The Relative Gut Length and Gastro-somaticindexes of the Mudskipper Periophthalmodon septemradiatus (Hamilton, 1822) from the HauRiver
Authors: Quang Dinh Minh , Lam Tran Thanh , Tien Nguyen Thi Kieu 
Published: September 2018

This study provided an understanding of feeding habit and intensity of the mudskipper Periophthalmodon septemradiatus, which was a potential aquarium pet, by analyzing the relative gut length (RGL) andgastro-somatic (GaSI) indexes. Fish specimens were caught by fishing rods from the estuary in Soc Trang province to the upstream in An Giang province of Hau River during a period of one year from August 2017 to July 2018. Data analysis of a collection of 1,504 fishes showed that RGL did not change with fish size, resulting in the feeding habit of P. septemradiatus did not change with fish size. By contrast, the feeding habit of this mudskipper varied with place, month and season as the RGL significantly different between place, month and season, but both males and females fall into carnivorous fish as RGL was <1. Similarly, the feeding intensity of this specice did not change with fish size, as the GaSI was not significantly different among four fish size groups. Meanwhile, the mudskipper displayed spatial, temporal and seasonal variations in feeding intensity since GaSI significantly changed with place, month and season. The changes of feeding habit and intensity of P. Septemradiatus were not regulated by the interaction of fish size and place, fish size and season, and place and season. These results provided new knowledge on feeding habit and intensity of this fish specice, being used for the understanding of fish adaption and conservation in the study region.
Keywords
Gastro-somatic index, mudskipper, Periophthalmodon septemradiatus, relative gut length
References
[1] Murdy, E. O. & Jaafar, Z., Taxonomy and systematics review, In: Z. Jaafar, E. O. Murdy (eds) Fishes out of water: biology and ecology of mudskippers, CRC Press, Boca Raton, pp. 1-36, 2017 [2] Murdy, E. O., A taxonomic revision and cladistic analysis of the oxudercine gobies (Gobiidae, Oxudercinae), Australian Museum Journal, 11 (1989) 93.[3] Murdy, E., Systematics of Oxudercinae, In: R. A. Patzner, J. L. V. Tassell, M. Kovacic, B. G. Kapoor (eds) The biology of gobies, Science Publishers, New Hampshire, United States, pp. 99-106, 2011 [4] Bhatt, N. Y., Patel, S. J., Patel, D. A. & Patel, H. P., Burrowing activities of goby fish in the recent intertidal mud flats along the Navinal coast, Kachchh, Western India, Journal of the Geological Society of India, 74 (2009) 515-530.[5] Al-Hussaini, A. H., On the functional morphology of the alimentary tract of some fish in relation to differences in their feeding habits: anatomy and histology, Quarterly Journal of Microscopical Science, 3 (1949) 109-139.[6] Desai, V. R., Studies on fishery and biology of Tor tor (Hamilton) from river Narmada. I. Food and feeding habits, Journal of the Inland Fisheries Society of India, 2 (1970) 101-112.[7] Le, T., Nguyen, M. T., Nguyen, V. P., Nguyen, D. C., Pham, X. H., Nguyen, T. S., Hoang, V. C., Hoang, P. L., Le, H. & Dao, N. C., Provinces and City in the Mekong Delta, Education Publishing House, Ha Noi, 2006.[8] Khaironizam, M. Z. & Norma-Rashid, Y., First record of the mudskipper, Periophthalmodon septemradiatus (Hamilton) (Teleostei: Gobiidae) from Peninsular Malaysia, Raffles Bulletin of Zoology, 51 (2003) 97-100.[9] Wand, M. P., Data-based choice of histogram bin width, The American Statistician, 51 (1997) 59-64.[10] Vo, T. T. & Tran, D. D., Study on nutritional characteristics of Oxyeleotris urophthalmus fish distributed along the Hau River, Can Tho University Journal of Science, Fishery (2014) 192-197.[11] Dinh, Q. M., Nguyen, D. T. & Danh, S., Food and feeding habits of the broadheah sleeper Eleotris melanosoma from coastline in Soc Trang, Proceedings of the 7th National Scientific Conference on Ecology and Biological Resources, Publishing house for Science and Technology, 1873-1879, 2017.[12] Tran, D. D., Some aspects of biology and population dynamics of the goby Pseudapocryptes elongatus (Cuvier, 1816) in the Mekong Delta, PhD thesis, Universiti Malaysia Terengganu, 2008.[13] Dinh, Q. M., Qin, J. G., Dittmann, S. & Tran, D. D., Seasonal variation of food and feeding in burrowing goby Parapocryptes serperaster (Gobiidae) at different body sizes, Ichthyological Research, 64 (2017) 179-189.[14] Dinh, Q. M. & Tran, M. T. D., Digestive tract morphology, food and feeding habits of the goby Stigmatogobius pleurostigma (Bleeker, 1849) from the Coastline in Soc Trang, VNU Journal of Science: Natural Sciences and Technology, 34 (2018) 46-55.