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  • Macrobenthic community status at coastal cage aquaculture area in Xuan Dai bay, Phu Yen province, Vietnam

    Phan, Thi Kim Hong; Nguyen, Ngoc Anh Thu; Dao, Tan Hoc; Nguyen, An Khang; Hua, Thai Tuyen; Mai, Xuan Dat; Ho, Thi Hoa (2022)
    Vietnam of Journal Marine Science and Technology
    Lobster cage culture started around 1990 in Xuan Dai bay and grew fast in recent years, contributing significantly to the socio-economic development of the region. But the impact on the ecological environment of cage culture operation also needs to consider. This paper points out the status of the macrobenthic community, studied at two stations inside the cage culture area (X1, X2) and one reference station (Xr) in the non-cage culture area. A total of 90 samples with 5 replicate samples per station were collected in six surveys during the dry and rainy seasons from June 2019 to May 2020. These samples were classified and recorded into 80 taxa belonging to 49 families and 5 classes. The class Polychaetes had the most diverse species composition with 53 taxa (66% of the total number of taxa). The crustacean group had 14 taxa (18%) belonging to 13 families; Molluscs had 9 taxa (11%) belonging to 6 families of class Bivalvia. The echinoderms had 4 taxa (5%). Capitella capitata, a species known as an indicator of organic pollution, was recorded in both stations of the culture area but was not present at the reference station. Furthermore, some dominant species presented in the culture stations such as Cossura longocirrata (contributed 43.52% in station X1) and Ceratonereis sp. (contributed 27.57% in station X2). These species are considered opportunistic species that can adapt to disturbed environmental conditions. Significantly, the species of echinoderms group were only recorded in the reference station. The species composition was only about 24% similar to those at the cage culture stations. The species richness index (D) values ranged from 1.50 (X2.6) to 6.82 (Xr.3). The diversity index (H′) varied from 0.88 (X2.4) to 2.98 (Xr.3). The evenness index (J) had the lowest average value at station X2 (J = 0.59 ± 0.20) and the highest value at the reference station Xr (J = 0.78 ± 0.03). The indices D, H′ and J of the macrobenthic community at the reference stations have higher average values compared to those estimated at cage culture stations. These results proved cage culture activities have gradually impacted the benthic fauna, reduced biodiversity, and encouraged the appearance of opportunistic species. Thus, further studies on the macrobenthic community dynamic with ecological criteria are necessary to establish a set of biological indicators to monitor the environmental quality of the coastal aquaculture area.
  • Fluctuation of associated microbial with building reef corals Acropora sp. from Hang Rai, Ninh Thuan

    Pham, Thi Mien; Vo, Hai Thi; Nguyen, Kim Hanh (2022)
    Vietnam of Journal Marine Science and Technology
    El Niño and the prolonged warm sea surface temperature significantly impacted coral reefs and caused coral bleaching in some parts of the world. This study evaluated the density of symbiotic algae and bacteria associated with the three coral species, namely Acropora hyacinthus, Acropora muricata, and Acropora robusta, collected in Hang Rai, Ninh Thuan in May, June, August 2016, and June 2017. The number of zooxanthellae with each coral species was statistically significant and correlated with several environmental factors, suggesting that symbiotic algae could play a key role in coral health. The number of associated microbial with the three coral species was significantly different; they tended to depend on sampling time rather than coral species-specific. At the time of ENSO (2016), the difference in the total associated bacteria with all three coral species was statistically significant. While the total number of related bacteria with all three species of coral collected in 2017 did not differ from the total of bacteria in ambient water. In conclusion, symbiotic algae tend to be species-specific, whereas bacteria fluctuate significantly over sampling time. Studying the molecular issues of microalgae, the presence, the role of some groups of bacteria involved in the N, C, P, and S cycles, and the influence of environmental parameters should also be encouraged to understand the relationship of coral holobiont better.
  • Morphological variation and haplotype diversity of Halimeda macroloba and H. opuntia (Chlorophyta: Halimedaceae) from Southern Vietnam

    Nguyen, Trung Hieu; Nguyen, Nhat Nhu Thuy; Nguyen, Xuan Thuy; Nguyen, Xuan Vy (2022)
    Vietnam of Journal Marine Science and Technology
    Plasticity in morphology is a common phenomenon of aquatic plants. Halimeda (Chlorophyta: Halimedaceae) is usually supersaturated with calcium carbonate and is found in tropical and subtropical regions. Among members of Halimeda, both species including Halimeda macroloba and H. opuntia, often occur in different habitats. Haplotype diversity and network of Halimeda were reported in the different sea and oceanic systems. However, there are no reports of the genetic diversity of Halimeda in Vietnamese waters. This present study carried out sample collections along the coast of Southern Viet Nam, including the coast sites, offshore islands, and Spratly (Truong Sa) islands. External morphological and anatomical characteristics of two dominant species, Halimeda macroloba and H. opuntia, were caparisoned. The genetic marker tufA was applied to find the haplotype diversity and network among Vietnamese and worldwide populations. The results showed that high morphology exists in both species. In contrast, the genetic variation in H. macroloba is very low, and H. opuntia tends to form a distinct group. We suggest that more samples of two species from other locations in Northern Vietnam be included.
  • Upwelling phenomenon in the marine regions of Southern Central of Vietnam: a review

    Bui, Hong Long; Phan, Minh Thu (2022)
    Vietnam of Journal Marine Science and Technology
    Upwelling is an oceanographic phenomenon that involves the physical process and contributes to changes in chemistry, biology, and natural resources. So, systematically, it is the particular ecosystems of whole marine regions with the upwelling. The strong upwelling waters in South Central Regions of Vietnam have uncertain features of the East Vietnam Sea (Bien Dong) and special characteristics of a coastal upwelling area, recorded in international scientific papers in the twentieth century. Their first signals were discovered in the early 1930s through conceptual ideas. The upwelling phenomenon is officially confirmed by scientific results of marine investigations of the NAGA Expedition (1959–1961). The paper aims to review and discuss the physical from Vietnamese investigation and results since 1990s. The following factors are the most contributing to forming and developing the strong upwelling in Southern Central Waters: (1) Influence scale (Mezo- and micro-scale); (2) Forming causes and developing mechanism of upwelling phenomenon, such as monsoon, morphography, shoreline, and western boundary current system of the East Vietnam Sea; (3) Influence of the water-mass from Mekong River on the upwelling area; (4) Ecological environmental consequences; (5) Impacts of the atmospheric-oceanic interaction processes on the western EVS on upwelling. Additionally, the review has targeted findings of upwelling phenomenon mainly in Vietnamese waters based on remote sensing analysis and reanalysis data series to simulate their forming, mechanizing, fluctuating models and the impacts of upwelling in the EVS on resources and ecosystems. The coupled atmosphere-ocean models resulted the upwelling mechanisms and formation. The long-time series of upwelling phenomenon (Macroscale) were evaluated by remote sensing and reanalyzed data series. It is also providing the supplementing and detailing causes and mechanisms of upwelling formation; impacts and interactions of upwelling on marine physics and hydrodynamics (ocean vortexes, seawater temperature), biochemical (nutrients, plankton organisms), and resources (fish, seafood). Within the framework of strong upwelling waters in the Southern Central Regions (Vietnam), the review has not only mentioned partly clarified scientific results but also indicates the limitations and challenges which were faced and encountered in the forecasters of upwelling phenomena in the future.
  • Water quality at Cai river mouth and Tac river mouth, Nha Trang bay (2015–2019)

    Pham, Hong Ngoc; Le, Hung Phu; Do, Anh Van; Nguyen, Hong Thu; Le, Trong Dung; Dao, Viet Ha (2022)
    Vietnam of Journal Marine Science and Technology
    Deltas of large rivers, especially in arid areas, have been used in ancient times for agriculture and are densely populated. In recent decades, many river deltas have been experiencing an increasing anthropogenic impact, contamination of watersheds, and marine pollution caused by the offshore extraction of hydrocarbons. Combining of these factors determines a considerable research interest in river mouth areas. This paper presents the annual monitoring data on the water environment of the two mouths of the Cai river and Tac river, Nha Trang bay, during the period 2015–2019. Statistical data showed an increase in dissolved oxygen demand (DO), biological oxygen demand BOD5, and the concentrations of ammonia, Zn and Cu. Seasonal variation revealed that most of studied parameters’ concentrations, especially nutrients, were higher in the rainy season. In contrast, the values of total suspended solids (TSS) and hydrocarbon (Cai River), and petroleum (Tac river) demonstrated a decrease. Generally, the average value of BOD5, concentrations of Cu and Pb at the Cai river mouth were lower than those at the Tac river mouth, whereas the concentration of Zn was higher. Overall, the water environment of both mouths was qualified for aquaculture and aquatic organism preservation purposes except for the case of coliform.
  • A study on the spawning season of 3 Acropora species in Nha Trang bay, Southern waters of Vietnam

    Vo, Si Tuan; Ho, Son Lam; Dang, Tran Tu Tram; Phan, Kim Hoang; Doan, Van Than; Mai, Xuan Dat (2022)
    Vietnam of Journal Marine Science and Technology
    Specimens for the study on coral spawning of three species were collected at two sites in Nha Trang bay, South Vietnam, in 2014, 2015, 2016, 2018 and 2019. The determination of spawning seasons was based on observations of gonadogenesis development of A. florida and A. robusta and variation of egg average sizes of these two species and A. hyacinthus. Data analysis and comparative discussions allow us to assume that the 3 Acropora species exhibited single cycle spawning annually and their spawning period occurred in March/April between the full moon and crescent moon. However, their maturity periods were not the same, starting before and ending after the full moon for A. florida and A. robusta but starting after the full moon and lasting until the crescent moon for A. hyainthus. Further studies are needed to improve the understanding of coral spawning and support coral restoration using sexual reproduction.
  • Observations biologiques sur les Stomatopodes

    Serene, Raoul (Institut Océanographique de Nhatrang (Viet-Nam), 1954)
    The present study deals with a systemic revision of Stomatopods belonging to the collection of the Institut Oceanographique de Nhatrang (Vietnam).
  • Nudibranches du Viet-Nam

    Risbec, Jean (Gouvernement Général de l'Indochine, 1956)
    Archives du Múseum National d'Histoire Naturelle, Paris. 7éme Série
    This study deals with detailed descriptions of nudibranchs belonging to the collection of the Oceanographic Institute of Vietnam.
  • Les hapalocarcinidés du Viet-Nam

    Fize, Antoinette; Serene, Raoul (Institut Océanographique de Nhatrang, 1942)
    Serene (1936) and Dawydoff (1952) reported several species of Hapalocarcinids on Indochina corals. This study does not aim to a revision of known species, but a preparatory work for next revisions. A great part of their work was dedicated to the description of species; two preliminary notes had already described 12 new species. This work interested 22 species, 6 already known, 12 already described briefly and 4 new.
  • Les batraciens de l'Indochine

    Bourret, René (Gouvernement Général de l'Indochine, 1942)
    This study on batrachians follows two previous works on Indochinese fauna, "Snakes of Indochina" and "Marine turtles of Indochina" by the same author. Hand drawings with all relevant details of every species have been included.
  • La pêche dans le eaux douces du Cambodge

    Chevey, P.; Le Poulain, F. (Gouvernement Général de l'Indochine, 1940)
    The importance of water in Cambodia's economy has always greatly impressed scientists and their work. This trend is spread over a period of more than 70 years. There were three distinct phases in the history of fishing and fish research in Cambodia. The phase of isolated workers (1865-1923), the phase of the first gathered researches, corresponding to the beginning of the work of the Oceanographic Institute of Indochina (1923-1936), and finally close cooperation phase between the Institute Oceanographic and Protectorate, inaugurated in 1936. The purpose of this 5th Memoire is exposing the knowledge on fishing activities in Cambodia in 1936.
  • Oiseaux des Iles Paracels

    Delacour, J.; Jabouille, P. (Gouvernement Général de l'Indochine, 1930)
    A survey on birds living on the Paracels Islands has been carried out by the two authors in 1926. During a research cruise, they visited some of the 36 islands composing the Paracels archipelago and list three bird families (Laridés, Stéganopodés, Zostéropidés) and their sub-families.
  • La forme des récifs coralliens et le régime des vents alternants

    Krempf, A. (Gouvernement Général de l'Indochine, 1927)
    This paper deals with the development of crescent-shaped reefs in the China Sea under control of northwest and southeast monsoon winds alternating in direction seasonally. The transport of sediment derived from windward side to leeward around reef ends has been studied. A description of the analogy of these large structures with individual coral colonies developing in similar manner under current action as micro atolls has given.
  • Zoanthaires du Viet-Nam

    Pax, Ferdinand; Müller, Ingeborg (1954)
    Memoires du Muséum National d'Histoire Naturelle, Nouvelle série, Série A, Zoologie
    The present note deals with a description of Zoanthids found on the coast of Vietnam.
  • Liste complémentaire des poissons marins de Nha-trang

    Fourmanoir, P.; Do-Thi, Nhu-Nhung (1965)
    Cahiers O.R.S.T.O.M. Série Océanographie
    This commented inventory of 310 fishes of Nhatrang Bay (Vietnam) completed the previous list compiled by P. Chevey, P. Chabanaud, J. Durand et Quang.
  • Une estimation de l'épaisseur de la croute terrestre au-dessous de la Mer de Chine

    Nguyen, Hai (1965)
    Archives Géologiques du Viêt-Nam
    Study on the dispersion of Rayleigh waves across the China Sea in 1964 has given following conclusions:- Thickness of the crust below the Sea could be varied from 12 to 15 km according to the area. -There would be a slight diminution of the thickness when the Sea depth becomes deeper. - Central part of the Sea very probably belongs to the regional character no. 3 of Santo. The present work is known as the first which estimates particularly the thickness of the crust below the China Sea.
  • Les poissons d'importance commerciale au Viet-Nam

    Tran, Ngoc Loi; Nguyén, Cháu (1964)
    Bulletin de la Société des Études Indochinoises, Nouvelle Série
    The fishery products represent one of the most important resources in Vietnam. The paper focuses on distribution, fishing gears, fishing seasons and current use of commercial fish species.
  • L'étagement du peuplement littoral sur les cȏtes rocheuses du Vietnam

    Pham, Hoang Ho (1963)
    Proceedings of the 4th International Seaweed Symposium
    So far, the assessment of Vietnamese coastal bios has not been thoroughly researched yet. Only two short notes of P. H. Fischer in 1952 on the coast of Indochina and Cap Saint-Jacques (Vungtau) can be cited. This paper gives a summary of work carried out since 1956. The study was conducted using measurements and sketches made on site and after photos.
  • La pêche aux matières explosives

    Nguyèn, Cháu; Phan, Hay (1962)
    Bulletin de la Société des Etudes Indochinoises, Nouvelle Séries
    Fishing with explosives dates back to previous times. It was practiced by few Vietnamese fishermen. The practice is widespread in the country during the last fifteen years due to the increasing availability of explosives. Certainly this method gives some significant advantages: it is easy to apply, inexpensive and promptly profitable. But we cannot underestimate the incalculable damages caused by bursting, disorder and desolation. Some of our fishermen, attracted by immediate gain, accomplished a work of terrible devastation. The following paper does not aim to encourage fishermen to develop and modernize fishing methods but it gives the results of an investigation on dangerous fishing methods.
  • Éponges intercoditales de Nha Trang (Viet Nam)

    Lévi, Claude (1961)
    Archives de Zoologie Expérimentale et Générale
    Thanks to the effort of many spongologists from worldwide, we know the most common sponges in the Indo-Pacific area. The author gives a description of 28 intertidal sponges collected in Nha Trang, Vietnam.

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