Nature and Management of Some Marine Ecosystems in Vietnam: A Case Study at The Hon Mun Island at Nha Trang

Nha Trang is a city in Vietnam endowed with several sceneries which has attracted several tourists around the world over the past few decades. The city is highly characterized by coastal features as well as beautiful landscapes. Among these features are; beaches, caves with swift-let birds, resort centers, islands, traditional temples, forts and so on. The act of enhancing economic activities, coupled with some natural factors like; climate change as well as the increasing number of tourists’ over the years has led to the alteration of some of these ecosystems, that gives the city its value, hence, sense of attracting numerous tourists from all walks of life. The Hon Mun Islands are located to the south of Nha Trang Bay. Hon Mun MPA is situated in central - South Vietnam, offshore from the coastal resort city of Nha Trang, Khanh Hoa Province. The name “Hon Mun” (means Black Island) comes from the high and rugged cliffs forming up caves, particularly black rock here as ebony, very rarely seen elsewhere. Due to the island’s location adjacent to the hot sea-currents from the equator, suitable to the development conditions of corals and various types of tropical sea creatures, the sea bed of Hon Mun is home to an abundant and diverse group of marine species, an interesting and useful place for researchers, oceanographers and tourists to observe and explore more of the sea creatures’ life [1]. It is for these reasons why this study was conducted to delve into the nature, management and threats posed on the ecosystems at the Hon Mun Island at Nha Trang in Vietnam.


Introduction
The International Union for Conservation of Nature (IUCN) defines a marine protected area as: "a clearly defined geographical space, recognized, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values". This study conducted to undertake line transect measurement in two different sites at the Hon Mun Island, to make some observations on some bottom features, coral reef types and their habitats, zonation, the nature and management of ecosystems at the Hon Mun Island at Nha Trang.
In recent years, with increasing economic development, the marine environment adjacent to Nha Trang City, especially around the Hon Mun Islands, has faced increased exploitation. Coral reefs have been destroyed by many, mainly human-induced, factors. Shipping, dynamite-fishing, coral harvesting and marine tourism have led to a decrease in marine biodiversity and the loss of precious genetic resources, such as those of the Hawksbill turtle, false killer whales and leatherback turtles, from the South China Sea. Destructive activities obviously diminish the benefits reaped from tourism in the islands [2]. It is for these reasons why this study was conducted to explore more the nature, management and threats posed on the ecosystems at the Hon Mun Island at Nha Trang in Vietnam.

Objectives
The main objectives of this study were to: 1. Give an overview of the current status of biodiversity at the Hon Mun Island and its marine environment 2. To briefly analyze data using Line transect measurement of some diversity in the area 3. To give a general view on how the island is being managed 4. Identify key problems affecting biodiversity at the Hon Mun Islands 5. Propose measures to mitigate these problems

Study Area
The Hon Mun Islands are located to the south of Nha Trang Bay. The total area of the complex is about 160 km 2 , in which 122 km 2 is sea and 38 km 2 is an island area. Since 1975, the National Marine Programme of Vietnam, which was implemented by National Centre for Natural Science and Technology, has run at Hon Mun to analyze and preserve marine creatures here. Currently, Hon Mun is a famous attraction in Nha Trang for Vietnamese and tourists [1]. The islands have a variety of habitats and ecosystems, including fringing coral reefs, mangrove forests and sea grass beds with an adjacent deep-water upwelling, which supports the local fishing industry. Hon Mun MPA is situated in central -South Vietnam, offshore from the coastal resort city of Nha Trang, Khanh Hoa Province. The MPA encompasses nine islands (Hon Tre, Hon Noc, Hon Mun, Hon Rom, Hon Vung, Hon Cau, Hon Mot, Hon Tam and Hon Mieu) and their surrounding waters, some 160 km 2 in total [3]. The nine islands, located from 1 km to 15 km offshore, provide the topographic basis for a wide range of coastal and marine habitat types, developed in relation to prevailing oceanographic conditions and gradients in mainland -oceanic influences ( Figure 1). The diverse array of tropical habitats includes coral reefs, soft bottom communities, sea grass beds, mangroves, sandy beaches and rocky shores.

Materials for data collection
Use of cellular phones, measuring tape for transects measurement, ruler, slate, pencil, thread and snorkeling masks.

Methods for data analysis
Personal and direct observations were made at the study area. Informal interviews were conducted with some personnel at the area to get more insight about the area. Secondary data from the internet and other literature were used to give detailed information on biodiversity of species and management of the ecosystem at the Hon Mun Island. Use of Microsoft office tools like; Microsoft word and excel worksheet as well as Shannon Weiner's index to calculate for the diversity of species in the area in quantitative analysis and formulation of charts.

Research strategy
The strategy used for this research was both qualitative and quantitative approach. Some quantitative tools were used in the collection and analyzing of data. No laboratory test or analyses were made to establish a logical base except quantitative tools outlined in section 6.2.

Research design
The research design adapted for this study is a case study design. A single case study was adapted to explore more world about the nature and management of ecosystems at the Hon Mun Islands, taking into consideration some areas that were measured for this study. Since, this study is a single case study, results or findings cannot be generalized for the entire islands in Vietnam or other islands at Nha Trang.

Limitation of the study
Limited funds did not enable us to visit the place more often to engage the most of the local people who are mainly farmers and fishermen, thus, participatory/action based research to delve more and broaden the objectives of this study. This limitation does not limit the validity and credibility of this study since, engagement of the people is not a main objective although it would have helped establish and give us more information. Language barrier also hindered our ability to engage most of the indigenous or local inhabitants although the primarily mode of data collection was through primary data as well as use of secondary data on the internet and from the site as well as engaging some few staff at the site.

Area Covered by Life-form x 100% Percentage Cover (%) = Total Distance
(Tables 1-6) In calculating for the variables in the tables above; Difference in transitional Life-form Code in the area measured by the Lifeform at that given area up to the next area or zone being measured. Hence, zones with the same life-form have their distance summed up (i.e., Sand (SND) covered in two or three areas are summed up; L1i+L1ii….L1n). Using Shannon Weiner's mode of calculating for diversity of species in a given area;

Management of ecosystem at the Mun Island
In an interview with a tourist guide at the Hon Mun Island, we were meant to understand that the site is being managed by the Government of Vietnam with sole responsibility given to the Ministry of Fisheries as the responsible agency. Khan Hoa PPC and the committees in some allocated communities or villages around the Hon Mun Island.
There are some forms of international support for management of Hon Mun Island from the World Conservation Union supporting the Marine Protected Area, funded by Global Environmental Facility (GEF) through the World Bank as well as the Royal Danish Government through DANIDA [4].

Objectives of Hon Mun marine protected area
• To conserve a representative example of internationally significant and threatened marine biodiversity.
• To enable local island communities to improve their livelihoods and in partnership with other stakeholders to effectively protect and manage the marine biodiversity at Hon Mun as a model for collaborative marine protected area management.

Enforcement plan:
The enforcement plan is aimed at eliminating illegal fishing in the area which destroys fish larvae and coral reefs, as well as enforcement of gear and no fishing restricted zones. Some zones have been demarcated for snorkeling, diving, boat settlement and so on, basically recreational activities [5] in the area. Marine protected areas village committees liaising with personnel from the government.
All stakeholders have been brought on deck to help manage the Hon Mun Island. Village committees have been set up in each village to represent the interest of their people, teaming up with Mun Island MPA Authority as well as provincial agencies in management of this zone.

Line transects measurement of species at Site A and Site B
The survey was conducted to measure diversity of species at the bottom zone at the Mun Island as well as to enable students to describe reef habitats. Per direct observation, some features which were found in the area can be classified into these (Table 7).
Per the tables, thus, Tables 3-6 outlined in the results of this study for the two given sites, it can be concluded that, both sites have limited variety of species in this ecosystem. Per Shannon Weiner's index of measuring species diversity in a given area, thus, equitability (E*), when E* is 1, means there are wide range of species in that area. Half this value means there are fair or moderate variety of species in the area. Before this value (E* <0.5) means limited diversity of species in an area. At site A, E* was calculated to be 0.2165 whereas at Site B, E* was calculated to be 0.19075 [6]. Hence, per these two given values which were being calculated from the data gathered from these two sites, we can logically state that, there are limited diversity of species, specifically, the life-forms in those two given areas or sites as well as other species which may be in the same group or family with these life forms outlined in Tables 4 and 5 but may not be available in these two areas.

Biodiversity of species at the Hon Mun Island
With reference to the tables illustrated above, it can be observed that, there is a wide range of species at the Mun Island from site report and per direct observations made ranging from fishes, crustaceans, echinoderms, molluscs, algae and corals as well as vegetative cover around the ocean with variety of birds and other terrestrial insects and animals.
The main objective of this study was to expose students to biodiversity of species at the site and to take transect measurement in shallow zones of the ocean where there are coral reefs, sand and rocky zones coupled with other species.

Coral reefs at the Mun Island
There were wide ranges of coral reef forms ranging from encrusting, columnar, plate-like, mushroom (Fungia sp.), free living, massive, semimassive and branching corals. These coral forms had several polyp growth forms like; plocoids, phaceloid, ceroid, meandering and flabellomeandroid growth forms embedded around them when observed from above ( Figure 2).

Coral reefs as a base for protection and habitat for some fishes, echinoderms, crustaceans and molluscs
Per direct observation, some dead corals, broken (fragmented) corals in a state of bleach with some still growing as well as a coral with half of its section being dead and half being alive in the images below (Figures 3 and 4).

Threats/Problems the Hon Mun Island is faced with:
• Over-harvesting of resources: Overfishing may cause algae bloom since some of these fishes feed on algae and when harvested excessively may increase the accumulation of algae.
In addition is harvesting corals for making jewelries and other ornaments.
• Illegal fishing • Tourism and other recreational activities like; diving, snorkeling and trampling, touching or walking on coral reefs by some tourist as well as anchor damage from boats especially during low tide zones ( Figure 5).
• Pollution: Some forms of solid waste like; clothes, baskets, old fishing nets and polythene bags were found beneath the ocean where there are coral reef platforms from direct observation. This goes a long way to breed algae and compete for space with corals ( Figure 6).
• Inputs from land like; nutrients and sediment run off from agricultural lands around the island or from mountainous farmlands. This causes smothering and growth of algae competiting with the corals (Figure 7).
• Invasion of some species thereby causing some corals to die off or bleach: e.g. Crown-of-thorn on some corals with some images captured from field study (Figure 8).

Living biotic features Substrata Others
Lively hard corals Sand Geomorphology

Conclusion
In nut-shell, participatory or action based approach as well as conservation, are two main approaches, which can be adhered to ensure sustainable use of resources if the right policy framework and monitoring mechanisms are properly structured through institutional capacity [7]. The factors spelt above delves into biodiversity of species at the Hon Mun Island, who manages the site, support, threats which degrade the site's pristine ecosystem and proposed measures which can be adapted to ensure sustainability of resources in that marine environment.