Digestive Tract Morphology and Gastro-somatic Index of the Mudskipper Oxuderces nexipinnis (Cantor, 1849) (Gobiidae: Oxudercinae) in Southwestern Vietnam
Main Article Content
Abstract
This study analyzes the morphological characteristics of the digestive tract and the feeding intensity of Oxuderces nexipinnis in the Mekong Delta, based on 616 specimens (223 females, 393 males) collected monthly from August 2024 to July 2025. The results showed that this species possesses a wide mouth, small teeth, short and dense gill rakers, a short esophagus, an indistinct stomach, and a long intestine – typical features of benthic omnivorous fishes. The Gastro-somatic Index (GI) indicated that feeding intensity was significantly higher in males and immature individuals compared to females and mature ones. Moreover, GI exhibited seasonal variation, with higher values in the dry season than in the rainy season, and spatial differences, with fish from the northern Hau River showing markedly higher GI values than those from the southern Hau River. These findings provide data on the digestive tract morphology and the variation in feeding intensity of O. nexipinnis, contributing to a better understanding of its feeding activity under the ecological conditions of intertidal flats and mangrove areas in the study region.
Keywords:
Feeding ecology, Gastro-somatic Index, Oxuderces nexipinnis.
References
[1] Z. Jaafar, L. R. Parenti, Systematics of the Mudskipper Genus Oxuderces Eydoux and Souleyet 1848 (Teleostei: Gobiidae: Oxudercinae) with Resurrection from Synonymy of O. nexipinnis (Cantor 1849), Zoological Journal of the Linnean Society, Vol. 180, 2017, pp. 195-215, https://doi.org/10.1111/zoj.12482.
[2] A. Ishimatsu, T. T. Gonzales, Mudskippers: Front Runners in the Modern Invasion of Land, in: R. A. Patzner, J. L. Van Tassell, M. Kovačić, B. G. Kapoor (Eds.), The Biology of Gobies, Science Publishers, Enfield, NH, USA, 2011, pp. 609-638.
[3] E. O. Murdy, A Taxonomic Revision and Cladistic Analysis of the Oxudercine Gobies (Gobiidae: Oxudercinae), Records of the Australian Museum, Supplement, Vol. 11, 1989, pp. 1-93, https://doi.org/10.3853/j.0812-7387.11.1989.93.
[4] N. M. Tai, N. V. Lam, T. X. Loi, Correlation between the Level of Amphibious Lifestyle and Moving Characteristics with the Pectoral During Water-to-terrestrial Transition of Mudskippers (Oxudercinea Subfamily), Vietnam Journal of Agricultural Sciences, Vol. 22, 2024, pp. 457-465, https://doi.org/10.31817/tckhnnvn.2024.22.4.
[5] G. Polgar, V. Bartolino, Size Variation of Six Species of Oxudercine Gobies along the Intertidal Zone in a Malayan Coastal Swamp, Marine Ecology Progress Series, Vol. 409, 2010, pp. 199-212, https://doi.org/10.3354/meps08597.
[6] L. X. Tran, T. T. K. Nguyen, T. T. Vo, Morphological Comparison of the Cranial Movement Apparatus in Mudskippers (Gobiidae: Oxudercinae), Zoology, Vol. 154, 2022, pp. 126042, https://doi.org/10.1016/j.zool.2022.126042.
[7] V. Ravi, Food and Feeding Habits of the Mudskipper, Boleophthalmus boddarti (Pallas, 1770) from Pichavaram Mangroves, Southeast Coast of India, International Journal of Marine Science, Vol. 3, 2013, pp. 98-104, https://doi.org/10.5376/ijms.2013.03.0012.
[8] A. Chaudhuri, S. Mukherjee, S. Homechaudhuri, Dietary Preference and Digestive Physiology of Plankti-Benthivorous Fishes Inhabiting Mudflats of Indian Sundarban Estuaries, Tropical Zoology, Vol. 29, 2016, pp. 53-72, https://doi.org/10.1080/03946975.2016.1154286.
[9] G. H. Phan, Q. M. Dinh, N. T. Truong, T. H. D. Nguyen, The Relative Gut Length and Gastro-Somatic Index of Glossogobius aureus from some Provinces in the Mekong Delta, TNU Journal of Science and Technology, Vol. 226, 2021, pp. 44-50.
[10] Y. T. N. Nguyen, T. T. H. Lam, Q. M. Dinh, The Relative Gut Length and Gastro-somatic Indexes of Butis koilomatodon Living in the Coastal Estuaries of Some Provinces in the Mekong Delta, TNU Journal of Science and Technology, Vol. 225, No. 08, 2020, pp. 358-365.
[11] C. C. Tran, T. H. Nguyen, H. T. Nguyen, L. T. Vo, G. H. Phan, Q. M. Dinh, The Intraspecific and Spatio-temporal Variations in Relative Gut Length and Gastro-somatic Indexes of Glossogobius sparsipapillus in the Mekong Delta, Vietnam, Aquaculture, Aquarium, Conservation and Legislation Bioflux, Vol. 14, No. 2, 2021,
pp. 841-848.
[12] V. U. Hua, Q. M. Dinh, T. H. D. Nguyen, Gastrointestinal Morphology and Feeding Intensity of Periophthalmus gracilis Caught from some Coastal Provinces in the Mekong Delta, Vietnam, Veterinary Integrative Sciences,
Vol. 21, No. 3, 2023, pp. 667-676, https://doi.org/10.12982/VIS. 2023.048.
[13] Q. M. Dinh, Aspects of Reproductive Biology of the Red goby Trypauchen vagina (Gobiidae) from the Mekong Delta, Journal of Applied Ichthyology, Vol. 34, 2018, pp. 103-110, https://doi.org/10.1111/jai.13521.
[14] V. R. Desai, 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, Vol. 2, 1970, pp. 101-112.
[15] M. L. D. Santos, F. P. Arantes, K. B. Santiago, J. E. Dos Santos, Morphological Characteristics of the Digestive Tract of Schizodon knerii (Steindachner, 1875) (Characiformes: Anostomidae): An Anatomical, Histological and Histochemical Study, Anais da Academia Brasileira de Ciências, Vol. 87, No. 2, 2015, pp. 867-878, https://doi.org/10.1590/0001-3765201520140230.
[16] R. D. Day, I. R. Tibbetts, S. M. Secor, Physiological Responses to Short-term Fasting among Herbivorous, Omnivorous, and Carnivorous Fishes, Journal of Comparative Physiology B, Vol. 184, 2014, pp. 497-512, https://doi.org/10.1007/s00360-014-0813-4.
[17] L. X. Tran, Y. Maekawa, K. Soyano, A. Ishimatsu, Morphological Comparison of the Feeding Apparatus in Herbivorous, Omnivorous and Carnivorous Mudskippers (Gobiidae: Oxudercinae), Zoomorphology, Vol. 140, 2021, pp. 387-404, https://doi.org/10.1007/s00435-021-00530-8.
[18] L. X. Tran, T. T. K. Nguyen, Morphology of the Buccal and Opercular Sealing Apparatus in Mudskippers (Gobiidae: Oxudercinae), Journal of Ichthyology, Vol. 63, No. 4, 2023, pp. 605-615, https://doi.org/10.1134/S0032945223040197.
[19] L. X. Tran, T. T. K. Nguyen, T. T. Vo, Vertebral Column Variation of Mudskippers (Gobiidae: Oxudercinae): Early Stages of Water-to-land Transition, Journal of Ichthyology, Vol. 63, 2023, pp. 192-205, https://doi.org/10.1134/S0032945223020212.
[20] K. Wołczuk, M. Ostrowski, A. Ostrowska, T. Napiórkowska, Structure of the Alimentary tract in the Atlantic Mudskipper Periophthalmus barbarus (Gobiidae: Oxudercinae): Anatomical, Histological and Ultrastructural Studies, Zoology, Vol. 128, 2018, pp. 38-45, https://doi.org/10.1016/j.zool.2018.04.002.
[21] I. G. Borlongan, R. M. Coloso, N. V. Golez, Feeding Habits and Digestive Physiology of Fishes, in: O. M. Millamena, R. M. Coloso, F. P. Pascual (Eds.), Nutrition in Tropical Aquaculture: Essentials of Fish Nutrition, Feeds, and Feeding of Tropical Aquatic Species, Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines, 2002, pp. 77-97.
[22] B. G. Kapoor, H. Smit, I. Verighina, The Alimentary Canal and Digestion in Teleosts Advances in Marine Biology, Elsevier, Vol. 13, 1976, pp. 109-239, https://doi.org/10.1016/S0065-2881(08)60281-3.
[23] S. M. Banan Khojasteh, The Morphology of the Post-gastric Alimentary Canal in Teleost Fishes: A Brief Review, International Journal of Aquatic Science, Vol. 3, No. 2, 2012, pp. 71-88.
[24] Q. M. Dinh, J. G. Qin, S. Dittmann, D. D. Tran, Seasonal Variation of Food and Feeding in Burrowing Goby Parapocryptes serperaster (Gobiidae) at Different Body Sizes, Ichthyological Research, Vol. 64, 2017, pp. 179-189, https://doi.org/10.1007/s10228-016-0553-4.
[2] A. Ishimatsu, T. T. Gonzales, Mudskippers: Front Runners in the Modern Invasion of Land, in: R. A. Patzner, J. L. Van Tassell, M. Kovačić, B. G. Kapoor (Eds.), The Biology of Gobies, Science Publishers, Enfield, NH, USA, 2011, pp. 609-638.
[3] E. O. Murdy, A Taxonomic Revision and Cladistic Analysis of the Oxudercine Gobies (Gobiidae: Oxudercinae), Records of the Australian Museum, Supplement, Vol. 11, 1989, pp. 1-93, https://doi.org/10.3853/j.0812-7387.11.1989.93.
[4] N. M. Tai, N. V. Lam, T. X. Loi, Correlation between the Level of Amphibious Lifestyle and Moving Characteristics with the Pectoral During Water-to-terrestrial Transition of Mudskippers (Oxudercinea Subfamily), Vietnam Journal of Agricultural Sciences, Vol. 22, 2024, pp. 457-465, https://doi.org/10.31817/tckhnnvn.2024.22.4.
[5] G. Polgar, V. Bartolino, Size Variation of Six Species of Oxudercine Gobies along the Intertidal Zone in a Malayan Coastal Swamp, Marine Ecology Progress Series, Vol. 409, 2010, pp. 199-212, https://doi.org/10.3354/meps08597.
[6] L. X. Tran, T. T. K. Nguyen, T. T. Vo, Morphological Comparison of the Cranial Movement Apparatus in Mudskippers (Gobiidae: Oxudercinae), Zoology, Vol. 154, 2022, pp. 126042, https://doi.org/10.1016/j.zool.2022.126042.
[7] V. Ravi, Food and Feeding Habits of the Mudskipper, Boleophthalmus boddarti (Pallas, 1770) from Pichavaram Mangroves, Southeast Coast of India, International Journal of Marine Science, Vol. 3, 2013, pp. 98-104, https://doi.org/10.5376/ijms.2013.03.0012.
[8] A. Chaudhuri, S. Mukherjee, S. Homechaudhuri, Dietary Preference and Digestive Physiology of Plankti-Benthivorous Fishes Inhabiting Mudflats of Indian Sundarban Estuaries, Tropical Zoology, Vol. 29, 2016, pp. 53-72, https://doi.org/10.1080/03946975.2016.1154286.
[9] G. H. Phan, Q. M. Dinh, N. T. Truong, T. H. D. Nguyen, The Relative Gut Length and Gastro-Somatic Index of Glossogobius aureus from some Provinces in the Mekong Delta, TNU Journal of Science and Technology, Vol. 226, 2021, pp. 44-50.
[10] Y. T. N. Nguyen, T. T. H. Lam, Q. M. Dinh, The Relative Gut Length and Gastro-somatic Indexes of Butis koilomatodon Living in the Coastal Estuaries of Some Provinces in the Mekong Delta, TNU Journal of Science and Technology, Vol. 225, No. 08, 2020, pp. 358-365.
[11] C. C. Tran, T. H. Nguyen, H. T. Nguyen, L. T. Vo, G. H. Phan, Q. M. Dinh, The Intraspecific and Spatio-temporal Variations in Relative Gut Length and Gastro-somatic Indexes of Glossogobius sparsipapillus in the Mekong Delta, Vietnam, Aquaculture, Aquarium, Conservation and Legislation Bioflux, Vol. 14, No. 2, 2021,
pp. 841-848.
[12] V. U. Hua, Q. M. Dinh, T. H. D. Nguyen, Gastrointestinal Morphology and Feeding Intensity of Periophthalmus gracilis Caught from some Coastal Provinces in the Mekong Delta, Vietnam, Veterinary Integrative Sciences,
Vol. 21, No. 3, 2023, pp. 667-676, https://doi.org/10.12982/VIS. 2023.048.
[13] Q. M. Dinh, Aspects of Reproductive Biology of the Red goby Trypauchen vagina (Gobiidae) from the Mekong Delta, Journal of Applied Ichthyology, Vol. 34, 2018, pp. 103-110, https://doi.org/10.1111/jai.13521.
[14] V. R. Desai, 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, Vol. 2, 1970, pp. 101-112.
[15] M. L. D. Santos, F. P. Arantes, K. B. Santiago, J. E. Dos Santos, Morphological Characteristics of the Digestive Tract of Schizodon knerii (Steindachner, 1875) (Characiformes: Anostomidae): An Anatomical, Histological and Histochemical Study, Anais da Academia Brasileira de Ciências, Vol. 87, No. 2, 2015, pp. 867-878, https://doi.org/10.1590/0001-3765201520140230.
[16] R. D. Day, I. R. Tibbetts, S. M. Secor, Physiological Responses to Short-term Fasting among Herbivorous, Omnivorous, and Carnivorous Fishes, Journal of Comparative Physiology B, Vol. 184, 2014, pp. 497-512, https://doi.org/10.1007/s00360-014-0813-4.
[17] L. X. Tran, Y. Maekawa, K. Soyano, A. Ishimatsu, Morphological Comparison of the Feeding Apparatus in Herbivorous, Omnivorous and Carnivorous Mudskippers (Gobiidae: Oxudercinae), Zoomorphology, Vol. 140, 2021, pp. 387-404, https://doi.org/10.1007/s00435-021-00530-8.
[18] L. X. Tran, T. T. K. Nguyen, Morphology of the Buccal and Opercular Sealing Apparatus in Mudskippers (Gobiidae: Oxudercinae), Journal of Ichthyology, Vol. 63, No. 4, 2023, pp. 605-615, https://doi.org/10.1134/S0032945223040197.
[19] L. X. Tran, T. T. K. Nguyen, T. T. Vo, Vertebral Column Variation of Mudskippers (Gobiidae: Oxudercinae): Early Stages of Water-to-land Transition, Journal of Ichthyology, Vol. 63, 2023, pp. 192-205, https://doi.org/10.1134/S0032945223020212.
[20] K. Wołczuk, M. Ostrowski, A. Ostrowska, T. Napiórkowska, Structure of the Alimentary tract in the Atlantic Mudskipper Periophthalmus barbarus (Gobiidae: Oxudercinae): Anatomical, Histological and Ultrastructural Studies, Zoology, Vol. 128, 2018, pp. 38-45, https://doi.org/10.1016/j.zool.2018.04.002.
[21] I. G. Borlongan, R. M. Coloso, N. V. Golez, Feeding Habits and Digestive Physiology of Fishes, in: O. M. Millamena, R. M. Coloso, F. P. Pascual (Eds.), Nutrition in Tropical Aquaculture: Essentials of Fish Nutrition, Feeds, and Feeding of Tropical Aquatic Species, Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines, 2002, pp. 77-97.
[22] B. G. Kapoor, H. Smit, I. Verighina, The Alimentary Canal and Digestion in Teleosts Advances in Marine Biology, Elsevier, Vol. 13, 1976, pp. 109-239, https://doi.org/10.1016/S0065-2881(08)60281-3.
[23] S. M. Banan Khojasteh, The Morphology of the Post-gastric Alimentary Canal in Teleost Fishes: A Brief Review, International Journal of Aquatic Science, Vol. 3, No. 2, 2012, pp. 71-88.
[24] Q. M. Dinh, J. G. Qin, S. Dittmann, D. D. Tran, Seasonal Variation of Food and Feeding in Burrowing Goby Parapocryptes serperaster (Gobiidae) at Different Body Sizes, Ichthyological Research, Vol. 64, 2017, pp. 179-189, https://doi.org/10.1007/s10228-016-0553-4.