Contents
1.1 Background
1.2 Purpose of this Report
1.3 Structure of the Report
2 Post Project coral Monitoring Survey Methodology
2.1 Monitoring Locations
2.2 Methodology
3 Post project Coral Monitoring Survey Results
3.1 Introduction
3.2 REA Survey Results
3.3 Results of Coral Colony
Monitoring
ANNEX
Annex A Photographic Results of Identified Coral Colonies in Zone A, B & C
Annex B RTC Table
1
Introduction
1.1
Background
NTT
Com Asia (NTTCA) proposed 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 landing site is at a new Beach
Manhole (BMH) and the cable is ultimately connected with a Data Centre in Tseung Kwan O (TKO) Industrial Estate. From Tseung
Kwan O, the cable extends westward 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 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)
for the Project. In accordance with
the EP conditions, an environmental monitoring and audit (EM&A) programme is required to be implemented in order to track
the environmental performance of the cable installation works of the Project.
Marine
works for the cable installation was completed in January 2013. In accordance with the EM&A Manual ([1])
, Post Project Coral Survey should be conducted within one month after
completion of the marine works in order to determine any detectable changes in
coral conditions which may be caused by the cable installation works.
1.2
Purpose of this Report
This
Post Project Coral Monitoring Survey Report (“the Report”) is prepared by
ERM-Hong Kong, Limited (ERM) on behalf of NTTCA to present the methodology and
findings of the Post Project Coral Monitoring Survey 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: Post Project Coral Monitoring Survey Methodology
Presents the Post Project Coral Monitoring
Survey methodology, parameters monitored, monitoring locations and depth in
accordance with the EM&A Manual.
Section
3: Post Project Coral Monitoring Survey Results
Reviews the conditions and health
status of corals at the monitoring stations as recorded during the Post Project
Coral Monitoring Survey for comparison with the baseline coral information in
order to determine any detectable changes that may be caused by the cable
installation works of the Project.
Section
4: Conclusion
Concludes findings from the Post
Project Coral Monitoring Survey.
2
Post
Project coral Monitoring Survey Methodology
This
section presents the methodology of the Post Project Coral Monitoring Survey which
is undertaken within one month after the marine works of the Project. The methodology adopted is the same as
that for the Baseline Coral Survey undertaken before the cable installation
works, except for the qualitative spot dive survey which was conducted for the Baseline
Survey only to determine the locations of monitoring transects. The employment of the same methodology would
allow for direct comparison of coral conditions and health status before and
after the cable installation works and hence, determines any detectable changes
in coral assemblages concerned after the works.
2.1
Monitoring
Locations
The
monitoring locations of marine ecological survey are shown in Figure 2.1. These included:
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
cable route where hard substrata were recorded from the geophysical
survey. The Post Project Coral Monitoring
Survey comprised the following two components:
§ Semi-quantitative
Rapid Ecological Assessment (REA) survey; and
§ Coral
Colony Monitoring.
Each of these surveys is described further in the
following sections.
Rapid Ecological Assessment Survey Method
A standardised semi-quantitative 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 Coral Survey and Post Project Coral Monitoring Survey would allow for
a direct comparison of coral conditions before and after the cable installation
works of the Project in order to determine any detectable changes in conditions
which may be caused by 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 and EM&A marine ecological
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 ([2]) for
marine environment of Hong Kong ([3]).
A series of REA surveys were 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 regions 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 regions were determined based on findings from the qualitative spot dive
survey which were undertaken during the baseline monitoring. 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 smaller
area of this Monitoring Station.
Following
the laying of the transect line, the coral specialist swam along the transect
slowly and conducted the REA survey.
The REA methodology encompassed 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 (Tables 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 to verify the REA data. 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 the Post Project
Coral Monitoring Survey to identify any evidence of sediment stress to corals
before and after cable installation works of the Project. 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;
§ 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 indicating
to corals were noted in the field.
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 re-locating the tagged corals given the generally low
visibility in the area and low light conditions in deep water. Instead, colonies of similar growth
forms and size would be selected for the Baseline and Post Project Coral Monitoring
Surveys.
3
Post
project Coral Monitoring Survey Results
3.1
Introduction
This
section presents findings of the Post Project Coral Monitoring Survey which is
undertaken within one month after completion of jetting works for the cable
installation of the Project.
Findings from the Post Project Coral Monitoring Survey are compared with
those obtained from the Baseline Coral Survey which was undertaken before cable
installations works in order to determine any detectable changes in coral
conditions and health status and the relationship of such changes, if any, to
the cable installation works of the Project.
The
Post Project Coral Monitoring Survey was conducted over two days on 18 and 19 February
2013. The weather condition was
mainly sunny, with light (Force 2) to moderate (Force 3) east to southeasterly winds. Slight to moderate swell presented in
the sea on the two survey days. The
underwater visibility was moderate and generally ranged between 3 to 5 m. Coral communities at Zone A: Cape Collinson, Zone B: Tai Long Pai and
Zone C: Tung Lung Chau were
monitored (see Figure 2.1 for
monitoring locations). Detailed
description and discussion of the monitoring results are presented below.
3.2
REA
Survey Results
Seabed
compositions along each monitored transects of Zone A to C are shown in Tables 3.1, 3.2a and 3.2b.
Each taxon in the inventory was ranked in terms of relative abundance
in the community and results recorded during the Baseline and Post Project
Coral Monitoring Surveys are shown in Table
3.3a and 3.3b, respectively. Findings of the REA surveys are
discussed below.
Zone
A – Cape Collinson
Major Abiotic Attributes
The
seabed at the REA survey area of Zone A was mainly composed of bedrocks in
shallow depth region (2-5 m CD) and bedrocks and boulders at deep depth region
(5-15m CD), except at the deep depth region of Transect 1 which was mainly
composed of sand and small boulders (Tables
3.2a-b). The estimated
percentage covers of the major abiotic attributes were noted to be similar
between the Baseline and Post Project Coral Monitoring Surveys.
Major Biotic Attributes
Both
hard coral and octocoral covers were less than 5% in
shallow depth region (2-5 m CD) as recorded during both the Baseline and Post
Project Coral Monitoring Surveys (Tables
3.2a-b). Compositions of coral
assemblages were also noted to be similar between the Baseline and Post Project
Coral Monitoring Surveys, with six (6) hard coral and eight (8) octocoral species recorded during both surveys (Tables 3.3a-b). Oulastrea crispata and Goniopora stutchburyi were the dominant hard coral species recorded
while Echinomuricea
sp. was the dominant octocoral species found.
Octocoral cover was
found between 6-10% while no hard coral was recorded in deep depth region (5-15
m CD) during both the Baseline and Post Project Coral Monitoring Survey (Tables 3.2a-b). Species compositions of coral
assemblages were similar between the Baseline and Post Project Coral Monitoring
Surveys, with 11 octocoral species recorded during
the Baseline Coral Survey while 13 octocoral species
were recorded during the Post Project Coral Monitoring Survey (Tables 3.3a-b). Echinomuricea sp. and Dendronephthya sp. were the
dominant octocoral species recorded.
Less
than 5% of macroalgae cover was recorded at both
shallow and deep depth regions during the Post Project Coral Monitoring in
February 2013 (Tables 3.2a-b). The presence of macroalgae
in winter during the Post Project Coral Monitoring in February 2013 but not
during the Baseline Coral Survey in September 2012 is due to the natural
seasonal cycle as with lower seawater temperature in winter which triggered the
growth of macroalgae.
Overall,
comparison of the Baseline and Post Project Coral Monitoring Survey results did
not indicate any detectable changes in coral conditions at Zone A before and
after the cable installation works.
Therefore, there did not appear to be any unacceptable ecological
impacts to coral assemblages at Zone A as a result of the cable installation
works.
Zone
B – Tai Long Pai
Major Abiotic Attributes
Seabed
at the REA survey area of Zone B was mainly composed of bedrocks in both shallow
(2-5 m CD) and deep (5-15m CD) depth regions (Tables 3.2a-b). The
estimated percentage covers of the major abiotic attributes were noted to be
similar between the Baseline and Post Project Coral Monitoring Surveys.
Major Biotic Attributes
Hard
coral and octocoral covers were less than 5% and
about 5% in shallow depth region (2-5 m CD) respectively as recorded during
both the Baseline and Post Project Coral Monitoring Surveys (Tables 3.2a-b). Species compositions of coral
assemblages were also similar between the Baseline and Post Project Coral Monitoring
Surveys, with four (4) hard coral and five (5) octocoral
species recorded respectively (Tables 3.3a-b). Goniopora stutchburyi and Tubastrea sp. were the dominant hard coral species
while Dendronephthya sp. was the dominant octocoral species recorded during both surveys.
Octocoral cover was between
11 – 30% in deep depth region (5-15 m CD) during both the Baseline and Post
Project Coral Monitoring Surveys (Tables
3.2a-b). No hard coral was
found in the deep depth region. Species
compositions of coral assemblages were similar between the Baseline and Post
Project Coral Monitoring Surveys, with 10 octocoral
species recorded during both surveys (Tables
3.3a-b). Echinomuricea sp. and Dendronephthya
sp. were the dominant octocoral species recorded.
Macroalgae covers were
found to be less than 5% and between 6-10% at shallow and deep depth regions,
respectively, during the Post Project Coral Monitoring in February 2013 (Tables 3.2a-b). The record of macroalgae
during the Post Project Coral Monitoring Survey only is due to the natural
seasonal cycle in winter as explained above.
Overall,
comparison of the Baseline and Post Project Coral Monitoring Survey results did
not indicate any detectable changes in coral conditions at Zone B before and after
the cable installation works.
Therefore, there did not appear to be any unacceptable ecological impacts
to coral assemblages at Zone B as a result of the cable installation works.
Zone
C – Tung Lung Chau
Major Abiotic Attributes
Seabed
at the REA survey area of Zone C was mainly composed of bedrocks, large and
small boulders in shallow depth region (2-5 m CD) whereas at the deep depth
region (5-15m CD) was predominantly composed of bedrocks (Tables 3.2a-b). The
estimated percentage covers of the major abiotic attributes were noted to be
similar between the Baseline and Post Project Coral Monitoring Surveys.
Major Biotic Attributes
Both
hard coral and octocoral covers were less than 5% in
shallow depth region (2-5 m CD) as recorded during both the Baseline and Post
Project Coral Monitoring Surveys (Tables
3.2a-b). Compositions of coral
assemblages were also noted to be similar between both surveys with nine (9) hard
coral and three (3) octocoral species recorded in the
Baseline Coral Survey, and 10 hard coral species and three (3) octocoral species recorded in the Post Project Coral
Monitoring Survey (Tables 3.3a-b). Montipora venosa and Goniopora stutchburyi were the dominant hard coral species while Dendronephthya sp. was the dominant octocoral species recorded.
Both
hard coral and octocoral covers were less than 5% and
less than 10% in deep (5-15 m CD) depth region respectively during both the
Baseline Coral Survey and Post Project Coral Monitoring Survey (Tables 3.2a-b). Comparison of coral assemblages were
similar between the Baseline and Post Project Coral Monitoring Surveys, with five
(5) hard coral species and seven (7) octocoral
species recorded during the Baseline Coral Survey, whereas five (5) hard coral
species and 11 octocoral species were recorded during
the Post Project Coral Monitoring (Tables
3.3a-b). Dendronephthya sp. and Scleronephythya sp. were the dominant octocoral species
recorded. As for Zone A and Zone B,
macroalgae were recorded at the deep depth region of Zone
C during the Post Project Coral Monitoring Survey in February 2013 but not the Baseline
Coral Survey in September 2012 (Tables 3.2a-b)
due to the natural seasonal cycle in winter which triggered the growth of
seaweed.
Overall,
comparison of the Baseline and Post Project Coral Monitoring Survey results did
not indicate any detectable changes in coral conditions at Zone C which serves
as a Control station that is unlikely to be affected by the cable installation
works.
Table 3.1 Description
of the Seabed Composition Recorded along Each REA Survey Transect ([4])
|
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 (between 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 (between 6-10%) with 6 species (Dendronethphya sp., Dichotella sp.,
Paraplexaura
sp., Echinomuricea
sp. and Euplexaura sp. and Viminella sp.) recorded. Two species of black corals, Antipathes curvata and Cirrhipathes sp., were
recorded. |
|
Transect 3 |
||
|
Shallow |
~5 |
The seabed
was mainly composed of bedrocks (~60%).
The hard coral cover was low (< 5%) with 3 hard coral species Oulastrea crispata, Goniopora stutchburyi and Plesiastrea versipora recorded. The octocoral
cover was low (< 5%) with 7 species (Dendronethphya sp., Scleronephthya gracillicum, Ellisella sp. Echinomuricea sp., Viminella sp., Paraplexaura sp., Euplexaura 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 between 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 between 11-30% with 8 species (Dendronephthya sp., Menella sp., Euplexaura sp., Paraplexaura
sp., Anthogorgia
sp., Acanthogorgia
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 between 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 7 hermatypic
hard coral species Goniopora stutchburyi, Psammocora superficialis, Cyphastrea chalcidicum, Plesiastrea versipora, Porites lobata, Montipora mollis and Montipora venosa 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.,
Paraplexaura 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 7 species Montipora peltiformis, Porites lobata, Cyphastrea chalcidicum, Favites chinensis, Goniopora stutchburyi, Montipora venosa and Plesiastrea verisipora recorded. One species of ahermatypic
hard coral Tubastrea/
Dendrophyllia sp. was 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.,
Echinomuricea sp., Euplexaura sp., Menella
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 5 species Montipora venosa, Porites lobata, Goniopora stutchburyi, Plesiastrea verisipora and Cyphastrea chalcidicum recorded.
One species of ahermatypic hard coral Tubastrea/ Dendrophyllia sp. was 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 Paraminabea sp.,
Euplexaura sp., Echinogorgia sp., Dendronephthya sp. and Scleronephthya gracillicum
recorded. Two species of black corals, Antipathes curvata and Cirrhipathes sp., were
recorded. |
Table 3.2a Ordinal Rank of Percentage
Cover of Seabed Attributes along the REA Survey Transects during the Baseline
Coral Survey
|
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. Also refer to Table 2.2.
Table 3.2b Ordinal Rank of
Percentage Cover of Seabed Attributes along the REA Survey Transects during the
Post Project Coral Monitoring
|
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 |
1 |
1 |
1 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
|
Macroalgae |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
0 |
0 |
0 |
1 |
1 |
1 |
|
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. Also refer to Table 2.2.