Diversity, extinction, conservation of Malaysian fishes 2010 JFB v76

Journal of Fish Biology (2010) 76, 2009–2066
doi:10.1111/j.1095-8649.2010.02685.x, available online at www.interscience.wiley.com
Diversity, extinction risk and conservation of Malaysian
fishes
V. C. Chong*†‡, P. K. Y. Lee* and C. M. Lau*
*Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia and
†Institute of Ocean and Earth Sciences, University of Malaya, 50603 Kuala
Lumpur, Malaysia
A total of 1951 species of freshwater and marine fishes belonging to 704 genera and 186 families are
recorded in Malaysia. Almost half (48%) are currently threatened to some degree, while nearly one
third (27%) mostly from the marine and coral habitats require urgent scientific studies to evaluate
their status. Freshwater habitats encompass the highest percentage of threatened fish species (87%)
followed by estuarine habitats (66%). Of the 32 species of highly threatened (HT) species, 16 are
freshwater and 16 are largely marine–euryhaline species. Fish extinctions in Malaysia are confined
to two freshwater species, but both freshwater and marine species are being increasingly threatened
by largely habitat loss or modification (76%), overfishing (27%) and by-catch (23%). The most
important threat to freshwater fishes is habitat modification and overfishing, while 35 species are
threatened due to their endemism. Brackish-water, euryhaline and marine fishes are threatened
mainly by overfishing, by-catch and habitat modification. Sedimentation (pollution) additionally
threatens coral-reef fishes. The study provides recommendations to governments, fish managers,
scientists and stakeholders to address the increasing and unabated extinction risks faced by the
Malaysian fish fauna. © 2010 The Authors
Journal compilation © 2010 The Fisheries Society of the British Isles
Key words: alien species; anthropogenic causes; endemic species; fish species; habitats threat
classification.
INTRODUCTION
Recent studies on biodiversity loss and its implications for ecosystem services have
uncovered unprecedented species extinctions at global and regional levels (Dulvy
et al., 2003; Baille et al., 2004). Large global data sets across spatial and temporal
scales indicate that as marine biodiversity declines, the ocean’s capacity to pro-
vide food, maintain water quality and recover from perturbations becomes severely
impaired (Worm et al., 2006). Biodiversity loss in coastal ecosystems impaired at
least three ecosystem services, namely provision of fisheries, nursery habitats and
filtering and detoxification services as provided by suspension feeders, submerged
vegetation and wetlands. In large marine ecosystems (LME), Worm et al. (2006)
further uncovered that 29% of currently fished species are considered collapsed by
2003 since passing the maximum yield in 1994 and that these collapses occurred at
‡Author to whom correspondence should be addressed. Tel.: +60379674220; fax: +60379674178; email:
chong@um.edu.my
2009
© 2010 The Authors
Journal compilation © 2010 The Fisheries Society of the British Isles

2010 V. C . C H O N G E T A L .
a higher rate in species-poor ecosystems. These studies show that the protection and
conservation of biodiversity are vital to ecosystem functioning and human interests.
Ironically, human interests are the main causes of aquatic biodiversity loss including
fish species. It has been stated that the root cause of the greatest loss of aquatic
biodiversity is the human population explosion (Leidy & Moyle, 1998). The IUCN
lists the main causes that are all man induced (the other is natural disasters) as over-
exploitation, habitat loss and degradation, pollution, by-catch and human disturbance
(Vie et al., 2008). These causes reflect past and present development activities and
vary in their importance from region to region (Darwall et al., 2009).
The global total number of extinct fishes is estimated as 93 (including 12 extinct
in the wild) in 2004 (Baille et al., 2004). The 2008 IUCN Red List lists 1275 threat-
ened fish species or 37% of the 3481 fish species that were evaluated. The number of
fishes evaluated is, however, very small (11%) considering that the estimated number
of described fish species in the world now stands at 30 700. Thus, it is conceivable
that more species had already become extinct and many more are imperiled unde-
tected. Given the widespread biogeographical distribution of many fishes, particularly
marine species, global extinction seems rare but not local extinctions (Dulvy et al.,
2003). Local extinctions are often cases attributable to their restricted distribution
or endemism. It is such local extinctions that are reason for concern, even for a
widespread species, particularly if it happens in its centre of origin. Hence, local or
regional assessment of fish extinction risk and cause of threat are necessary in order
that protective management could be immediately instituted.
Malaysia is identified as one of the world’s 12 mega-diversity centres and belongs
to one of the six countries of the Coral Triangle, which boasts the most diverse and
richest coral reefs in the world with >3000 species of reef fishes. Malaysia, with a
total coastline length of 4675 km, comprises two land masses (Peninsular or West
Malaysia and East Malaysia) separated by the South China Sea. Its total land area
is c. 330 000 km2, while its territorial waters cover 549 500 km2 (MOSTE, 1997).
Inland water bodies and wetlands including rivers, peat swamps, reservoirs, former
mining pools and paddy fields occupy a total surface area of 45 459 km2 (Yusoff &
Gopinath, 1995). Coastal mangroves occupy 5669 km2 (Wong, 2004), while coral
reefs occupy an estimated ocean space of 4006 km2
(Burke et al., 2002). Thus, the
large expanse of water space and varied aquatic habitats provide good opportunity
for fish colonization. MOSTE (2007) tabulates 4000 marine and 449 freshwater
fish species, the former is a dubious ballpark value not substantiated by research.
To date, there is no attempt to collate research data from the various published
sources on the distribution of extant Malaysian fishes in their varied habitats. There
is also no assessment of the existence or status of Malaysian fishes, which were first
documented by Cantor (1849) who described 300 species including 14 freshwater
species. The status of Malaysian fishes in their various freshwater and marine habitats
is practically unknown.
The present study collated and analysed fish species data from more recent works
(1987 to present), with the objectives: to take stock of the current fish diversity by
habitats, to assess extinction risks and status and to identify the causes of threat.
It is hoped that such species data and spatial distribution would be useful for the
protection and rational exploitation of Malaysian fishes.
© 2010 The Authors
Journal compilation © 2010 The Fisheries Society of the British Isles, Journal of Fish Biology 2010, 76, 2009–2066

C O N S E RVAT I O N S TAT U S O F M A L AY S I A N F I S H E S 2011
MATERIALS AND METHODS
Data on marine fishes by states in Peninsular Malaysia were extracted from the following
sources: Kedah (Khoo, 1990; Chong et al., 2005a, b; V. C. Chong, unpubl. data); Perlis
(Chong, 2007a); Penang (Abu-Talib et al., 2000); Perak (Sasekumar et al., 1994; Chong,
2005; Then, 2009), Selangor (Sasekumar et al., 1992; Chong et al., 2005c; V. C. Chong,
unpubl. data), West Johor (Sasekumar et al., 1990; Sasekumar, 1999), East Johor (Chong
& Sasekumar, 2002a), Pahang (Chong, 2001) and Kelantan (Chong et al., 2010). Published
marine fish data by species from Sarawak and Sabah were, however, depauperate, but four
main texts and two papers largely on commercial catches were useful: Mohsin & Ambak
(1996) (also covers Peninsular Malaysia), Chin (1998), Atack (2006), Yano et al. (2005),
Wong (2007) and Samsudin et al. (2007). Fish data were extracted from published and
unpublished works on seven coral reefs, namely Payar Island (Yusri, 2006), Tinggi Island
(Harborne et al., 2000), Tioman Island (Harborne et al., 2000; Yusri et al., 2005) and Redang
Island (Harborne et al., 2000) in Peninsular Malaysia, and the Tunku Abdul Rahman Marine
Park (Allen, 1992), Bodgaya Islands (Wood & Wood, 1987; Allen, 1992) and Sipadan (Wood
& Wood, 1987; Allen, 1992) in Sabah. These data, spanning a period of c. 20 years, cov-
ered fish species recorded from mangrove, seagrass bed, mudflat, coral reefs and inshore and
offshore waters.
The knowledge of the Malaysian freshwater fish fauna is, however, poorly documented,
especially for East Malaysia (Sabah and Sarawak). This problem is exacerbated by frequent
taxonomic revisions. The required information were extracted from the following references:
Inger & Chin (1962, 2002), Mohsin & Ambak (1983), Lee et al. (1993a, b), Lim et al. (1993),
Kottelat & Lim (1995), Lim & Ng (1999), Ng & Tan (1999), Rachmatika et al. (1999), K. K.
P. Lim & H. H. Tan (unpubl. data), Tan & Ng (2005), Kottelat et al. (2006), Tan (2006) and
Atack (2006). Brunei’s freshwater fishes were also included in this study for geographical
reasons, being a small state locked between Sarawak and Sabah.
The sites where the present analysis was based on are given in Fig. 1. In total, the number
of coral reef, marine and freshwater sites evaluated were seven, 14 and 20, respectively.
DATA TREATMENT AND ANALYSIS
Fish species names were entered into Excel spreadsheets with the following minimum
fields: place, habitat type, family, species, common name, intrinsic vulnerability, threatened
or risk status and threats. The levels of habitat types were peat swamp (PS), other freshwater
swamps (PW), paddy field (PF), river (RV), stream (ST) and lake, pond or pool (LK), coral
reef (CR), seagrass bed (SG), mangrove swamp (MG), mixed mangrove with seagrass habitat
(M-S), mixed mangrove with coral habitat (M-C), estuary (ES), coastal or inshore waters
including mudflats (CW) and offshore waters (OF). Family, species and common names were
checked against those given in Fishbase (http://www.fishbase.org/), which was used as the
expert system or standard to avoid synonyms.
The intrinsic vulnerability index (IV) of each fish species is defined as the risk of local
extinction associated with the life-history and ecological characteristics of the fish (Cheung
et al., 2005). It has been derived by a fuzzy logic expert system based on relevant fish or fish
population variables that include maximum length, age at first maturity, Von Bertalanty growth
function (VBGF) parameters, natural mortality, maximum age, fecundity, spatial behaviour
strength and geographic range. IV values available in Fishbase were extracted, and the values
were classified as follows for analysis: low (IV values from 1 to <25), moderate (25 to <50),
high (50 to <75) and very high (75 to 100).
The threat or risk status of all fishes was first checked against the IUCN Red List (IUCN,
2009). If evaluated by IUCN, the IUCN evaluation was accepted as the overriding status but
only if it was higher than the present categorization (see below). Many species, however,
have not been evaluated. Thus, a simple method based on the available data was devised
to provide a provisional listing of threaten status of the Malaysian fishes. Three levels of
assessment could be applied depending on the available data. Quantitative or rank data of
abundance allowed assessment to the third level.
The threat-status categories were based on a six-category or point system, arbitrarily named
as locally extinct (LE, category 6), highly threatened (HT, 5), moderately threatened (MT, 4),
© 2010 The Authors

2012 V. C . C H O N G E T A L .
Thailand
PeninsularM
alaysia
M
alacca
Indonesia
Strait
F1
M2
M1
M3
M4
M5
M6
M7
C1 C2
F2
F3
M13
M12
M11
M10
F4
F5
F6
F11
F13
F12
F10
F9
F7
F8
C3
C4
M9M8
South China Sea
M19
M20
M18
M17
M16
M14 M15
F14
M21M22
East Malaysia
M23
C5
M24
Sarawak
F16
F15
F17
F18
F19
Sabah
Philippines
M25
M26
M27
M28
F20
C7
C6
10°
8°
6°
4°
2°
0°
120°116°112°108°104°100°
Fig. 1. Sites investigated. Fresh waters: Kedah: Langkawi (F1); Penang (F2); Perak: Bukit Merah (F3), Chen-
deroh (F4), Perak River (F5); Selangor: North Selangor peat-swamp forest–Bernam basin (F6); Johor:
Muar (F7), Mawai-Sedili (F8), Endau (F9); Pahang: South-east Pahang peat-swamp forest (F10), Tasek
Bera (F11), Pahang River (F12); Terengganu (F13); Sarawak: Batang Ai & Lanjak Entimau (F14),
Lambir Hill (F15), Gunung Mulu (F16), Brunei: Belalong-Temburung (F17); Sabah: Beaufort (F18),
Kudat (F19), Segama-Kinabatangan (F20). Marine waters: Perlis: Kuala Perlis (M1); Kedah: Langkawi
(M2), Merbok (M3); Penang (M4); Perak: Matang (M5), Lekir (M6); Selangor: Klang (M7); Johor:
Pulai (M8), W. Johor (M9); Pahang: S. Pahang (M10), N. Pahang (M11); Terengganu: M12; Kelantan:
Bachok (M13); Sarawak: Kuching (M14), Batang Lupar (M15), Off Kuching (M16), Mukah (M17), Bin-
tulu (M18), Off Bintulu (M19), Miri (M20); Brunei: M21; Sabah: Kota Kinabalu (M22), Tuaran-Kota
Belud (M23), Kudat (M24), Marudu (M25), Tambisan (M26), Lahad Datu (M27), Tawau (M28). Coral
reefs: Kedah: Payar Island (C1); Terengganu: Redang Island (C2); Pahang: Tioman Island (C3), Tinggi
Island (C4); Sabah: Tunku Abdul Rahman Marine Park (C5), Bodgaya Islands (C6), Sipadan Island (C7).
least threatened (LT, 3), not threatened (OT, 2) and data deficient (DD, 1). This study did not
adopt the IUCN Red List’s assessment procedure (IUCN Standards and Petitions Working
Group, 2008) because fish assessment based on its criteria was very problematic due to the
high mobility and ‘low visibility’ of fishes, non-discrete area of occupancy (except freshwa-
ter bodies), sufficiently validated identification and the often inadequate data set both on a
spatial and temporal basis. Instead, a probability of encounter was used based on frequency
occurrence of the fish species sampled over the entire country.
The LE category of this study included those species that were believed to be extinct
in the country and equates to the ‘regionally extinct’ category (RE) of the IUCN Red List
Categories (IUCN Standards and Petitions Working Group, 2008). The DD category of this
study refers to those species not categorized due to insufficient data and equates to also the
‘data deficient’ (DD) category of the IUCN Red List. The remaining categories of the present
study were adjudged from the frequency of occurrence of the species (by site). An encounter
probability of ≥0·5 was taken to define OT, whereas a probability of <0·1 defined the HT
category. The MT and LT categories were defined as having encounter probability of 0·10
to <0·25 and 0·25 to <0·50, respectively. Fishes were categorized according to freshwater,
marine and coral-reef habitats.
At the second level of assessment, distance of occurrence was given weight since a longer
distance of occurrence would imply a lower risk. Therefore, the derived point or category
was downgraded one point if surveyed sites fell on at least two of the three large provinces
of Peninsular Malaysia, Sarawak and Sabah. For instance, if the same species is found in
both the Peninsula and the Sarawak, its HT status is downgraded to MT on the grounds that
the species is likely to be present over a wider region and with lower risk of extinction.
Downgrading was applied only to the HT, MT and LT categories.
© 2010 The Authors

At the third level of assessment, which requires abundance data, downgrading (one point
or category down) was applied to HT and MT cases only if it was known that the population
number was very abundant or had increased. On the other hand, upgrading (one point up)
was applied if the population was endemic and numbers were rare. Abundance ranking fol-
lowed the four-point hierarchy, namely rare, occasional, common and abundant as adopted
by Wood & Wood (1987). A species categorized as HT was further subjected to moderation
by examining distribution data, previous records and number of records of the species in the
region or world as available in the Global Biodiversity Information Facility (GBIF) portal
(http://data.gbif.org/species/). The present categorization rationale followed to some extent
the stringent criteria proposed by the IUCN Red List for category B, which considers extent
of occurrence, fragmentation of locations and number of mature individuals.
Three fish families, namely the Gobiidae, Blennidae and Apogonidae, were not fully eval-
uated, especially many species from coral reefs, due to taxonomic difficulty, under-reporting
and their nocturnal habits (Wood & Wood, 1987). Many were placed under the DD category.
Imports or alien species were not assessed. It is stressed that results from this categorization
procedure are provisional for the purpose of this study.
Fish species were evaluated against the following potential threats: overharvesting (OH),
by-catch (BC), habitat loss or degradation (HD), pollution (PO), dams (DM), human dis-
turbance (HD), water extraction (WE), alien invasive species (AS), natural disasters (NS),
climate change (GC), endemicity (VE) and others (OS). Pollution refers to all types of pollu-
tion including sedimentation. Human disturbance includes trawling, logging, dredging, sand
mining and tourism activities that disrupt fish aggregation, feeding and breeding activities.
‘Others’ include factors not stated above, e.g. impingements at power plants. Threats were
only identified for threatened fish species, i.e. those with scores higher than NT.
The spreadsheet data were sorted and analysed. The data were further analysed by classi-
fication tables and histograms using the software Statistica ver. 8 (www.statsoft.com).
RESULTS AND DISCUSSION
NUMBER OF FISH FAMILIES AND SPECIES
A total of 1951 species of freshwater and marine fishes belonging to 704 gen-
era, 186 families and 37 orders were recorded for Malaysia (Table I). The seven
most speciose families with >50 species each were Cyprinidae (150), Gobiidae
(131), Pomacentridae (108), Labridae (85), Serranidae (68), Apogonidae (57) and
Carangidae (53).
FISH HABITATS
The number of primary or strictly freshwater, brackish-water and marine species
are 470, 81 and 1400 species, respectively. Marine–euryhaline (250 species) and
brackish-water species (81 species) occupy the various coastal habitats such as man-
groves, seagrass meadows, estuaries or mixed habitats, at one stage of their life
history (Table II). The largest number of marine species are found in coral reefs with
925 species including 815 exclusive species. Primary freshwater species occupy habi-
tats that include streams, rivers, lakes, ponds, paddy fields, peat swamps and other
freshwater swamps.
Fifteen fish families are strictly freshwater, while 66 families are wholly marine.
All other families have representatives from both brackish and marine waters. Four-
teen families including Ambassidae, Anguillidae, Ariidae, Batrachoididae, Belonidae,
© 2010 The Authors

2014 V. C . C H O N G E T A L .
TableI.DiversityandhabitattypesofMalaysianﬁshes
TaxaHabitat*
OrderFamilyNumberofgeneraNumberofspeciesFWESMWRangeofhabitattypes†
HexanchiformesHexanchidae11XCW,OF
HeterodontiformesHeterodontidae11XCW,OF
OrectolobiformesRhincodontidae11XCW,OF
Orectolobidae11CR,SG,ES,CW,OF
Hemiscylliidae15XXCR,SG,MG,M-S,M-C,ES,CW
Stegostomatidae11XCR,CW
Ginglymostomatidae11XCR
LamniformesLamnidae11XCW,OF
Alopiidae12XCW,OF
CarcharhiniformesScyliorhinidae34XCR,MW,OF
Triakidae12XCW,OF
Hemigaleidae44XCW,OF
Carcharhinidae723XCR,CW,OF
Sphyrnidae23XCR,CW,OF
SqualiformesCentrophoridae11XOF
Squalidae11CW,OF
SquatiniformesSquatinidae11OF
PristiformesPristidae12XXXRV,ES,CW
TorpediniformesNarcinidae26XCR,OF
Torpedinidae11XCR,CW
RajiformesRhinobatidae37XXCR,ES,CW,OF
Rajidae12XOF
Plesiobatidae11XOF
Dasyatidae725XXXRV,CR,SG,MG,M-S,M-C,ES,CW
Myliobatidae59XXCR,MG,M-C,ES,CW,OF
Gymnuridae23XXCR,MG,ES,CW,OF
© 2010 The Authors

C O N S E RVAT I O N S TAT U S O F M A L AY S I A N F I S H E S 2015TableI.Continued
TaxaHabitat*
OsteoglossiformesOsteoglossidae11XPS,PW,RV,LK
Notopteridae23XPW,RV,ST,LK
ElopiformesElopidae11XXSG,MG,M-C,ES,CW
Megalopidae11XSG,MG,M-S,M-C,ES,CW
AlbuliformesAlbulidae11XES,CW
AnguilliformesAnguillidae14XXXPW,RV,ST,SG,M,MS,ES,CW
Moringuidae11XXCR
Muraenidae516XXCR,SG,MG,M-S,ES,CW
Ophichthidae56XXCR,CW,OF
Congridae33XCR,CW
Muraenesocidae12XXSG,MG,M-S,ES,CW
ClupeiformesClupeidae1322XXXRV,LK,CR,SG,MG,M-S,M-C,ES,CW
Engraulidae519XXXPW,RV,LK,CR,SG,MG,M-S,M-C,ES,CW
Chirocentridae12XXSG,MG,M-S,ES,CW
Pristigasteridae26XXSG,MG,M-S,ES,CW
Sundasalangidae11XRV
GonorynchiformesChanidae11XXCR,SG,MG,ES,CW
CypriniformesCyprinidae49150XPS,PW,RV,ST,LK
Cobitidae832XPS,PW,RV,ST
Balitoridae1573XPS,RV,ST
SiluriformesSiluridae828XPS,PW,RV,ST,LK
Schilbeidae22XRV
Pangasiidae38XXRV,ST,LK,ES
Bagridae933XXPS,PW,RV,ST,LK,ES
Chacidae11XPW,ST
Clariidae211XPS,PW,PF,RV,ST,LK
© 2010 The Authors

2016 V. C . C H O N G E T A L .
TableI.Continued
TaxaHabitat*
Amblycipitidae11XST
Akysidae49XPS,PW,RW,ST,LK
Sisoridae24XPS,PW,RV,ST
Ariidae1119XXXPS,PW,RV,ST,LK,SG,MG,
M-S,M-C,ES,CW,OF
Plotosidae23XXCR,SG,MG,M-S,M-C,ES,CW
AteleopodiformesAtelepoididae11XOF
AulopiformesSynodontidae410XXCR,SG,MG,M-S,ES,CW,OF
LampriformesLampridae11XCW
GadiformesBregmacerotidae11XCW
OphidiiformesOphidiidae11XCW,OF
Carapidae11XCR
BatrachoidiformesBatrachodidae12XXXRV,SG,MG,M-S,M-C,ES,CW
LophiiformesLophiidae11XCW,OF
Antennariidae15XXCR,SG,MG,M-S,CW,OF
Chaunacidae11XCW,OF
Ogcocephalidae11XCW,OF
GobiesociformesGobiesocidae11XCR
AtheriniformesAtherinidae24XCR,MG
Phallostethidae24XPW,RV,ST
CyprinodontiformesAplocheilidae11XXPS,PA,PF,RV,ST,LK,ES
BeloniformesBelonidae57XXXPW,RV,CR,SG,MG,M-S,M-C,
ES,CW
Hemiramphidae411XXXPS,PW,PF,LK,RV,ST,CR,SG,
MG,M-S,M-C,ES,CW
Exocoetidae24XCW,OF
© 2010 The Authors

TaxaHabitat*
BeryciformesHolocentridae419XCR
Anomalopidae22XCR
ZeiformesParazenidae11XOF
Zeidae11XOF
GasterosteiformesIndostomidae11XST
Pegasidae11XCW,OF
SyngnathiformesAulostomidae11XCR
Fistulariidae12XCR,CW
Centriscidae22XCR
Solenostomidae11XCR
Syngnathidae816XXXRV,ST,CR,SG,MG,M-S,ES,CW,OF
SynbranchiformesSynbranchidae11XPS,PW,PF,RC,ST,LK
Mastacembelidae29XPS,PW,RV,ST,LK
Chaudhuriidae44XPS,PW,PF,RV,ST,LK
ScorpaeniformesScorpaenidae1017XXCR,SG,MG,M-S,ES,CW
Synanceiidae33XCR,CW
Aploactinidae11XCR
Dactylopteridae12XCW
Platycephalidae910XXCR,SG,MG,M-S,M-C,ES,CW
Triglidae11XCW,OF
PerciformesCentropomidae11XXSG,MG,M-S,M-C,ES,CW
Ambassidae37XXXCR,SG,MG,M-S,ES,CW
Latidae11XXCR,ES,CW
Acropomatidae22XOF
Serranidae1565XXCR,SG,MG,M-S,M-C,ES,W
© 2010 The Authors

2018 V. C . C H O N G E T A L .
TableI.Continued
TaxaHabitat*
Pseudochromidae57XCR
Plesiopidae11XCR
Terapontidae34XXCR,SG,MG,M-S,ES,CW
Priacanthidae37XCR,CW
Apogonidae1157XXCR,SG,MG,M-S,M-C,ES,CW
Sillaginidae15XXSG,MG,M-S,M-C,ES,CW
Malachantidae33XCR,CW,OF
Lactariidae11XCW
Rachycentridae11XCR
Echeneidae11XCR
Carangidae1853XXCR,SG,MG,M-S,M-C,ES,CW
Coryphaenida11XCR,CW,OF
Menidae11XCW,OF
Leiognathidae716XXCR,SG,MG,M-S,M-C,ES,CW
Lutjanidae1038XXCR,SG,MG,M-S,M-C,ES,CW,OF
Caesionidae310XCR
Lobotidae11XXMG,M-C,ES,CW
Datnioididae12XXPW,PF,RV,ES
Gerreidae25XXCR,MG,M-S,M-C,ES,CW
Haemulidae324XXCR,SG,MG,M-S,M-C,ES,CW,OF
Sparidae34XXCR,M-C,ES,CW
Lethrinidae523XXCR,SG,M-S,ES,CW
Nemipteridae433XXCR,MG,M-C,ES,CW
Sciaenidae1225XXSG,MG,M-S,M-C,ES,CW
Polynemidae48XXXRV,MG,M-S,ES,CW
Mullidae319XXCR,SG,MG,M-S,M-C,ES,CW,OF
© 2010 The Authors

TaxaHabitat*
Pempheridae25XCR
Glaucosomatidae11XCW
Toxotidae13XXCR,SG,MG,M-S,M-C,ES,CW
Kyphosidae12XCR,CW
Drepaneidae12XSG,MG,M-S,M-C,ES,CW
Monodactylidae11XXCR,SG,MG,M-S,ES
Chaetodontidae745XXCR,SG,MG,M-S,ES
Pomacanthidae618XCR
Pentacerotidae11XCW
Nandidae24XPS,PW,PF,RV,ST
Cirrhitidae35XCR
Cepolidae22XCW,OF
Mugilidae612XXCR,SG,MG,M-S,M-C,ES,CW
Pomacentridae10108XCR,CW
Labridae3085XXCR,SG,MG,M-S,ES,CW
Scaridae727XCR
Champsodontidae11XMW,OF
Uranoscopidae12XCR
Trichonotidae12XCR
Pinguipedidae28XCR
Pholidichthyidae11XCR
Tripterygiidae24XCR
Blenniidae1736XXCR,ES
Callionymidae611XXCR,SG,MG,M-S,M-C,ES,CW
Rhyacichthyidae11XFW
Eleotridae46XXXPW,RV,LK,ES
© 2010 The Authors

2020 V. C . C H O N G E T A L .
TableI.Continued
TaxaHabitat*
Gobiidae52133XXXRV,ST,LK,CR,SG,MG,M-S,M-C,ES,CW
Microdesmidae13XCR
Ptereleotridae47XCR
Kurtidae11XCW
Ephippidae26XXCR,SG,MG,M-S,M-C,ES,CW
Scatophagidae11XXSG,MG,M-S,M-C,ES,CW
Siganidae117XXCR,SG,MG,M-S,M-C,ES,CW
Zanclidae11XCR
Acanthuridae529XCR
Sphyraenidae18XXCR,SG,MG,M-S,M-C,ES,CW,OF
Trichiuridae44XXCW,ES
Scombridae919XXCR,SG,MG,M-S,M-C,ES,CW,OF
Istiophoridae22XCW,OF
Centrolophidae11XCW
Nomeidae11XCW,OF
Ariommatidae12XCW,OF
Stromateidae12XXSG,MG,M-S,ES,CW
Anabantidae11XPS,PW,PF,RV,ST,LK
Osphronemidae840XPS,PW,PF,RV,ST,LK
Helostomatidae11XPS,PW,RV,LK
Channidae17XPS,PW,PF,RV,ST,LK
PleuronectiformesPsettodidae11XCR,CW
Paralichthyidae16XXCR,SG,MG,M-S,M-C,ES,CW
Bothidae44XCR,CW
Cynoglossidae29XXXSG,MG,M-S,M-C,ES,CW
Soleidae712XXXRV,ST,CR,SG,M-S,ES,CW
© 2010 The Authors

TableI.Continued
TaxaHabitat*
TetraodontiformesTriacanthodidae11XCW
Triacanthidae23XXCR,SG,MG,M-S,M-C,ES,CW
Balistidae914XXCR,ES,CW
Monacanthidae1423XXCR,SG,MG,M-S,M-C,ES,CW
Ostraciidae38XXCR,M-C,ES
Tetraodontidae1134XXXPW,PF,RV,ST,LK,CR,SG,MG,
M-S,M-C,ES,CW
Diodontidae25XCR
Molidae11XCW,OF
Total3718670419514674155
OrdersFamiliesGeneraSpeciesFamiliesfoundinthe
respectivehabitats
*Habitat:FW,freshwater;ES,estuary;MW,marinewaters.
†Rangeofhabitattypes:ST,streams;RV,rivers;LK,lakeorpoolsorponds;PS,peatswamp;PW,otherfreshwaterswamps;PF,paddyﬁelds;MG,mangroves;
ES,estuaries;CW,coastalwaters;SG,seagrassbeds;CR,coralreefs;M-S,mixedmangroves-seagrass;M-C,mixedmangroves-coral;OF,offshorewaters.
© 2010 The Authors

2022 V. C . C H O N G E T A L .
Table II. Species richness of Malaysian aquatic habitats
Type of fish Habitat type Number of species
Freshwater Streams 341
(470 species) Rivers 291
Lakes and ponds 70
Peat swamps 92
Other freshwater swamps 78
Paddy fields 9
Brackish water Estuaries 326
(81 species) Mangroves 296
Seagrass meadows 182
Mixed mangrove and seagrass 178
Marine Coral reefs 925
(1400 species) Mixed mangrove and coral 110
Coastal waters 539
Offshore waters 100
Total number of species 1951
Clupeidae, Dasyatidae, Engraulidae, Gobiidae, Hemiramphidae, Polynemidae, Solei-
dae, Syngnathidae and Tetraodontidae have representatives from all three types of
habitats.
CLASSIFICATIO N OF THREATENED SPECIES
The categorized threat levels by number of species for the Malaysian fishes show
the following distribution: LE two (0·1%), HT 32 (1·6%), MT 252 (12·9%), LT 657
(33·7%), OT 479 (24·6%) and DD 529 (27·1%). The results indicate that almost half
(48·3%) of the Malaysian fishes are currently threatened to some degree (LT and
above), while almost a third (27%) of them (DD), especially those from the marine
and coral habitats, requires urgent scientific studies to evaluate their status.
Threat categorization of fishes by habitat is given in Fig. 2. Freshwater habitats
gave the highest percentage (87%) or proportion (396/456) of evaluated fish species
that were threatened (LT:3 and above). The next highest for threatened species were
those from estuarine habitats, comprising 66% (35/53) of brackish-water species and
53·8% (112/208) of marine–euryhaline species. Coral and mixed-coral habitats con-
tained 57% (335/588) and 36% (27/76) threatened species, respectively. Information
regarding most of the fishes in the marine habitat, however, was largely deficient for
evaluation, although 38 of 41 species evaluated were threatened. Nevertheless, three
evaluated marine species were HT.
A large number of Malaysian coral-reef fishes were also not evaluated because of
lack of studies. The IUCN Red List, however, lists 130 coral-reef fishes in Malaysia
evaluated at the global level (IUCN, 2009). To test the agreement of the present risk
assessment results with that in the IUCN list, the categories of the present study were
equated to the IUCN Red List Categories as follows: LE = regionally extinct (IUCN,
RE); HT = critically endangered (IUCN, EN); MT = endangered (IUCN, EN); LT =
vulnerable (IUCN, VU); OT = near threatened (IUCN, NT) + least concern (IUCN,
LC). Of the 54 cases that could be compared (excluding DD), the present evaluation
© 2010 The Authors

0 0
5
10
15
20
25
30
35
50
0
0 0
10
20
30
40
50
60
50
100
150
200
250
300
40
80
120
160
200
240
0
20
40
42
96
73
27
12
60
80
100
120
14
184
227
253 261
74
34
49
22
5
1718
1 2 3
3 3
4 5
1 2 3 4 5
1 2 3 4
Category
1 2 3 4
1 2 3 4 5
1 2 3 4 56
60
123
255
16 2 1
6
28
18
28(a) (b)
(c) (d)
(e) (f)
100
150
200
250
300Numberofspecies
Fig. 2. Threat status or extinction risks of (a) freshwater, (b) brackish-water, (c) marine, (d) marine–euryhaline,
(e) coral-reef and (f) mixed-coral fish species in Malaysia. Category: 1, data deficient; 2, not threatened;
3, least threatened; 4, moderately threatened; 5, highly threatened; 6, locally extinct. Numerals above
histograms indicate actual number of species.
agrees with the Red List categorization in most of the cases (74%). Eleven cases
(20%) were evaluated higher than IUCN including nine and one case with +1 and +2
points higher (i.e. higher risks), respectively. Only three cases (5·5%) were evaluated
at −1 point [Himantura uarnak (Gmelin) and Plectorhinchus gibbosus (Lacépède)]
and −2 points [Aetomylaeus nichofii (Bloch & Schneider)] lower (i.e. lower risk).
Two species of freshwater fish considered locally extinct (LE) in the country
are cyprinids [Balantiocheilos melanopterus (Bleeker) and Neobarynotus microlepis
(Bleeker)] found in clean rivers or swamps (Table III). The freshwater highly
threatened (HT) species were from peat swamps (five species) and the rest (11
species) were from streams and upper reaches of rivers. Seven HT species were
elasmobranchs: a coastal shark and eagle ray; an eagle ray that frequents mixed
habitats of mangrove and coral; two estuarine or coastal sawfishes and two freshwa-
ter stingrays. Of the marine HT species, four were pelagic species, while 12 were
demersal species. The highly threatened frogfishes (Antennariidae), cardinal fishes
© 2010 The Authors

2024 V. C . C H O N G E T A L .
TableIII.ListofextinctandthreatenedﬁshspeciesinMalaysia
TaxaCausesofthreatThreatindex†
FamilySpeciesHabitats*IV
Overharvesting(OH)
By-catch(BC)
Habitatdegradation(DH)
Pollution(PO)
Dams(DA)
Humandisturbance(HD)
Endemicity(VE)
Threatlevel
Threatcategory
Freshwater
CyprinidaeBalantiocheilosmelanopterusPW,RV46OHDHPO6LE
CyprinidaeNeobarynotusmicrolepisRV41OHDHPO6LE
BalitoridaeSundoreonectestiomanensisST10DHVE5HT
BalitoridaeVaillantellaeuepipteraST21DHVE5HT
ClariidaeEncheloclariascurtisomaPS10DHVE5HT
ClariidaeEncheloclariaskelioidesPS10DHVE5HT
ClariidaeEncheloclariasprolatusPS10DHVE5HT
ClariidaeClariasbatuST32DHVE5HT
CyprinidaeProbarbusjullieniRV87OHDHPODA5HT
CyprinidaeTordouronensisRV,ST38OHDHPODA5HT
CyprinidaeTortambraRV,ST68OHDHPODA5HT
CyprinidaeTortambroidesRV,ST69OHDHPODA5HT
CyprinidaeNeolissochilushendersoniST67DHPOVE5HT
CyprinidaePuntiusdunckeriST28DHVE5HT
DasyatidaeHimanturachaophrayaRV90OHBCDHPOVE5HT
DasyatidaeHimanturasigniferRV43OHDHPODA5HT
OsphronemidaeBettachiniPS10DH5HT
© 2010 The Authors

C O N S E RVAT I O N S TAT U S O F M A L AY S I A N F I S H E S 2025TableIII.ListofextinctandthreatenedﬁshspeciesinMalaysia
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
OsphronemidaeBettapersephonePS10DH5HT
AkysidaeAcrochordonichthyspachydermaST10DH4MT
AkysidaeAcrochordonichthysrugosusST10DH4MT
AkysidaeAcrochordonichthysseptentrionalisST10DH4MT
AkysidaePseudobagariusalfrediPS10DHVE4MT
AkysidaePseudobagariusbaramensisST10DH4MT
AkysidaeParakysislongirostrisPS10DH4MT
AkysidaeParakysisverrucosusPS10DH4MT
BagridaeHemibagrusgracilisRV,ST51OHDHVE4MT
BagridaeHemibagrussabanusRV34OHDH4MT
BagridaeLeiocassisdoriaeRV,ST34DH4MT
BagridaeLeiocassismerabensisRV,ST–DH4MT
BagridaeMystusbimaculatusPS14OHDHPO4MT
BagridaeNanobagrusnebulosusST10DHVE4MT
BagridaePseudomystusleiacanthusPS13DH4MT
BagridaePseudomystusrobustusRV39DHPO4MT
BalitoridaeBarbuccadiabolicaST10DH4MT
BalitoridaeGastromyzonaequabilisST10DHVE4MT
© 2010 The Authors

2026 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
BalitoridaeGastromyzonauronigrusST10DHVE4MT
BalitoridaeGastromyzonborneensisST16DHVE4MT
BalitoridaeGastromyzoncornusaccusST10DHVE4MT
BalitoridaeGastromyzoncrenastusST10DH4MT
BalitoridaeGastromyzonctenocephalusST10DH4MT
BalitoridaeGastromyzonextrosusST10DHVE4MT
BalitoridaeGastromyzoningeriST10DHVE4MT
BalitoridaeGastromyzonkatibasensisST10DHVE4MT
BalitoridaeGastromyzonocellatusST10DHVE4MT
BalitoridaeGastromyzonpariclavisST11DHVE4MT
BalitoridaeGastromyzonspectabilisST11DHVE4MT
BalitoridaeGastromyzonumbrusST10DHVE4MT
BalitoridaeGastromyzonviriosusST10DHVE4MT
BalitoridaeGlaniopsisdenudataST10DH4MT
BalitoridaeHomalopteraogilvieiPS10DH4MT
BalitoridaeHomalopteraorthogoniataPS23DH4MT
BalitoridaeHypergastromyzoneubranchusST10DHVE4MT
BalitoridaeNemacheiluselegantissimusST10DHVE4MT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
BalitoridaeNeohomalopterajohorensisPS10DH4MT
BalitoridaeNeogastromyzoncrassiobexST10DHVE4MT
BalitoridaeNeogastromyzonpauciradiatusST11DHVE4MT
BalitoridaeParhomalopteramicrostomaST12DHVE4MT
BalitoridaeProtomyzonborneensisST10DH4MT
BalitoridaeProtomyzongriswoldiST12DH4MT
ChacidaeChacabankanensisPS,ST10DH4MT
ChannidaeChannagachuaPS,ST,RV25DH4MT
ChannidaeChannamarulioidesRV,LK,PW,PS22DH4MT
ChannidaeChannamelasomaRV,PW,PS28DH4MT
ChaudhuriidaeBihunichthysmonopteroidesPS10DH4MT
ChaudhuriidaeChaudhuriacaudataPW,ST10DH4MT
ChaudhuriidaeNagaichthysﬁlipesPS10DH4MT
ClariidaeClariasleiacanthusPW,PS27DH4MT
ClariidaeClariasmeladermaPW,PS35DH4MT
ClupeidaeClupeichthysaff.aesarnensisRV10DH4MT
ClupeidaeClupeichthysperakensisRV,LK10DH4MT
CobitidaeLepidocephalichthyssandakanensisST10DH4MT
© 2010 The Authors

2028 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
CobitidaeLepidocephalichthystomaculumRV,ST,PS20DH4MT
CobitidaePangiosandakanensisST11DH4MT
CyprinidaeBorarasmaculatusPS10DH4MT
CyprinidaeHampalasabanaRV,ST56OHDH4MT
CyprinidaeLabiobarbusleptocheilusRV,ST43DH4MT
CyprinidaeLeptobarbushoeveniiRV,ST69OHDH4MT
CyprinidaeLuciosomapellegriniRV,ST27DH4MT
CyprinidaeOsteochiluschiniST34OHDHVE4MT
CyprinidaeOsteochilusmelanopleurusRV,ST,LK64OHDH4MT
CyprinidaeOsteochilusspilurusPS18DH4MT
CyprinidaeOsteochiluswaandersiiRV,ST35OHDH4MT
CyprinidaePaedocyprismicromegethesPS10DH4MT
CyprinidaePuntioplitesbuluRV,LK38OHDH4MT
CyprinidaePuntioplitesproctozysronRV,LK35OHDH4MT
CyprinidaePuntiushexazonaPS11OHDH4MT
CyprinidaePuntiuslineatusPS13DH4MT
CyprinidaeThynnichthysthynnoidesRV,ST,LK33OHDHPO4MT
CyprinidaeTrigonostigmaheteromorphaPS,PW10OHDH4MT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
CyprinidaeRasboragracilisPS13DH4MT
EleotridaeOxyeleotrismarmorataRV,LK,PW60OHDH4MT
MastacembelidaeMacrognathusaculeatusRV,ST,PW,PS24DH4MT
MastacembelidaeMastacembeluserythrotaeniaRV,ST,LK42OHDH4MT
NandidaeNandusprolixusPW,ST10DH4MT
OsphronemidaeBettaakarensisPS,PW15DH4MT
OsphronemidaeBettaanabatoidesPS12DH4MT
OsphronemidaeBettabalungaPS10DH4MT
OsphronemidaeBettabrownorumPS10DH4MT
OsphronemidaeBettacoccinaPS10DH4MT
OsphronemidaeBettagladiatorPS10DHVE4MT
OsphronemidaeBettahipposiderosPS10DH4MT
OsphronemidaeBettaibanorumPS11DHVE4MT
OsphronemidaeBettalehiPS10DH4MT
OsphronemidaeBettalividaPS10DHVE4MT
OsphronemidaeBettamacrostomaST10OHDH4MT
OsphronemidaeBettapulchraPS10DH4MT
OsphronemidaeBettastigmosaST10DH4MT
© 2010 The Authors

2030 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
OsphronemidaeBettataeniataST10DH4MT
OsphronemidaeBettatomiST10DH4MT
OsphronemidaeBettatussyaePS10DH4MT
OsphronemidaeBettaunimaculataST13DH4MT
OsphronemidaeLuciocephaluspulcherPS25DH4MT
OsphronemidaeOsphronemuslaticlaviusRV48OHDH4MT
OsphronemidaeOsphronemusseptemfasciatusRV48OHDH4MT
OsphronemidaeParosphromenusnagyiPS10DH4MT
OsphronemidaeParosphromenusharveyiPS10DH4MT
OsphronemidaeParosphromenuspaludicolaPS10DH4MT
OsphronemidaeSphaerichthysosphromenoidesPS10DH4MT
OsphronemidaeTrichogasterleeriiPS,PW12DH4MT
OsteoglossidaeScleropagesformosusST,RV,PW,PS,LK48OHDHPO4MT
PangasiidaeHelicophaguswaandersiiRV31OHDH4MT
PangasiidaePangasiuskinabatanganensisRV19OHDHVE4MT
PangasiidaePangasiusmacronemaRV,ST,LK27OHDH4MT
PangasiidaePangasiusnasutusRV39OHDH4MT
RhyacichthyidaeRhyacichthysasproST21DH4MT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
SiluridaeOmpokborneensisRV,ST12DH4MT
SiluridaeSilurichthysphaiosomaPS25DH4MT
SiluridaeSilurichthysschneideriST26DH4MT
SiluridaeWallagoleeriiRV,ST86OHDH4MT
SiluridaeWallagomaculatusRV,ST66DH4MT
SisoridaeBagariusyarrelliRV90DH4MT
SisoridaeGlyptothoraxplatypogonoidesST10DH4MT
GlyptothoraxsiamensisST10DH4MT
SundasalangidaeSundasalanxcf.praecoxRV10DHPODA4MT
SyngnathidaeDoryichthysboajaRV,ST40DH4MT
SyngnathidaeDoryichthysdeokhatoidesRV,ST23DH4MT
SyngnathidaeDoryichthysmartensiiRV,ST18DH4MT
TetraodontidaeTetraodonsabahensisRV15DH4MT
Brackishwater
KurtidaeKurtusindicusES,CW10BCDHPOHD5HT
AnguillidaeAnguillabicolorES,RV,PW,ST63DH4MT
EleotridaeEleotrismelanosomaES,RV,ST37DH4MT
GobiidaeBrachygobiuskabiliensisES,MG,RV10DH4MT
© 2010 The Authors

2032 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
GobiidaeRedigobiusbikolanusES,RV,ST12DH4MT
GobiidaeStenogobiusingeriES,RV21DH4MT
PangasiidaePangasiuspolyuranodonES,RV,LK51OHDH4MT
Marine
AnthennariidaeAntennariuscommersonSG,MG,M-S20BCDHPOHD5HT
AnthennariidaeAntennariusstriatusSG,MG,M-S,CW,OF13BCDHPOHD5HT
ApogonidaeApogoncavitensisSG,MG,M-S,ES10BCDHPOHD5HT
CarcharhinidaeCarcharhinushemiodonCW65OHBCHD5HT‡
CynoglossidaeCynoglossusmacrostomusSG,MG,M-S,ES27OHBCDHHD5HT
CynoglossidaeParaplagusiabilineataCW35OHBCDHHD5HT
LampridaeLamprisguttatusCW82OHBC5HT
LutjanidaeLutjanusstellatusSG,M-C,ES40OHDHVE5HT
MyliobatidaeAetomylaeusmaculatusM-C,CW61OHBCHD5HT
MyliobatidaeAetomylaeusnichoﬁiCW,OF50OHBCHD5HT‡
PristidaePristismicrodonRV,ES,CW87OHDHHD5HT
PristidaePristiszijsronRV,ES,CW86OHDHHD5HT
ScorpaenidaeScorpaenodesguamensisSG,MG,M-S,ES33BCDHHD5HT
SoleidaeBrachirusorientalisSG,MG,M-S,ES39OHBCDHHD5HT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
TerapontidaeTeraponputaSG,MG,M-S,ES23OHBCDHPOHD5HT
AcanthuridaeAcanthurusbarieneCR37OH4MT
AcanthuridaeNasobrachycentronCR67OHBC4MT
AcanthuridaeNasolopeziCR52OH4MT
AlbulidaeAlbulavulpesCW43OHDH4MT
AnguillidaeAnguillanebulosaCW73OHDHHD4MT
AnomalopidaeAnomalopskatoptronCR19PO4MT
AntennariidaeAntennarispictusCR16DHPO4MT
AntennariidaeAntennariusdorehensisCR10DH4MT
AploactinidaeAcanthosphexleurynnisCR10BCDH4MT
AriidaeAriusariusCW47BCDHHD4MT
AtherinidaeAtherinomorusduodecimalisCW43BC4MT
AtherinidaeStenatherinapanatelaCR23BCDH4MT
BothidaeArnoglossustapeinosomaCW24OHBCDHHD4MT
BothidaeEngyprosopongrandisquamaCW27OHBCDHHD4MT
BothidaeGrammatobothuspolyopthalmusCW31OHBCDHHD4MT
BregmacerotidaeBregmacerosmclellandiCW10OHBC4MT
CarangidaeAlectisciliarisCW,CR67OH4MT
© 2010 The Authors

2034 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
CarangidaeAlepeskleiniiCW16OHBC4MT
CarangidaeCaranxlugubrisCR60OH4MT
CarangidaeCaranxpapuensisCR42OH4MT
CarangidaeDecapterusmacarellusCR40OH4MT
CarangidaeDecapterusmacrosomaCW,CR24OH4MT
CarangidaeScomberoidestalaCW,CR37OH4MT
ChaetodontidaeChaetodonburgessiCR11DHPO4MT
ChaetodontidaeChaetodondecussatusCR15DH4MT
ChaetodontidaeChaetodonplebeiusCR12DH4MT
ChaetodontidaeChaetodontriangulumCR12DH4MT
ChaetodontidaeCoradionmelanopusCR11BCDH4MT
ChaetodontidaeForcipigerlongirostrisCR15DHPO4MT
ChaetodontidaeParachaetodonocellatusCW,CR12PO4MT
ChirocentridaeChirocentrusnudusCW48OH4MT
CynoglossidaeCygnoglossuscygnoglossusCW30OHBC4MT
DasyatidaeHimanturableekeriCW53OHBCDHHD4MT
DasyatidaeHimanturagranulataCW,CR86OHBC4MT
DasyatidaeTaeniurameyeniCR77OHHD4MT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
DiodontidaeCyclichthysorbicularisCR16DH4MT
DiodontidaeCyclichthysspilostylusCR18PO4MT
EngraulidaeEncrasicholinaheterolobaCW38OHBCDH4MT
EphippidaePlataxbatavianusCR50OHDH4MT
FistulariidaeFisturiapetimbaCW71BCHD4MT
HaemulidaePlectorhinchusschotafCR57OH4MT
HaemulidaePlectorhinchusvittatusCR60OH4MT
HaemulidaePomadasysargyreusCW36OHBCHD4MT
LabridaeAnampsesmelanurusCR23PO4MT
LabridaeCheilinusundulatusCR,SG73OHDH4MT
LabridaeCymolutestorquatusCR30PO4MT
LabridaeHologymnosusannulutasCR41PO4MT
LabridaeHologymnosusdoliatusCR52PO4MT
LethrinidaeGymnocraniusmicrodonCR36BCDH4MT
LethrinidaeLethrinusmicrodonCR46OH4MT
LethrinidaeLethrinusminiatusCR53OH4MT
LethrinidaeLethrinusrubrioperculatusCR39OH4MT
LethrinidaeLetrhinusxanthochilusCR57OH4MT
© 2010 The Authors

2036 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
LutjanidaeAprionvirescensCR61OH4MT
LutjanidaeEteliscarbunculusCR42OH4MT
LutjanidaeLutjanusbouttonCR43OH4MT
LutjanidaeLutjanusfulvusCR23OH4MT
LutjanidaeLutjanusrivulatusCW,CR42OH4MT
LutjanidaeLutjanussanguineusCW46OHDHHD4MT
LutjanidaeLutjanussebaeCR62OH4MT
LutjanidaeSymphorusnematophorusCR49OH4MT
MicrodesmidaeGunnelichthyscuriosusCR10BCDH4MT
MicrodesmidaeGunnelichthysviridescensCR10DH4MT
MonacanthidaeAnacanthusbarbatusCW37BCDHHD4MT
MonacanthidaeCantherhinesfronticinctusCR33BCDH4MT
MonacanthidaeParamonacanthuspusillusCW30BCDHHD4MT
MugilidaeLizatadeCW48OHDHHD4MT
MullidaeParupeneusciliatusCR,SG31DH4MT
MyliobatidaeMantabirostrisCW,CR79OHBCHD4MT
NarcinidaeTemerahardwickiiCW,CR24OHDHPO4MT
NemipteridaeNemipteruscelebicusCR25OH4MT
© 2010 The Authors

Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
OphichthidaeOphichthusaltipennisCR47DHPO4MT
OstraciidaeTetrosomusgibbosusCR16BCDH4MT
ParalichthyidaePseudorhombusdiplospilusCR36PO4MT
ParalichthyidaePseudorhombuselevatusCW20OHBCDHHD4MT
ParalichthyidaePseudorhombusnatalensisCW12OHBCDHHD4MT
PlatycephalidaeCociellacrocodilusCW37BCDHHD4MT
PlatycephalidaeKumocociusrodericensisCW–BCHD4MT
PomacanthidaePomacanthussemicirculatusCR47DH4MT
PomacentridaeAmblyglyphidodonindicusCR22DH4MT
PomacentridaeChromisovatiformesCR21BCDH4MT
PomacentridaeChrysipterableekeriCR16BCDH4MT
PomacentridaeChrysipterabrownriggiiCR16OHDH4MT
PomacentridaeDascylluscarneusCR14DH4MT
PomacentridaePlectroglyphidodonleucozonusCR23DHPO4MT
PomacentridaePomacentruspavoCR22BCDH4MT
PomacentridaePristotisobtusirostrisCR17BCDH4MT
PomacentridaeStegatesnigricansCR13PO4MT
PristigasteridaeIlishakampeniCW12OHBC4MT
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2038 V. C . C H O N G E T A L .
Overharvesting(OH)
By-catch(BC)
Pollution(PO)
Dams(DA)
Endemicity(VE)
Threatlevel
Threatcategory
PseudochromidaeCongrogadussubducensCR23PO4MT
PseudochromidaePictichromisdiademaCR10DH4MT
RhinobatidaeRhinobatosschlegeliiCR46OH4MT
ScaridaeChlorurusbleekeriCR33DH4MT
SciaenidaeChrysochiraureusCW30OHBCHD4MT
SciaenidaeJohniusamblycephalusCW26OHBCHD4MT
SciaenidaeLarimichthyspolyactisCW29OHBCDHHD4MT
SciaenidaeNibeachuiCW30OHBCDHHD4MT
SciaenidaeOtolithoidesbiauritusCW68OHBCDHHD4MT
SciaenidaePennahiaargentataCW22OHBCDHHD4MT
ScombridaeEuthynnusafﬁnisCW,CR46OHBCDH4MT
ScombridaeRastrelligerfaughniCW38OHBCDH4MT
ScombridaeScomberjaponicusCR56OHDH4MT
ScorpaenidaeScorpaenopsisvenosaCR41OHPO4MT
ScorpaenidaeTaenianotustriacanthusCR29DHPO4MT
SerranidaeBelonopercachabanaudiCR22PO4MT
SerranidaeEpinephelusamblycephalusCR41OH4MT
SerranidaeEpinepheluscorallicolaCR41OH4MT
© 2010 The Authors

Overharvesting
(OH)
By-catch(BC)
Habitatdegradation
(DH)
Pollution(PO)
Dams(DA)
Humandisturbance
(HD)
Endemicity(VE)
Threatlevel
Threatcategory
SerranidaeEpinephelusmultinotatusCW,CR39OH4MT
SillaginidaeSillagochondropusCW32OHDHHD4MT
SoleidaePardachiruspavoninusCR29DH4MT
SoleidaeSoleaelongataCW32OHBCDHHD4MT
SoleidaeSynapturacommersonniiCW33OHBCDHHD4MT
SolenostomidaeSolenostomuscyanopterusCR10PO4MT
SparidaeAcanthopagrusberdaCW42OHDHHD4MT
SparidaeDentexangolensisCW59OHDHHD4MT
SphyrnidaeSphyrnalewiniCW,CR82OHBCDH4MT
StegostomatidaeStegostomafasciatumCW,CR73BCDH4MT
SynanceiidaeInimicusdidactylusCR13PO4MT
SyngnathidaeCosmocampusbanneriCR10BCDH4MT
SyngnathidaeSyngnathoidesbiaculeatusCW26OHBCDHHD4MT
SynodontidaeSauridagracilisCR25BCDH4MT
TetraodontidaeArothronimmaculatusCW30BC4MT
TorpedinidaeTorpedofuscomaculataCR68OH4MT
*Habitat:FW,freshwater;ES,estuary;MW,marinewaters.
†LE,locallyextinct(6);HT,highlythreatened(5);MT,moderatelythreatened(4).ThesewereCarcharhinushemiodon(DD)andAetomylaeusnichofii(MT).
‡Tablealsoincludestwomarinespeciesclassifiedasdatadeficient(DD)andMTinpresentstudybutupgradedtoHTbasedontheRedList’sevaluationascritically
endangered(CR).
© 2010 The Authors

2040 V. C . C H O N G E T A L .
300
250
200
150
100
50
0
0 25 50 75 100 0 25 50 75 100
0 25 50 75 100
0 25 50 75 100 0 25 50 75 100
0 25 50 75 100
273
154
31
7
(a)
50
40
30
20
10
0
29
36
6
2
(b)
(c) (d)
(e) (f)
120
100
80
60
40
20
0
160
120
80
40
0
102
58
41
16
73
123
36
14
500
400
300
200
100
0
80
60
40
20
0
386
358
64
3
26
61
17
5
Numberofspecies
I.v
Fig. 3. Intrinsic vulnerability (IV) of (a) freshwater, (b) brackish-water, (c) marine, (d) marine–euryhaline,
(e) coral-reef and (f) mixed-coral fish species in Malaysia. IV: 1 to <25, low; 25 to <50, moderate; 50
to <75, high; 75 to 100, very high.
(Apogonidae), sole (Soleidae), tongue-soles (Cynoglossidae) and terapons (Terapon-
tidae) were those from a mixed mangrove and seagrass habitat.
INTRINSIC VULNERABILI TY
The distribution of IV of Malaysian fishes is as follows: low, 845 fish (43·3%),
moderate, 832 (42·6%), high, 195 (9·9%), very high, 47 (2·4%) and with 32 cases
(1·7%) not classified by Fishbase. IV categorization according to habitats is shown
in Fig. 3. These results indicate that IV for species from freshwater and coral-reef
habitats was more skewed to the left, with 59% and 48% of species at the low
level (IV<25), respectively, as compared to fishes from other marine and mixed
habitats, which had 24–30% at low level, but 47–56% at moderate level (IV =
25–<50). Marine and mixed habitats also had 4·6–7·4% of fishes with very high IV
as compared to freshwater and coral-reef habitats with 1·5 and 0·4%, respectively.
The analysis, however, shows non-significant correlation between IV values and
threaten status values (Spearman rank r = −0·078, P > 0·05). Of the 249 species
of fishes that were moderately threatened, 132 species or 53% had a low IV of <25,
© 2010 The Authors

while twelve of 32 species that were highly threatened (HT) had a low IV (Table III).
This indicates that fishes with low intrinsic vulnerability still face extinction risk
independent of biological factors. In fact, IV has been recommended to be combined
with external factors such as degradation of essential habitats to derive an overall
extinction risk (Cheung et al., 2005).
IDENTIFIED THREATS
Threats that could contribute to fish extinction were analysed by examining the
specific fish habitats. Of the potential threats listed in the methodology, only over-
harvesting, by-catch, habitat loss or degradation, pollution, human disturbance and
endemism have been identified as the causes of their threaten status. No cases were
threatened by water extraction, invasive alien species and climate change. Table IV
lists the threats against the number of threatened fish species (LT and above) from
fresh water, coral reef and other marine habitats.
Overall, the most frequent threat to Malaysian fishes was habitat loss or degrada-
tion (76%). Overharvesting (27%) and by-catch (23%) ranked about equal. The most
important threat to freshwater fishes was habitat degradation accounting for 96% of
the threatened species followed by overharvesting (20%). Thirty-seven species of
highly or moderately threatened fishes owed their status to their vulnerability as
endemic species (3·9%) (Table IV). Hydroelectric and reservoir dams across large
rivers may have posed life cycle problems to migratory freshwater stingrays Himan-
tura signifer Compagno & Roberts and Himantura chaophraya Monkolprasit &
Roberts as well as to the Isok barb Probarbus jullieni Sauvage and the Malayan
marsheers Tor tambra (Valenciennes), Tor douronensis (Valenciennes) and Tor tam-
broides (Bleeker). For strictly coral-reef fishes, the most important threats identified
were habitat degradation (63%), pollution including sedimentation (34%), by-catch
(28%) and overfishing (22%). Habitat degradation of Sabah coral reefs in the past
had been due to blast fishing (Pilcher & Cabanban, 2000), but since the establishment
of marine parks in the major coral reefs since 1994, blast fishing within and around
such reef areas has been largely controlled.
For marine and marine–euryhaline fishes, by-catch posed the highest threat (>70%
of threatened species). Both brackish-water and marine–euryhaline species are highly
threatened by degradation and disturbance of their nursery habitats. They are also
very vulnerable as by-catch because of their small size in these habitats and shallow
waters.
The two locally extinct freshwater species had been subjected to habitat degrada-
tion, overharvesting and pollution. Of the 32 species of HT species, 28 species face
risk from habitat degradation, while 17 species are being overharvested (Table III).
The large cyprinids inhabiting clean and fast-flowing water of large rivers also face
pollution risk. Ten species (only one marine) are especially vulnerable due to their
presence in particular habitat or area.
Fish species with low IV still face extinction risk, particularly when the analy-
sis indicates that of the 144 species that were threatened (HT+MT), 130 species
had problems with habitat degradation, while only 17 and 22 species are being
overharvested and fished as by-catch.
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2042 V. C . C H O N G E T A L .
TableIV.CausesofthreattoMalaysianﬁshes
Typeofﬁsh
Numberof
species
Number
evaluated
Numberof
species
underthreatOverharvestingBy-catch
Habitat
degradationPollutionDams
Human
disturbanceEndemicity
Freshwater470456396802382256835
Brackishwater81533566251050
Marineeuryhaline25020811262836980641
Marine225413824301710181
Mixed-coral1107627114111090
Coral8155883357395213115040
Alltypes19511422943256220717151610837
Percentage27·123·376·016·00·611·53·9
© 2010 The Authors

MAIN CAUSES OF THREATS
Habitat destruction and degradation
Fish habitat destruction is the leading threat to freshwater fishes because major
freshwater bodies, their watersheds and surroundings are subjected to intense devel-
opment pressure and pollution. Reservoirs constitute the largest body of lacustrine
water body (160 000 ha); they are primarily built for hydroelectric power genera-
tion, drinking water supply, irrigation or flood mitigation (Ambak & Jalal, 2006).
Since most reservoirs originate from river impoundment, their fish fauna comprise
mainly riverine species. Although reservoirs sustain Malaysia’s freshwater fish pro-
duction, they are generally unproductive (1·3 to 20 kg ha−1 year−1) due to deep
water (Yusoff et al., 1995). This phenomenon is attributed to the fact that the origi-
nal riverine species are not planktivores and are thus not able to exploit the open area
of these reservoirs; these fishes are mainly detrivorous (e.g. Puntius and Osteochilus
species) and carnivores (e.g. Channa and Hampala species) that are only able to
adapt well in the shallow littoral areas. Similarly, the large riverine species such
as Tor spp. (Malayan mahseers) and Neolissochilus spp. cannot adapt to the lentic
conditions (Ambak & Jalal, 2006). The threatened Malayan mahseers (Tor sp.) are
also severely limited by reduction of their natural food (wild seeds of dipterocarp
trees) due to river inundation.
Malaysian rivers are a degraded ecosystems. Rivers are subjected to impoundment,
diversion, channelization, sedimentation and pollution as a result of surrounding land
clearance and development. The clearing of riparian vegetation that flanks these rivers
destroys the breeding areas and food sources of fishes. River degradation has been
shown to have adverse effects on the native fish species as in the case of the Pusu
River (Klang River basin) where 40% of species had disappeared (Zakaria-Ismail,
1997). In the same river basin, the Gombak River has lost 60% of its indigenous
fish species over the last 20 years mainly because of water quality problems (Ho,
1994). In the large Perak River, Khoo et al. (1987) reported the loss of six of nine
commercially exploited species due to habitat degradation, pollution and overfishing.
Peat swamps in Peninsular Malaysia used to cover 0·67 million ha (1981) but
has dwindled to 0·34 million ha within a decade due to loss from logging, aquacul-
ture, agriculture, industries and human settlements (UNDP, 2006). Of the remaining
peat-swamp forest, 67% are designated as permanent forest reserves (PFR), while the
remainder is stateland forests that could be converted for other land use. Although
logging in PFR is permitted on a sustainable basis, the logging activity (including
run-over, trampling, log retrieval and increased turbidity) and forest fires have been
reported to be detrimental to peat swamp fishes (Lee, 2003).
The various coastal habitats have been traditionally and commercially utilized in
many ways, either directly (use of in situ marine organisms or their products) or
indirectly (any form of alienation of the habitat to various human uses, e.g. aqua-
culture). Often such uses lead to overexploitation of the fish resources within, and
the wide-scale destruction or degradation of these habitats by land use (Table V).
Both effects are considered deleterious to fish diversity and abundance. Although
mangrove forest reserves in Malaysia have contracted by c. 14% from 505 345 to
445 802 ha (1980 to 2004), five of 13 states have lost between 31 and 85% (Chong,
2007b). The causes of mangrove destruction or degradation are varied but the main
causes are due to agriculture, urbanization and aquaculture development. Nonethe-
less, the latest expansion of Port Klang, Malaysia’s largest port, and urbanization
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2044 V. C . C H O N G E T A L .
Table V. Causes of loss or degradation of selected freshwater and coastal habitats in
Malaysia (modified from Chong & Sasekumar, 2002b)
Causes of damage Rivers Peat swamp Mangrove Seagrass Coral reef
Forestry (overexploitation) x x x
Illegal logging x x x
Agriculture x x x x
Fishing x x
Aquarium–live–curio trade x
Aquaculture x x x
Mining (aggregates, minerals and oil) x x
Salt pan–ponds x
Pollution* x x x x x
Waste disposal x x x x
Airports x x
Ports and harbours x x
Boat traffic x x
Dredging x x x
Land reclamation x x x x x
Industrialization x x x x
Settlement–urbanization x x x x x
Recreation–tourism x x
*They include oil, industrial, nutrient and sedimentation.
have removed almost the entire mangrove forest that formerly occupied 6250 ha on
Indah Island, Selangor. A 35–50% fall in fisheries catches post-1990 despite a fall in
fishing effort has been attributed to concomitant 23% reduction in mangrove forests
in Peninsular Malaysia (Chong, 2007b).
Some 35% of the Malaysian coral reefs are reported to have <50% coral cover
(Chou, 1998). Sabah that has most of Malaysia’s coral reefs is reported to suffer
widespread dead coral cover in 70% of surveyed sites indicating a significant degree
of reef damage; only 10% of reefs have <10% dead coral (Pilcher & Cabanban,
2000). According to Burke et al. (2002), a total of 87% of Malaysia’s coral reefs
currently face medium to higher threat from human activities. The percentages of
reefs threatened by these activities are destructive fishing (68% of reefs), overfishing
(56%), sedimentation (23%), coastal development (23%) and marine-based pollution
(5%). Destructive fishing and reef damage in the 1990s are believed to be the main
causes of decline of Sabah’s coral-reef fishes (Pilcher & Cabanban, 2000). Blast
fishing kills all fishes in the area; >2500 dead fishes were counted over an area
<100 m2, mostly damsels, small fusiliers and juvenile fishes (Oakley et al., 2000).
Formerly pristine coral reefs off Semporna (Sabah) were ruined by blast fishing and
cyanide fishing.
The loss of seagrass beds has not been quantified, but the main threats are siltation
caused by coastal reclamation and development, as well as aggregate dredging and
shellfish harvests by digging (Japar et al., 2006). The single largest tract of seagrass
bed in Peninsular Malaysia at the Pulai River estuary faces the largest threat from
first, the development of a container port at Tanjong Pelepas, and now, port opera-
tions, siltation and pollution including from nearby Singapore. Just south of the Pulai
© 2010 The Authors

seagrass bed, the mangrove forest at Tanjong Piai, a recently declared Ramsar site,
is beset with coastal erosion problem aggravated by ship-induced waves. A total of
57 coastal reclamation projects involving 27 810 ha of coastal mudflats have been
reported on the west coast of Peninsular Malaysia (NAHRIM, 1997).
Human disturbance
Trawls continuously scour the sea bottom, which not only destabilizes the subtidal
habitats of bottom-dwelling fishes such as soles, gobies, flounders and flatheads but
also disturb their breeding and feeding activities. Sediment disturbance and changes
in turbidity, oxygen level and water chemistry often stress fish populations so that
only the hardiest species such as ariid catfishes can survive the reduced water quality.
Trawling interactions with the bottom meio and macroinvertebrate community, a
source of food for fishes, are likely, although these have not been fully studied. Such
disturbed areas as in Selangor are now observed to be heavily colonized by a starfish
Luidia penangensis and sea cucumber Acaudina molpadioides (pers. obs.).
Overharvesting
The present marine fish landing in Malaysia is c. 1·2 million t (Annual Fisheries
Statistics, 2005), a figure that had arisen by about five times since fisheries statistics
were first documented in 1961. The contribution of fish catch from the inshore sector
is c. 82%, the remainder 18% comes from the deep-sea sector. Present freshwater
or inland fisheries harvests, however, amount to only 4600 t annually mainly from
reservoir fisheries (Annual Fisheries Statistics, 2005).
Abu-Talib et al. (2000) reported that the average catch rate of inshore areas in
the Strait of Malacca (Malaysian side) had declined by 80% from 141·7 kg h−1
(1972) to 25·9 kg h−1 (1992), while in offshore waters, the average catch rate fell
by 59% from 1987 to 1997. They also noted changes in the species composition of
both offshore and inshore waters, where in the former, saurids and priacanthids now
dominated when in the past lutjanids were dominant by mass. Their comparison of
the inshore catch composition for trawl surveys carried out in 1970 and 1992 by
the fisheries department gave the following results: (1) Mullidae that was the most
highly ranked group based on abundance in 1970 dropped to eighth place in 1992, (2)
squids (Loligoidae) moved up from ninth position in 1970 to first position in 1992,
and consistently assumed first or second position since 1980, (3) disappearance of
the false trevally Lactarius lactarius (Bloch & Schneider), the once dominant species
of the 1960s when they contributed 3% of the total catch and (4) new species that
appeared in 1992 included the priacanthids and ribbonfishes.
The coastal demersal fishes in Sarawak and Sabah were reported in 1998 to be also
overfished and heavily overfished, respectively, while the offshore demersal fishes
as well as coral fishes in Sabah were heavily overfished (Oakley et al., 2000). The
live reef food-fish trade (LRFFT) is one of the main contributory factors to selective
reef-fish depletion including reef damage due to extreme fishing methods. In Sabah,
the humphead wrasse Cheilinus undulatus Rüppell are taken by hook-and-line and
cyanide often as juveniles that are grown out in cages before they are exported in
quantities that have steadily increased over the years. Cheilinus undulatus exports
to Hong Kong increased from 2402 kg in 1999 to 9951 kg in 2003 (Sadovy et al.,
2003). Groupers are also subjected to threats from overfishing for the LRFFT and
© 2010 The Authors

2046 V. C . C H O N G E T A L .
have emerged as a particular vulnerable group of fishes due to selective fishing,
which targets spawning aggregations and multiple life-history phases. Together with
the C. undulatus, the coral hind Cephalopholis miniata (Forssk˚al) and the polka dot
grouper Cromileptis altivelis (Valenciennes) are also popular fishes for the LRFFT
to Hong Kong, Taiwan and Singapore. A large portion of the grouper export of 394 t
to Hong Kong in 1998 came from Sabah (Biusing, 2001).
Seahorses (Syngnathidae) are traded as traditional Chinese medicines with an
annual global market trade of 20 million seahorses (Vincent, 1996). According to
Choo & Liew (2005), the annual exploitation and trade of seahorses in Malaysia
accounted for at least 565 000 seahorses that were exported overseas to China, Tai-
wan and Hong Kong, a figure that is far greater than previously thought. Although
seahorses are mainly caught by trawlers, they are also targeted by artisanal fishermen
using drift nets and scoop nets in shallow mangrove estuaries. Seahorse populations
of all species in Peninsular Malaysia are fast disappearing due to overharvesting.
In Sabah, the bottom gillnets, which could span several kilometres long, indis-
criminately catch sharks (Selachii), rays (Batoidea), guitar fishes (Rhinobatidae),
trevallies (Carangidae), tunas (Scombridae) and turtles (Cheloniidae). Illegal fishing
methods and overfishing have apparently caused a decline in fish diversity and abun-
dance in the Bodgaya Islands (Sabah), which once had the highest diversity of reef
fishes. One consequence of overfishing trigger fishes is the population explosion of
sea urchins (Pilcher & Cabanban, 2000).
Freshwater fishes are an important cheap source of protein to the inland, riverine
rural communities. Most of the freshwater fishes in Malaysia are being overfished,
in particular, the large riverine fishes such as mahseers, P. jullieni and pangasiids.
Overfishing coupled with the degradation of the riverine environment by pollution
and siltation has led to the demise of the riverine fisheries. The current focus is
on freshwater aquaculture and to some extent, reservoir fisheries. Certain species
such as the Asian bony tongue Scleropages formosus (Müller & Schlegel) and some
Bettas spp., however, are believed to be overfished for the ornamental fish trade.
By-catch
By-catch or accidental catch in fishing gears kills large numbers of unintended
species. The by-catch problem is due to the introduction of trawl fishing in 1965,
which by the mid-1970s had intensively targeted the abundant prawn resource in
coastal waters. Codend mesh sizes became smaller and smaller to increase the trawl’s
efficiency in harvesting most commercially valuable prawns. It has been estimated
that for every unit mass of prawns caught, about two to four times the mass of trash
fishes are caught (Chong, 1984).
Trawl fishing in Malaysia contributes 54% of the total marine fish landing, while
the latter comprised 25% trash fishes (Annual Fisheries Statistics, 2005). Trawl fish-
ing accounts for 90% of the annual total trash fishes of c. 300 000 t. Between 30
and 60% of the catch of artisanal fishing gears such as beach seines, tidal bag nets
and scoop nets (permitted by law to operate within 9·26 km (5 nautical miles) of
coastal waters) are trash fishes. Research trawl surveys carried out by the fisheries
department (FD) from 1971 to 1988 (nine surveys), however, indicate that the aver-
age catch rate of trash fishes varied from year to year, from 6·2 to 43·3% with no
definite pattern (Ahmad Adnan, 1997). The 1988 FD trawl survey reported at least
© 2010 The Authors

58 species of fish species or taxa, including leiognathids, apogonids, cynoglossids,
bothids, gobiids, teraponids, mullids, nemipterids, scorpaenids and rays.
Pollution
Pollution from land-based sources is the most serious, particularly in the Strait of
Malacca where the west coast of peninsular Malaysia has the largest concentration of
human population. The amount of pollutants discharged into the rivers and then into
the strait in 1989 were biological oxygen demand (BOD) 64 000 t year−1
, chemical
oxygen demand (COD) 100 000 t year−1, total nitrogen 4200 t year−1, total phos-
phorus 500 t year−1 and total suspended solids (TSS) 75 000 t year−1 (Chua et al.,
1997). The sources of these pollutants are from agricultural and animal husbandry
practices, sewage and domestic waste disposal, soil erosion due to land clearing
and development, agri-industries and other industrial and manufacturing industries.
The 1987–1996 TSS value of the strait’s waters ranging from 100 to 200 mg l−1
had then exceeded the 50 mg l−1 interim standard adopted by the Department of
Environment. The BOD measurements ranged from 1·33 to 9·95 mg l−1, while low
dissolved oxygen (DO) of 1 to 2 mg l−1
were also observed in some areas, particu-
larly in Juru (Penang), Chuah (Negeri Sembilan) and in the Penang and Johor Strait
(Chua et al., 1997). Although legislative measures were adequate for controlling pol-
lution, enforcement had been ineffective due to shortage of manpower, funds and
facilities (MOSTE, 1997).
Recent reports by WEPA (2009) shows vast improvement in water quality attributed
to good environmental management practices and increased enforcement. In 2006,
of the 146 river basins that were monitored according to the water quality index
(WQI), 80 river basins were considered clean, 59 slightly polluted and seven were
polluted. The TSS values recorded from coastal waters, however, still exceeded the
interim marine water quality standards (IMWQS) in 75% of 229 monitoring stations
and similarly for E. coli (55%) and oil and grease (35%). Sources of TSS are from
agriculture and tourism activities, coastal reclamation, logging and road construction.
The sources of E. coli are from domestic and animal wastes, while oil and grease
are discharged from vessels during tank cleaning, deballasting, bilges and bunkering,
and leakages and disposal of oil from vessels.
SOME SPECIES OF CONSERVATIO N PRIORITY
Descriptions of the two locally extinct and several highly threatened species
are provided below. The locally extinct fishes and some highly threatened species
(Table III) could be considered for restocking in the wild with careful consideration.
Freshwater species
Balantiocheilos melanopterus (Cyprinidae) is listed as endangered in the Red List
(IUCN, 2009), but in Malaysia it is considered LE. This is a classic example of
how the aquarium trade can cause local extinction. The supply of this very popular
aquarium fish was very dependent on the wild stock. Juveniles and breeding adults
were overcollected causing the collapse of its wild population (Ng & Tan, 1997).
This fish was previously found in the Pahang and Perak River basins. In Perak,
however, it has not been caught since the 1950s (Zahaitun & Ali, 1996). In Pahang,
it has not been reported since the 1960s. Status: LE (6), (Red List, EN).
© 2010 The Authors

2048 V. C . C H O N G E T A L .
Another local fish known as umbut, N. microlepis (Cyprinidae) was evaluated and
given the LE status since it was reported >50 years ago and not seen since. This
species is, however, still found in Kalimantan (Indonesia), Cambodia and Vietnam.
This species is, however, not evaluated by IUCN. Status: LE (6), (Red List, NE).
The freshwater bladefin catfish Encheloclarias curtisoma Ng & Lim (Clariidae)
is restricted only to North Selangor peat-swamp forest (Ng & Lim, 1993). The peat
swamp, however, has been under tremendous development pressure where many for-
est compartments have been alienated, cleared and converted to oil palm plantations
and other uses. Other areas designated as production forest are being logged (Lee,
2003). Status: HT (5), (Red List, CR).
Another freshwater catfish Encheloclarias kelioides Ng & Lim (Clariidae) was first
collected in the 1930s in southern Johor and described as Encheloclarias
tapeinopterus (Bleeker). Further specimens were again collected in 1992 near Kuan-
tan when it was described as E. kelioides. These collection sites were subsequently
destroyed due to rapid and extensive development of its habitat (Ng & Lim, 1993).
The current population status is not known; hence, it is maintained as a highly
threatened species. Status: HT (5), (Red List, CR).
The small black fighting fish Betta persephone Shaller (Osphronemidae) is
restricted to and endemic to peat-swamp forest in south-western Johor. Betta perse-
phone was last collected from Ayer Hitam area in 2006 (H. H. Tan, pers. comm.).
Recent attempts to collect this specimen have not been successful as the known col-
lection sites have been converted to oil palm plantation or being degraded (D. Yong,
pers. comm.). Status: HT (5), (Red List, CR).
The white-edge freshwater whipray Himantura signifier Compagno & Roberts
(Dasyatidae) is known to be distributed from Thailand, Sumatra to Borneo. It is
possibly the only species of Himantura known to be found in fresh water. It was
first reported in the Perak River by Taniuchi (1979) as Dasyatis bennetti (Müller
& Henle) but subsequently identified as H. signifier after taxonomic revision by
Compagno & Roberts (1982). Since then, there was no further report of this species
from the river. Its long absence coincided with the construction of four dams at
the headwaters of the Perak River. The dams alter the river flow regime, and with
pollution, it is believed that the species has become locally extinct in Perak (K. H.
Khoo, pers. comm.). During a year-long fish survey in the large Pahang River in
1993, only a single specimen was caught in the lower reaches of Pahang River (Khan
et al., 1996). A 6 year study of elasmobranchs funded by SEAFDEC (1999–2004)
reported five specimens endemic to only the upper reaches of the Pahang River (Yano
et al., 2005). This fish is popularly sought as a table food and aquarium fish. Status:
HT (5), (Red List, VU).
According to Ng & Tan (1999), the freshwater whiptail H. chaophraya (Dasyati-
dae) was reported by sport fishers in Endau River basin. This was the first report of
its presence in Peninsular Malaysia. Positive confirmation of its rarity came from a
single specimen collected from Buket River, Sabah, in 1997 during the 18 month
long Shark Specialist Group’s Darwin Project on elasmobranch biodiversity and
conservation (Yano et al., 2005). The species is reported to be now present only in
the Kinabatangan River in Sabah (Yano et al., 2005). Status: HT (5), (Red List, NE).
The Asian bony tongue S. formosus (Osteoglossidae) is currently under threat from
overharvesting for the aquarium trade, especially the red and golden varieties, which
are highly prized and are only found in freshwater swamps in Kerian and Bukit
© 2010 The Authors

Merah. The green variety, present in Lake Bera and Lake Temenggor, although not
highly prized, is also harvested extensively. The pressure on this species, however,
has been eased due to successful commercial breeding. Nevertheless, the threat of
habitat degradation to the natural populations is still a concern. Status: MT (4), (Red
List, EN).
The masheers or kelah T. douronensis, T. tambra and T. tambroides (Cyprinidae)
are classified as moderately threatened in Malaysia because only in totally protected
areas, such as the National Park, are the populations stable. These species prefer
clean, swift flowing waters. They are highly sought after as food fishes and of great
interest to sport fishers. Unfortunately, exploited wild populations have not shown
good recovery and conservation measures have not been taken to protect their habitat.
Status: MT, (Red List, NE).
Estuarine species
The largetooth sawfish Pristis microdon Latham (Pristidae) is an intertidal and
estuarine elasmobranch that is known to migrate up freshwater rivers including lakes.
It also probably breeds in fresh water (Yano et al., 2005). In 1959, the species was
reported to be common in Malaysia but only two specimens (one measuring 456 cm
total length, LT ) were captured by trawlers in the Malacca Strait from 1996 to 2004
(Yano et al., 2005). Older fishers claimed that the fish used to occur at the large
Pahang River (P. K. Y. Lee, pers. obs.). Status: HT (5), (Red List, CR).
The longcomb sawfish Pristis zijsron Bleeker has the same habitat as P. microdon.
One large specimen (610 cm LT) was caught during the SEAFDEC (1996–2004)
survey in 2002 off Bintulu, Sarawak (Yano et al., 2005). The fish used to be caught
by gillnets and trawls. Status: HT (5), (Red List, CR).
Another species of sawfish Anoxypristis cuspidata (Latham) (Pristidae) was
reported to occur in Pahang River (five specimens), Tembeling, and in Aur River,
Port Klang, by Chan (1954). At the latter site, he observed one specimen (1·83 m
LT, 22·7 kg) caught by a local fisher using a hand-line baited with a grey mullet
(Mugilidae). When the A. cuspidata’s belly and stomach were slit open, he saw a
full grown Plotosus canius Hamilton (Plotosidae). The A. cuspidata could be another
Malaysian sawfish species or a misidentified P. microdon. If this is a third species,
it is in all likelihood extinct. The Aur River area is now developed as part of the
Port Klang municipality. Status: HT (5), (Red List, CR).
The tropical shad Tenualosa toli (Valenciennes) (Clupeidae), locally called
terubok, lives in fast-flowing, turbid estuaries and adjacent coastal waters. The fish
used to be very common and harvested in large numbers in Peninsular Malaysia
and Sabah (Gambang, 1988), but their numbers have decreased considerably with
no present fishery [it is, however, possible that the peninsular species is Tenualosa
macrura (Bleeker) (Blaber, 2000)]. Although the fish was reported to be present in
all coastal waters and estuaries in Sarawak, it is now believed to be mainly confined
to the Batang Lupar River and a very few nearby estuaries where it is harvested
for its meat and its highly priced roe (Gambang, 1988). This fish is a protandrous
hermaphrodite migrating up the middle reaches of the estuary as a male to spawn
before changing into a female (Blaber et al., 1996). Status: MT (4), (Red List, NE).
© 2010 The Authors

2050 V. C . C H O N G E T A L .
Marine species
The oriental sole Brachirus orientalis (Bloch & Schneider) (Soleidae) is believed
to be anadromous ascending rivers to spawn, just like T. toli (GBIF). This species
has not been reported in Malaysia except in 1998 by Sasekumar (1999) who recorded
one specimen from the Pulai River estuary, Johor. The habitat type is of mixed man-
grove and seagrass. The species has a wide distribution in the region; Singapore has
10 records of the species dating from 1904 to 1984 (mostly undated), the last was
collected from Angler Buoy in 1984 (GBIF). Its rarity is probably due to habitat
degradation, human disturbance and pollution. Status: HT (5), (Red List, NE).
The Malabar tongue sole Cynoglossus macrostomus Norman (Cynoglossidae) is
another rare flatfish recorded only from the Pulai Estuary (Sasekumar et al., 1990).
The GBIF shows one record of the species in western Sumatra, four in Pakistan and
16 in southern India. Status: HT (5), (Red List, NE).
The small-scaled terapon Terapon puta Cuvier (Terapontidae) is currently known
in the Pulai Estuary (Sasekumar et al., 1990), but later visits to the site in 1998
(Sasekumar, 1999) and from 2008 until present yielded none. According to the GBIF,
this species has a single record in Penang (East Indies), collected in 1860, and another
record in Brunei Bay (Sipitang), collected in 1984. There are many records, however,
of its presence in the Philippines, Thailand, Sri Lanka and Australia. Hence, it is
considered only locally endangered. Status: HT (5), (Red List, NE).
The Commerson frogfish Antennarius commerson (Latreille) (Anthennariidae) was
listed by Sasekumar (1999) in his fish collection from the Pulai Estuary. Present
surveys in the estuary since 2008 show none. Although a cosmopolitan species, its
occurrence is rarely reported in south-east Asia; one record each from Singapore and
Indonesia (Ambon) dating back to 1908 and 1828, respectively, (GBIF). This species
appears to be a local critically endangered species. Status: HT (5), (Red List, NE).
The whiteline cardinalfish Apogon cavitensis (Jordan & Seale) (Apogonidae) was
also collected from the seagrass beds of the Pulai River estuary (Sasekumar, 1999).
This species appears to be locally rare, with more frequent occurrences in the Philip-
pines and Australia. It has one record each from Singapore (Salu Islet) and Indonesia
(Ambon) (GBIF). Status: HT (5), (Red List, NE).
The Indian humphead Kurtus indicus Bloch (Kurtidae) has a distribution from
the Indian Ocean to the tropical west Pacific Ocean. Malaysia has nine previous
records dating from 1863 (Penang), 1894 (Sarawak) and 1963 (Johor) according to
GBIF. The two recent and only collections of the species were from Selangor coastal
waters (between Penang and Johor), one specimen during a 15 month trawl survey
from 1996 to 1998 (Zgozi, 2007) and four specimens collected from impingement
screens at the Kapar power plant during a 2 month study in 2004 (Azila, 2005). This
indicates its rarity and low abundance, and hence its status as highly threatened at
the local level. Status: HT (5), (Red List, NE).
The star snapper Lutjanus stellatus Akazaki (Lutjanidae) was first recorded in
Malaysia and the region in 2003 (Chong et al., 2005a). One pair was caught in the
Kilim Estuary (Langkawi), a mixed mangrove–reef habitat. Two more subsequent
visits in 2005 and 2006 yielded none of the species. Lutjanus stellatus has so far
being recorded from southern Japan to Hong Kong and never previously reported
in the Indian Ocean (Allen, 1985). It does appear to be endemic to this part of the
island, which has recently being declared the region’s first UNESCO Geopark. This
status, however, does not accord protection of its marine resources, and the various
© 2010 The Authors

estuaries and adjacent coastal waters are fished by artisanal fishers. Status: HT (5),
(Red List, NE).
The mottled eagle ray Aetomylaeus maculatus (Gray) (Myliobatidae) was recorded
in the Kisap River estuary (2003) and the coastal Peluru Strait (2004) in Langkawi
(Chong et al., 2005b). Only one specimen each was sampled from these waters of
mixed mangrove and coral. While the global record of this species is only 15, an
undated record of its presence in the Straits Settlement or Penang as it is now known
(GBIF) suggests a collection before 1947. Status: HT (5), (Red List, CR).
Cheilinus undulatus (Labridae) is globally listed as endangered in the Red List
(EN A2bd+3bd). It is also the first coral-reef fish to be listed in the appendices of
CITES. This is due to overharvesting and its high value in the live reef-fish trade of
Asia (Sadovy et al., 2003). The fish’s vulnerability is due to its slow attainment of
sexual maturity (5 years), protogynous hermaphrodism and slow population turnover.
In the Bodgaya and Sipadan islands, Sabah, this fish was reported by Wood & Wood
(1987) to be rare in 1980, but occasional (10–50 individuals in total of all dives) by
Allen (1992). In its habitat, the species is threatened by unsustainable illegal fishing
methods including blast and cyanide fishing. Status: MT (3), (Red List, EN).
The hedgehog seahorse Hippocampus spinosissimus Weber, spotted seahorse Hip-
pocampus kuda Bleeker and longnose seahorse Hippocampus trimaculatus (Leach)
(Syngnathidae) are all globally listed as vulnerable (VU A4cd) in the Red List and
in CITES, Appendix II. According to Choo & Liew (2005), populations of all three
species are rapidly declining due to trawl activity (particularly H. spinosissimus
and H. trimaculatus) and their occurrence as by-catches. These are traded as tradi-
tional Chinese medicines. Hippocampus kuda although appearing more protected in
mixed mangrove and seagrass habitats is, however, targeted by traditional fishers.
Hippocampus kelloggi Jordan & Snyder appears more rare (Choo & Liew, 2005).
Status: LT (3), (Red List, VU).
Vulnerability due to endemicity
Endemicity poses extinction risks to fishes that have long evolved and adapted
themselves to specific environmental conditions. Endemic fishes are therefore vulner-
able to environmental changes such as habitat degradation, human disturbance and
pollution. The number of endemic fish species in Malaysia cannot be determined
fully or with certainty because of the lack of extensive freshwater fish surveys and
information of freshwater fishes in the region. There are, however, almost no endemic
marine fishes (given the present knowledge) attributed to the fact that marine waters
are relatively more homogeneous and habitats are less isolated. Elsewhere there are
exceptions, e.g. Harrison’s dogfish Centrophorus harrissoni McCulloch and south-
ern dogfish Centrophorus uyato (Rafinesque) in Australia, and damba mipentina
Paretroplus maculatus Kiener & Maugé in Madagascar (Baille et al., 2004).
The present compilation gives 81 endemic species of freshwater fishes, of which
58 species are from East Malaysia and are restricted to mainly clear, fast-flowing hill
streams with rocky beds (Table VI). Fifteen species or about a fifth of the endemic
species are from blackwater habitats.
The Balitoridae dominates the East Malaysian endemic species. Of the 35 species
recorded from this family, 23 species belong to the genus Gastromyzon, which is
endemic to Borneo (Inger & Chin, 1961; Roberts, 1982, 1989; Tan, 2006). These
fishes exhibit significant morphological adaptations to bottom dwelling in torrential
© 2010 The Authors

2052 V. C . C H O N G E T A L .
Table VI. List of endemic freshwater fishes of Malaysia
Species Region Notes (occurrence; habitats)
Cyprinidae
Barbodes strigatus East Malaysia Sabah; rivers, streams
Hampala sabana East Malaysia Sabah; rivers, streams
Labiobarbus sabanus East Malaysia Sabah: Kinabatangan and
Segama basins
Nematabramis everetti East Malaysia Sabah; rivers, streams
Nematabramis steindachnerii East Malaysia Sabah; rivers, streams
Neolissochilus hendersoni Peninsular Malaysia Penang Island; streams
Osteochilus chini East Malaysia Sabah
Osteochilus ingeri East Malaysia Sabah
Paedocypris micromegethes East Malaysia Sarawak; peat swamps
Puntius dunckeri Peninsular Malaysia Johor: Pontian and Sedili;
acidic swamps.
Puntius sealei East Malaysia Sabah; rivers, streams
Rasbora hubbsi East Malaysia Sabah; rivers, streams
Cobitidae
Acantopsis octoactinotos East Malaysia Sabah
Lepidocephalichthys sandakanensis East Malaysia Sabah
Pangio alcoides Peninsular Malaysia Terengganu and Johor;
swamps, open areas with
leaf litter.
Pangio filinaris Peninsular Malaysia Pahang and Terengganu:
Tersat River; fast-flowing
clearwater forested streams
Balitoridae
Gastromyzon aequabilis East Malaysia Sabah: Kuamut drainage,
Kinabatangan basin;
fast-flowing rocky streams
Gastromyzon auronigrus East Malaysia Sabah: Sungai Kinarom
draining into Marudu Bay;
Gastromyzon bario East Malaysia Sarawak: Upper Trusan,
Limbang and Baram basins;
fast-flowing unshaded hill
streams with rocky and
large boulders
Gastromyzon borneensis East Malaysia Sabah: Mengalong basin;
Gastromyzon cornusaccus East Malaysia Sabah: Sungari Kinarom;
Gastromyzon crenastus East Malaysia Sarawak; fast-flowing rocky
streams
Gastromyzon danumensis East Malaysia Sabah: fast-flowing rocky
streams
Gastromyzon extrorsus East Malaysia Sabah: Kimanis and Petagas
River basins; unshaded
fast-flowing rocky rivers
and streams
© 2010 The Authors

Table VI. Continued
Gastromyzon farragus East Malaysia Sarawak; fast-flowing rocky
streams
Gastromyzon fasciatus East Malaysia Sarawak: Baleh River, Rejang
basin; fast-flowing rocky
streams
Gastromyzon ingeri East Malaysia Sabah: Tawau Hills Park,
Wallace Bay basins;
Gastromyzon introrsus East Malaysia Sabah: Padas and Labuk River
basins; unshaded
fast-flowing rocky rivers
and streams
Gastromyzon katibasensis East Malaysia Sarawak: Lanjak Entimau, Ulu
Katibas drainage, Rejang
streams
Gastromyzon megalepis East Malaysia Sarawak: Rejang basin;
Gastromyzon monticola East Malaysia Sabah: Wariu and Marudu Bay
basins; fast-flowing rocky
streams
Gastromyzon ocellatus East Malaysia Sarawak: Bau, Sarawak basin;
Gastromyzon pariclavis East Malaysia Sabah: Kuamut, Kinabatangan
basin
Gastromyzon scitulus East Malaysia Sarawak: Serian, Sadong
streams
Gastromyzon spectabilis East Malaysia Sabah: Segama River basin;
Gastromyzon stellatus East Malaysia Sarawak: Sarawak, Sadong
and Lupar River basins;
Gastromyzon viriosus East Malaysia Sarawak: Tatau River basin;
Glaniopsis denudata East Malaysia Sabah
Glaniopsis hanitschi East Malaysia Sabah
Hypergastromyzon eubranchus East Malaysia Sarawak: Lupar basin;
Nemacheilus elegantissimus East Malaysia Sabah
Neogastromyzon chini East Malaysia Sarawak: Rejang, Lupar and
Sadong River basins;
Neogastromyzon pauciradiatus East Malaysia Sarawak: Baleh River, Rejang
streams
Protomyzon aphelocheilus East Malaysia Sabah
Protomyzon borneensis East Malaysia Sabah
© 2010 The Authors

2054 V. C . C H O N G E T A L .
Table VI. Continued
Protomyzon griswoldi East Malaysia Sabah
Protomyzon whiteheadi East Malaysia Sabah
Sundoreonectes sabanus East Malaysia Sabah
Sundoreonectes tiomanensis Peninsular Malaysia Pahang: Tioman Island; stream
flowing through a cave.
Bagridae
Leiocassis doriae East Malaysia Sarawak
Leiocassis merabensis East Malaysia Sabah
Hemibagrus gracilis Peninsular Malaysia Clear and fast-flowing forested
streams.
Hemibagrus sabanus East Malaysia Sabah
Hyalobagrus ornatus Peninsular Malaysia Streams
Nanobagrus nebulosus Peninsular Malaysia Streams
Pseudomystus robustus East Malaysia Sabah
Pangasiidae
Pangasius kinabatanganensis East Malaysia Sabah
Akysidae
Akysis microps Peninsular Malaysia Streams
Pseudobagarius alfredi Peninsular Malaysia Pahang: only known from
Tasek Bera; small
slow-flowing forested
streams with acidic waters.
Siluridae
Wallago maculatus East Malaysia Sabah; rivers and tributaries
Clariidae
Clarias batu Peninsular Malaysia Pahang: Tioman Island; fast
and torrential rocky streams.
Encheloclarias curtisoma Peninsular Malaysia Selangor: Bernam; peat
swamp forests
Encheloclarias prolatus East Malaysia Sarawak: Kuching;
peat-swamp forests
Mastacembelidae
Mastacembelus keithi East Malaysia Sabah
Gobiidae
Stenogobius ingeri East Malaysia Sabah
Stiphodon aureorostrum Peninsular Malaysia Pahang: Tioman Island;
streams with slow-moderate
flow.
Osphronemidae
Betta chini East Malaysia Sabah: Beaufort; peat-swamp
forests
Betta gladiator East Malaysia Sabah: Maliau basin; heath
forest
Betta ibanorum East Malaysia Sarawak: peat-swamp forests
Betta livida Peninsular Malaysia Selangor: Bernam;
peat-swamp forests
Betta persephone Peninsular Malaysia Johor: Ayer Hitam;
peat-swamp forests
© 2010 The Authors

Diversity, extinction, conservation of Malaysian fishes 2010 JFB v76

Diversity, extinction, conservation of Malaysian fishes 2010 JFB v76

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