A Survey of Seagrass Beds in Kampot, Cambodia

A survey of seagrass beds in Kampot, Cambodia

Building Resilience to Climate Change Impacts in Coastal Southeast Asia (BCR)

Petchrung Supkong and Louis Bourne

The designation of geographical entities in Citation: Supkong, P. and Bourne, L. this book, and the presentation of the (2014). A survey of seagrass beds in material, do not imply the expression of any Kampot, Cambodia. Thailand: IUCN. opinion whatsoever on the part of IUCN or 91pp. the European Union concerning the legal status of any country, territory, or area, or of Cover photo: Aerial view of a its authorities, or concerning the delimitation seagrass bed in Kampot, Cambodia of its frontiers or boundaries. The views © IUCN/Roengchai Kongmuang expressed in this publication do not necessarily reflect those of IUCN, the Photos in-text: © Roengchai European Union or any other participating Kongmuang, Louis Bourne and organizations. Petchrung Supkong

This publication has been made possible by Layout by: Ria Sen/Nguyen Thuy funding from the European Union. Anh

Published by: IUCN Asia in Bangkok, Produced by: IUCN Southeast Asia Thailand Group

Copyright: © 2014 IUCN, International Union Available from: IUCN Asia Regional for Conservation of Nature and Natural Office, 63 Soi Prompong, Sukhumvit Resources 39, Wattana 10110 Bangkok, Thailand Reproduction of this publication for educational or other non-commercial Tel: +66 2 662 4029 purposes is authorized without prior written permission from the copyright holder www.iucn.org/building-coastal- provided the source is fully acknowledged. resilience

Reproduction of this publication for resale or other commercial purposes is prohibited without prior written permission of the copyright holder.

Acknowledgements

We would like to thank the provincial government of Kampot and the Fisheries Administration and the Department of Environment for their collaboration and participatory role in aiding the success of the seagrass survey. Special thanks to all those who joined the survey team and took part in the seagrass survey in Kampot namely Mr. Ven Virak (Director of Coastal Resources Center and Deputy Director of Environmental Department, Kampot); Mr. Chak Sineath (Deputy Chief of Kep Fishery Division); Miss Minhchan Soriya (Environmental Officer, Department of Environment); Mr. Suy Chanras (Environmental Officer, Department of Environment); Mr. Tran Poli (Fishery Officer, Kampot fishery administration cantonment), and Mr. Voen Seila ( Vice chief of fishery administration division).Thank you to Mr. Suy Thea (Director of Environmental Department, Kampot), and Mr. Sor Sorin (director of Kampot Fishery administration cantonment) who authorized their staff to be part of a great seagrass survey team. The seagrass survey would have never been possible without you all. We would also like to voice our thanks to all IUCN staff who helped one way or another, especially the IUCN Cambodia team who helped mainly on the ground level and particularly Sun Kong for organizing logistics and workshops, setting up meetings with the provincial government and community fishery members and allowing the seagrass survey to run smoothly. Also, thanks to Soriya for later taking over logistics of the seagrass survey. Thanks to Dararat Weerapong for raising publicity of the seagrass surveys and the importance of the seagrass bed in Kampot. Much appreciation is shown for Robert Mather for his support and Maeve Nightingale for the technical support of the seagrass survey. We would also like to thank Roengchai Kongmuang and Roengrit Kongmuang for photographing the seagrass surveys and seagrass bed and taking an important role in the aerial survey. Much appreciation to Thai PBS for documenting the seagrass surveys and the paramotor pilots for making the aerial survey possible. Thanks to all the community fishery and village members for participating in the numerous workshops. Special thanks to the EU for funding the BCR project and making the seagrass surveys possible.

Foreword

Sea-grass meadows are incredibly important coastal ecosystems. They provide spawning and nursery areas for many species, sequester large amounts of carbon and provide significant support to local livelihoods. The coastline of Kampot Province in Cambodia hosts one of the most important seagrass areas in Southeast Asia, but so far is relatively unknown and has not been subject to any in-depth study. Its importance and value to local livelihoods, and its significance in terms of climate change mitigation and adaptation are not properly understood, and are consequently not sufficiently taken into account in development planning. Large scale development projects with direct impacts on sea-grass such as port and harbor construction are already underway and are rapidly destroying and degrading significant areas of this precious resource before its real value to the people of Kampot Province and the rest of Cambodia are fully understood.

Kampot is one of eight Provinces in three countries selected for pilot activities in the “Building Resilience to Climate Change – Coastal Southeast Asia” Project (BCR) funded by the EU and implemented by IUCN and partners.

This report is the first in a series of linked reports looking at the biological condition, socio-economic importance and conservation management priorities for Kampot seagrass, in the broader context of overall coastal spatial planning of Kampot Province.

Table of contents

Executive Summary ...... 8

1. Introduction ...... 9

2. Objectives ...... 12

3. Survey methods ...... 12

3.1 Spot check survey ...... 12

3.2 Line transect survey ...... 14

3.3 Order of surveyed areas ...... 14

3.4 Water quality testing ...... 15

4. Results ...... 15

4.1 Seagrass species composition and abundance ...... 16

4.2 Seagrass distribution ...... 22

4.3 Seagrass status ...... 26

4.4 Water quality ...... 28

4.5 Seagrass spatial distribution...... 28

5. Discussion ...... 43

5.1 Species composition and variation ...... 43

5.2 The health of seagrass ...... 44

5.3 Sediment type ...... 46

5.4 Water quality ...... 46

5.5 Previous findings ...... 47

5.6 Threats to the seagrass bed ...... 48

6. Conclusion and recommendations...... 51

7. References ...... 53

8. Appendixes ...... 54

List of figures and tables

I. Maps Map 1 The geography of Kampot province 10 Map 2 The location of the seagrass bed in Kampot, UNEP 2004 10 Map 3 The division of the different seagrass survey areas 15 Map 4 Distribution of seagrass in Kampot 31 Map 5 Seagrass survey points with only seagrass present 32 Map 6 Seagrass bed in Kampot 33 Map 7 Boundary of seagrass beds in each section 34 Map 8 Seagrass bed Section A (East of Preaek Trapeang Ropoue to West of Preaek Kdat) 35 Map 9 Seagrass bed Section B (East of Preaek Kdat to West of Preaek Kaoh Toal) 36 Map 10 Seagrass bed Section C (East of of Preaek Kaoh Toal to Kampot river mouth) 37 Map 11 Seagrass bed Section D (East of Kampot river to East of Koun Satv commune) 38 Map 12 Seagrass bed Section E (Kampong Trach district) 39 Map 13 Seagrass bed Section F (Kaoh Sec) 40 Map 14 Seagrass status in Kampot 41 Map 15 Sedimentation type in Kampot 42

II. Figures Figure 1 Modified spot check survey methodology on the boat 14 Figure 2 Frequency of seagrass species presence within 881 surveyed points 16 Figure 3 Seagrass species composition and overall abundance surveyed in Kampot 17 Figure 4 Percentage frequency of seagrass species occur in each section 18

III. Pictures Picture 1 Spot check survey using the manta tow method 13 Picture 2 Images of seagrass species surveyed in Kampot 19 Picture 3 High density of various seagrass species in Section E 44 Picture 4 High seagrass density in Section E of Thalassia hemprichii 44 Picture 5 High density meadow of Enhalus acoroides in the intertidal zone of Section C 45 Picture 6 Sand gobbler living amongst the seagrass attached to Enhalus acoroides 46 Picture 7 Intertidal zone with distribution of Halodule pinifolia and other various seagrass 47 species in Section C Picture 8 Mari-culture of seaweed farms in Section B 48 Picture 9 Evidence of some degree of sedimentation smothering Enhalus acoroides and 49 reducing the available light reaching the seagrass Picture 10 Aerial photo of the seaport construction in section C 50 Picture 11 Closer look at land filling on top of the seagrass in the seaport construction site 51 Picture 12 Aerial photo of the seaport construction showing the seagrass to be land filled 51

IV. Tables Table 1 Distribution of seagrass species in Kampot province in 2013 18 Table 2 Seagrass status determined by percentage cover 26 Table 3 Kampot seagrass status in 2013 27 Table 4 Water quality found within the Kampot seagrass bed 28

Executive Summary

The seagrass bed of Kampot is located along the coastal region of Cambodia and is among one of the largest seagrass beds in the South China Sea. Seagrass habitats are well recognized for providing a range of vital ecosystem services including the support of a wide biodiversity of marine species, oxygenation and binding of hypoxic sediment, reduction of storm surges and contribution to carbon fixation in the ocean. Since preliminary studies on the seagrass bed in 2004, very little was known on the current status and situation of the seagrass bed until the present surveys were conducted. The objective of the surveys was to collect, map and update detailed baseline data on the seagrass bed of Kampot Province and record its current status. Depending on the field situation, two survey methods were used to survey the seagrass (i) spot check survey (ii) line transect survey. The seagrass surveys in Kampot took a total of 23 days to complete from 13th May to 3rd July 2013 during the monsoon season. The Kampot seagrass bed comprises of 11 seagrass species. The dominant species were eelgrass (Enhalus acoroides), turtle grass (Thalassia hemprichii), fiber strain grass (Halodule pinifolia), and toothed seagrass (Cymodocea serrulata). Different areas of the seagrass bed housed varied numbers of different seagrass species and the main sediment types were silt, fine sand and silt, and sand. The mapped seagrass bed covers an area of 8,435.80 hectares and is relatively healthy with a ‘moderate’ to ‘good’ status. Anthropogenic threats to the seagrass bed include destructive fishing practices, coastal development, sedimentation, pollution and mariculture. The most significant threat is the construction of a seaport directly on the seagrass bed, which could cause severe sedimentation throughout the whole seagrass bed destroying large habitat areas. Without immediate long term monitoring and conservation efforts to mitigate the threats, the seagrass bed may be under too poor conditions to adapt to the future impacts of climate change or largely wiped out before climate change impacts become noticed. Coastal livelihoods will be at risk if action is not taken soon.

1. Introduction

Seagrass meadows are an important ecosystem that supports a large biodiversity of marine species and provides a range of fundamental ecosystem services for marine fauna, the physical environment and food security (Short F. et al, 2007). They provide nursery and spawning grounds for many juvenile marine organisms including commercially important species of fish, crustaceans and invertebrates (UNEP, 2004). Consequently, seagrass habitats help to promote fish and invertebrate population recruitment and provide protective shelter from predators. Furthermore, migration of adult fish between seagrass, mangroves and coral reefs is a natural part of their daily activities, usually foraging for food in the seagrass bed at night.

Seagrass is a source of nutrition for grazers such as turtles, dudongs and some herbivorous fish like wrasse and rabbit fish (Mat Bjork et al, 2008). Other fish and fauna permanently living within the seagrass feed on algae and invertebrates growing on the seagrass leaves. Currently, the seagrass is home to some marine species vulnerable to extinction not just in Cambodian waters but also worldwide, including dugongs, seahorses and green turtles.

The leaves, rhizome and root systems of seagrass help trap and bind sediment, preventing the re-suspension of sediment and thus, coastal erosion. Seagrass also attenuate waves, reducing wave and storm surges, protecting the coast from potentially harmful storms. They oxygenate the hypoxic sediment that they tend to grow in, thereby sustaining high microbial activity with increased oxygen levels, allowing nutrients to be effectively recycled from dead organic matter and available to the seagrass roots (Mat Bjork et al, 2008).

Furthermore, with increased CO2 released into the atmosphere influencing global warming, it has been estimated that seagrass worldwide fixate 1% of the total carbon fixed in the ocean but store 12% (UNEP, 2004 & Mat Bjork et al, 2008). This is largely because seagrass decompose at a slow rate. Seagrass beds are economically valued as one of the most important ecosystems in the world, approximately $3.8 trillion USD worldwide. As a whole seagrass beds are vital to sustaining biodiversity and the economy of the region (UNEP, 2004).

Cambodia has 435km of coastline that extends from the borders of Thailand to Vietnam. There are 4 provinces situated along the coast, Koh Kong, Sihanoukville, Kampot and Kep. Kampot province is the last province along the coast before Vietnam, adjacent to Phu Quoc island and borders Kep province (UNEP, unknown date). Out of the 435km of Cambodian coastline, Kampot covers 66.5km of it and has a total area of 4873km2. Mangroves fringe the coastline and small patches of coral reef can be found. The seagrass bed in Kampot is among the most extensive coastal ecosystems and stretches approximately 50km along the Kampot coastline, extending through Kep and further past the Vietnamese border in Hat Yien. Some of the seagrass extends along the coastline of Phu Quoc. Overall, the seagrass along this stretch of coastline and Phu Quoc island is growing as large patchy areas within close proximity to each other, which

are all ecologically inter-related and can be considered as parts of the same seagrass ecosystem. However, this report will focus primarily on the seagrass bed in Kampot province.

Kampot Province

Map 1 The geography of Kampot province

Kampot has a tropical climate consisting of two seasons, the tropical monsoon season, May to October; and the dry season, November to April. The average annual temperature is 28 C with the minimum and maximum average monthly temperature of 17 C in January and 38 C in April. Annual rainfall along the coastline of Cambodia can be as much as 5,000 mm. Furthermore, the coastline is affected by cyclones and storms from the Pacific Ocean especially from August to November, with October having the highest storm frequency. Mountain chains along the coast reduce some of

the storm strength, protecting coastal areas from full exposure.

Map 2 The location of the seagrass bed in Kampot, UNEP 2004

Map 2 shows the map of the seagrass bed from seagrass surveys financed by UNEP in 2004. The first area extends from Prek Trapeang Ampil to Prek Khdat (1,795 hectares), the second area extends from Prek Kdat to Koh Touch (380 hectares) and the third and largest area extends from Koh Touch to Kep Municipality (23,065 hectares). Also, the seagrass extends into Kampong Trach district, which is not shown in map 2. In total according to the UNEP study, the seagrass bed covers an area of 25,240 hectares. As indicated in the Cambodian National Strategy and Action Plan for Mangroves for the Future initiative, of the 25,240 hectares of seagrass in Kampot alone, 1,500 hectares is under community management from Chang Hourn to Trapeang Ropov. No further baseline surveys on the Kampot seagrass bed have been conducted since 2004 so variation in seagrass distribution, abundance and overall area/size of the seagrass bed has been largely unknown until now.

The seagrass bed is 1 - 4m deep depending on the tide and visibility varies with seasons with the rainy season having the lowest visibility. Salinity range is 24 – 30 ppt or sometimes more (UNEP, 2004). The sea surface temperature varies from 26 - 30 and the pH ranges from 7-8. The sediment varies with a mixture of sand and mud (UNEP, unknown date).

Previous to the current survey, some limited surveys and studies had been undertaken on the seagrass bed of Kampot including species abundance, biodiversity of associated marine fauna, distribution over time (UNEP, unknown date). The health of the seagrass beds however was largely unknown.

Previously 8 species of seagrass were reported from Cambodia namely Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium, Cymodocea rotundata, Halodule univervis, Cymodocea serrulata, Halophila ovalis and Halodule pinifolia. (UNEP, 2004).

In 2004, the Fisheries Administration reported that there were a total of 6 seagrass species in Kampot: Enhalus acoroides, Thalassia hemprichii, Halophila decipiens, Syringodium isoetifolium, Cymodocea rotundata, and Halodule uninervis (UNEP, 2004). Enhalus acoroides and Cymodocea rotundata were found to be the most dominant species.

Ouk Vibol et al (2011), reported 12 species of seagrass in Kampot, identified as Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium, Cymodocea rotundata, Halodule univervis, Cymodocea serrulata, Halophila ovalis, Halodule pinifolia, Halophila minor, Halophila decipiens, Halophila beccarii and Ruppia maritima. However, it is still unclear where they found Halophila beccarii and Ruppia maritima.

In Phu Quoc it has been reported that there are 113 species of macro-algae, 71 species of molluscs, 26 species of crustaceans, 19 species of annelids and 15 species of echinoderms (UNEP/GEF Project). The seagrass of Kampot is situated closely adjacent to Phu Quoc island so it is likely to provide a habitat for most of these species.

Cetaceans can be found along Cambodia’s coastlines, including the indo-pacific humpback dolphin, common bottlenose dolphin, indo-pacific bottlenose dolphin,

11 pantropical spotted dolphin, spinner dolphin, common dolphin, false killer whale, short- finned pilot whale and finless porpoise (Beasley et al, 2007). It is considered in local Khmer folklore and superstition ‘unlucky’ to catch cetaceans. Also, due to lack of educational awareness, these cetaceans can sometimes be mistaken as big marketable fish and caught for that purpose.

Dugongs on the other hand are less fortunate and are considered ‘lucky’ to catch. They feed entirely on seagrass and are listed as vulnerable to extinction in the IUCN red list. Their bones and tusks are used in traditional medicine to cure fevers and protect livestock from illness and meat and internal organs are valuable, considered a local delicacy. The meat can be sold for $1.10 USD/Kg and their bones and tusks for up to $100 USD (Beasley et al, 2007). Thus, Dugongs are considered the most threatened marine mammals in Cambodian waters. It is estimated that there are only 10 dugongs remaining in Con Dao Island and between100 to 300 around Phu Quoc.

2. Objectives

The aim of the study was to collect, map and update detailed baseline data on the seagrass bed of Kampot province and record its current status. This included the collection and record of seagrass species, the seagrass percentage cover, sediment identification, water quality and depth found throughout the seagrass beds.

3. Survey methods

Depending upon the field situation, two survey methods were applied (i) spot check survey and (ii) line transect survey. The spot check survey was used in sub-tidal zones of the seagrass and the line transect survey was used in inter-tidal zones. The seagrass survey team consisted of a total of 9 team members, whose roles included: i. Boat Captain (1 person) ii. Boat Assistant (1 person) iii. Seagrass Observer (6 people) iv. GPS navigator / data recorder (1 person)

The Kampot seagrass bed survey took a total of 7 weeks to complete.

3.1 Spot check survey

The boundary of the seagrass bed was mapped out first by travelling in straight transect lines from the coast out towards the sea using a long-tail boat. The end of the seagrass bed boundary was marked when there was 0 to <5 % seagrass cover. Then the boat would turn parallel to the shore and continue along a line adjusting its course depending on the boundary of the seagrass bed. Once a large seagrass bed patch boundary was mapped in this way, the boat would subsequently travel in transect lines from the shore towards sea or parallel to the coastline within the mapped boundary. The transect lines travelled by the boat were never absolutely straight and were never 100% consistently parallel to each other due to sea conditions. However, the approach was repeated enough times to give adequate information on the seagrass bed. A Garmin GPS Map

78s and Map 60cx with a downloaded map was used to keep track of the distance travelled and helped identify areas that still needed to be surveyed.

Three free divers (observers) were manta towed throughout the course of the boats journey. Every 2 minutes, a person on board handling the GPS would signal to the free divers to free dive and observe the seagrass bed. This was called a spot check. Each spot check recorded the following data: i. Overall seagrass percentage cover. ii. Seagrass species composition iii. Depth iv. Sediment type v. Observations on marine fauna vi. Photograph of seagrass observed with time and date stamp In addition on these spot checks seagrass species samples were sometimes collected.

Water quality was sampled at the beginning of each seagrass survey, which included the measurement of: i. pH ii. Dissolved Oxygen iii. Turbidity iv. Salinity v. Temperature

The role of the GPS person on board the boat was to: i. Work with the boat captain to navigate the boat. ii. Keep track of location of the boat. iii. Record time of GPS spot check points and their GPS location. iv. Signal to the observers when to free dive.

Figure 1 Modified spot check survey methodology on the boat

Due to rough weather conditions, the boat could not always turn efficiently enough with the drag of three people being manta towed. Therefore, a spot check method without a manta tow was used in these situations where observers would dive in from the boat at each spot check. In areas deeper than 7m, the survey team used SCUBA gear dive down at each spot check. Once at the bottom of the seabed two divers using an underwater compass and camera would survey and film a 10 minute transect line

13 towards shore. If seagrass was present percentage cover, species composition and sediment type was recorded.

Picture 1 Spot check survey using the manta tow method

3.2 Line transect survey

The line transect survey was used in intertidal areas of the seagrass bed during low tide. The transect lines were marked and followed by a GPS and each way point and direction was navigated using the GPS. The survey consisted of three people where one person handled the GPS and the other two were the observers. The observers threw a quadrat size 50cm x 50cm in every 50m to observe and record (i) overall seagrass percentage cover (ii) the species composition and (iii) the individual species percentage cover to the total seagrass cover within the quadrat. The GPS person took a photo of each quadrat and recorded latitude & longitude of quadrat, time, date, species composition, individual species percentage cover and overall seagrass percentage cover. Due to the size of the surveyed areas, two to three transect lines were undertaken in a direction parallel to the shoreline.

3.3 Order of surveyed areas

The seagrass survey was divided into 6 sections/areas using river mouths as boundaries for each section (Map 3). Due mainly to weather dependent factors, the survey took a duration of 7 weeks to complete. The areas surveyed in chronological order were sections A, B, C, D, E, and F (Map 3). The following are the locations marking the boundaries between each section:

Section A: Preaek Tnaot commune (East of Preaek Trapeang Ropoue to West of Preaek Kdat) Section B: Kaoh Touch commune (East of Preaek Kdat to West of Preaek Kaoh Toal) Section C: Boeng Tok commune (East of of Preaek Kaoh Toal to Kampot river mouth)

Section D: Traeuy Kaoh commune to Koun Satv commune (East of Kampot river to East of Koun Satv commune) Section E: Kampong Trach district Section F: Kaoh Ses

A B C D

F E

Map 3 The division of the different seagrass survey areas

3.4 Water quality testing

The dissolved oxygen, pH, salinity and turbidity were measured at the start of the seagrass surveys. Dissolved oxygen and pH were measured using field test kits. Salinity was measured using a refractometer and the turbidity was measured using a secchi disc. All water quality testing equipment was used on board the boat and rinsed with fresh water after each use.

4. Results

Kampot has around 66 kilometres of shoreline from the west to the east coast of mostly mudflat terrain. The seagrass meadow in Kampot is situated adjacent and inter- connected to the mangrove forest all along the coastline with an intertidal zone of 2- 4km between the shore and subtidal zone. During peak high tide the depth can reach up to 5m. Coral reef patches can be found growing in sandy sediment amongst the seagrass in sections B, and F.

The spot check survey method involving the boat was the main method used (free diving and SCUBA diving in the deep area) in subtidal zones. The line transect method

15 was the survey method used in all intertidal zones. The seagrass baseline survey took a total of 23 days to complete from 13th May to 3rd July 2013 during the beginning of the monsoon season. A total seagrass area of 8,435.80 hectares was mapped for the intertidal and sub-tidal zones.

4.1 Seagrass species composition and abundance

The distribution pattern of the seagrass bed is continuous and interspersed with a few gaps of un-vegetated sediment. Eleven species of seagrass in Kampot province were recorded in 2013. Seagrass species were identified by the leaf shape, the pattern of veins on the leaves, and rhizome. Due to the water conditions, sedimentation and turbidity, there were variations of leaf shapes of certain seagrass species to cope or adapt in such water environments. Some seagrass species had very long rhizomes rising up from sea floor that grew up to 50cm in the water column to reach the light.

There were a total of 11 seagrass species found in Kampot, which were Eelgrass ߒលុយគុម្ព (Enhalus acoroides) , Fiber strain grass (Halodule pinifolia), Turtle grass ߒលុយ厶ត (Thalassia hemprichii ), Toothed seagrass ߒលុយរនងបងកង់ (Cymodocea serrulata ), Round-tipped seagrass ߒលុយរនង (Cymodocea rotundata), Fiber-stand grass ߒលុយ厶ត習លឹកតូច (Halodule uninervis), Syringe grass ߒលុយ埒លុង (Syringodium isoetifolium), Veinless spoon-grass ߒលុយស្លលប掶ន់ (Halophila decipiens), Small spoon- grass (Halophila minor), Spoon-grass 習មៅζក់習ម្ុទ្រ (Halophila ovalis), and Estuarine spoon-seagrass (Halophila beccarii) a new record of seagrass species in the intertidal zone of Cambodian waters. However, the team did not find the hairy seagrass (Ruppia maritime) which was previously reported in 2010 (Ouk Vibol et al).

Figure 2 Frequency of seagrass species presence within 881 surveyed points

Figure 3 Seagrass species composition and overall abundance surveyed in Kampot province

The dominant species across the whole seagrass bed were eelgrass (Enhalus acoroides), turtle grass (Thalassia hemprichii), fiber strain grass (Halodule pinifolia), and toothed seagrass (Cymodocea serrulata) (for images of the seagrass species surveyed, turn to page 18). The leaves of these species are long and blade-like for better access to sunlight, especially in turbid waters. Figure 2, below shows the number of spot check points and frequency of seagrass species presence. Enhalus acoroides was the most frequently found and present in 267 points out of the total 881 spot checks.

Percentage frequency of Enhalus acoroides (31%) and Thalassia hemprichii (20%) showed the highest abundance in the seagrass survey (figure 3). The third most abundant species was Halodule pinifolia showing 18% abundance, followed by Cymodocea serrulata 11%, Halophila ovalis 6%, Syringodium isoetifolium 4.5%, Cymodocea rotundata 3%, Halodule uninervis 4%, Halophila beccarii 1%, Halophila minor 1%, and Halophila decipiens 0.5%.

The dominant species in the intertidal zone were Halodule pinifolia mixed with other oval shaped leaf species such as Halophila ovalis, commonly found growing on fine sand and silt. In the mudflat areas of the intertidal zone which was mostly silt, the dominant species were Enhalus acoroides, Thalassia hemprichii, Cymodocea serrulata, and Halodule uninervis. Overall, Section C had the most continuous distribution of seagrass and Section D had the largest intertidal zone of seagrass starting from the mangrove forest and out towards the subtidal zones of 5km during peak low tide with a depth of 4.2m during peak high tide. The species diversity was found to be highest in sections C and D with 10 species found in those areas (Table 1). Eelgrass (Enhalus acoroides), and Turtle grass (Thalassia hemprichii) are the dominant species throughout all the sections surveyed (figure 4). However, fiber strain grass (Halodule pinifolia) was the most dominant species found in section D.

Figure 4 Percentage frequency of seagrass species occurring in each section

Enhalus acoroides 60 Thalassia hemprichii 50 Syringodium isoetifolium

Cymodocea serrulata 40 Cymodocea rotundata

30 Halodule pinifolia

Halodule uninervis 20 Halophila beccarii

Percentagefrequency(%) 10 Halophila decipiens Halophila minor 0 A B C D E Halophila ovalis F Sections Spotted check (points)

Table 1 Distribution of seagrass species in Kampot province in 2013 Section Section Section Section Section Section Dominant Seagrass Species A B C D E F species CYMODOCEACEAE

Cymodocea rotundata ߒលុយរនង * * * *

Cymodocea serrulata ߒលុយរនងបងកង់ * ** * ** ** *

Halodule pinifolia ** ** **** * 

Halodule uninervis ߒលុយ厶ត習លឹកតូច * * * * *

Syringodium isoetifolium ߒលុយ埒លុង * * * * *

HYDROCHARITACEAE Enhalus acoroides ߒលុយគុម្ព **** *** **** *** *** **** 

Thalassia hemprichii ߒលុយ厶ត *** **** *** * **** *** 

Halophila beccarii * * *

Halophila decipiens ߒលុយស្លលប掶ន់ * *

Halophila minor *

Halophila ovalis 習មៅζក់習ម្ុទ្រ * * *

Total Species Found 9 5 10 10 8 3

Picture 2 Images of seagrass species surveyed in Kampot

Estuarine spoon seagrass (Halophila becarii)

Fiber-stand grass (Halodule pinifolia)

Fiber-stand grass (Halodule uninervis)

Small spoon-grass (Halophila minor)

Spoon grass (Halophila ovalis)

Syringe grass (Syringeodium isoetifolium)

Toothed seagrass (Cymodocea serrulata)

Tropical eel grass (Enhalus acoroides)

Turtle grass (Thalassia hemprichii) 21

4.2 Seagrass distribution

The distribution of seagrass extends 50km along the Kampot coastline adjacent to fringing mangrove habitats. The seagrass cover pattern is continuous and extends 2 – 5km from the shore and out to sea with an average depth between 0.3 to 4.2m. Below are descriptions of the geography, species composition, seagrass percentage cover, present human activities and current threats to the seagrass of each surveyed section.

4.2.1 Section A Section A starts from the east of Preaek Trapeang Ropoue and continues to the west of Preaek Kdat in PreaekTnaot commune, covering about 11km of coastline from 10°36'20.29"N, 103°55'10.19"E; to 10°34'6.76"N, 104° 0'30.49"E. The geography of the area is fringed with mangrove forests growing on mudflats adjacent to the seagrass bed, where the sediment is mainly comprised of silt and sand in front of Chang Hoan village. The depth of seagrass distribution is from 0.5 – 3 meters with an average depth of 1.3 meter. The data collected was combined from intertidal and subtidal surveys using the spot check methodology to estimate seagrass percentage cover. The distribution of seagrass in section A covers 1,320.53 hectares.

Within the total area surveyed, 215 data points were collected where 121 data points showed the distribution of seagrass and 94 points showed no presence of seagrass. There were 9 seagrass species found in Section A, which were Eelgrass (Enhalus acoroides) , Turtle grass(Thalassia hemprichii), Fiber strain grass (Halodule pinifolia), Syringe grass(Syringodium isoetifolium), Round-tipped seagrass (Cymodocea rotundata), Toothed seagrass (Cymodocea serrulata), Fiber-stand grass (Halodule uninervis), Spoon-grass (Halophila ovalis), and Esturine spoon-seagrass (Halophila beccarii). There were three dominant species Enhalus acoroides, Thalassia hemprichii, and Halodule pinifolia.

The average percentage cover of seagrass distribution in Section A was 29.81% and considered to be under ‘moderate’ status. The intertidal zone had 1-2 species present per data point and around 32.77% seagrass cover density and the subtidal zone had 1- 4 species present with 29% cover.

Human activities observed in Section A were mainly fishery activities 1-5 km from the shore. These included shell collecting, catching banana shrimp, sea cucumber, swimming crabs, fishing and aquaculture (fish cages). There was also a rice mill factory located near the Preaek Tnaot river mouth.

Unsustainable fishing practices of trawling boats from Preaek Trapeang Ropoue to Preaek Tnaot river, placement of mouse tail traps and sedimentation are the common threats to seagrass growing in Section A.

4.2.2 Section B Section B is 8.3km long and starts from the East of Preaek Kdat (10°34'2.11"N, 104° 0'30.96"E) to the West of Preaek Kaoh Toal (10°32'51.41"N, 104° 4'42.01"E) in Kaoh Touch commune, Kampot. There are mangrove forests adjacent to the seagrass bed in

Changhaon village and patchy areas of mangroves along the coast with a sandy beach extending from Thma Koul village to Preaek Kaoh Toal. The beach profile has a gentle slope of 5m. The sediment in this area is sand and fine sand and the depth is around 0.3 – 3m with the average depth of 1.8m. Patches of coral reef and sponges growing on sandy sediment can be found amongst the seagrass bed. The most diverse and dense area of seagrass species is located close to Nattaya Resort, where there were 5 species for each surveyed point. The data gathered from the subtidal zone was done using the spot check methodology to estimate the percentage cover of the seagrass bed. The distribution of seagrass in section B is 976.63 hectares.

Within the total area surveyed, 52 data points were collected where 32 data points showed presence of seagrass and 20 points showed no presence of seagrass. There were 5 seagrass species found in Section B, which were Turtle grass (Thalassia hemprichii), Eelgrass (Enhalus acoroides), Toothed seagrass (Cymodocea serrulata), Syringe grass (Syringodium isoetifolium), and Fiber-stand grass (Halodule uninervis). There were three dominant species Thalassia hemprichii, Enhalus acoroides, and Cymodocea serrulata. Conversely, Halodule uninervis was only present in one data point.

The distribution of seagrass was within 1-2m depth and the average percentage cover of seagrass was 51.24%, which is considered to be under ‘good’ status. Human activities observed in Section B were fisheries and aquaculture such as seaweed farming, oyster farming, use of swimming crab traps and fishing. Sedimentation and erosion are the main threats of the seagrass bed in this area, especially the seagrass meadow nearer to land reclamation activities of the Eastern side of Preaek Kaoh Toal.

4.2.3 Section C Section C covers Boeng Tuk commune which is from the Eastern part of Preaek Kaoh Toal to the Western part of the Kampot river mouth, next to Traeuy Kaoh commune. The coastline stretches around 9.4 km starting from East of Preaek Kaoh Toal (10°32'12.11"N, 104° 4'44.02"E) to West of Kampot river mouth (10°33'30.89"N, 104° 9'1.76"E). There are mangrove forests growing on mudflat adjacent to the seagrass bed with a sediment mixture of silt, fine sand and silt. Also, there is the development and construction of a seaport operating in the area where there is extensive land reclamation happening, 3km on the seagrass bed out towards sea. The depth of the seagrass distribution is 0.2 – 4.2m with an average depth of 2.3 meters. The data collected was combined from intertidal and subtidal surveys using the spot check methodology to estimate seagrass percentage cover. The distribution of seagrass in section C covers 2,581.80hectares.

Within the total area surveyed, 216 data points were collected where 140 data points showed the distribution of seagrass and 76 points showed no presence of seagrass. There were 10 seagrass species found in Section C, which were Eelgrass (Enhalus acoroides) , Turtle grass (Thalassia hemprichii), Fiber strain grass (Halodule pinifolia), Toothed seagrass (Cymodocea serrulata), Spoon-grass (Halophila ovalis), Syringe grass (Syringodium isoetifolium), Fiber-stand grass (Halodule uninervis), Small spoon- grass (Halophila minor), Esturine spoon-seagrass (Halophila beccarii), and Round-

23 tipped seagrass (Cymodocea rotundata). There were three dominant species Enhalus acoroides, Thalassia hemprichii, and Halodule pinifolia. The Small spoon-grass (Halophila minor) and Estuarine spoon-seagrass (Halophila beccarii) were present in the intertidal zone at the West of Kampot river mouth. The average percentage cover of seagrass distribution in section A is 46.78%, which is considered to be ‘moderate’ status. To compare between the intertidal and subtidal zones: the distribution of seagrass in the intertidal zone has 1-5 species per survey point with an average density of 56.91%, which is higher density than the subtidal zone with only 37%.

Human activities in Section C are the development of the seaport, land reclamation, channel dredging and fishery activities within 1-5 km from Kep Thmei coastal village. Local fishermen fish for banana shrimps, swimming crabs and collect shells. Sedimentation and change of underwater currents due to newly formed land obstruction from the seaport construction will be the biggest threats to the seagrass ecosystem. These anthropogenic activities will cause changes to land use patterns and have a significant impact on the healthy seagrass ecosystem.

4.2.4 Section D Section D covers the area from Traeuy Kaoh commune to Koun Satv commune. This section of coastline is around 17.8km long, stretching from the East of Kampot river (10°33'22.13"N, 104° 8'56.88"E) to the East of Koun Satv commune (10°32'57.96"N, 104°15'57.18"E). There are mangrove forests growing on mudflats adjacent to the seagrass bed with a sediment mixture of silt, sand, fine sand and silt. There are three main river mouths that deposit a large amount of silt causing natural occurrences of high sedimentation. The depth of seagrass distribution here is 0.2 – 3.8 meters with the average depth of 1.8m. The data collected was combined from intertidal and subtidal surveys using the spot check methodology to estimate seagrass percentage cover. The distribution of seagrass in section D covers 2,384.57 hectares.

Within the total area surveyed, 306 data points were collected where 161 data points showed the presence of seagrass and 145 points showed no presence of seagrass. There were 10 seagrass species found in Section D, which were Fiber strain grass (Halodule pinifolia), Eelgrass (Enhalus acoroides), Toothed seagrass (Cymodocea serrulata), Turtle grass (Thalassia hemprichii), Spoon-grass (Halophila ovalis), Fiber- stand grass (Halodule uninervis), Round-tipped seagrass (Cymodocea rotundata), Syringe grass (Syringodium isoetifolium), Esturine spoon-seagrass (Halophila beccarii), and Veinless spoon-grass (Halophila decipiens). There were three dominant species Halodule pinifolia, Enhalus acoroides, and Cymodocea serrulata. Halophila beccarii and Halophila decipiens were present in only 1 data point, each at the depth of 1 meter and 2.9 meter.

The average percentage cover of seagrass distribution was 52.78% which is considered to be of ‘good’ status. Human activities observed in Section D are local and commercial fisheries and aquaculture (shrimp farms). Local fishermen collected cockles at Preaek Kampong Pouthi during low tide. Threats to the seagrass bed are sedimentation and change in underwater currents from the seaport construction in Section C and seabed erosion from sand dredging.

4.2.5 Section E The coastline of Section E is 3.9km long in Kampong Trach district. Mangrove forests fringe the coast and grow adjacent to the seagrass bed. The northwest of Kampong Trach district borders Kep province (10°26'29.65"N, 104°24'58.81"E), and the East of Kampong Trach district is the border between Cambodia and Vietnam (10°25'26.31"N, 104°26'15.93"E). The sediment in this area is sand and fine sand and the depth is around 0.3 – 3.5 meters with the average depth of 1.8 meters. The distribution of seagrass in section E is 1117.55 hectares.

Within the total area surveyed, 63 data points were collected where 47 data points showed the distribution of seagrass and 16 points showed no presence of seagrass. Small shell fragments combined with coarse sand were found combined with other sediments like sand and fine sand. Sometimes sponges were observed growing on silt sediment and one seahorse (Hippocampus mohnikei) was found in the seagrass meadow.

There were 8 seagrass species found in Section E, which were Turtle grass (Thalassia hemprichii ), Eelgrass (Enhalus acoroides) , Toothed seagrass (Cymodocea serrulata), Fiber-stand grass (Halodule uninervis), Fiber strain grass (Halodule pinifolia), Veinless spoon-grass (Halophila decipiens), Round-tipped seagrass (Cymodocea rotundata), and Syringe grass (Syringodium isoetifolium). There were 2 dominant species Thalassia hemprichii, and Enhalus acoroides. On the other hand, Syringodium isoetifolium, and Cymodocea rotundata were found in only one data point each.

The percentage cover of seagrass in section E is 52.2%, which is considered to be under ‘good’ status. The seagrass bed in Kampong Trach is in a relatively natural or somewhat ‘pristine’ condition, likely because it is situated and protected within the Fisheries Community area.

Human activities in Section E are fisheries with a trawling boat pier at the river mouth. However, no trawling activities or evidence of trawling on the seagrass bed was observed. Threats to the area are sedimentation on the seagrass bed and poor water quality from the fishing pier.

4.2.5 Section F Section F is in Kaoh Ses (10°25'43.12"N, 103°48'11.03"E), a small island near Kaoh Thmei in Sihanoukville province. The island itself is approximately four kilometers long from the north to the south of the island. North of Kaoh Ses is Kaoh Thmei, and to the east and the south of the island is Phu Quoc island of Vietnam. The northern beach surveyed, comprises of a sandy beach, small patches of mangrove forest and a seagrass bed growing amongst patchy coral reef and macro algae on the sandy seabed. The beach profile is flat and has a gentle slope of 3m. The sediment is mainly sand and fine sand. The depth of seagrass distribution is from 0.3 – 1.5 meters with the average depth of 1m. The eastern bay is deeper than the north of the island with a depth of 1.4 – 2.9m. The distribution of seagrass in section F covers 54.72 hectares.

Within the total area surveyed, 29 data points were collected where 16 data points showed the presence of seagrass and 13 points showed no presence of seagrass. There were 3 seagrass species found in Section F, which were Eelgrass (Enhalus acoroides), Turtle grass (Thalassia hemprichii), and Toothed seagrass (Cymodocea serrulata) found growing amongst patches of coral in shallow water.

The average percentage cover of seagrass distribution in the northern beach is 47.18%, which is considered to be of ‘moderate’ status. In the eastern bay there was only one data point of Enhalus acoroides in 2.6m depth. There is a small fishing community settlement in the eastern bay and the main human activities appeared to be fisheries. Threats to the area are unsustainable fishing practices and poor water quality around the fishing village in the eastern bay of Kaoh Ses.

4.3 Seagrass status

The seagrass percentage cover is classified into different status classes using guidelines outlined by the Phuket Marine Biological Center (Table 2).

Table 2 Seagrass status determined by percentage cover Percentage cover of seagrass Seagrass status Description > 75% Very Good Over 75% cover of all seagrass species 51 - 74.99% Good 51 - 74.99% cover of all seagrass species 25 - 50.99% Moderate 25 - 50.99% cover of all seagrass species 1 – 24.99% Natural Cover Less than 25% cover of all seagrass species Less than 25% cover of all seagrass species 1 – 24.99% Degraded and impacted by human activities 0% No seagrass No seagrass in this point

Classification or identification of the seagrass status was taken from the average percentage cover of the seagrass meadow of the area or section surveyed. The average percentage cover of the seagrass bed in the different surveyed zones of Kampot province is between 28.74% and 52.20%, which is considered to be in a ‘moderate’ to ‘good’ status (Table 2). The seagrass percentage cover can change due to natural seasonal changes and changes in the physical environment. Table 3 shows an overall summary of the average seagrass percentage cover and ‘status’ of the seagrass in each section as well as sediment type, total species found and threats encountered.

The seagrass beds in section D and section E have the highest species diversity with a high percentage cover and are ranked as having ‘good’ status. The seagrass bed of section C has ten species with ‘moderate status (Table 3). Sediment type of the Kampot seagrass meadow is predominantly silt to fine sand with the grain size between 0.01 and 0.5mm. Land reclamation, coastal development projects, aquaculture, and destructive fishing gears are the main anthropogenic activities that threaten the wellbeing of the seagrass ecosystem.

Table 3 Kampot seagrass status in 2013

Seagrass Average Area Seagrass Section Location species cover Sedimentation Threats (hectare) status found (%) East of Preaek Trapeang Ropoue - Sedimentation - Destructive fishing practice (trawling A to West of Preaek Kdat 1,320.53 9 29.81 Moderate Silt; Sand boat)

- Sedimentation - Aquaculture impact (seaweed East of Preaek Kdat to farming) B 976.63 5 51.24 Good Sand; Fine sand West of Preaek Kaoh Toal - Change of underwater currents from the coastal development project

- Sedimentation - Seagrass area loss from land East of of Preaek Kaoh Toal to Silt; Fine sand & reclamation C 2,581.80 10 46.78 Moderate - Change of underwater currents from Kampot rivermount silt the coastal development project - Erosion from sand dredged

- Sedimentation - Algae and epiphytic algae (reduce Traeuy Kaoh commune to the ability of seagrass to D 2,384.57 10 52.78 Good Silt; Sand photosynthesis) Koun Satv commune - Change of underwater currents from the coastal development project

- Sedimentation Sand; Fine sand - Destructive fishing practice (trawling E Kampong Trach 1,117.55 8 52.20 Good & silt boat)

Sand; Fine sand - Habitat change from macro algae F North of Kaoh Ses 54.72 3 47.18 Moderate competition & silt TOTAL 8,435.80 11

4.4 Water quality

Water samples were taken in three main locations within section A, C, and D. Dissolved oxygen ranged from 6-12 ppm, (mean = 7.5; mode =6). The pH ranged from 7.3 to 8, the average being 7.5 which is quite a standard measurement for sea water (table 4). The salinity ranged from 23-29 ppt with an average salinity of 27ppt (table 4). Marine waters in close proximity to land means increased fresh water input from rivers and streams, so the salinity may range even more between monsoon and dry seasons. The turbidity ranged from 1 to 4m, the most common being 1 m in the intertidal zone. On average the turbidity was 1.7 m (table 4).

Table 4 Water quality found within the Kampot seagrass bed

UTM 48P Location Dissolved pH Salinity Turbidity Oxygen (ppt) (m) (ppm) X Y

387087 1169689 Section A 6 8 23 1 Intertidal Zone

387086 1169686 Section A 6 8 27 1 Subtidal Zone

404262 1166944 Section C 6 7.6 26 1.05 Intertidal Zone

401250 1162205 Section C 6 7.3 28 2.25 Subtidal Zone

411707 1165689 Section D 12 7.3 27 1 Intertidal Zone

409450 1159584 Section D 9 7.3 29 4 Subtidal Zone

AVERAGE 7.5 7.5 27 1.7

4.5 Seagrass spatial distribution

Seagrass surveys in Kampot mapped the overall distribution of seagrass and highlighted additional details of each section. A total of 881 data points were mapped using the Geographic Information System (GIS) using ArcInfo and ArcMap. The total approximate area of seagrass distribution in Kampot is 8,435.8 hectares, which was estimated based on distance and area between the boundary of seagrass from shore edge of the intertidal zone and the outer edges of the seagrass bed in the subtidal zone. The following seagrass maps show presence and absence of seagrass in each data/survey point; distribution of sedimentation types; section boundaries; seagrass distribution patterns; species composition in each section (A-F); and seagrass status.

These maps of the Kampot seagrass bed are based on seagrass surveys conducted in May-June 2013.

Map 4 shows all the spot check points in the seagrass survey that either have seagrass present or no seagrass, indicating the seagrass distribution of the seagrass bed. The map also gives a perspective of the extent of the survey, location and number of each survey point and justification of the mapped seagrass bed. Overall, there were more points with seagrass distribution than without seagrass distribution with 517 survey points showing presence of seagrass and 364 points without seagrass. The seagrass bed is confined to close proximity of the coast and does not seem to be growing in areas too far out to sea. This is apparent in all sections. Furthermore, map 4 shows that in section C and D there were survey points out to sea as far as Koh Karang and along areas close to Kep Province that showed strong evidence that no seagrass was growing in depths more than 7m. Also, the number of survey points covered quite an extensive area. Ouk Vibol et al (2010) also did not find any seagrass more than 7m deep. Map 5 shows only the survey points that have seagrass present validating the area of the mapped seagrass bed.

The total calculated area of the seagrass bed from all the surveyed sections is 8,435.8 hectares. Map 6 is the mapped area of the seagrass bed without the survey points and shows the seagrass bed does not exceed very far out towards sea and is confined to growing near the coastline, throughout all sections surveyed. Map 7 shows the seagrass bed divided into its individual sections with Sections A and B growing in the closest proximity to the coast and sections C, D and E the seagrass growing furthest out to sea.

Maps 8-13 look at each section in further detail, giving the size of the seagrass area, species composition and degree of species dominance in each individual section. The seagrass area in Section A was 1320.53 hectares, Section B 976.63 hectares, Section C 2581.80 hectares, Section D 2384.57 hectares, Section E 1117.55 hectares and Section F 54.72 hectares. The largest of the seagrass areas was Section C with Section D not far behind. The seagrass areas in Sections A, B and E were similar in size. Section F of the seagrass bed being the furthest away from all the other sections surveyed also had the smallest area of seagrass. Section C has a large ‘chunk’ of the seagrass missing between the seagrass in Sections B and C. The large area missing is most likely due to the location and situation of the seaport construction.

Map 14 shows the distribution of seagrass patch status throughout the seagrass bed. Some areas of the seagrass patches are predominantly ‘good’ and others ‘moderate’ while some areas have a mixture of statuses. Overall, ‘degraded or natural cover’ statuses appear to be the least common status areas present and are usually found next to ‘moderate’ status areas. Section A has some good status areas but there are more areas with ‘moderate’ to ‘degraded or natural cover’ statuses. Section B has a lot more areas with ‘good’ status than ‘moderate’ and ‘degraded or natural cover’ and a few patches with ‘very good’ status. Section C has predominantly more ‘moderate’ status seagrass patches in a concentrated area than ‘good’ seagrass areas. There are two main areas of seagrass opposite each other with one being predominantly

‘moderate’ status and the other main area being mostly ‘very good’ status, however, there is slightly more ‘moderate’ and ‘degraded or natural cover’ status patches. Section D has more ‘good’ status areas than ‘moderate’ to ‘degraded or natural cover status’ areas. Section E has more ‘good’ and ‘very good’ statuses than ‘moderate’ or ‘degraded statuses’, showing a healthy seagrass bed. Section F has almost an equal mixture of ‘good’ and ‘moderate’ statuses around the island.

Map 15 shows the distribution of sediment types across the whole seagrass bed and surrounding areas with presence/absence of seagrass. Section A predominantly has sand and silty sediment with some areas of fine sand and silt and coarse sand. The survey points with seagrass presence in Section A seem to coincide with mostly silt or sandy sediment and sometimes in fine sand and silt. Section B appears to be mostly dominated with sand and coarse sand sediment where seagrass and patches of coral reef were found growing. Areas outside the seagrass bed in Section B comprised mainly of coarse sand. The majority of seagrass in Section C was found growing in sandy or silt sediment. Surrounding areas without seagrass comprised mainly of coarse sand and fine sand and silt. The seagrass growing in Section D was predominantly found growing in silt, fine sand and fine sand and silt sediment. The seagrass was rarely found growing in sand and coarse sand sediment in this area. However, areas surrounding the outside of the seagrass bed comprised of coarse sand, fine sand, fine sand and silt and silt sediment. The seagrass in Section E was found growing in the most varied types of sediment. Silt, fine sand and silt, sand and coarse sand were the main sediments found with seagrass. The area in Section F was mostly composed of sandy sediment where much of the seagrass was found growing around the island.