, Thailand and Vietnam (Di Dario 2018). The distribution of freshwater clupeid in Peninsular Malaysia, Clupeichthys perakensis is restricted to the Perak River system (Ng et al. 2019). Hence, the species recorded in this study (identified as Clupeichthys sp.) (Fig. 3) are neither of these species and need further study on their taxonomic identities (Aqmal-Naser et al. 2021).

Figure 3.  

Clupeichthys sp. fresh specimen (top) and preserved specimen (bottom).

Acantopsis dialuzona van Hasselt, 1823

Material   Download as CSV 
  1. locality:
    Cacing River, Lepar River, Lawit River, Siput River, Saok River, Ikan River, Cicir River
    ; samplingProtocol:
    Electrofishing, Literature; Zakaria. M.Z., Yaacob. K.K.K., Noor. J.M. (1997), Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2018, 2019, 2021
    ; catalogNumber:
    UMTZC7633
Native status: 

Native species.

Conservation status: 
LC

Acanthopsoides molobrion Siebert, 1991

Material   Download as CSV 
  1. locality:
    Kiang River, Mandak River, Cicir River, Perepek River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7676
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 4).

Figure 4.  

Acanthopsoides molobrion.

Pangio doriae (Perugia, 1892)

Material   Download as CSV 
  1. locality:
    Perepek River
    ; samplingProtocol:
    Scoop net
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7974
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 5).

Figure 5.  

Pangio doriae.

Pangio filinaris Kottelat and Lim, 1993

Material   Download as CSV 
  1. locality:
    Siput River, Kiang River, Lawit River
    ; samplingProtocol:
    Electrofishing, Literature; Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7011
Native status: 

Native species.

Conservation status: 

LC

Pangio semicincta (Fraser-Brunner, 1940)

Material   Download as CSV 
  1. samplingProtocol:
    Literature
    ; recordedBy:
    Ambak. M.A., Jalal. K.C.A. (1998)
Native status: 

Native species.

Conservation status: 
LC

Balitoropsis zollingeri (Bleeker, 1853)

Material   Download as CSV 
  1. locality:
    Ikan River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7689
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 6).

Figure 6.  

Balitoropsis zollingeri.

Homaloptera ogilviei Alfred, 1967

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2019
    ; catalogNumber:
    UMTZC7641
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 7).

Figure 7.  

Homaloptera ogilviei.

Homalopteroides tweediei (Herre, 1940)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
Native status: 

Native species.

Conservation status: 
LC

Pseudohomaloptera leonardi (Hora, 1941)

Material   Download as CSV 
  1. locality:
    Buluh Nipis River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2020
    ; catalogNumber:
    UMTZC8681
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 8).

Figure 8.  

Pseudohomaloptera leonardi.

Nemacheilus masyae Smith, 1933

Material   Download as CSV 
  1. locality:
    Cacing River, Lepar River, Lawit River, Siput River, Kiang River, Cicir River, Perepek River, Cenana River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983), Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7681
Native status: 

Native species.

Conservation status: 
LC

Barbichthys laevis (Valenciennes, 1842)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995), Zakaria. M.Z., Yaacob. K.K.K., Noor. J.M. (1997)
Native status: 

Native species.

Conservation status: 
LC

Barbodes rhombeus (Kottelat, 2000)

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Literature; Cramphorn. J. (1983), Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017
    ; catalogNumber:
    UMTZC7646
Native status: 

Native species.

Conservation status: 
LC

Barbodes sellifer Kottelat and Lim, 2021

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7691
Native status: 

Native species.

Conservation status: 
LC

Barbodes lateristriga (Valenciennes, 1842)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Cramphorn. J. (1983), Ambak. M.A., Jalal. K.C.A (1998).
Native status: 

Native species.

Conservation status: 
LC

Barbonymus gonionotus (Bleeker, 1849)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z. & Ambak. M.A. (1995)
Native status: 

Introduced species. The species was introduced into Kenyir Reservoir through the restocking programme in 1988-1990 by the Department of Fisheries.

Barbonymus schwanefeldii (Bleeker, 1854)

Material   Download as CSV 
  1. locality:
    Lawit River, Perepek River, Lepar River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983), Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7661
Native status: 

Native species.

Conservation status: 
LC

Crossocheilus oblongus Kuhl and van Hasselt, 1823

Material   Download as CSV 
  1. locality:
    Perepek River, Ikan River, Kiang River, Siput River, Cenana River, Pengait River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983) Department of Fisheries (1994), Yusoff. F.M., Zaidi. MZ., Ambak. M.A. (1995)
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7682
Native status: 

Native species.

Conservation status: 
LC

Cyclocheilichthys apogon (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Kiang River, Lawit River, Mandak River, Cicir River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1994), Kamaruddin. I.S., Mustafa-Kamal. A.S., Christianus. A., Daud. A., Yu-Abit. L. (2011)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7674
Native status: 

Native species.

Conservation status: 
LC

Cyclocheilichthys armatus (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Cacing River, Cicir River
    ; samplingProtocol:
    Electrofishing, Gills net
    ; year:
    2019, 2018, 2020
    ; catalogNumber:
    UMTZC8678
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 9).

Figure 9.  

Cyclocheilichthys armatus.

Cyprinus carpio Linnaeus, 1758

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z. & Ambak. M.A. (1995)
Native status: 

Introduced species. The species was introduced into Kenyir Reservoir through the restocking programme in 1988-1990 by the Department of Fisheries.

Ceratogarra cambodgiensis (Tirant, 1884)

Material   Download as CSV 
  1. locality:
    Saok River, Ikan River, Siput River
    ; samplingProtocol:
    Electrofishing, Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7706
Native status: 

Native species.

Conservation status: 
LC

Hampala macrolepidota Kuhl and van Hasselt, 1823

Material   Download as CSV 
  1. locality:
    Saok River, Cicir River, Siput River, Cenana River, Pengait River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983). Department of Fisheries (1995), Zakaria. M.Z., Yaacob. K.K.K., Noor. J.M. (1997)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7844
Native status: 

Native species.

Conservation status: 
LC

Labiobarbus leptocheilus (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Lepar River, Kiang River, Mandak River, Siput River, Lawit River, Cicir River, Perepek River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M. A., Jalal. K. C. A. (1998), Kamaruddin. I.S., Mustafa Kamal. A.S., Christianus. A., Daud. A., Yu Abit. L. (2011)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7638
Native status: 

Native species.

Conservation status: 
LC

Lobocheilos rhabdoura (Fowler, 1934)

Material   Download as CSV 
  1. locality:
    Cacing River, Saok River, Perepek River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983), Yusoff. F. M., Zaidi. M. Z., Ambak. M. A. (1995)
    ; catalogNumber:
    UMTZC7766
Native status: 

Native species.

Conservation status: 
LC

Mystacoleucus chilopterus Fowler, 1935

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Cramphorn. J. (1983)
Native status: 

Native species.

Conservation status: 
LC

Mystacoleucus obtusirostris (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Siput River, Kiang River, Lepar River, Saok River, Lawit River, Cicir River, Perepek River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983), Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7778
Native status: 

Native species.

Conservation status: 
LC

Neolissochilus soroides (Duncker, 1904)

Material   Download as CSV 
  1. locality:
    Saok River, Siput River, Pengait River, Cenana River
    ; samplingProtocol:
    Electrofishing, Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995), Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC8679
Native status: 

Native species.

Conservation status: 
LC

Osteochilus scapularis Fowler, 1939

Material   Download as CSV 
  1. locality:
    Saok River, Ikan River, Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC8697
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 10).

Figure 10.  

Osteochilus scapularis.

Osteochilus vittatus (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Cacing River, Lepar River, Lawit River, Siput River, Kiang River, Saok River, Cicir River, Perepek River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Yusoff. F. M., Zaidi. M. Z., Ambak. M. A. (1995)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7650
Native status: 

Native species.

Conservation status: 

LC

Osteochilus waandersii (Bleeker, 1853)

Material   Download as CSV 
  1. locality:
    Lepar River, Ikan River, Siput River, Saok River, Cacing River, Lawit River, Cicir River, Perepek River, Kiang River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1994), Amirrudin. A., Siti Azizah. M.N., Yusri. Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7663
Native status: 

Native species.

Conservation status: 
LC

Poropuntius normani Smith, 1931

Material   Download as CSV 
  1. locality:
    Lepar River, Kiang River, Ikan River, Saok River, Siput River, Pengait River, Cenana River
    ; samplingProtocol:
    Electrofishing, Literature; Zakaria. M.Z., Yaacob. K.K.K., Noor. J.M. (1997)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7607
Native status: 

Native species.

Conservation status: 
LC

Probarbus jullieni Sauvage, 1880

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Kamaruddin. M.K.A., Mustafa-Kamal, A.S., Christianus. A., Daud. A., Abit. L.Y. (2011); Personal communication; Syed Muhammad Fuaad (2019)
Native status: 

Introduced species. The species was introduced into Kenyir Reservoir by the Department of Fisheries to increase the fisheries resources.

Conservation status: 
CR

Puntioplites bulu (Bleeker, 1851)

Material   Download as CSV 
  1. locality:
    Mandak River
    ; samplingProtocol:
    Gill net
    ; year:
    2020
    ; catalogNumber:
    UMTZC8682
    ; recordedBy:
    Aqmal-Naser. M., Ahmad. A.B. (unpublished)
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 11).

Figure 11.  

Puntioplites bulu.

Tor tambra (Valenciennes, 1842)

Material   Download as CSV 
  1. locality:
    Kiang River, Cenana River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983); Department of Fisheries (1995)
    ; year:
    2019
    ; recordedBy:
    Ambak. M.A., Jalal. K.C.A.
Native status: 

Native species.

Conservation status: 
DD

Esomus metallicus Ahl, 1924

Material   Download as CSV 
  1. locality:
    Kiang River
    ; samplingProtocol:
    Electrofishing, Scoop net
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7131
Native status: 

Introduced species.

Notes: 

New record to Kenyir Reservoir (Fig. 12). A common fish that thrives well in flood-plain or man-made habitats (Aqmal-Naser and Ahmad 2018a, Aqmal-Naser and Ahmad 2018b). Previously, this species is known as a native species in Peninsular Malaysia (Mohsin and Ambak 1983). However, it has been treated as an introduced species by Khan et al. (1996) and all recent studies without any justification. The identity of this species will soon be determined and the article on its status is being prepared. Hence, at the moment, we regarded this species as introduced species.

Figure 12.  

Esomus metallicus.

Raiamas guttatus (Day, 1870)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Ambak. M.A., Jalal. K.C.A (1998)
Native status: 

Native species.

Conservation status: 
LC

Rasbora myersi Brittan, 1954

Material   Download as CSV 
  1. locality:
    Lepar River, Saok River, Kiang River, Lawit River, Cicir River, Perepek River, Mandak River, Siput River
    ; samplingProtocol:
    Electrofishing, Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7635
Native status: 
Native species
Conservation status: 
LC

Rasbora notura Kottelat, 2005

Material   Download as CSV 
  1. locality:
    Ikan River
    ; samplingProtocol:
    Electrofishing, Literature; Amirrudin. A., Siti Azizah. M.N., Yusr.i Y., Norainy. M.H., Mohd Asnizam. A., Ali. A.B. (2002)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7675
Native status: 

Native species.

Conservation status: 

LC

Rasbora sp. 1

Material   Download as CSV 
  1. locality:
    Ikan River, Kiang River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2019, 2019
    ; catalogNumber:
    UMTZC7675
Native status: 

Native species.

Conservation status: 
NE
Notes: 

New record to Kenyir Reservoir. The Rasbora sp. 1 in this study has a thicker and anteriorly tapered mid-lateral stripe and the subdorsal blotch is absent, which did not fit into the description of Rasbora notura by Kottelat (2005) (Fig. 13).

Figure 13.  

Rasbora notura (A) and Rasbora sp. 1 (B). SDB: Subdorsal blotch.

Rasbora paucisqualis Ahl, 1935

Material   Download as CSV 
  1. locality:
    Papan River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2020
    ; catalogNumber:
    UMTZC8683
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 14).

Figure 14.  

Rasbora paucisqualis.

Rasbora paviana Tirant, 1885

Material   Download as CSV 
  1. locality:
    Ikan River, Saok River, Kiang River, Lawit River, Siput River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1994)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7647
Native status: 

Native species.

Conservation status: 
LC

Rasbora sp. 2

Material   Download as CSV 
  1. locality:
    Ikan River, Papan River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2018, 2019, 2020
    ; catalogNumber:
    UMTZC7648
Native status: 

Native species.

Conservation status: 
NE
Notes: 

New record to Kenyir Reservoir. There were two forms of Rasbora sp. collected in this study. A more common form has an incomplete mid-lateral stripe (not reaching gill opening) which is different from the real Rasbora paviana (Fig. 15A). It has the mid-lateral line that begins to diffuse at the mid-section of the body, known as a mid-humeral diffuse patch (MDP) (Lumbantobing 2014) (Fig. 15B). One specimen displayed a unique set of characteristics: high and pointed dorsal fin (vs. rounded), long and, when adpressed, reaching beyond the base of the anal fin (vs. only half); pectoral fin long and overlapping pelvic fin (vs. not reaching the pelvic fin); pelvic fin elongated and reaching half of the dorsal fin base (vs. not overlapping) and possessing diamond-shape caudle peduncle blotch (vs. longitudinally elongated diamond) (Fig. 15C). Due to a lack of specimens, a detailed comparison was not made at this moment.

Figure 15.  

Rasbora paviana (A) and Rasbora sp. 2 (B & C). Mid-humeral diffuse patch (MDP).

Leptobarbus rubripinna (Fowler, 1937)

Material   Download as CSV 
  1. locality:
    Lawit River
    ; samplingProtocol:
    Gill net, Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
    ; year:
    2019
Native status: 

Introduced species. The species was introduced into Kenyir Reservoir through the restocking programme in 1988-1990 by the Department of Fisheries.

Hypophthalmichthys nobilis (Richardson, 1845)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
Native status: 

Introduced species. The species was introduced into Kenyir Reservoir through the restocking programme in 1988-1990 by the Department of Fisheries.

Oxygaster anomalura van Hasselt, 1823

Material   Download as CSV 
  1. locality:
    Cicir River
    ; samplingProtocol:
    Electrofishing, Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
    ; year:
    2019
    ; catalogNumber:
    UMTZC7690
Native status: 

Native species.

Conservation status: 

LC

Piaractus brachypomus (Cuvier, 1818)

Material   Download as CSV 
  1. samplingProtocol:
    Literature
    ; recordedBy:
    Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
Native status: 

Introduced species used for recreational cage culture in Kenyir Reservoir.

Hemibagrus capitulum (Popta, 1906)

Material   Download as CSV 
  1. locality:
    Lepar River, Ikan River, Siput River, Saok River, Cicir River, Cenana River, Pengait River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A (1998)
    ; year:
    2017, 2019, 2020
    ; catalogNumber:
    UMTZC7637
Native status: 

Native species.

Conservation status: 
LC

Hemibagrus gracilis Ng and Ng, 1995

Material   Download as CSV 
  1. locality:
    Siput River, Lepar River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983)
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7631
Native status: 

Native species.

Conservation status: 
LC

Hemibagrus wyckii (Bleeker, 1858)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Cramphorn. J. (1983); Department of Fisheries (1994)
Native status: 

Native species.

Conservation status: 
LC

Mystus castaneus Ng, 2002

Material   Download as CSV 
  1. locality:
    Budu River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2020
    ; catalogNumber:
    UMTZC8684
Native status: 

Native species.

Conservation status: 
LC

Mystus singaringan (Bleeker, 1846)

Material   Download as CSV 
  1. locality:
    Ikan River,
    ; samplingProtocol:
    Electrofishing
    ; year:
    2020
    ; catalogNumber:
    UMTZC8685
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 16).

Figure 16.  

Mystus singaringan.

Amblyceps foratum Ng and Kottelat, 2000

Material   Download as CSV 
  1. locality:
    Kiang River, Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7711
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 17).

Figure 17.  

Amblyceps foratum.

Glyptothorax fuscus Fowler, 1934

Material   Download as CSV 
  1. locality:
    Perepek River, Kiang River, Siput River
    ; samplingProtocol:
    Electrofishing, Literature; Cramphorn. J. (1983)
    ; year:
    2017
    ; catalogNumber:
    UMTZC8687
Native status: 

Native species.

Conservation status: 
LC

Glyptothorax schmidti (Volz, 1904)

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7705
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 18).

Figure 18.  

Glyptothorax schmidti.

Pangasianodon hypophthalmus (Sauvage, 1878)

Material   Download as CSV 
  1. locality:
    Lawit River
    ; samplingProtocol:
    Literature; Shahid. S.M., Fairuz. M.S.M., Jamil. Z.A., Radzali. M.M., Hariz. A.R.M., Fahimee. J.M., Wira. A.B., Zafrul. A.R.M., Hasliana. K. (2010) , Personal communication; Syed Muhammad Fuaad
    ; year:
    2020
Native status: 

Introduced species. The species was introduced through the restocking programme to increase the fisheries resources.

Pangasius nasutus (Bleeker, 1863)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M.A. (1995)
Native status: 

Introduced species used for recreational cage culture in Kenyir Reservoir.

Conservation status: 
LC

Ompok siluroides Lacepède, 1803

Material   Download as CSV 
  1. locality:
    Lawit River, Kiang River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7782
Native status: 
Native species
Conservation status: 
LC

Wallagonia leerii (Bleeker, 1851)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Ambak. M.A., Jalal. K.C.A. (1998)
Native status: 

Native species.

Conservation status: 
LC

Clarias aff. batrachus (Linnaeus, 1758)

Material   Download as CSV 
  1. locality:
    Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1995)
    ; year:
    2019
    ; catalogNumber:
    UMTZC7792
Native status: 

Native species.

Conservation status: 
NE
Notes: 

The distribution of Clarias batrachus is restricted to Java, Indonesia (Ng and Kottelat 2008). The species is widely introduced for cultivation, but originated from an Indochinese subpopulation that may represent undescribed species (Ng and Low 2019). The previously-identified population of C. batrachus in north-eastern India is presently known as Clarias magur. Other populations were known as Clarias aff. batrachus ‘Indochina’ (from Mekong River drainage) and Clarias aff. batrachus ‘Sundaland’ (from the Malay Peninsula and Borneo) (Fig. 19).

Figure 19.  

Clarias aff. batrachus from Kenyir Reservoir.

Clarias leiacanthus Bleeker, 1851

Material   Download as CSV 
  1. locality:
    Ikan River, Kiang River, Lawit River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7750
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 20).

Figure 20.  

Clarias leiacanthus.

Oxyeleotris marmorata (Bleeker, 1852)

Material   Download as CSV 
  1. locality:
    Kiang River, Siput River, Lepar River, Cicir River, Perepek River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7760
Native status: 

Native species.

Conservation status: 
LC

Glossogobius giuris (Hamilton, 1822)

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2019
    ; catalogNumber:
    UMTZC7386
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 21).

Figure 21.  

Glossogobius giuris.

Pseudogobiopsis oligactis (Bleeker, 1875)

Material   Download as CSV 
  1. locality:
    Ikan River, Kiang River, Siput River, Lepar River, Cicir River, Perepek River, Mandak River, Cenana River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7696
Native status: 

Native species.

Conservation status: 
LC

Macrognathus circumcinctus (Hora, 1924)

Material   Download as CSV 
  1. locality:
    Kiang River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC8688
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 22).

Figure 22.  

Macrognathus circumcinctus.

Mastacembelus favus Hora, 1923

Material   Download as CSV 
  1. locality:
    Siput River, Kiang River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2017, 2019
    ; catalogNumber:
    UMTZC7694
Native status: 

Native species.

Conservation status: 
LC

Mastacembelus unicolor Cuvier, 1832

Material   Download as CSV 
  1. locality:
    Kiang River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017
    ; catalogNumber:
    UMTZC8689
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 23).

Figure 23.  

Mastacembelus unicolor.

Monopterus javanensis Lacepède, 1800

Material   Download as CSV 
  1. locality:
    Mandak River, Kiang River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2018, 2019
    ; catalogNumber:
    UMTZC8690
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 24).

Figure 24.  

Monopterus javanensis.

Betta stigmosa Tan and Ng, 2005

Material   Download as CSV 
  1. locality:
    Ikan River
    ; samplingProtocol:
    Electrofishing, Scoop net
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC8691
Native status: 

Native species.

Conservation status: 
DD
Notes: 

New record to Kenyir Reservoir (Fig. 25).

Figure 25.  

Betta stigmosa.

Osphronemus goramy Lacepède, 1801

Material   Download as CSV 
  1. locality:
    Saok River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1994); Ambak. M.A., Jalal. K.C.A. (1998)
    ; year:
    2018, 2019
    ; catalogNumber:
    UMTZC8692
Native status: 

Native species.

Conservation status: 
LC

Trichopodus trichopterus (Pallas, 1770)

Material   Download as CSV 
  1. locality:
    Siput River, Cicir River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2019, 2020
    ; catalogNumber:
    UMTZC7636
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 26).

Figure 26.  

Trichopodus trichopterus.

Trichopsis vittata (Cuvier, 1831)

Material   Download as CSV 
  1. locality:
    Kiang River
    ; samplingProtocol:
    Electrofishing, Scoop net
    ; year:
    2019, 2020
    ; catalogNumber:
    UMTZC8693
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 27).

Figure 27.  

Trichopsis vittata.

Channa limbata (Cuvier, 1831)

Material   Download as CSV 
  1. locality:
    Saok River
    ; samplingProtocol:
    Electrofishing, Scoop net
    ; year:
    2020
    ; catalogNumber:
    UMTZC8694
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 28).

Figure 28.  

Channa limbata.

Channa lucius (Cuvier, 1831)

Material   Download as CSV 
  1. locality:
    Cacing River
    ; samplingProtocol:
    Gill net,
    ; year:
    2014
    ; recordedBy:
    Fahmi-Ahmad. M., Walton. S. (unpublished)
Native status: 

Native species.

Conservation status: 
LC

Channa marulioides (Bleeker, 1851)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Department of Fisheries (1995)
Native status: 

Native species.

Conservation status: 
LC

Channa micropeltes (Cuvier, 1831)

Material   Download as CSV 
  1. locality:
    Cacing River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A (1998)
    ; year:
    2019, 2020
Native status: 

Native species.

Conservation status: 
LC

Channa striata (Bloch, 1793)

Material   Download as CSV 
  1. locality:
    Siput River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A (1998)
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC7654
Native status: 

Native species.

Conservation status: 
LC

Pristolepis grootii (Bleeker, 1852)

Material   Download as CSV 
  1. locality:
    Lepar River, Siput River, Kiang River, Mandak River
    ; samplingProtocol:
    Electrofishing, Literature; Department of Fisheries (1994)
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7695
Native status: 

Native species.

Conservation status: 

LC

Lates calcarifer (Bloch, 1790)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Yusoff. F.M., Zaidi. M.Z., Ambak. M. (1995)
Native status: 

Introduced species for sports fishing in the Kenyir Reservoir.

Oreochromis niloticus (Linnaeus, 1758)

Material   Download as CSV 
  1. samplingProtocol:
    Literature; Department of Fisheries (1995)
Native status: 

Introduced species.

Gambusia affinis (Baird and Girard, 1853)

Material   Download as CSV 
  1. locality:
    Saok River
    ; samplingProtocol:
    Electrofishing,
    ; year:
    2017, 2018, 2019
    ; catalogNumber:
    UMTZC8696
Native status: 

Introduced species. Probably introduced via human-mediated translocation.

Xenentodon canciloides (Bleeker, 1854)

Material   Download as CSV 
  1. locality:
    Cacing River
    ; samplingProtocol:
    Electrofishing, Gills net
    ; year:
    2014
    ; catalogNumber:
    UMTZC7741
Native status: 

Native species.

Conservation status: 
LC
Notes: 

New record to Kenyir Reservoir (Fig. 29).

Figure 29.  

Xenentodon canciloides.

Pao leiurus (Bleeker, 1850)

Material   Download as CSV 
  1. locality:
    Siput River
    ; samplingProtocol:
    Electrofishing, Literature; Ambak. M.A., Jalal. K.C.A (1998)
    ; year:
    2017
    ; catalogNumber:
    UMTZC7716
Native status: 

Native species.

Conservation status: 
LC

Parambassis siamensis (Fowler, 1937)

Material   Download as CSV 
  1. locality:
    Cicir River, Perepek River, Kiang River, Mandak River
    ; samplingProtocol:
    Electrofishing
    ; year:
    2017, 2018, 2019, 2020
    ; catalogNumber:
    UMTZC7785
Native status: 

Native species.

Conservation status: 
LC

Discussion

The species recorded contributed 25.95% of the total 289 freshwater fishes of Peninsular Malaysia (Zakaria-Ismail et al. 2019). We expect more fish species can be recorded by increasing the sampling efforts, since several families and species were already reported within the Terengganu River Basins, such as Balitoridae (Homaloptera parclitella), Nemacheilidae (Nemacheilus selangoricus), Xenocyprididae (Parachela spp.), Bagridae (Leiocassis poeciloptera and Pseudomystus spp.), Syngnathidae (Doryichthys spp.) and Akysidae (Akysis spp. & Acrochordonichthys spp.) (Aqmal-Naser et al. in press), but currently were not recorded in Kenyir Reservoir.

In his study, Cramphorn (1983) recorded the presence of Mystacoleucus chilopterus, but the post-inundation surveys failed to record this species. This species could have been present before, but was diminished or reduced as a result of impoundment or we did not hit the right spot to collect this species. This species is a common species found in the larger rivers, especially in the eastern part of Peninsular Malaysia (Zakaria-Ismail et al. 2019). Other species, such as Barbichtyhs laevis and Wallagonia leerii, were only recorded during the early post-inundation (Yusoff et al. 1995, Ambak and Jalal 1998). It was known that Barbichthys laevis cannot cope with the impoundment (Rainboth 1996), while Wallagonia leerii is a highly migratory species Riede (2004) where the impoundment could have impacted the migratory pathway for these species. Further assessments are needed to confirm the presence of these species through comprehensive field sampling. One species, Scleropages formosus, is now facing the threat for its highly ornamental values.

More studies also are encouraged to be done on other species especially in the Data Deficient category especially Tor tambra (Walton et al. 2016) and Betta stigmosa (Low 2019) for the updated status on their distribution and populations. We also did find any species in the ghost nets in the streams that are vulnerable to migratory fish species especially, cyprinids fish, concurrent with the finding of Aqmal-Naser and Ahmad (2020), which found dead Tor tambra entangled in the ghost net. Nevertheless, it is very difficult to monitor or control the fishing activities in Kenyir Reservoir due to its massive waterbody and limited enforcement.

There were three native species which were introduced for fisheries enrichment (i.e. Pangasius nasutus and Probarbus jullieni) and sports fishing (i.e. Lates calcarifer). Both P. jullieni and Lates calcarifer are thriving well in the lentic ecosystem of Kenyir Reservoir and were collected by the local people for artisanal fisheries but no information regarding Pangasius nasutus till now. The mosquito-fish, Gambusia affinis is the most widespread especially in the human-associated area. It is unknown how this species ended up in Kenyir Reservoir, but probably a result of aquarium dumping, one of the major practices which lead to the alien fish species introduction (Aqmal-Naser and Ahmad 2020). However, other introduced species are rarely seen or collected, which sparks a debate on their ability to survive. For example, the juveniles of Barbonymus gonionotus and Hypopthalmichthys nobilis have been released by the Department of Fisheries (Yusoff et al. (1995), but they have never been reported or collected till the present day. The fish could be present and caught by the local fisherman, but there are no documentation and records.

All six fish species highlighted required taxonomic revision and molecular evidence to elucidate their true taxonomic lineage. The cryptic diversity amongst freshwater fishes, especially from the genus Rasbora, is one of the interesting subjects to begin with. We recommend more studies that integrate both morphology and the molecular aspect to resolve the taxonomic ambiguity of freshwater fishes, generally. The new fish records in Kenyir Reservoir revealed its importance as one of the conservation areas in Peninsular Malaysia. The presence of successful alien fish species like Gambusia affinis which can have negative impacts on the native aquatic fauna should be monitored.

Acknowledgements

We thank Universiti Malaysia Terengganu for the facilities and sampling equipment provided. We thank PERHILITAN, KETENGAH and DOF for the assistance to do research in the Kenyir Reservoir. We thank Mr. Syed Muhammad Fuaad who assisted during the data collection. The first author is sponsored by Biasiswa Universiti Malaysia Terengganu (BUMT). This article is a part of the Ph.D. thesis of the first author.

Author contributions

Aqmal-Naser, A: Data collection, Data curation, Investigation, Methodology, Writing- original draft, editing and final draft. Ali, N. S.: Data collection, Data curation, Investigation. Azmi, N. U.: Data collection, Data curation, Investigation. Fahmi-Ahmad, M.: Data collection, Data curation, Investigation. Rizal, S. A.: Data collection, Investigation, Methodology. Ahmad, A. B.: Conceptualisation, Funding acquisition, Project administration, Data collection, Data curation, Investigation, Methodology, Writing- original draft, editing and final draft.

References

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