Original Article Study of Diversity and Morphometry in Edible Bivalves
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1 Original Article 2 Study of Diversity and Morphometry in Edible Bivalves and Gastropods from a Coastal 3 Wetland in Sarawak 1* 3 1 1 4 Mohd Hanafi Idris , Hadi Hamli , Abu Hena Mustafa Kamal , Roslizawati Ab Lah , Nik 5 Mohd Shibli Nik Jaafar2 6 7 1Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, 8 Terengganu, Malaysia 9 2Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala 10 Nerus, Terengganu, Malaysia 11 3Department of Animal Science and Fishery, Faculty of Agriculture and Food Sciences 12 Universiti Putra Malaysia Bintulu Sarawak Campus 13 Nyabau Road, P.O. Box 396, 97008, Bintulu, Sarawak, Malaysia 14 *Corresponding author, Email address: [email protected] 15 16 Abstract 17 Diversity and morphometry of edible, bivalve and gastropod classes of mollusc were 18 investigated from July e82010 to January 2012, for a particular set of bivalve species, at 19 selected coastal divisions of Sarawak including Kuching, Sibu, Mukah, Bintulu, Miri, 20 Limbang, and Lawas. A total of 41 edible species were recorded and identified; comprising 21 11 families of gastropods represented by 21 species, and 12 family of bivalves represented by 22 20 species. For bivalves, species of the family Cyrenidae (Geloina erosa, G. expansa and G. 23 bengalensis) were more widely distributed than bivalve species. The gastropod, family of 24 Potamididae (Cerithidea obtusa, C. quadrata, C. rizophorarum and Telescopium 25 telescopium) were also commonly observed along the entire seven divisions. Species 26 diversity was found to be highest in Bintulu division for both classes, and consisted of 13 27 species of gastropod and 11 species of bivalve. Jaccard’s index showed high similarity 28 amongst edible bivalves for Limbang division versus Miri division (0.75), and for Limbang 29 versus Lawas (0.75). For gastropods, Sibu versus Mukah showed higher similarity (0.50). 30 Morphometric study of bivalves indicated that VPM/SL and LCT/SL features were 31 applicable as an identification key to differentiate between Geloina spp. This morphometric 32 identification key could be developed further for identification of other species in the mollusc 33 family. 34 35 Keywords: Edible gastropod, bivalve, diversity, distribution, Sarawak 36 37 1. Introduction 38 The State of Sarawak, Malaysia contains vast areas of wetlands, including brackish 39 water, coastal marine, and mangrove areas. The state wetlands comprise contains 1.24 million 40 hectares which covers 13% of the state’s total land area (Page, 2011). This wetland provides 41 support for extensive floral and faunal biodiversity. Molluscs are part of the faunal 42 composition of the wetlands of Sarawak, and one of the most important protein resources to 43 surrounding human the communities. Apart from providing good nutrition, molluscs play an 44 important economic role in Sarawak. 45 The contribution of edible mollusc to local economies within Sarawak is high, 46 notwithstanding, this resource has yet to be well documented. To the best of our knowledge, 47 only a few studies have documented species of bivalves and gastropods occurring in 48 Malaysia; (Hamli et al., 2015a; Hamli et al., 2015b; Idris et al., 2011; Abdullah, Sidi, & Aris, 49 2007; Sallih, 2005; Abu Hena et al., 2004; Nakao, Nomura & Satar, 1989). Previous study 50 has recorded edible mollusc distribution in the tropical region of Thailand (Nateewathana, 51 1995), but it is difficult to develop an accurate figure for local consumption of edible bivalve 52 and gastropod species in Sarawak, Malaysia. This paper aims to investigate the diversity, 53 morphological characteristics and habitat of edible mollusc to improve information for the 54 selected division in Sarawak. The majority of the bivalve and gastropod species found in 55 wetland coastal waters of Sarawak, in the coastal divisions, hence this regional study provides 56 valuable information on bivalves and gastropods, which could be used to further develop bivalve and 57 gastropod fisheries in future. 58 59 2. Materials and Methods 60 2.1 Study Area 61 Samples were collected from native markets, and fish markets from the selected seven 62 divisions of Kuching, Mukah, Sibu, Bintulu, Sibu, Bintulu, Miri, and Lawas, Sarawak. 63 (Figure 1). Samples were preserved in ice-filled boxes and transferred to the laboratory for 64 further analysis and study. 65 2.2 Species Identification and Morphometric Study as a Demarcation Tool 66 The identification of bivalves was conducted following procedures common to a 67 number of researchers, namely, Morton (1984), Poutiers (1998), Mass, O’ Mullan, Lutz, and 68 Vrijenhoek (1999), Yuh-Wen, Hon-Cheng, Sin-Che and Chaolun (2001), and Okutani 69 (2017). Gastropod samples were identified following the studies by Nateewathana (1995), 70 Kohler and Glaubrecht (2001), Poutiers (1998), Perez, Clark and Lydeard (2004), Tan and 71 Clements (2008), and Mujiano (2009). Specimens of bivalve and gastropod were measured 72 according to morphometric characteristics using digital Mitutyo vernier calliper (0.01±mm) 73 (Hamli et al., 2015a and Idris et al., 2008). A total of 20 characteristics (15 for bivalve and 5 74 for gastropods) were used to differentiate the species (Table 1; Figure 2). 75 The current morphometric focused only on a single genus of bivalve from Geloina 76 genus (G erosa, G. expansa, G. bengalensis.) with a total of 436 matured individuals. The 77 sum of 15 shell morphometrics, numbered one through fifteen (Table 1) had been measured, 78 which were then divided by shell length to convert the measurements to proportionate ratio 79 by size, for each Geloina species. 80 2.3. Statistical Analysis 81 Measurements of collected species from the selected Sarawak divisions were 82 correlated with geographical source to establish a distribution pattern. Similarities in species 83 numbers within the respective divisions were evaluated as either present (1), or absent (0) 84 based on Jaccard’s Index (Ludwig & Reynolds, 1988). 85 Jaccard’s Index = A/(A+B+C) 86 Where 87 A = total number of species present in both communities 88 B = the number of species present in community 1 but not at community 2 89 C = the number of species present in community 2 but not at community 1 90 The samples from the Geloina species, from the study areas in the present study were 91 chosen for morphometric differentiation within species by scrutinising shell proportion ratio 92 using analysis of variance (ANOVA) with general linear model (GLM), and using statistical 93 analysis computer software (SAS) version 9.1 (SAS Institute, 2004). 94 95 3. Results and Discussion 96 3.1 Distribution 97 A total of 41 edible species comprised 12 families of bivalves representing 20 species 98 (Table 2), and 11 families of gastropods representing 21 species (Table 3) were recorded, and 99 identified from seven divisions of Sarawak (Figures 3 and 4). Cyrenidae (Bivalve) and 100 Potamididae (Gastropod) families were widely distributed in seven and six divisions, 101 respectively. Bintulu division presented the greatest variety of bivalves and gastropods with a 102 total of 24 species (13 gastropods, and 11 bivalves) recorded, while Sibu division presented 103 only minor variation. 104 Mollusc species presented in this study were low when compared to Printrakoon, 105 Wells and Chitramvong (2008), and other studies, due to the current study focus on edible 106 species alone. Printrakoon et al. (2008), Frith, Tantanasiriwong and Bathia et al. (1976) and 107 Brandt (1974) recorded 47, 43 and 56 species of mangrove, coastal, and estuarine mollusc, 108 respectively in Thailand. Macintosh, Ashton and Havanon (2002) found 34 species of 109 mollusc in the Ranong biosphere reserve in Thailand. Jiang and Li (1995) recorded 52 110 species of in the Jiulong river estuary, China. However, the above studies were taxonomic, 111 diversity and distribution studies, rather than studies specific to edible molluscs in specified 112 coastal, tropical wetlands. The current study indicates that the diversity of edible mollusc in 113 this region is less, although Somchai (1995) reported that gastropods were a major class of 114 mollusc with high market value on Phuket Island, Thailand. 115 The marsh clams, Geloina erosa and G. bengalensis were both within the sampling 116 area. Within the Indo-Pacific area, they can be described under the subgenus Geloina 117 (Morton, 1984), which subgenus is also distributed in the mangrove area of China (Han et al., 118 2003), Australia (Wells, 1986) and Thailand (Printrakoon et al., 2008). Species Geloina 119 expansa (Bivalvia), Cerithidea rizophorarum, and C. obtusa (Gastropoda) were found 120 distributed within four divisions in Sarawak. Other gastropod and bivalve species were found 121 within one to three divisions only. Presence of G. erosa and G. bengalensis at almost study 122 area was equivalent with to presence of mangrove area at Sarawak. 123 124 3.2 Similarity Indices 125 Analysis of the similarity index, described above, showed high similarities for 126 bivalves in Limbang versus Miri (0.75), and in Limbang versus Lawas (0.75), and high 127 lower similarity for edible gastropod in Sibu versus Mukah (0.50). Similarities as low as 0.00 128 was observed for bivalves in Kuching versus Mukah divisions and in Lawas versus Kuching. 129 Similarities were also as low as 0.00 for edible gastropod in Lawas versus Sibu, Lawas versus 130 Mukah, Lawas versus Bintulu, Lawas versus Miri, Lawas versus Limbang, Bintulu versus 131 Sibu and Bintulu versus Mukah divisions. The similarity index value for edible bivalve and 132 gastropod between each division could probably account for or be related to the psence of 133 wide mangroves and muddy area supporting suitable habitats these molluscs. Furthermore, 134 Puri, Namboothri and Shanker (2014) described that increasing similarity of gastropod 135 communities showed a relationship with decreasing geographical distance between study 136 locations. 137 3.3 Morphometrics 138 Study on 14 calculated ratios of morphometric characteristics on Geloina erosa, G.