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The coral reef ecosystem plays an important role in scientific research and economy. An assessment research on status of the coral reefs was carried out at 6 sites of coastal water from Nghi Son (Thanh Hoa province) to Vung Ro (Khanh Hoa province), Viet Nam between October and December 2015. The research was done using the manta tow method for rapid reef assessment and reef area determination, using reef check for detailed assessment of reef substrate types, etc. 288 species of hard corals under 57 genera and 14 families were identified from the study sites. These species mainly belonged to 4 families, namely Acroporidae, Faviidae, Poritidae and Fungiidae. The research showed the bad condition of the reef at all study sites through such indicators as a low live hard coral cover (average cover of 19.8%), high dead coral cover, recently killed coral, fleshy seaweed, etc. Most of surveyed transects had poor level of hard coral cover, the number of transects having good coral cover was unsignificant. The total reef area of 6 surveyed sites was 809.5 hectares, mainly occupied in Son Tra and Vung Ro. This was the first time coral disease and bleaching widely ranged had been observed and described. However, the reason of this phenomenon has not been mentioned yet and there is a need for more detailed researches on these problems in the coming time to have a basis for protection and management of coral reef ecosystem in Vietnam’s coastal water.

One survey was done with SCUBA diving in Ha Long Bay and Cat Ba Island, Northern Vietnam (December 2013) and another one at Nha Trang Bay Marine Protected Area, Nha Trang city, Central Vietnam and Phu Quoc Marine Protected Area, Kien Giang Province, Southern Vietnam (November 2014). Sixteen species of the genus Loxoconcha and fourteen species of the genus Xestoleberis were found and identified. Eight species of the genus Loxoconcha were identified in group A, three species in group B, two in group C and three unidentified. Meanwhile, twelve species of the genus Xestoleberis were classified in group A and two in group B according to phylogenetic groups. From geographical distribution of the pore groups of the species in two genera Loxoconcha and Xestoleberis showed that the fauna of these genera in Vietnam is close to those of southern part of Japanese Island Arc, i.e., from Amami Island to the Philippines and Australia rather than Japanese Island Arc faunas.

This study is a first report of an interstitial ostracod from Southeast Asia. The ostracod species, Paracobanocythere vietnamensis sp. n., was found in the marine interstitial environment of Phu Quoc Island, Vietnam. Thus far, three species of this genus have been described. The morphology of the carapace as well as the appendages of this new species are quite similar to Paracobanocythere hawaiiensis and Paracobanocythere watanabei. However, we found that they could be easily distinguished according to the morphology of the male copulatory organ. Additionally, we estimated the evolutionary distances among these three species based on nucleotide and amino acid sequences of the mitochondrial CO1 gene. Similar morphologies of carapaces and appendages, and relatively small evolutionary distances according to CO1 between Paracobanocythere vietnamensis sp. n. and Paracobanocythere watanabei suggest that these two species are very closely related.

The marine protected area (MPA) of Nha Trang Bay, in eastern Vietnam, was created in 2002 as a pilot initiative to enable an adequate management of the fringing reef communities, while providing opportunities for alternative livelihoods to the local fisher populations. A reassessment of the data obtained during the baseline survey performed in 2002 and of an inventory performed in 2005 indicates a reasonable decline in faunal diversity and density in the MPA. Multivariate analyses of a great number of species suggest a cascading effect: a general negative trend in the richness of hard-corals at different depths is associated with an increase in macro-algal cover, and this links with a marked decline in the density of herbivorous fish. The reef of Hon Mun, a core zone at the hearth of the MPA and an attraction for underwater tourists, showed some recovery of the coral cover and density of other macroinvertebrates. Despite the loss in fish density, the structure of the fish food web seemed to remain unaltered. Reefs in the buffer area of Hon Mieu and Hon Mot showed, on the contrary, great declines in the faunal component and a clear increase in algal cover. These reefs are those most affected by human derived impacts, including urban run-off, shipping, silting, mariculture, fishing and tourism. The most distant reef analysed, at Hon Tre, although formally a core zone, is allegedly under strong fishing pressure owing to lack of surveillance enforcement. The major impact, so far, seems to be a marked decline in diversity and density of fish. Whilst the present data were collected during the initial stages of marine protection and need further replication, it is becoming evident that urban development and, particularly, fisheries and mariculture, which depend on great amounts of wild seed and feed collected in the area, may become antagonistic activities to the recovery of the reef to earlier states. Managers devising future management plans have now a base for re-scaling the size and zonation regime of the protected area, as well as that of adjacent industrial activities.

Three new species of Ostracoda, Loxoconcha noharai sp. nov., L. santosi sp. nov. and L. sesokoensis sp. nov., are described from the Okinawa Islands, southern Japan. The two species Loxoconcha noharai sp. nov. and L. santosi sp. nov. live in estuaries, whereas the species L. sesokoensis sp. nov. lives in coral reefs. These species can be easily distinguished from other previously described Loxoconcha species by their morphological differences, mainly in the male copulatory organ, and distribution pattern of their pore systems. In addition, L. sesokoensis sp. nov. is suggested to be phylogenetically apart from any other Loxoconcha species which have been reported so far from Japan and the adjacent seas.