Construction of the Tok Bali channel-jetty and channelization of the Semerak River in Bachok had removed and reduced its fringing mangroves, nevertheless, the river modification has improved estuarine circulation. There was invasion of the estuary by at least 59 marine and euryhaline species, including 47 fish species, but prawn and crab fauna were poor. The fish in the estuary included economically-important species of leiognathids, lutjanids, catfishes, barracudas, pomfrets and squids. Bachok's coast provides habitat, feeding and nursery areas to mainly juveniles of 71 fish and 22 invertebrate species. Leiognathids, mullids, cephalopods and portunid crabs were the dominant coastal fishes and invertebrates. The coastal fish fauna including a few reefassociated species was much richer (59 species) to the north of Tok Bali jetty than south of it (16 species). The Leiognathidae with eight species displayed clear spatial distribution from coastal to estuarine waters.
ABSTRAKPembinaan terusan-jeti Tok Bali dan pelurusan Sungai Semerak di Bachok telah mengakibatkan kehilangan hutan bakau tebing sungai di kawasan sekitarnya. Walaupun bagaimanapun, pengubahsuaian sungai ini telah memperbaiki peredaran air di muara. Terdapat invasi kawasan muara oleh sekurang-kurangnya 59 spesis eurihalin, termasuk 47 spesis ikan, namun demikian bilangan fauna ketam dan udang adalah rendah. Spesies ikan yang ditemui di muara termasuklah spesis yang penting dari segi ekonomi seperti leiognatid (kekek), lutjanid (jenahak), catfish (ikan duri), barracuda (alu-alu), bawal dan sotong. Pesisiran Bachok menyediakan habitat, serta kawasan nurseri dan pemakanan bagi 71 spesies ikan juvenil dan 22 spesis invertebrata. Leiognathid (kekek), mullid (belanak), sotong dan ketam portunid merupakan ikan dan invertebrata pesisir yang utama. Kepelbagaian fauna ikan, termasuk beberapa spesis yang berkait dengan terumbu karang adalah lebih tinggi (59 spesies) di utara Tok Bali berbanding bahagian selatan. Spesis ikan kekek menunjukkan taburan spatial yang jelas dari pesisir ke muara sungai.