ABSTRACT:The mudskipper Boleophthalmus boddarti is an amphibious fish widely distributed in the mudflat regions in Asia, but its reproductive biology was poorly stydied. This study was conducted in the Tran De, Soc Trang, Vietnam, from March 2013 to February 2014, to investigate reproductive parameters of B. boddarti. Data analysis based on a total of 360 collected fish (188 females and 172 males) suggest that the sex ratio of this mudskipper was not significantly different between dry and wet seasons. This fish was a multiple reproducer and spawned in the wet season with a peak spawning in three main months of this season (August to October) as difference stages of oocytes were observed in the ovaries. The male B. boddarti released sperms during the reproductive season since different type of spermatogonia were found in stage V testis sections. This fish reached 11.52 cm total length at first sex maturation and was high fecundity (9,800-33,800 eggs), indicating a possible adaptation of this species to the monsoonal climate. The understanding of the reproductive biology of B. boddarti provides useful knowledge of its reproductive adaptation to the mudflat toward sustainable management in the study region.
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.
Nghiên cứu này cung cấp dữ liệu về biến đổi đặc điểm hình thái của loài Glossogobius sparsipapillus ở Đồng bằng sông Cửu Long. Một tập hợp 355 cá thể, gồm 155 cá cái và 200 cá đực, được thu thập từ Cái Răng, tỉnh Cần Thơ và Long Phú, tỉnh Sóc Trăng từ tháng 1 đến tháng 12 năm 2020 để phân tích hình thái. Các phân tích thống kê cho thấy chiều dài tổng (TL) của cá có mối quan hệ chặt chẽ với chiều dài chuẩn (SL), chiều cao cơ thể (BH) và chiều dài đầu (HL) do các giá trị r2 cao của các phép hồi quy, ví dụ SL = aTLb, HL = aTLb và BD = aTLb (r2 > 0,666 cho mọi trường hợp). Các giá trị độ dốc (b) hồi quy TL-SL và TL-HL cho thấy A- và I ở đực nhưng I và A+ ở cái tương ứng; trong khi đó b của hồi quy TL-HL cho cùng kết quả ở hai giới tính (A-). Nó chỉ ra rằng giới tính cá có thể được xác định từ các hồi quy TL-SL và TL-BH. Sự thành thục của cá có thể được ước tính từ ba hồi quy khi giá trị b hiển thị I ở cá trưởng thành nhưng A ở cá chưa trưởng thành. Các hồi quy TL-HL và TL-BH có thể được sử dụng để đánh giá thời gian và địa điểm đánh bắt cá vì các giá trị b thay đổi theo các mùa và địa điểm khác nhau. Kết quả cho thấy chúng ta có thể sử dụng SL và BL để xác định giới tính cá; SL, BL và HL để xác nhận thời điểm, địa điểm đánh bắt cá và thời điểm cá trưởng thành.
This study centers around Vietnamese students, with a comparison with East and Southeast Asian students who share the same cultural idea, at higher education level who want to acquire better writing skills in English in and out of academic settings. Since English is not the students' first language, they normally craft an essay from the vocabulary that they know. This is understandable, but a good piece of writing in standard American English is not supposed to be traced word by word. Understanding this fact in-depth and practicing it regularly is the core requirement for English major students. In return, they can join any workplace with their strong writing skills that they have to acquire during their undergraduate years, or more if they attend graduate schools. This group of students is known to be timid since they were raised in a collectivistic community in which many of them make their higher education choices based on firstly the current trend, then what is suitable for them. Thus, by making a bolder choice of declaring English as a major, double major, or minor, they could have better insight into English rhetoric and composition to apply them as a multi-meaning sign to their writings properly.
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