Seagrass Surveys in Kampot

Transcription

1 Coastal Annual Forum 23 rd October 2014 Sihanoukville, Cambodia Seagrass Surveys in Kampot Presentation by Louis Bourne INTERNATIONAL UNION FOR CONSERVATION OF NATURE

2 Presentation Overview Location and Setting of Seagrass Surveys Objectives Methods Results Recommendations 2

3 Seagrass Survey Location Situated along the coast between Koh Kong, Sihanoukville, and Kep province and borders Vietnam. Kampot covers 66.5km of coastline Total area 4873km 2 3 Kampot Province

4 Introduction to seagrass survey Seagrass surveys took 23 days from 13 th May to 3 rd July The seagrass survey divided into 6 sections using river mouths as boundaries Reasons being: extensive size of the seagrass bed 4

5 Division of seagrass survey sections The sections surveyed in chronological order were sections A, C, D, E, B and F 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 5

6 Objective of the seagrass survey Until now there has been very little to no information on the: 1. current seagrass species composition 2. variation in seagrass distribution and abundance 3. health of the seagrass 4. overall area/size of the seagrass bed. OBJECTIVE: To collect, map and update detailed baseline data on the seagrass bed of Kampot province and record its current situation and status. 6

7 Methodology There were two main survey methodologies used to survey the seagrass bed 1. Spot check survey in the subtidal zone 2. Line transect survey in the intertidal zone 7

8 Spot Check Survey 3 free divers (observers) were manta towed throughout the course of the boats journey. Every 2 minutes, a person on board handling the GPS person would signal to the free divers to free dive and observe the seagrass bed. This was called a spot check. Each spot check recorded data of the following indicators: 1. Overall seagrass percentage cover. 2. Seagrass species composition 3. Depth 4. Sediment type 5. Observations on marine fauna 6. Photograph of seagrass observed with time and date stamp 7. Sometimes collect seagrass species samples. 8

9 Spot Check Survey The role of the GPS person on board the boat was to: 1. Coordinate with the boat captain to navigate the boat. 2. Keep track of location of the boat. 3. Record time of GPS spot check points and their GPS location. In rough weather conditions, it was not possible to continue the manta tow so observers would dive from the boat at each spot check. In areas deeper than 7m, survey team used SCUBA gear to dive down at each spot check. Two divers using an underwater compass and camera would survey and film a 10 minute transect line towards land. If seagrass was present, % cover, species composition and sediment type was recorded. 9

10 Line Transect Survey 3 people: 1 person handled the GPS and 2 were the observers. The transect lines were marked by a GPS. 2-3 transect lines were conducted parallel to the shoreline. 50 x 50m quadrat used in every 50m to observe and record: 1. Total seagrass % cover 2. species composition 3. % cover of each individual species within the quadrat Role of GPS person: 1. Photo of each quadrat 2. Recorded latitude & longitude of quadrat, 3. Time and date 4. Species composition, 5. % cover of each individual species within the quadrat 6. Average total seagrass percentage cover. 10

11 Seagrass Survey Team The seagrass survey team consisted of a total of 9 team members, whose roles included: I. Boat Captain (1 person) II. III. IV. Boat Assistant (1 person) Seagrass Observer (6 people) GPS navigator / data recorder (1 person) 2 people from Fisheries Administration 3 people from Department of Environment All survey members are now fully capable of conducting their own surveys. 11

12 Seagrass Survey Team 1. Ms. Petchrung Sukpong (IUCN) 2. Mr. Louis Bourne (IUCN) 3. Mr. Poli (FiA) 4. Ms. Soriya Minhchan (DoE) 5. Mr. Chanrhea (DoE) 6. Mr. Venvirak (DoE) 7. Mr. Senead (FiA) Pictures taken by Roengchai Kongmuang. 12

13 Overview of Results Seagrass Spatial Distribution Water quality Summary of Species Composition Summary of each section Summary of seagrass percentage cover and status Observed Threats 13

14 Seagrass survey showing all survey points with or without seagrass Seagrass Beds Survey in in Kampot, Cambodia 14

15 Overall Spatial Distribution of the Seagrass Bed and Area Mapped Seagrass Survey in Kampot, Cambodia Total mapped area of the seagrass bed = 8,435.8 hectares 15

16 Water Quality Measured water quality during the start of most surveys. Water quality apparatus: 1. DO Field Test Kit 2. ph Field Test Kit 3. Refractometer 4. Secchi Disc Average water quality across the seagrass bed: 1. Dissolved Oxygen 7ppm 2. ph Salinity 27ppt 4. Turbidity 1.7m 16

17 Species Composition There were a total of 11 seagrass species found: Red Font = Dominant Species Family CYMODOCEACEAE 1) Cymodocea rotundata 2) Cymodocea serrulata 3) Halodule uninervis 4) Halodule pinifolia 5) Syringodium isoetifolium Family HYDROCHARITACEAE 6) Enhalus acoroides 7) Halophila beccarii 8) Halophila decipiens 9) Halophila minor 10) Halophila ovalis 11) Thalassia hemprichii There were also variations of some species: Thalassia hemprichii, Cymodocea Serrulata, and Halodule uninervis. 17

18 Summary of Species Composition Halodule pinifolia Enhalus acoroides Thalassia hemprichii Cymodocea serrulata Halophila beccarii Cymodocea rotundata Halophila ovalis Syringodium isoetifolium Red boxes = Dominant species Halophila minor 18 Halodule uninvervis Halophila ovalis

19 Phuket Marine Biological Center seagrass status guidelines The seagrass percentage cover is classified into different statuses using guidelines outlined by the Phuket Marine Biological Center Table showing Seagrass status determined by percentage cover Percentage cover of seagrass Seagrass status Description > 75% Very Good Over 75% cover of all seagrass species % Good % cover of all seagrass species % Moderate % cover of all seagrass species % Natural Cover Less than 25% cover of all seagrass species % Degraded Less than 25% cover of all seagrass species which impact by human activities 0% No seagrass No seagrass in this point 19

20 Section A Depth = 0.5-3m Dominant Sediment Type = Silt, Sand Turbidity = 1m Dissolved Oxygen = 6 ph = 8 Salinity = 25ppt Section Location Area (hectare) Seagrass Species found Average Cover (%) Seagrass Status Sedimentation Threats A East of Preaek Trapeang Ropoue to West of Preaek Kdat 1, Moderate Silt; Sand - Sedimentation - Destructive fishing practice (trawling boat) 20

21 Detailed map: Cut Section A Species Composition: Cymodocea rotundata, Cymodocea serrulata, Halodule pinifolia, Halodule uninervis, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii, Halophila beccarii, Halophila ovalis Seagrass Survey in Kampot, Cambodia 21

22 Section B Depth = 0.3-3m Dominant Sediment Type = Silt, fine sand, silt Section B Location East of Preaek Kdat to West of Preaek Kaoh Toal Area (hectare) Seagrass Species found Average Cover (%) Seagrass Status Sedimentation Threats Good Sand; Fine sand - Sedimentation - Aquaculture impact (seaweed farming) - Change of underwater currents from the coastal development project 22

23 Detailed map: Cut Section B Species Composition: Cymodocea serrulata, Halodule uninervis, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii Seagrass Survey in Kampot, Cambodia 23

24 Section C Depth = m Dominant Sediment Type = Silt, fine sand & silt Turbidity = 1.65m Dissolved Oxygen = 6ppm ph = 7.5 Salinity = 27ppt Section C Location East of of Preaek Kaoh Toal to Kampot rivermount Area (hectare) Seagrass Species found Average Cover (%) Seagrass Status Sedimentation Threats 2, Moderate Silt; Fine sand & silt - Sedimentation - Seagrass area loss from land reclamation - Change of underwater currents from the coastal development project - Erosion from sand dredging 24

25 Detailed map cut Section C Species Composition: Cymodocea rotundata, Cymodocea serrulata, Halodule pinifolia, Halodule uninervis, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii, Halophila beccarii, Halophila minor, Halophila ovalis Seagrass Survey in Kampot, Cambodia 25

26 Section D Depth = m Dominant Sediment Type = Silt, Sand Turbidity = 2.5m Dissolved Oxygen = 10.5ppm ph = 7.3 Salinity = 27ppt Section D Location Traeuy Kaoh commune to Koun Satv commune Area (hectare) Seagrass Species found Average Cover (%) 2, Good Silt; Sand Seagrass Status Sedimentation Threats - Sedimentation - Algae and epiphytic algae competition from increased nutrient input (reduce the ability of seagrass to photosynthesis) - Change of underwater currents from the coastal development project 26

27 Detailed map: Cut Section D Species Composition: Cymodocea rotundata, Cymodocea serrulata, Halodule pinifolia, Halodule uninervis, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii, Halophila beccarii, Halophila decipiens, Halophila ovalis Seagrass Survey in Kampot, Cambodia 27

28 Section E Depth = m Sedimentation = Sand, fine sand & Silt Section Location Area (hectare) Seagrass Species found Average Cover (%) Seagrass Status Sedimentation Threats E Kampong Trach 1, Good Sand; Fine sand & silt - Sedimentation - Destructive fishing practice (trawling boat) 28

29 Detailed map: Cut Section E Species Composition: Cymodocea rotundata, Cymodocea serrulata, Halodule pinifolia, Halodule uninervis, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii, Halophila decipiens Seagrass Survey in Kampot, Cambodia 29

30 Section F Depth = m Sedimentation = Sand, fine sand & silt Section Location Area (hectare) Seagrass Species found Average Cover (%) Seagrass Status Sedimentation Threats F North of Kaoh Ses Moderate Sand; Fine sand & silt - Habitat change from macro algae competition from increased nutrient input from the small fishing settlement 30

31 Detailed map: Cut Section F Species Composition: Cymodocea serrulata, Enhalus acoroides, Thalassia hemprichii Seagrass Survey in Kampot, Cambodia 31

32 Seaport Construction: potential impacts to the seagrass bed Construction of a seaport ongoing for 6 years. Impacts: 1. Significant sedimentation (increased water turbidity and decrease in available light = little to no photosynthesis). 2. Newly formed land obstruction from the seaport will (i) block and change natural underwater currents (ii) change sediment composition, (iii) change of ecosystem Sections C, D and B most at risk to severity of impacts. Almost all if not all of the seagrass in section C will likely be destroyed. 32

33 33 Picture by Roengchai Kongmuang

34 34 Picture by Roengchai Kongmuang

35 35 Picture by Roengchai Kongmuang

36 36 Picture by Roengchai Kongmuang

37 Recommendations Set up long term monitoring program 1. Impact monitoring: Sections C, D and B 2. Status monitoring: Sections A, E and D 3. Research and monitor seagrass ecology 4. Monitoring of changes in natural water currents, sediment and beach profiles should be considered. Enhanced public awareness Implementation of Integrated Coastal Zone Management (ICZM) along the coast of Kampot province. 37

38 Thank you for listening Are there any questions? 38