Contents

1                      Introduction                                                                          

1.1                   Background                                                                           

1.2                   Purpose of this Report                                                    

1.3                   Structure of the Report                                                

2                      BASELINE coral Monitoring Methodology             

2.1                   Monitoring Locations                                                       

2.2                   Methodology                                                                         

3                      Baseline Coral Monitoring Results                         

4                      Conclusion                                                                             

 

ANNEX

Annex A 

Photographic Results of Identified Coral Colonies in Zone A B & C

 

 

1                                            Introduction

1.1                                      Background

NTT Com Asia (NTTCA) proposes to install a telecommunication cable (Asia Submarine-cable Express (ASE) cable) of approximately 7,200 km in length, connecting Japan and Singapore with branches to the Philippines, Hong Kong SAR (HKSAR) and Malaysia.  NTTCA is responsible for securing the approval to land the ASE cable in Tseung Kwan O, Hong Kong SAR (HKSAR).  The proposed landing site will be at a new Beach Manhole (BMH) and ultimately connect with a Data Centre in Tseung Kwan O (TKO) Industrial Estate which is scheduled for completion in 2012.  It should be noted that Tseung Kwan O is currently the landing site for a number of submarine cables.  From Tseung Kwan O, the cable will extend eastward approaching the Tathong Channel.  Near to Cape Collinson, the cable is approximately parallel to the Tathong Channel until north of Waglan Island where the cable travels eastward to the boundary of HKSAR waters where it enters the South China Sea.  The total length of cable in Hong Kong SAR waters is approximately 33.5 km.  A map of the proposed cable route is presented in Figure 1.1.

A Project Profile (PP-452/2011) which includes an assessment of the potential environmental impacts associated with the installation of the submarine telecommunications cable system was prepared and submitted to the Environmental Protection Department (EPD) under section 5.(1)(b) and 5.(11) of the Environmental Impact Assessment Ordinance (EIAO) for the application for Permission to apply directly for Environmental Permit (EP).  The Environmental Protection Department, subsequently issued an Environmental Permit (EP- 433/2011).

In accordance with the EM&A Manual, Baseline Coral Survey should be conducted within one month before jetting works for the cable installation commenced.  The objective of the Baseline Coral Survey is to identify suitable coral monitoring locations and to collect baseline monitoring data of corals at those locations for comparison with data collected during the Post Project Survey.  The comparison of baseline and post Project data would be used to determine any observable impacts to corals as a result of the cable installation works.  The Baseline Coral Monitoring Survey Report should be submitted within two weeks after the completion of the baseline monitoring

1.2                                      Purpose of this Report

This Baseline Coral Monitoring Survey Report (“the Report”) is prepared by ERM-Hong Kong, Limited (ERM) on behalf of NTT Com Asia (NTTCA) to present the methodology and findings of the Baseline Coral Survey for the Project in accordance with requirements of the EM&A Manual. 

1.3                                      Structure of the Report

The remainder of the report is structured as follows:

Section 2: Baseline Coral Monitoring Methodology

Presents the baseline monitoring methodology, parameters monitored, monitoring locations and depth, monitoring date, time, frequency and duration in accordance with the EM&A Manual.

 

Section 3: Baseline Coral Monitoring Results

Summarize the baseline coral monitoring results together with the information including monitoring methodology, parameters monitored, monitoring locations and depth, monitoring date, time, frequency and duration in accordance with the EM&A Manual.

 

Section 4: Conclusion

Conclude findings from the Baseline Coral Survey of the Project.

2                                            BASELINE coral Monitoring Methodology

2.1                                      Monitoring Locations

Baseline coral monitoring was undertaken at Cape Collinson and Tai Long Pai (Monitoring Station), and a Control Station at Tung Lung Chau which is located more than 2 km from the cable alignment.  The monitoring locations of marine ecological survey are shown in Figure 2.1 and detailed below:

Monitoring Stations:

§      Zone A: Cape Collinson; and

§      Zone B: Tai Long Pai.

Control Station:

§      Zone C: Tung Lung Chau.

2.2                                      Methodology

Subtidal dive surveys were undertaken at subtidal hard bottom habitats within and in close proximity to the Project Area with a key focus along the proposed cable route where hard substrata were noted from the geophysical survey.  The Baseline Coral Survey comprised the following three components:

§      Qualitative spot dive survey;

§      Semi-quantitative Rapid Ecological Assessment (REA) survey; and

§      Coral Colony Monitoring.

Each of these surveys is described further in the following sections. 

Qualitative Spot Dive Survey

The qualitative spot dive survey was undertaken as part of the Baseline Survey only to identify suitable coral monitoring locations at Cape Collinson, Tai Long Pai and Tung Lung Chau (survey areas refer to Figure 2.1).  During the survey, spot dive reconnaissance checks were conducted within the designated Monitoring and Control Stations by SCUBA to collect qualitative information including coral composition, abundance and distribution.  Based on the information collected, locations within which significant coral habitats/identified coral communities (defined as locations within relatively higher coral abundance and species/ genus number for the purpose of this coral monitoring programme) were selected for the subsequent REA survey and coral colony monitoring during the Baseline and Post Project Coral Surveys.  The depth range (shallow and deep) to be monitored were also finalized based on observed coral distribution.

Rapid Ecological Assessment (REA) Survey Method

A standardised semi-quantitative Rapid Ecological Assessment (REA) survey technique was used to investigate the general conditions of the coral communities (hard, soft and black corals) associated with subtidal hard bottom habitats at the Monitoring and Control Stations.  The collection of REA data during the Baseline and Post-Project Surveys would allow for a comparison of coral conditions before and after cable installation works in order to determine any changes in conditions due to the works.

The REA technique allows semi-quantitative information on the ecological attributes of the subtidal habitat to be obtained in a relatively simple way without compromising scientific rigour.  This technique is the standard practices for EIA marine baseline surveys in Hong Kong and has been modified from the standardised REA survey technique established for the assessment of coral communities on the Great Barrier Reef ([1]) for marine environment of Hong Kong ([2]).

A series of REA surveys were be conducted by qualified coral ecologists by SCUBA at the Monitoring stations (Cape Collinson and Tai Long Pai) and Control Station (Tung Lung Chau) with the aim to record the condition of substratum, estimate the diversity and relative abundance of coral assemblages (ie hard corals, octocorals and black corals) and with all hard coral colonies identified to species level while octocorals and black corals recorded to genus level.  The survey was undertaken on REA transects laid onto the seabed, each of which measure 100 m in length, at the following two depth zones of each station:

§     Shallow depth region: -2 to -5 m CD (typically the depth range of hard coral colonies associated with subtidal hard bottom habitat); and

§     Deep depth region: -5 to -15 m CD.

The location of the REA transects as well as the depth ranges of the monitored depth zones were determined based on findings from the qualitative spot dive survey.  A total of three (3) REA transects were monitored at each depth region of Cape Collinson and Tung Lung Chau, while two (2) transects were monitored at each depth region of Tai Long Pai due to limited survey area at this Monitoring Station.

Following the laying of the transect line, the coral specialist swam along the transect slowly and conduct the REA survey.  The REA methodology would encompass an assessment of the benthic cover (Tier I) and taxon abundance (Tier II) undertaken in a swathe ~ 4 m wide, 2 m either side of each transect.  The belt transect width was dependent on underwater visibility and might be adjusted to a swathe ~ 2 m wide, 1 m either side of each transect in case of reduced visibility.  An explanation of the two assessment categories (Tiers) used in the survey is presented below.

Tier I – Categorisation of Benthic Cover

Upon the completion of each survey transect, five ecological and seven substratum attributes were assigned to one of seven standard ranked (ordinal) categories (Table 2.1 and 2.2).

Table 2.1        Categories used in the REA Surveys – Benthic Attributes

Ecological

Substratum

Hard coral

Hard Substratum

Dead standing coral

Continuous pavement

Soft coral

Bedrock

Black coral

Rubble

Macroalgae

Sand

Turf Algae

Silt

 

Large boulders (>50 cm)

 

Small boulders (<50 cm)

 

Rocks (<26 cm)

Table 2.2        Categories used in the REA Surveys – Ordinal Ranks of Percentage Cover

Rank

Percentage Cover (%)

0

None recorded

1

1-5

2

6-10

3

11-30

4

31-50

5

51-75

6

76-100

 

Tier II – Taxonomic Inventories to Define Types of Benthic Communities

An inventory of benthic taxa were compiled for each transect.  Taxa were identified in situ to the following levels:

§     Scleractinian (hard) corals to species wherever possible;

§     Soft corals, gorgonians, black corals, anemones and conspicuous macroalgae recorded according to morphological features and to genus level where possible; and

§     Other benthos (including sponges, zoanthids, ascidians and bryozoans) recorded to genus level wherever possible but more typically to phylum plus growth form.

Following the completion of each transect survey, each taxon in the inventory was ranked in terms of abundance in the community (Table 2.3).  These broad categories rank taxa in terms of relative abundance of individuals, rather than the contribution to benthic cover along each transect.  The ranks are subjective assessments of abundance, rather than quantitative counts of each taxon.

Table 2.3        Ordinal Ranks of Taxon Abundance

Rank

Abundance

0

Absent

1

Rare (a)

2

Uncommon

3

Common

4

Abundant

5

Dominant

Note:

(a) The classification of “rare” abundance refers to low abundance (small quantity) on the transect, rather than in terms of distribution in Hong Kong waters.

A set of environmental site descriptors were recorded for each REA transect as follows:

(A)  The degree of exposure to prevailing wave energy was ranked from 1 – 4, where:
1 = sheltered (highly protected by topographic features from prevailing waves);

2 = semi-sheltered (moderately protected);

3 = semi-exposed (only partly protected); and

4 = exposed (experiences the full force of prevailing wave energy).

(B)  Sediment deposition on the reef substratum (particle sizes ranging from very fine to moderately coarse) rated on a four point scale, from 0 -3, where:

0 = no sediment;

1 = minor (thin layer) sediment deposition;

2 = moderate sediment deposition (thick layer), but substrate can be cleaned by fanning off the sediment; and

3 = major sediment deposition (thick, deep layer), and substrate cannot be cleaned by fanning.

A suite of representative photographs was taken for each REA transect.  All field data were checked upon completion of each REA transect and a dive survey proforma sheet was completed at the end of the fieldwork day.  Photographs were compiled for each REA transect which was then reviewed and REA data be verified.  Verified REA data were presented in terms of:

§      Site (transect) information (Tier I and II data), depth and environmental  descriptors;

§      Species abundance data for each transect; and

§      Species lists, species richness and mean values for ecological and substratum types were compiled.  The rank abundance values were converted to a mid-value percentage cover.

Coral Colony Monitoring

Coral colony monitoring was undertaken during the Baseline Coral Survey and will also be conducted during the Post-Project Survey to identify any evidence of sediment stress to corals before and after cable installation works.  At each coral monitoring station, a total of fifteen (15) hard coral colonies and fifteen (15) octocoral/black coral colonies were selected for monitoring.  Priority was given to selecting colonies of horizontal plate-like and massive growth forms which present large stable surfaces for the interception and retention of settling solids.  Each of the selected corals was identified to species or genus levels and photographed.  The following data were collected:

§      Maximum diameter of the identified hard coral and soft coral colonies;

§      Maximum height and width of the identified gorgonians and black corals;

§      Percentage of sediment cover on the identified colonies and the colouration, texture and approximate thickness of sediment on the coral colonies and adjacent substrate.  Any contiguous patches of sediment cover >10 % were recorded;

§      Percentage of bleached area on the identified colonies of which two categories were recorded: a. blanched (ie pale) and b. bleached (ie whitened);

§      Percentage of colony area showing partiality mortality; and

§      Physical damage to colonies, tissue distension, mucous production and any other factors relevant will be noted in the field.

Other information such as the survey date, time, weather, sea and tidal conditions should also be recorded.  The coral colony monitoring exercise was undertaken to ensure colonies of similar growth forms and size would be selected for the Baseline and Post Project Monitoring.  Although coral tagging is a common practice for repeated monitoring of individual colony, this technique was not employed in this monitoring programme due to difficulties in locating the tagged corals given the generally low visibility in the area and low light conditions in deep water. 

3                                            Baseline Coral Monitoring Results

The Baseline Coral Survey was conducted over two days on 24 and 25 September 2012.  The weather condition was mainly cloudy with sunny intervals, with moderate (Force 4) to fresh (Force 5) east to northeasterly winds.  Slight to moderate swell was present in the sea on the two survey days.  The visibility was moderate and generally ranged between 1.5 to 3.0 m.

3.1.1                               Results of Qualitative Spot Dive Checks

Zone A - Cape Collinson

Results of qualitative dive survey at Cape Collinson (Zone A) confirmed that the seabed was composed of hard bottom substrates which were mainly bedrocks and large boulders.  Generally, cover of hard corals was less than 5% in the shallow water (from -2 to -5m CD) with 8 hermatypic hard coral species recorded.  The estimated cover of hard coral was lower in the deep water (from -5 to -15m CD) than the shallow water region.  Octocoral assemblage was also observed at low estimated cover of 5-10% in both shallow and deep water regions with a total of 6 species recorded (Table 3.1).

Similar abiotic composition was found along the entire Zone A.  At the south of Cape Collinson and northern part of Ngan Wan, more hard coral species and larger hard coral colonies were found although the estimated coral cover and number of octocoral species recorded was similar to other areas in Zone A.  As such, the northern part of Ngan Wan was considered as significant coral habitats/identified coral communities and was selected as the area for the REA survey and coral colony monitoring (Figure 3.1). 

Zone B – Tai Long Pai

Results of qualitative dive survey at Tai Long Pai (Zone B) confirmed that the seabed was composed of hard bottom substrates which were mainly bedrocks.  Coverage and abundance of hard corals was very low (less than 5%) with 7 hermatypic hard coral species and 1 ahermatypic coral species being recorded.  Hermatypic hard coral was only found in the southwestern part of Tai Long Pai.  A total of 7 octocoral species and 2 black coral species were recorded along the shoreline of Tai Long Pai with an estimated cover of 5-10% in shallow water and 11 to 30% in deep water. 

The cover and diversity of octocoral were similar within the shoreline of Zone B while hard corals were only recorded at the southwestern part of Tai Long Pai.  As such, REA survey and coral colony monitoring were undertaken at that area which is considered as significant coral habitat/identified coral communities (Figure 3.1).  REA survey and coral colony monitoring were also undertaken at the southeastern region which is closer to the proposed cable route.

Zone C – Tung Lung Chau

Results of qualitative dive survey at Tung Lung Chau (Zone C) confirmed that the seabed was composed mainly of bedrock and large boulders.  Nine hermatypic hard coral species, one ahermatypic hard coral species and several octocorals species (ie Euplexaura sp., Dendronephthya sp.) were recorded at the sheltered area east of the Tung Lung Chau headland.  The estimated covers of hard coral and octocoral were lower than 10%.  The coral assemblage in this area is considered similar and being comparable to the biotic assemblages in Impact Monitoring Sites at Zone A and Zone B and were thus selected as the Control Site for the REA survey and coral colony monitoring.  On the eastern part of Zone C, only some encrusting hard coral colonies were recorded but no octocorals could be observed.

The coordinates of the significant coral habitats/ identified coral communities at the south of Cape Collinson and northern part of Ngan Wan (Zone A) and at the southwestern part of Tai Long Pai (Zone B), and the distance from the nearest point to the proposed cable alignment is presented in Table 3.2.

Table 3.1        Coral Species Recorded at the Qualitative Spot-Check Zone A, B & C

Taxon

Family

Species

Zone A - Cape Collinson (Impact Site)

Hard Coral Species

Acroporidae

Montipora mollis

 

Coscinaraea

Coscinaraea n sp.

 

Dendrophyllidae

Turbinaria peltata

 

Faviidae

Plesiastrea versipora

 

 

Favia rotumana

 

Poritidae

Goniopora stutchburyi

 

 

Porites lobata

 

Siderastreidae

Psammocora superficialis

Octocoral Species

Plexauridae

Menella sp.

 

 

Paraplexaura sp.

 

 

Echinomuricea sp.

 

Ellisellidea

Ellisella sp.

 

Alcyoniidae

Sinularia sp.

 

Nephtheidae

Dendronephthya sp.

Zone B – Tai Long Pai (Impact Site)

 

 

Hard Coral Species

Acroporidae

Montipora mollis

 

Faviidae

Cyphastrea chalcidicum

 

 

Favites abdita

 

 

Plesiastrea versipora

 

Poritidae

Goniopora stutchburyi

 

 

Porites lobata

 

Siderastreidae

Psammocora superficialis

Ahermatypic Coral Species

Dendrophyllidae

Tubastrea/ Dendrophyllia sp.

Octocoral Species

Plexauridae

Echinomuricea sp.

 

 

Euplexaura sp.

 

 

Paraplexaura sp.

Menella sp.

 

Acanthogorgiidae

Anthogorgia sp.

 

Nephtheidae

Dendronephthya sp.

 

Elliseillidae

Verrucella sp.

Black Coral Species

Antipathidae

Antipathes curvata

 

 

Cirrhipathes sp.

Zone C – Tung Lung Chau (Control Site)

Hard Coral Species

Acroporidae

Montipora mollis

 

 

Montipora peltiformis

 

Faviidae

Cyphastrea seralia

 

 

Cyphastrea chalcidicum

 

 

Leptastrea pruinosa

 

 

Plesiastrea versipora

 

Poritidae

Porites lobata

 

 

Goniopora stutchburyi

 

Siderastreidae

Psammocora superficialis

Ahermatypic Coral Species

Dendrophyllidae

Tubastrea/ Dendrophyllia sp.

Octocoral Species

Nephtheidae

Dendrophthya sp.

 

Table 3.2        Coordinates of the Significant Coral Habitats/ Identified Coral Communities and the Distances from their Nearest Points to the Proposed Cable Alignment

Significant Coral Habitat/ Identified Coral Community

Easting

Northing

Distance from Proposed Cable Alignment (m)

South of Cape Collinson and North of Ngan Wan

844492.67

813577.80

~230

Southwestern Tai Long Pai

845454.83

810593.43

~270

 

3.1.2                                Results of REA Survey

The seabed compositions along each transect of Zone A to C were shown in Tables 3.3 - 3.5.   Locations of REA survey are presented in Figure 3.1. 

Zone A – Cape Collinson

The seabed at the REA survey area of Zone A was predominately composed of bedrocks in shallow depth region (2-5 m CD) while at deep depth region (6-10m CD) the seabed was also mainly composed of bedrocks and boulders.  However, the deep depth region of Transect 1 was mainly composed of sand and small boulders.

Cover of hard corals was less than 5% in shallow depth region (2-6 m CD), with only five hard coral species (Oulastrea crispata, Goniopora crispata, Psammocora superficialis, Cyphastrea chalcidicum and Plesiastrea versipora) being recorded.  A relatively more diverse and abundant octocoral community was found at deep depth region beyond -5 m CD.  Ten species of octocorals (Paraplexaura sp., Echinomuricea, Viminella sp., Ellisella sp., Menella sp., Euplexaura sp., Muricella sp., Sinularia sp., Dendronephthya sp. and Scleronephthya gracillicum) and two species of black corals (Antipathes curvata and Cirrhipathes sp.) were recorded during REA survey.  Echinomuricea sp., Dendronepthya sp. and Scleronephthya gracillicum were the dominant octocoral species found in the region.  All coral species recorded are common and have a widespread distribution throughout Hong Kong’s nearshore waters.

Zone B – Tai Long Pai

Two areas were selected around Tai Long Pai for REA survey (one located on the southeastern side, one on the southwestern side).  The seabed was predominately composed of bedrocks in both shallow and deep depth zones.

Three hermatypic hard coral species (Goniopora stutchburyi, Cyphastrea chalcidicum and Psammocora superficialis) were recorded in shallow depth zone along the transect located on the southwestern side of Tai Long Pai.  One ahermatypic hard coral species (Tubastrea/ Dendrophyllia sp.) were recorded in shallow depth zone of the whole Zone B.  A relatively more diverse and abundant octocoral community were recorded in deep depth zone in the entire Zone B.  Seven species of octocorals (Menella sp., Euplexaura sp., Paraplexaura sp., Echinomuricea sp., Anthogorgia sp., Verrucella sp. and Dendronephthya sp.) were recorded in relatively higher abundance while Dendronephthya sp. was the dominant species.  Two species of black corals, Antipathes curvata and Cirrhipathes sp., were recorded.  Crinoids and starfish are commonly found.

Zone C – Tung Lung Chau

The seabed in both shallow and deep depth zones of Zone C were predominately composed of bedrocks and large boulders.  

Hard coral community was recorded in shallow depth zone (2-6 mCD) with 8 hermatypic hard coral species ( Goniopora stutchburyi, Psammocora superficialis, Cyphastrea chalcidicum, Plesiastrea versipora, Porites lobata, Montipora mollis, Monitpora peltiformis and Favites chinensis) and one species of ahermatypic hard coral species (Tubastrea/ Dendrophyllia sp.) recorded.  Relatively low diversity and abundance of octocorals (Acanthogorgia sp., Euplexaura sp., Dendronephthya sp. and Scleronephthya gracillicum) were observed in deep depth zone (beyond -6 m CD).  All coral species recorded are common and have a widespread distribution throughout Hong Kong’s nearshore waters.

Table 3.3        Description of the Seabed Recorded along Each Transect in REA

Transect

Depth (-m CD)

Description

Zone A - Cape Collinson (Monitoring Site)

Transect 1

Shallow

~5

The seabed was composed of rubbles and small boulders.  The hard coral cover was low (< 5%) with 4 hard coral species Oulastrea crispata, Goniopora stutchburyi, Psammocora superficialis and Cyphastrea chalcidicum recorded.  The octocoral cover was low (< 5%) with four species (Paraplexaura sp., Echinomuricea sp., Viminella sp. and Ellisella sp.) recorded.

Deep

~9

The seabed was mainly composed of sand (~50%).  No hard coral colonies were found.  The octocoral cover was low (< 6-10%) with gorgonians growing on sand.  Seven species of octocorals (Echinomuricea sp., Paraplexaura sp., Menella sp., Euplexaura sp., Muricella sp., Sinularia sp. and Dendronephthya sp.) were recorded.

Transect 2

Shallow

~5

The seabed was mainly composed of bedrocks (~60%).  The hard coral cover was low (< 5%) with 2 hard coral species Oulastrea crispata and Psammocora superficialis recorded.  The octocoral cover was low (< 5%) with  6 species (Dendronethphya sp., Ellisella sp. Echinomuricea sp., Euplexaura sp., Paraplexaura sp. and Menella sp.) recorded.

Deep

~8-9

The seabed was mainly composed of bedrocks (~50%).  No hard coral colonies were found.  The octocoral cover was low (< 6-10%) with 4 species (Dendronethphya sp., Paraplexaura sp., Echinomuricea sp. and Euplexaura sp.) recorded.

Transect 3

Shallow

~5

The seabed was mainly composed of bedrocks (~60%).  The hard coral cover was about 5% with 3 hard coral species Oulastrea crispata, Goniopora stutchburyi and Plesiastrea versipora recorded.  The octocoral cover was low (< 5%) with 6 species (Dendronethphya sp., Scleronephthya gracillicum, Ellisella sp. Echinomuricea sp., Viminella sp., Paraplexaura sp. and Menella sp.) recorded.

Deep

~9

The seabed was mainly composed of bedrocks (~60%).  No hard coral species was found.  The octocoral cover was about 6-10% with 6 species (Paraplexaura sp., Echinomuricea sp., Euplexaura sp., Anthogorgia sp., Dendronephthya sp. and Scleronephthya gracillicum) recorded.                                            

Zone B – Tai Long Pai (Monitoring Site)

Transect 1

Shallow

~2-5

The seabed was mainly composed of bedrocks (> 80%).  No hermatypic hard coral species was recorded while 1 species of ahermatypic hard coral (Tubastrea/Dendrophyllia sp.) was recorded. The octocoral cover was about 5% with 4 species (Dendronephthya sp., Menella sp., Euplexaura sp., Paraplexaura sp.) recorded.

Deep

~5-15

The seabed was mainly composed of bedrocks (> 80%).  No hard coral species was recorded.  The octocoral cover was about 11-30% with 7 species (Dendronephthya sp., Menella sp., Euplexaura sp., Paraplexaura sp., Anthogorgia sp., Verrucella sp. and Echinomuricea sp.) recorded.  Black coral colonies, Antipathes curvata and Cirrhipathes sp. were observed.

Transect 2

Shallow

~2-5

The seabed was mainly composed of bedrocks (> 80%).  The hard coral cover was extremely low (< 5%) with 3 species Goniopora stutchburyi, Cyphastrea chalcidicum and Psammocora superficialis recorded.  Colonies of ahermatypic hard coral Tubastrea/ Dendrophyllia sp. were found.  The octocoral cover was about 5% with 3 species (Euplexaura sp., Paraplexaura sp. and Echinomuricea sp.) recorded.

Deep

~5-15

The seabed was mainly composed of bedrocks (> 80%).  No hard coral species were recorded.  The octocoral cover was about 11-30% with 7 species (Dendronephthya sp., Menella sp., Euplexaura sp., Paraplexaura sp., Anthogorgia sp., Verrucella sp. and Echinomuricea sp.) recorded.  Black coral colonies, Antipathes curvata and Cirrhipathes sp. were observed.

Zone C – Tung Lung Chau (Control Site)

Transect 1

Shallow

~5

The seabed was mainly composed of bedrocks (~80%).  The hard coral cover was low (< 5%) with 6 hermatypic hard coral species Goniopora stutchburyi, Psammocora superficialis, Cyphastrea chalcidicum, Plesiastrea versipora, Porites lobata and Montipora mollis recorded.  One species of ahermatypic hard coral Tubastrea/ Dendrophyllia sp. was recorded.  The octocoral cover was very low (< 5%) with Dendronephthya sp. and Scleronephthya gracillicum recorded.

Deep

~10

The seabed was mainly composed of bedrocks (~60%).  The hard coral cover was low (<5%).  The octocoral cover was low (< 10%) with Euplexaura sp., Dendronephthya sp. and Scleronephthya gracillicum recorded.

Transect 2

Shallow

~5

The seabed was mainly composed of bedrocks (~40%).  The hard coral cover was low (< 5%) with 6 species Montipora peltiformis, Porties lobata, Cyphastrea chalcidicum, Favites chinensis, Goniopora stutchburyi and Plesiastrea verisipora recorded.  The octocoral cover was very low (< 5%) with only a few small colonies of Dendronephthya sp. recorded.

Deep

~8

The seabed was mainly composed of bedrocks (~80%).  The hard coral cover was low (< 5%) with 3 species Plesiastrea versipora, Porites lobata and Psammocora superficialis recorded.  The octocoral cover was low (< 10%) with Acanthogorgia sp., Euplexaura sp., Dendronephthya sp. and Scleronephthya gracillicum recorded.

Transect 3

Shallow

5

The seabed was mainly composed of bedrocks and small boulders.  The hard coral cover was low (< 5%) with 4 species Porites lobata, Goniopora stutchburyi, Plesiastrea verisipora and Cyphastrea chalcidicum recorded. The octocoral cover was very low (< 5%) with Echinomuricea sp. recorded.

Deep

~9

The seabed was mainly composed of bedrocks (50%).  The hard coral cover was low (< 5%) with 4 species Montipora peltiformis, Goniopora stutchburyi, Cyphastrea chalcidicum and Psammocora superficialis recorded.  The octocoral cover was low (< 10%) with Euplexaura sp., Dendronephthya sp. and Scleronephthya gracillicum recorded.

 

Table 3.4        Seabed Attributes along the Semi-Quantitative Survey Transects

Zone

A

B

C

Depth (a)

S1

S2

S3

D1

D2

D3

S1

S2

D1

D2

S1

S2

S3

D1

D2

D3

Seabed attributes (b)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bedrock

0

5

4

1

5

5

6

6

6

6

6

4

4

5

6

4

Boulders – large

3

2

3

2

3

3

1

2

3

3

0

3

3

2

2

2

Boulders – small

3

2

3

3

3

2

1

1

2

2

0

3

3

2

0

3

Rock

1

1

1

1

1

1

0

0

0

0

1

2

1

1

0

1

Rubble

3

2

1

2

1

1

1

1

1

1

1

2

1

2

0

2

Sand

2

1

1

4

1

1

1

1

1

1

1

1

1

1

1

1

Silt

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Ecological attributes (b)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hard coral

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Dead standing coral

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Octocoral

1

1

1

2

2

2

1

1

3

3

1

1

1

2

2

2

Black coral

0

0

0

0

0

0

0

0

1

1

0

0

0

0

0

0

Turf algae

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Macroalgae

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Coralline algae

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

 

Notes:       (a)        s = shallow water; m = mid water; d=deep water

            (b)        1=<5% Cover, 2= 6-10% Cover, 3 = 11-30% Cover, 4 = 31-50% Cover, 5 = 51-75%
Cover, 6 = 76-100% Cover.

 


Table 3.5        Seabed Attributes along the Semi-Quantitative Survey Transects

Type

Taxon/ Family

Species

A

A

A

A

A

A

B

B

B

B

C

C

C

C

C

C

 

 

Depth (a)

S1

S2

S3

D1

D2

D3

S1

S2

D1

D2

S1

S2

S3

D1

D2

D3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hard Coral

Acroporidae

Montipora peltiformis

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

2

 

 

Montipora mollis

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Siderastreidae

Psammocora superficialis

1

1

 

 

 

 

 

1

 

 

2

 

 

 

2

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dendrophyllidae

Turbinaria peltata

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tubastrea/ Dendrophyllia sp.

 

1

 

 

 

 

3

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Faviidae

Cyphastrea chalcidicum

1

 

 

 

 

 

 

1

 

 

2

2

2

 

 

1

 

 

Favites chinensis

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

Oulastrea crispata

3

1

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Plesiastrea versipora

 

 

1

 

 

 

 

 

 

 

2

2

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Poritidae

Goniopora stutchburyi

2

 

1

 

 

 

 

2

 

 

2

2

2

 

2

1

 

 

Porites lobata

 

 

 

 

 

 

 

 

 

 

2

1

2

 

2

 

Octocoral

Acanthogorgiidae

Acanthogorgia sp.

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

Anthogorgia sp.

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

Muricella sp.

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alcyoniidae

Sinularia sp.

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nephtheidae

Dendronephthya sp.

 

2

4

1

1

4

 

 

3

3

 

 

 

3

 

2

 

 

Scleronephythya sp.

 

 

1

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Plexauridae

Astrogorgia sp.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Echinogorgia sp.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Echinomuricea sp.

2

3

3

4

2

1

 

 

2

2

 

 

 

 

 

 

 

 

Euplexaura sp.

 

2

2

 

 

2

 

 

2

 

 

 

 

2

1

1

 

 

Menella sp.

 

 

 

 

 

 

 

 

2

2

 

 

 

 

1

 

 

 

Paraplexaura sp.

1

1

2

1

1

2

 

 

1

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ellisiidae

Ellisella sp.

1

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Black Coral

Antipathidae

Antipathes sp.

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

Cirrhipathes sp.

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                      


3.1.3                                Results of Coral Colony Monitoring

Coral Colony Monitoring was undertaken at Zone A, Zone B and Zone C.  The monitoring area was the same as the REA survey area (Figure 3.1).

The following data were collected for the identified hard coral, soft coral, black coral and gorgonian colonies and summarized in Table 3.6 to 3.8:

§     Maximum diameter of the identified hard coral and soft coral colonies;

§     Maximum height and width of the identified gorgonians and black corals;

§     Percentage of sediment cover on the identified colonies and the colouration, texture and approximate thickness of sediment on the coral colonies and adjacent substrate.  Any contiguous patches of sediment cover >10 % were recorded;

§     Percentage of bleached area on the identified colonies of which two categories were recorded: a. blanched (ie pale) and b. bleached (ie whitened);

§     Percentage of colony area showing partiality mortality; and

§     Physical damage to colonies, tissue distension, mucous production and any other factors relevant will be noted in the field.

Photographic records of the identified coral colonies are shown in Annex A.

Due to the natural high sedimentation rate in the region, encrusting (ie Oulastrea crispata or Psammocora superficialis) and submassive (ie Goniopora stutchburyi, Cyphastrea chalcidicum) hermatypic hard corals were commonly found to be covered by sediments of less than 1 mm thickness during the Baseline Coral Survey.  Octocorals, except for Dendronephthya sp. and Scleronephthya gracillicum, were generally free of sediments.  The health conditions of hard corals and octocorals were found to be good with no bleaching or partial mortality recorded.

Coral Colony Monitoring will be undertaken in the Post Project Monitoring in which coral colonies with similar growth forms and size to those monitored during the Baseline Coral Survey will be selected and measured.  The comparison of baseline and post Project data would allow for determination of any observable adverse impacts to the health conditions of coral colonies as a result to the cable laying works.


Table 3.6   Species, Size, Sediment Cover, Bleached Area, Partial Mortality and Physical Damage to the Identified Coral Colonies in Zone A (Cape
        Collinson)

Coral No.

Family

Genus

Species

Max. diameter (cm)

Max. height (cm)

Max. width (cm)

Sediment cover (%)

Sediment color

Sediment Texture

Sediment thickness (cm)

Bleached area (%)

Partial mortality

Physical damage to colonies

Hard Corals

 

 

 

 

 

 

 

 

 

 

 

 

1

Poritidae

Goniopora

stutchburyi

15

N/A

N/A

1

Light yellow

Fine

1mm

N/A

N/A

N/A

2

Faviidae

Oulastrea

crispata

2

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

3

Faviidae

Oulastrea

crispata

2

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

4

Faviidae

Oulastrea

crispata

1

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

5

Faviidae

Oulastrea

crispata

1

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

6

Poritidae

Goniopora

stutchburyi

14

N/A

N/A

5

Light yellow

Fine

<1mm

N/A

N/A

N/A

7

Faviidae

Oulastrea

crispata

2

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

8

Faviidae

Oulastrea

crispata

4

N/A

N/A

5

Light yellow

Fine

<1mm

N/A

N/A

N/A

9

Siderastreidae

Psammocora

superficialis

15

N/A

N/A

5

Light yellow

Fine

<1mm

N/A

N/A

N/A

10

Faviidae

Plesiastrea

versipora

15

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

11

Faviidae

Favia

rotumana

33

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

12

Acroporidae

Montipora

mollis

12

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

13

Dendrophyllidae

Turbinaria

peltata

19

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

14

Dendrophyllidae

Turbinaria

peltata

18

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

15

Poritidae

Goniopora

stutchburyi

40

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

Octocorals

 

 

 

 

 

 

 

 

 

 

 

 

1

Plexauridae

Paraplexaura

 

N/A

10

15

N/A

N/A

N/A

N/A

N/A

N/A

N/A

2

Plexauridae

Echinomuricea

 

N/A

26

22

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

3

Plexauridae

Echinomuricea

 

N/A

26

25

N/A

N/A

N/A

N/A

N/A

N/A

N/A

4

Plexauridae

Echinomuricea

 

N/A

25

13

N/A

N/A

N/A

N/A

N/A

N/A

N/A

5

Ellisellidae

Viminella

 

N/A

23

0.5

N/A

N/A

N/A

N/A

N/A

N/A

N/A

6

Ellisellidae

Ellisella

 

N/A

16

7

N/A

N/A

N/A

N/A

N/A

N/A

N/A

7

Nephtheidae

Dendronephthya

 

12

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

8

Nephtheidae

Dendronephthya

 

14

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

9

Nephtheidae

Dendronephthya

 

7

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

10

Ellisellidae

Ellisella

 

N/A

11

3

N/A

N/A

N/A

N/A

N/A

N/A

N/A

11

Plexauridae

Echinomuricea

 

N/A

13

4

N/A

N/A

N/A

N/A

N/A

N/A

N/A

12

Nephtheidae

Scleronephthya

gracillicum

12

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

13

Acanthogorgiidae

Muricella

 

N/A

20

11

N/A

N/A

N/A

N/A

N/A

N/A

N/A

14

Alcyoniidae

Sinularia

 

14

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

15

Antipathidae

Antipathes

curvata

N/A

110

50

N/A

N/A

N/A

N/A

N/A

N/A

N/A

 

Table 3.7  Species, Size, Sediment Cover, Bleached Area, Partial Mortality and Physical Damage to the Identified Coral Colonies in Zone B (Tai Long Pai)

Coral No.

Family

Genus

Species

Max. diameter (cm)

Max. height (cm)

Max. width (cm)

Sediment cover (%)

Sediment color

Sediment Texture

Sediment thickness (cm)

Bleached area (%)

Partial mortality

Physical damage to colonies

Hard Corals

 

 

 

 

 

 

 

 

 

 

 

 

1

Poritidae

Goniopora

stutchburyi

5

N/A

N/A

1

Light yellow

Fine

1mm

N/A

N/A

N/A

2

Siderastreidae

Psammocora

superficialis

8

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

3

Siderastreidae

Psammocora

superficialis

11

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

4

Faviidae

Cyphastrea

chalcidicum

9

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

5

Faviidae

Cyphastrea

chalcidicum

9

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

6

Dendrophyllidae

Dendrophyllia

-

4

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

7

Dendrophyllidae

Dendrophyllia

-

3.5

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

8

Dendrophyllidae

Dendrophyllia

-

3.5

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

9

Poritidae

Goniopora

stutchburyi

5

N/A

N/A

5

Light yellow

Fine

<1mm

N/A

N/A

N/A

10

Faviidae

Cyphastrea

chalcidicum

10

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

11

Dendrophyllidae

Dendrophyllia

-

3.5

N/A

N/A

5

Light yellow

Fine

1mm

N/A

N/A

N/A

12

Faviidae

Plesiastrea

versipora

23

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

13

Dendrophyllidae

Dendrophyllia

-

2

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

14

Poritidae

Goniopora

stutchburyi

12

N/A

N/A

5

Light yellow

Fine

<1mm

N/A

N/A

N/A

15

Faviidae

Cyphastrea

chalcidicum

11

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

Octocorals

 

 

 

 

 

 

 

 

 

 

 

 

1

Nephtheidae

Dendronephthya

 

18

N/A

N/A

1

Light yellow

Fine

<1mm

N/A

N/A

N/A

2

Nephtheidae

Dendronephthya