Climbing Gastropods of Setiu Wetland, Terengganu, Malaysia 1*Faridah
Mohamad, 2Fetysella Olyndra Juli, 1Nursalwa Baharuddin 1School of Marine and Environmental Sciences, 2School of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia *
[email protected]
Abstract: Studies on Gastropod diversity is scarce in Malaysia. Climbing
gastropods has got even less attention. This poster reports a few species of climbing gastropods from Setiu Wetland, Terengganu on the east coast of Peninsular Malaysia. From a three-month survey, we collected and identified seven genera from three sampling plots in the area i.e. Assiminea, Cassidula,
Cerithidea, Clithon, Dostia, Littoraria and Neritina. These gastropods were observed with different population sizes among the plots, and show some kind of microhabitat preference among the three sampling plots. A further analyses on the existing data and also a further study will be carried out in the area to get a clearer picture of the biology and behaviour of these climbing gastropods.
Introduction: Setiu Wetland is a marine/brackish water ecosystem on the
east coast of Peninsular Malaysia. It provides habitats for various types of invertebrates. Some species which lives in this intertidal areas have the ability to migrate according to tidal level and salinity. Among them are the climbing snails (Mollusca; Gastropoda) which comprises a few genera including Cerithiidae, Littorinidae and Amphibolidae. Other than found on muds, these snails could also be found hanging on leaves and trunks of mangrove trees. In 1981, Purchon reported 301 species (52 families) marine Gastropods in Malaysia. To date, the number was added up to 384 species, 38 of them could be found in Setiu Wetland (Wong and Arshad, 2011). The vertical distribution of mangrove gastropods has been reported elsewhere but very little information is available for Malaysian species. The migratory and climbing behaviour of the genus Cerithidea which is abundant in Malaysian mangroves are vastly studied (Hodgson & Dickens, 2012; Belgrad & Smith, 2014). Whereas the periwinkle of a genus Littoraria (as Littorina) is also widely reported to exhibit avoidance behavior of climbing up trees in salt marshes and mangroves around the world (Henry et al., 1993; Blanco & Cantera, 1999). We report the occurrence of some of these species from Setiu Wetland, Terengganu.
Materials and methods: Study site: Lagoon area at Setiu Wetland, Terengganu (Figs. 1&2) Study period: December 2015 to February 2016, low tide Sample collection: Gastropods residing on roots, trunks or leaves handpicked Sample identification: By morphological observation Identification guide: 1. WoRMS website 2. Pictorial guide by Nursalwa and Marshall (2014)
Fig. 5. Cassidula could be found congregating on the fronds and leaves of Nypa, and also on trunks and stems of Avicennia and Rhizophora trees.
N 05o40.958’ E 102o43.445’
N 05o40.669’ E 102o42.618’
Fig. 6. Cerithidea are normally found on stems and leaves of Rhizophora and Avicennia, with a few found climbing on the roots.
N 05o40.381’ E 102o42.949’
Fig. 1. Map showing the study location and specific sampling sites
Fig. 2. The setting of one of the sampling sites, showing2, stands of 1% 1,mangrove 0% Rhizophora and Nypa. 51, 8%
Results:
653 individuals from six genera of climbing snails were collected (Figs. 3&4). They could be found in all sampling sites with Cassidula sp. being the most abundant followed by Cerithidea sp. and Littoraria sp. These snails were found on various mangrove trees and on different parts as shown in Figs. 5-7, some in congregations and some as singletons.
235, 37%
147, 23%
Cassidula Cerithedia Littoraria Dostia
195, 31%
Fig. 3. Proportion of climbing snails found in Setiu Wetland
Assiminea Clithon
Fig. 7. Littoraria are found resting mainly on the underside of Rhizophora leaves, or on top of a protected leaf.
Conclusions: Our observation shows that these snails could climb on any tree,
occupy any elevated parts of the tree i.e. leaves, branches, fronds etc. and generally did not show any preference. However, we did observe larger congregation of Cassidula on Nypa fronds than Rhizophora trunks/stems. A closer look into the populations of climbing gastropods in Setiu Wetland should provide more data on these under-researched invertebrates from the east coast of Peninsular Malaysia.
Acknowledgements: 1. UMT teaching grant for undergraduate final year project. 2. Azwarfarid, Fawwaz, Calvin, Shikin, Anis & Rusman for field assistance.
References: • •
Fig. 4. Relative size of climbing snails in Setiu wetland. From left Cerithidea, Dostia, Littoraria, Cassidula, Neritina and Assiminea. Clithon is not shown.
• • • • •
Belgrad, B.A. & Smith, N.F. 2014. Effects of predation and parasitism on climbing behaviour of the marine snail, Cerithidea scalariformis. J. Exp.l Mar. Biol. Ecol. 458: 20-26. Blanco, J.F. & Cantera, J.R. 1999. The vertical distribution of mangrove gastropods and environmental factors relative to tide level at Buenaventura Bay, Pacific Coast of Colombia. Bull. Mar. Sc. 65(3): 617-630. Henry, R.P., McBride, C.J. & Williams, A.H.1993. Responses of the marsh periwinkle, Littoraria (Littorina) irrota to temperature, salinity and desiccation, and the potential physiological relationship to climbing behavior. Mar. Behav. Physiol. 24(1): 45-54. Hodgson, A.N. & Dickens, J. 2012. Activity of the mangrove snail Cerithidea decollate (Gastropoda: Potamididae) in a warm temperate South African estuary. Est. Coast. Shelf Sc. 109: 98-106. Nursalwa, B. & Marshall, D. J. 2014. Common Aquatic Gastropods of Brunei. Institute for Biodiversity and Environmental Research. Brunei. Purchon, R. D. & Purchon, D. E. A. 1981. The Marine Shelled Mollusca of West Malaysia and Singapore. Part I. General Introduction and an account of the collecting Stations. J. Mollusc. Stud. 47: 290-312. Wong, N. L. W. S. & Arshad, A. 2011. A Brief Review on Marine Shelled Mollusca(Gastropoda and Bivalvia) Records in Malaysia’. J. Fish. Aqua. Sc. 6 (7): 669−699.
