CONTENTS

1....... Introduction.. 1

1.1       Background. 1

1.2       Objectives of the Baseline Study Report on Phytoplankton, Zooplankton and Benthic Organisms. 1

1.3       Structure of the Report 2

2....... Baseline Study Methodology.. 3

2.1       Phytoplankton Survey. 3

2.1.1      Survey Locations. 3

2.1.2      Survey Frequency. 3

2.1.3      Survey Methodology. 3

2.1.4      Laboratory Analyses. 4

2.2       Zooplankton Survey. 4

2.2.1      Survey Locations. 4

2.2.2      Survey Frequency. 4

2.2.3      Survey Methodology. 4

2.2.4      Laboratory Analyses. 5

2.3       Benthic Organism Survey. 5

2.3.1      Survey Locations. 5

2.3.2      Survey Frequency. 5

2.3.3      Survey Methodology. 5

2.3.4      Laboratory Analyses. 6

3....... Baseline Study Results.. 7

3.1       Survey Programme. 7

3.2       Phytoplankton. 7

3.3       Zooplankton. 9

3.4       Benthic Organisms. 10

3.5       Summary. 12

 

Annexes

Annex A       Methodology for Baseline Study on Phytoplankton, Zooplankton and Benthic Organisms

Annex B       Raw Data for Phytoplankton

Annex C       Raw Data for Zooplankton

Annex D       Raw Data for Benthic Organism

List of Tables

Table 3.1      Survey Programme for the Baseline Study. 7

Table 3.2      Density and Species Diversity for Phytoplankton. 8

Table 3.3      Dominant Phylum of Phytoplankton. 8

Table 3.4      Density, Biomass and Species Diversity for Zooplankton. 9

Table 3.5      Top Five Dominant Phylum of Zooplankton. 10

Table 3.6      Density and Species Diversity for Benthic Organisms. 11

Table 3.7      Top Five Dominant Phylum of Benthic Organisms in terms of Abundance  12

List of Figures

Figure 1.1     Indicative Location of Key Project Components

Figure 2.1     Locations for Phytoplankton, Zooplankton and Benthic Organism Surveys

Figure 3.1     Representative Photos for Phytoplankton Surveys

Figure 3.2     Representative Photos for Zooplankton Surveys

Figure 3.3     Representative Photos for Benthic Organism Surveys

 

1.               Introduction

1.1           Background

To support the increased use of natural gas in Hong Kong from 2020 onwards, Castle Peak Power Company Limited (CAPCO) and The Hongkong Electric Co., Ltd. (HK Electric) have identified that the development of an offshore liquefied natural gas (LNG) receiving terminal in Hong Kong using Floating Storage and Regasification Unit (FSRU) technology (‘the Hong Kong Offshore LNG Terminal Project’) presents a viable additional gas supply option that will provide energy security through access to competitive gas supplies from world markets.  The Hong Kong Offshore LNG Terminal Project will involve the construction and operation of an offshore LNG import facility to be located in the southern waters of Hong Kong, a double berth jetty, and subsea pipelines that connect to the gas receiving stations (GRS) at the Black Point Power Station (BPPS) and the Lamma Power Station (LPS).

The Environmental Impact Assessment (EIA) Report for the Hong Kong Offshore LNG Terminal Project was submitted to the Environmental Protection Department (EPD) of the Hong Kong Special Administrative Region Government in May 2018.  The EIA Report (EIAO Register No. AEIAR-218/2018) was approved by EPD and the associated Environmental Permit (EP) (EP-558/2018) was issued in October 2018.  An application for Further Environmental Permits (FEP) was made on 24 December 2019 to demarcate the works between the different parties.  The following FEPs were issued on 17 January 2020 and the EP under EP-558/2018 was surrendered on 5 March 2020:

§    the double berth jetty at LNG Terminal under the Hong Kong LNG Terminal Limited, joint venture between CAPCO and HK Electric (FEP-01/558/2018/A) ([1]);

§    the subsea gas pipeline for the BPPS and the associated GRS in the BPPS under CAPCO (FEP-03/558/2018/A) ([2]); and

§    the subsea gas pipeline for the LPS and the associated GRS in the LPS under HK Electric (FEP-02/558/2018/A) ([3]). 

The location plan for the works associated with the double berth jetty at LNG Terminal (‘the Project’) is provided in Figure 1.1. 

1.2           Objectives of the Baseline Study Report on Phytoplankton, Zooplankton and Benthic Organisms

This Baseline Study Report on Phytoplankton, Zooplankton and Benthic Organisms for the Project has been prepared in accordance with Condition 2.10 of the Further Environmental Permit FEP-01/558/2018/A.

FEP No. FEP-01/558/2018/A, Condition 2.10: “The Permit Holder shall, no later than 1 month before the commencement of construction for the Project, submit 3 hard copies and 1 electronic copy of baseline study report on phytoplankton, zooplankton & benthic organisms at both the seawater intake and discharge points of the FSRU vessel to the Director for approval.”

This report presents the results of the baseline study on phytoplankton, zooplankton and benthic organisms conducted between August 2019 and February 2020 before the commencement of construction for the Project.  It should be noted that the FSRU vessel will be moored with its bow facing south at an orientation of 165°N while the seawater intake and discharge locations of the FSRU vessel will be located at ~10m below water surface near the vessel bow on port and starboard sides.  This information has been considered in the planning of the survey design of the baseline study on phytoplankton, zooplankton and benthic organisms, which have been agreed with the Agriculture, Fisheries and Conservation Department (AFCD) prior to the commencement of the baseline study.

1.3           Structure of the Report

The remainder of this Baseline Study Report on Phytoplankton, Zooplankton and Benthic Organisms is set out as follows:

§    Section 2 presents the methodology for baseline study on phytoplankton, zooplankton and benthic organisms; and

§    Section 3 presents the results of the baseline study on phytoplankton, zooplankton and benthic organisms.

 

2.               Baseline Study Methodology

The baseline study comprises phytoplankton, zooplankton and benthic organisms.  The survey methodology has been agreed with AFCD prior to the commencement of the baseline study.  The survey methodologies of each component are provided in Annex A and summarised below.

2.1           Phytoplankton Survey

2.1.1       Survey Locations

The phytoplankton surveys were conducted at three (3) locations in southern Lantau waters as presented in Figure 2.1.  These locations cover areas in the vicinity of the proposed Offshore LNG Terminal, i.e. the seawater intake and discharge points of the FSRU vessel (Stations S1 and S2), and a reference area (Station R1).  Actual survey locations were recorded using global positioning system (GPS) and water depth was measured using portable sonar system.

2.1.2       Survey Frequency

The surveys were undertaken at all locations twice in each of the wet (between April and October) and dry (between November and March) seasons during daytime (i.e. 08:00 – 16:00) prior to the commencement of the marine construction works of the Project.  The survey frequency has taken into account the seasonality in phytoplankton assemblages([4])([5]), and allows replication within each season given the dynamic nature of these assemblages while maintaining the timing of sampling within a day which may influence survey results, and is thus considered to be adequate for the purpose of this survey.

2.1.3       Survey Methodology

Considering the proposed seawater intake and discharge locations of the FSRU vessel (~10 m below water surface), it is proposed to monitor both shallow (1-2 m below water surface) and deep (2-4 m above seabed) water zones for the phytoplankton survey.  

The survey methodology follows published scientific literature and has also been adopted in similar studies in the region ([6])([7])([8]).  A Van Dorn Bottle Sampler (~2 L) (Model 1920-H62, Wildco or equivalent) was used to collect phytoplankton samples at shallow and deep water zones.  The sampler was firstly opened by raising both end seals, and then lowered to the proposed sampling depth; a physical messenger was sent to trigger a mechanism which closes the end seals.  At each depth, three replicates of 6 L of seawater were collected.  Each replicate was filtered through a 10 µm mesh to collect the phytoplankton samples and they were immediately preserved by 4% Lugol's solution or 4% borax-buffered formalin in labelled bottles after collection.

In addition to the phytoplankton sampling, other relevant data were also recorded, including time, weather conditions, sea conditions, special phenomena (if any), and other activities undertaken around the survey areas that may influence the survey results. 

2.1.4       Laboratory Analyses

The phytoplankton of each replicate was sorted and identified to the lowest taxonomic level where practical based on morphology ([9]) and number counted under inverted microscope in the laboratory using the Utermöhl method ([10]).  The abundance of phytoplankton is presented in density, i.e. number of cells/ Litre. 

2.2           Zooplankton Survey

2.2.1       Survey Locations

The zooplankton surveys were conducted at three (3) locations in southern Lantau waters as presented in Figure 2.1.   These locations cover areas in the vicinity of the proposed Offshore LNG Terminal, i.e. the seawater intake and discharge points of the FSRU vessel (Stations S1 and S2), and a reference area (Station R1).  Actual survey locations were recorded using GPS and water depth was measured using portable sonar system.

2.2.2       Survey Frequency

The surveys were undertaken at all locations twice in each of the wet (between April and October) and dry (between November and March) seasons during daytime (i.e. 08:00 – 16:00) prior to the commencement of the marine construction works of the Project.  The survey frequency has taken into account the seasonality in zooplankton assemblages ([11]), and allows replication within each season given the dynamic nature of these assemblages while maintaining the timing of sampling within a day which may influence survey results, and is thus considered to be adequate for the purpose of this survey.

2.2.3       Survey Methodology

Considering the proposed seawater intake and discharge locations of the FSRU vessel (~10 m below water surface), both shallow (1-2 m below water surface) and deep (2-4 m above seabed) water zones were monitored for the zooplankton survey.

The survey methodology follows published scientific literature and has also been adopted in similar studies in the region ([12])([13])([14]).  A bongo plankton net of 50 cm mouth diameter and 300 µm mesh (Aquatic research Instruments, USA or equivalent) was deployed to collect zooplankton at shallow and deep water zones at each survey location.  A flow meter (Model 2030R, General Oceanics Inc., USA or equivalent) was fitted at mouth of the net to record the volume of water filtered.  At each depth, three replicate tows were conducted, and each tow with a duration of at least 5 minutes at a speed of ~2 knots.   The zooplankton collected at the cod-end was immediately fixed in 4% borax-buffered formalin in labelled bottles after collection and then transferred into 75% ethanol for subsequent preservation in the laboratory.

In addition to the zooplankton sampling, other relevant data were also recorded, including time, weather conditions, sea conditions, special phenomena (if any), and other activities undertaken around the survey areas that may influence the survey results.

2.2.4       Laboratory Analyses

The zooplankton was sorted and identified to the lowest taxonomic level where practical based on external morphology ([15]).  The abundance of zooplankton is reported in density, i.e. number of individuals per m3, and their biomass is reported in wet weight, i.e. wet weight per m3 according to the following procedure in the laboratory ([16]).

The abundance of zooplankton was counted under microscope.  Common zooplankton taxa (ie protozoans, cladocerans, copepods, decapod larvae, mysids etc.) and their species were enumerated in subsample or aliquot of 10% to 25%.  The percentage of aliquot could be increased or decreased depending on the abundance of zooplankton in the sample.  For rare taxa, the total counts of specimens in the samples shall be made.  The biomass of zooplankton was measured by gravimetric method.  Subsamples were filtered to remove the interstitial water by blotting paper and the wet weight of zooplankton was determined.

2.3           Benthic Organism Survey

2.3.1       Survey Locations

The benthic organism surveys were conducted at three (3) locations in southern Lantau waters as presented in Figure 2.1.   These locations cover areas in the vicinity of the proposed Offshore LNG Terminal, i.e. the seawater intake and discharge points of the FSRU vessel (Stations S1 and S2), and a reference area (Station R1).  Actual survey locations were recorded using global positioning system (GPS).

2.3.2       Survey Frequency

Benthic organism surveys were conducted once in each of the wet (between April and October) and dry (between November and March) seasons, prior to the commencement of the marine construction works of the Project.  As indicated in the EIA study of this Project, benthic assemblages are quite homogenous in nature.  The survey frequency has already taken into account the seasonality in benthic assemblages and is thus considered to be adequate for the purpose of this survey.

2.3.3       Survey Methodology 

The survey methodology follows that of the EIA study of this Project.  Sediment sample was collected at each survey location using a modified Van Veen grab sampler (960 cm2 sampling area; 11,000 cm3 capacity) with a supporting frame attached to a swiveling hydraulic winch cable.  Duplicate sediment grab samples were obtained at each survey location.  The sediment samples were evaluated for acceptance based upon the degree of disturbance, penetration depth, and amount of leakage from the grab.  In the following cases, a sediment sample would be rejected and another sample collected:

§    The sediment sampler doors open in recovery, causing possible surface washout.

§    Half sample obtained where the sediment sampler had not struck a flat area of seabed, or improper deployment of benthic grab, or half sample of sediment.

§    Disruption of the sample by heavy shaking or contamination (these can occur when a sample is badly handled or if the sediment sampler strikes the side of the vessel during operations).

§    The sample represents less than 30% of the sediment sampler’s total capacity (i.e. less than 15 cm penetration).

§    Grab deployment location deviates from the designated position ([17]).

Before sieving each sample on site, the grab, frame and sample containers were washed with seawater to avoid cross contamination of samples.

Sediments for biological analysis were sieved on board the survey vessel.  The sediments were washed into a sieve stack (comprising 1 mm and 500 µm meshes) and gently rinsed with seawater to remove all fine materials.  Following rinsing, any material remaining on the two screens was combined and carefully rinsed using a minimal volume of seawater into pre-labelled thick triple-bagged ziplock plastic bags.  A 5% solution of borax-buffered formalin containing Rose Bengal in seawater was then added to the bag to ensure tissue preservation.  Samples were sealed in plastic containers for transfer to the taxonomy laboratory for sorting and identification.

In addition to the sediment sampling, other relevant data were also recorded, including time, weather conditions, sea conditions, special phenomena (if any), and other activities undertaken around the survey areas that may influence the survey results.

2.3.4       Laboratory Analyses

The laboratory performed sample re-screening after the samples have been held in formalin for a minimum 24 hours to ensure adequate fixation of the organisms.  Individual samples were gently rinsed with fresh water into a 250 µm2 sieve to remove the formalin from the sediments.  Sieves were partially filled while rinsing a specific sample to maximize washing efficiency and prevent loss of material.  All materials retained on the sieve were placed in a labeled plastic jar, covered with 70% ethanol, and lightly agitated to ensure complete mixing of the alcohol with sediments.  Original labels were retained with the re-screened sample material.

Standard and recognized techniques were used for sorting organisms from the sediments.  Small fractions of a sample were placed in a petri dish under a 10-power magnification dissecting microscope and scanned systematically with all animals and fragments removed using forceps.  Each petri dish was sorted at least twice to ensure removal of all animals.  Organisms representing major taxonomic groups, such as Polychaeta, Arthropoda, Mollusca and miscellaneous taxa were sorted into separate, labeled vials containing 70% ethanol.

Taxonomic identifications were performed using stereo dissecting and high-power compound microscopes to determine the species diversity and abundance of benthic organisms of each sample.  These are generally to the species level except for unidentified taxa, which are identified to genus as far as practical.  The careful sampling procedure employed minimizes fragmentation of organisms.  If breakage of soft-bodied organisms occurred, only anterior portions of fragments would be counted, although all fragments would be retained and weighed for biomass determinations (wet weight).

3.               Baseline Study Results

3.1           Survey Programme

The baseline study for phytoplankton, zooplankton and benthic organisms was conducted between August 2019 and February 2020, covering wet and dry seasons, prior to the marine construction works of the Project as presented in Table 3.1 below. 

Table 3.1       Survey Programme for the Baseline Study

Survey	Survey Programme	Sampling Time	Weather / Sea Conditions	Water Depth (m) of the Monitoring Locations
Phytoplankton Survey	Wet season: 19 September 2019; 3 October 2019   Dry season: 18 December 2019; 12 February 2020	10:00 – 16:00 10:00 – 16:00     10:00 – 16:00 10:00 – 16:00	Sunny / Moderate Sunny / Moderate     Sunny / Moderate Cloudy / Moderate	Location S1: ~14m Location S2: ~15m Location R1: ~15m
Zooplankton Survey	Wet season: 19 September 2019; 3 October 2019   Dry season: 18 December 2019; 12 February 2020	10:00 – 16:00 10:00 – 16:00     10:00 – 16:00 10:00 – 16:00	Sunny / Moderate Sunny / Moderate     Sunny / Moderate Cloudy / Moderate
Benthic Organism Survey	Wet season: 27 August 2019   Dry season: 30 December 2019	10:30 – 12:00     11:00 – 12:30	Sunny / Moderate     Cloudy / Moderate

 

3.2           Phytoplankton

The raw data (density) of phytoplankton surveys are presented in Annex B.  Representative photos taken during the phytoplankton surveys are presented in Figure 3.1.  A total of 190 species, belonging to seven (7) phyla of phytoplankton, were recorded during the surveys.  No rare species or species of conservation importance were recorded during the surveys.  The survey results in terms of density, species diversity and evenness ([18]) are summarised in Table 3.2.

 

Table 3.2       Density and Species Diversity for Phytoplankton

Monitoring Location (Depth)	Total No. of Species (1)	Mean No. of Species (2)	Mean Density (Cells / Litre) (3)	Mean Shannon Diversity (H’) (4)	Mean Pielou’s Evenness (J) (4)
Wet Season
S1 (Shallow)	84	28.7	45012	2.5	0.8
S1 (Deep)	94	29.3	297538	2.3	0.7
S2 (Shallow)	85	26.3	34184	2.3	0.7
S2 (Deep)	87	30.3	124478	2.3	0.7
R1 (Shallow)	69	21.5	93614	2.1	0.7
R1 (Deep)	82	27.3	135187	2.2	0.7
Dry Season
S1 (Shallow)	89	40.7	53222	2.9	0.8
S1 (Deep)	80	32.5	22833	2.8	0.8
S2 (Shallow)	89	41.3	36000	3.0	0.8
S2 (Deep)	80	39.2	46944	2.8	0.8
R1 (Shallow)	97	46.3	44944	2.9	0.7
R1 (Deep)	80	39.3	66639	2.7	0.7
Notes: (1)  Total no. of species is calculated by counting the individual species recorded from all the replicates collected. (2)  Mean no. of species is calculated by averaging the number of individual species recorded from each replicate collected. (3)  Mean density is calculated by averaging the density of phytoplankton recorded from each replicate collected. (4)  Mean Shannon Diversity / Pielou’s Evenness is calculated by averaging the indexes for each replicate collected.

The mean number of species and the mean Shannon Diversity (H’) recorded were generally higher in dry season than in wet season at both shallow and deep water zones of all survey locations.  The mean density of phytoplankton varied between wet and dry seasons, and the mean densities of phytoplankton were generally higher in deep water zone during wet season of the three survey locations.  The dominant phylum of phytoplankton was Bacillariophyta, which contributed to >95% of the overall mean density of phytoplankton recorded in the surveys, followed by Dinophyceae, Ochrophyta, Euglenophyta, Cyanobacteria, Chlorophyta and Cryptophyta (Table 3.3).

Table 3.3       Dominant Phylum of Phytoplankton

	Mean Density (Cells / Litre)
Phylum	Wet Season	Dry Season
Bacillariophyta	119927	52616
Chlorophyta	125	14
Cryptophyta	52	42
Cyanobacteria	64	139
Dinophyceae	1243	1773
Euglenophyta	153	194
Ochrophyta	105	454

 

3.3           Zooplankton

The raw data (density and biomass) of zooplankton surveys are presented in Annex C.  Representative photos taken during the zooplankton surveys are presented in Figure 3.2.  A total of 135 species, belonging to ten (10) phyla of zooplankton, were recorded during the surveys.  No rare species or species of conservation importance were recorded during the surveys.  The survey results in terms of density, species diversity and evenness are summarised in Table 3.4.

Table 3.4       Density, Biomass and Species Diversity for Zooplankton

Monitoring Location (Depth)	Total No. of Species (1)	Mean No. of Species (2)	Mean Density (No. / m3) (3)	Mean Biomass (g/m3) (3)(4)	Mean Shannon Diversity (H’) (5)	Mean Pielou’s Evenness (J) (5)
Wet Season
S1 (Shallow)	67	33.5	2770	0.07	2.1	0.6
S1 (Deep)	61	34.2	2299	0.14	2.3	0.6
S2 (Shallow)	59	31.3	2453	0.13	2.2	0.6
S2 (Deep)	64	33.8	2225	0.34	2.3	0.7
R1 (Shallow)	61	29.0	1788	0.14	1.9	0.6
R1 (Deep)	57	28.3	2037	0.20	2.0	0.6
Dry Season
S1 (Shallow)	69	51.8	254	0.09	3.0	0.8
S1 (Deep)	73	37.5	545	0.11	2.5	0.7
S2 (Shallow)	68	44.5	337	0.13	2.5	0.7
S2 (Deep)	74	42.0	374	0.15	1.9	0.5
R1 (Shallow)	52	38.2	375	0.12	1.9	0.5
R1 (Deep)	77	43.3	269	0.13	2.4	0.7
Notes: (1)  Total no. of species is calculated by counting all the individual species recorded from all the replicates collected. (2)  Mean no. of species is calculated by averaging the number of individual species recorded from each replicate collected. (3)  Mean density / biomass is calculated by averaging the density / biomass of zooplankton recorded from each replicate collected. (4)  The biomass is determined by measuring the wet weight of each sample.  Each sample may contain substances other than zooplankton that cannot be separated (e.g. phytoplankton and detritus). (5)  Mean Shannon Diversity / Pielou’s Evenness is calculated by averaging the indexes for each replicate collected.

The mean number of species and the mean Shannon Diversity (H’) recorded were generally higher in dry season than in wet season at both shallow and deep water zones of the survey locations, and the mean number of species recorded was generally higher at locations S1 and S2.  The mean density of zooplankton was higher in wet season than in dry season. 

The mean density (no. per m3) of the top five dominant phyla in each season are presented in Table 3.5.  Arthropoda (mainly contributed by Copepoda, Brachiopoda and Malacostraca) was the most abundant phylum, followed by Chaetognatha (mainly Sagittoidea), Chordata (mainly Appendicularia and Vertebrata), Mollusca (mainly Gastropoda) and Cnidaria (mainly Hydrozoa).

 

 

Table 3.5       Top Five Dominant Phylum of Zooplankton

	Mean Density (No. / m3)
Phylum	Wet Season	Dry Season
Arthropoda	1875	166
Chaetognatha	313	80
Chordata	32	68
Mollusca	19	4
Cnidaria	12	1

 

3.4           Benthic Organisms

The raw data (abundance and biomass) of benthic organism surveys are presented in Annex D.  Representative photos taken during the benthic organism surveys are presented in Figure 3.3.  A total of 77 species, belonging to seven (7) phyla of benthos, were recorded during the surveys.  No rare species or species of conservation importance (e.g. the amphioxus Branchiostoma belcheri) were recorded during the surveys.  The survey results in terms of density, species diversity and evenness are summarised in Table 3.6.

Table 3.6       Density and Species Diversity for Benthic Organisms

Monitoring Location	Total Number of Infaunal Individuals (1)	Mean Number of Individuals per Sample (2)	Mean Number of Individuals per m2 (3)	Mean Taxonomic Richness (No. Families) per Sample (4)	Mean Taxonomic Richness (No. Species) per Sample (5)	Mean Pielou’s Evenness (J) (6)	Mean Shannon Diversity (H’) (6)	Total Biomass (g/m2 wet weight) (7)	Mean Biomass per Individual (g/m2 wet weight) (8)
Wet Season
S1	97	48.5	505.21	21.0	24.0	0.94	2.98	7.06	0.07
S2	72	36.0	375.00	17.5	19.0	0.88	2.58	4.93	0.07
R1	275	137.5	1432.29	33.5	39.5	0.89	3.28	24.33	0.09
Dry Season
S1	62	31.0	322.92	17.0	18.0	0.94	2.69	12.94	0.21
S2	41	20.5	213.54	12.5	13.5	0.94	2.45	6.38	0.16
R1	238	119.0	1239.58	33.0	37.0	0.90	3.25	141.85	0.60
Notes: (1)  Total number of infaunal individuals is calculated by counting all the individuals recorded from all the replicates collected. (2)  Mean number of individuals per sample is calculated by averaging the total number of infaunal individuals recorded from each replicate collected. (3)  Mean number of individuals per m2 is calculated by averaging the mean number of infaunal individuals per sample over the sampling area (i.e. 960 cm2) collected. (4)  Mean taxonomic richness (number of families) per sample is calculated by averaging the number of families recorded from each replicate collected. (5)  Mean taxonomic richness (number of species) per sample is calculated by averaging the number of species recorded from each replicate collected. (6)  Mean Shannon Diversity / Pielou’s Evenness is calculated by averaging the indexes for each replicate collected. (7)  Total biomass is calculated by summation of the biomass of each replicate collected. (8)  Mean biomass per individual is calculated by averaging the biomass per individual for each replicate collected.

The total number of infaunal individuals, the mean number of individuals (per sample / per m2), mean taxonomic richness (family and species levels), mean Shannon Diversity (H’) and total biomass were higher at location R1 during both wet and dry seasons.  Higher biomass was recorded at location R1 during dry season and it is mainly contributed by the mantis shrimp Miyakella nepa.  The mean number of infaunal individuals and species diversity were generally higher in wet season than in dry season.    

The mean abundance (no. per m2) of the top five dominant phyla groups in each season is presented in Table 3.7.  Annelida was the most abundant phylum during wet and dry seasons, followed by Echinodermata / Arthropoda, Nemertea, Sipuncula / Mollusca.

Table 3.7       Top Five Dominant Phylum of Benthic Organisms in terms of Abundance

Wet Season		Dry Season
Phylum	Mean Abundance (Number of Infaunal Individuals)	Phylum	Mean Abundance (Number of Infaunal Individuals)
Annelida	51.17	Annelida	32.83
Echinodermata	9.00	Arthropoda	9.50
Arthropoda	8.17	Echinodermata	5.67
Nemertea	3.33	Nemertea	4.00
Sipuncula	1.33	Mollusca	2.33

 

3.5           Summary

The baseline study for phytoplankton, zooplankton and benthic organisms was conducted between August 2019 and February 2020, covering wet and dry seasons, prior to the marine construction works of the Project to obtain information on the conditions of phytoplankton, zooplankton and benthic organisms in the vicinity of the proposed Offshore LNG Terminal (i.e. the seawater intake and discharge points of the FSRU vessel).  No rare species or species of conservation importance (e.g. the amphioxus Branchiostoma belcheri) were recorded during the surveys.