Contents
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
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.