Ichthyofauna of Sungai Merbok Mangrove Forest Reserve, northwest Peninsular Malaysia, and its adjacent marine waters

Abstract

Sungai Merbok Mangrove Forest Reserve, encompassing the Merbok river estuary, was established as a permanent forest reserve in 1951 and is the second-largest intact mangrove forest patch in Peninsular Malaysia. Despite its importance, few studies have been conducted to assess its aquatic biodiversity. In this study, we surveyed the fish diversity of the Merbok river estuary, and its adjacent marine waters. We recorded 138 fish species belonging to two classes, 18 orders, 47 families, and 94 genera. The richest order is Perciformes, with 32 recorded species, represents 23% of the alpha diversity, followed by Carangiformes with 21 recorded species or 14% of the diversity. Low taxonomic diversity overlaps with previous inventories and indicates that the inventory is still incomplete. All specimens examined are catalogued and deposited in a local museum collection. The fish checklist presented here represents a step forward in the conservation of fish diversity in the Merbok river estuary.

DNA-based taxonomy of a mangrove-associated community of fishes in Southeast Asia

“…Aquaculture activities regularly import non-native seeds from various sources, with no or poor records of origins. The divergence observed within this species (4.12%) could be the consequence of the presence of both native and alien (escaped from aquaculture farms) individuals in Merbok estuary 15 .…”

“…The second case is interesting because the marking patterns of the specimens of D. nigroviridis and D. cf. fluviatilis are distinctly different 15 . However, the genetic distance between these two species is only 1.1%.…”

“…Our DNA barcodes reference library associated with voucher collections previously established 15 can be used for further biological evaluation and biomonitoring effort in Merbok Estuary and nearby regions. Future research endeavours to assess ecosystem health status in which a reference DNA barcoding library is needed, such as COI-based environmental DNA (eDNA) surveys or metabarcoding assays, can use this database.…”

“…Due to its biological, ecological, and socio-economic importance, the Merbok Estuary has been the focus of research during the last two decades, including some biodiversity inventories (trees and gastropods 13 ; shrimps 11 ; fishes 12 , 14 ; mangrove trees 10 ). The latest ichthyological survey has inventoried 138 fish species from 47 families in the estuary and adjacent marine environment, revealing a rich fish fauna 15 . However, because of taxonomical uncertainties when considering morphological characters alone, the identifications of some species were challenging, especially for some speciose families such as Mugilidae, Gobiidae or Eleotridae 15 .…”

“…The latest ichthyological survey has inventoried 138 fish species from 47 families in the estuary and adjacent marine environment, revealing a rich fish fauna 15 . However, because of taxonomical uncertainties when considering morphological characters alone, the identifications of some species were challenging, especially for some speciose families such as Mugilidae, Gobiidae or Eleotridae 15 . Furthermore, cryptic diversity is frequently encountered in tropical highly biodiverse regions 16 , 17 , and it is possible that some morphology-based species hide more than one species.…”