|
Consultancy
Ref.: AFCD/FIS/02/19 Consultancy Service for Environmental Impact Assessment
Study for Designation of New Fish Culture Zones Environmental
Impact Assessment (EIA) Report for Establishment of Fish Culture Zone at
Outer Tap Mun November
2022 |
This Section presents the findings of
the marine ecological impact assessment associated with the construction and
operation of the Project. It also
summarises the key findings on the baseline ecological conditions, the details
of which are presented in Appendices 4A to 4C.
The criteria and scope for evaluating marine ecological
impacts are laid out in the Annexes 8 and 16 of the EIAO-TM and the
Study Brief. Legislative requirements
and evaluation criteria relevant to this assessment are listed below. The details on each are presented in Appendix 4A.
n
Marine Parks Ordinance (Cap.
476);
n
Wild Animals Protection
Ordinance (Cap. 170);
n
Protection of Endangered
Species of Animals and Plants Ordinance (Cap. 586);
n
Country Parks Ordinance (Cap.
208);
n
Town Planning Ordinance (Cap.
131);
n
Environmental Impact
Assessment Ordinance (Cap. 499) and the Technical Memorandum on Environmental
Impact Assessment Process under the Environmental Impact Assessment Ordinance (EIAO-TM);
n
Environmental Impact
Assessment Ordinance (EIAO) Guidance Notes No. 6/2010, 7/2010 and
11/2010;
n
Hong Kong Planning Standards
and Guidelines Chapter 10 (HKPSG);
n
United Nations Convention on
Biodiversity (1992); and
n
Peoples’ Republic of China
(PRC) Regulations and Guidelines.
In accordance with Clause 3.4.4.2
of the Study Brief, the Assessment Area for marine ecological impact assessment
(Figure
B1.1 of Appendix 4B) shall be the
same as the assessment area for Water Quality Impact Assessment covering the
Mirs Bay Water Control Zone (WCZ) and the Tolo Harbour and Channel WCZ. Detailed description of the physical
characteristics of the marine environment of the Assessment Area and compliance
of WQOs is provided in Section 3.
Marine ecological
important habitats and species within and in the vicinity of the Project site
as well as within the Assessment Area are evaluated, including existing marine
parks, horseshoe crab breeding and nursery grounds, mangroves, seagrass beds,
coral communities, marine benthos of conservation interest, and marine
ecological important species including Finless Porpoises (FPs), amphioxus and
horseshoe crabs. The marine ecological profiles
and characteristics of these habitats and species are described in further
details below. A habitat map on the
marine ecology of the Assessment Area is provided in Figure 4A.2.1 of Appendix 4A.
A literature review was conducted to review the baseline marine
ecological conditions within the Assessment Area and to identify information
gaps to determine whether field surveys are required to provide sufficient
information for the marine ecological impact assessment. Findings of this literature review are
presented in detail in Appendix 4A.
Some of the baseline information was collected recently and is
considered to be up-to-date and representative of the existing conditions of
the Assessment Area. In accordance with
the requirements in Appendix C of the Study Brief, field surveys at selected
habitats within the Assessment Area where potential impact could occur and
up-to-date baseline information is not present were conducted to fill the
identified data gaps, verify and update the latest marine ecological conditions
of these habitats. The methodology for
the field surveys is presented in Appendix 4B. Field survey findings are presented in detail
in the following sections.
Marine ecological
surveys were conducted in Outer Tap Mun in accordance to the methodology as
stated in Appendix 4B. Surveys
were conducted from September 2020 to February 2021 and the details are
summarised in Table 4.1.
Table 4.1 Marine Ecological Baseline Surveys
|
Survey |
Season & Date |
|
Subtidal Benthos Survey |
Wet Season: 25 Sep 2020,19 Oct 2020 Dry Season: 26 Jan 2021, 1 Feb
2021 |
|
Coral Survey |
17 Nov 2020, 23 Nov 2020 |
|
Drop Camera Survey |
18 Dec 2020 |
A total of 119 individual organisms were collected from the five grab
samples from Outer Tap Mun during the wet season survey (Figure B2.3
of Appendix 4B). The specimens belong to 5 Phyla with a total of 7 classes, 19 families and 25 species identified.
Table 4.2 provides a summary on the
abundance, biomass, taxonomic richness, Pielou’s Evenness and Shannon Diversity
of infauna collected at each location. A
complete set of raw data is presented in Table 4C.1 of Appendix 4C.
Results of the wet season survey
showed that infaunal abundance, biomass and taxonomic richness (here
represented by number of families and species of infaunal organisms) were low
in general compared to dry season (Table 4.2
and Table 4.3). In terms of infaunal abundance, the majority
(~81%) of organisms recorded were from the Phylum Annelida. The polychaete worm Sigambra hanaokai was the most abundant species (total abundance = 50 individuals). No species of conservation interest were
recorded in the survey. In terms of
infaunal biomass, organisms from the Phylum Mollusca contributed ~54% of the total biomass recorded,
while organisms from Annelida
also contributed significant biomass (~36%).
The high biomass of Mollusca
was contributed by a number of species,
primarily by a bivalve species, Jitlada
culter.
A total of 835 individual organisms were collected from the five
grab samples during the dry season survey.
The specimens belong to 7 Phyla
with a total of 10 classes, 44
families and 59 species
identified. Table 4.3 provides a summary on the abundance, biomass and
taxonomic richness of infauna collected at each location. A complete set of raw data is presented in Table 4C.2 of Appendix 4C.
Results of the dry season survey
showed that infaunal abundance, biomass and taxonomic richness (here
represented by number of families and species of infaunal organisms) were
relatively high comparing to wet season
(Table 4.2
and Table 4.3). In terms of infaunal abundance, the majority
(~76%) of
organisms recorded were from the Phylum Annelida. The polychaete worm, Sigambra hanaokai, was the most abundant species (total abundance =
143
individuals). No species of conservation
interest were recorded in the survey. In
terms of infaunal biomass, organisms from the Phylum Annelida contributed ~58% of the total biomass recorded,
while organisms from Mollusca also
contributed significant biomass (~37%).
The high biomass of Annelida
was contributed by a number of species,
primarily by a polychaete species, Anelassorhynchus sabinus.
Table 4.2 Density and Indices of Richness, Evenness and Diversity of Infaunal Assemblages at the Sampling Locations for the Soft Bottom Habitat Surveys at the Assessment Area during the Wet Season
|
Station |
Number
of Infaunal Individuals |
Number
of Individuals per m2 |
Taxonomic
Richness (No. Families) |
Taxonomic
Richness (No. Species) |
Pielou’s
Evenness (J) |
Shannon
Diversity (H’) |
Total
Biomass (g wet weight) |
Mean
Biomass per Individual (g wet weight) |
|
OTM1 |
37 |
385.42 |
7 |
7 |
0.56 |
1.10 |
0.0730 |
0.0020 |
|
OTM2 |
8 |
83.33 |
5 |
5 |
0.86 |
1.39 |
0.0227 |
0.0028 |
|
OTM3 |
7 |
72.92 |
4 |
4 |
0.92 |
1.28 |
0.0102 |
0.0015 |
|
OTM4 |
23 |
239.58 |
8 |
9 |
0.82 |
1.81 |
0.1579 |
0.0069 |
|
OTM5 |
44 |
458.33 |
15 |
17 |
0.91 |
2.57 |
0.0501 |
0.0011 |
Table 4.3 Density and Indices of Richness, Evenness and Diversity of Infaunal Assemblages at the Sampling Locations for the Soft Bottom Habitat Surveys at the Assessment Area during the Dry Season
|
Station |
Number
of Infaunal Individuals |
Number
of Individuals per m2 |
Taxonomic
Richness (No. Families) |
Taxonomic
Richness (No. Species) |
Pielou’s
Evenness (J) |
Shannon
Diversity (H’) |
Total
Biomass (g wet weight) |
Mean
Biomass per Individual (g wet weight) |
|
OTM1 |
201 |
2093.75 |
15 |
21 |
0.75 |
2.28 |
5.2208 |
0.0260 |
|
OTM2 |
142 |
1479.17 |
12 |
17 |
0.76 |
2.16 |
1.1418 |
0.0080 |
|
OTM3 |
155 |
1614.58 |
17 |
20 |
0.75 |
2.26 |
1.3613 |
0.0088 |
|
OTM4 |
69 |
718.75 |
15 |
19 |
0.83 |
2.43 |
0.4120 |
0.0060 |
|
OTM5 |
268 |
2791.67 |
40 |
46 |
0.86 |
3.29 |
2.4827 |
0.0093 |
During
the surveys, the weather was fine and the sea was calm. The visibility was however poor and generally
ranged between 0.5 m and 2 m. The
general substrata and biological conditions noted along each transect during
the qualitative spot dive reconnaissance check are presented in Table 4.4.
Table 4.4 Description of the Seabed Recorded along Each Transect during the Qualitative Surveys (Spot Dive Reconnaissance Check Surveys)
|
Transect |
Depth |
Description |
|
T1 |
-3 to - 6 mCD |
The seabed was mainly composed of boulders, sand and hard corals in
shallow water (-3 to - 4 mCD) with mixture of sand, boulders and rocks in
deep water (-5 to -6 mCD). Plesiastrea versipora was found to be common in shallow water. Black coral Antipathes curvata was found to be sparse in shallow and deep
waters. |
|
T2 |
-3 to -6 mCD |
The seabed was mainly composed of hard corals and boulders in shallow water
(-3 to - 4 mCD) with a mixture of mainly sand, rocks and hard corals in deep
water (-5 to -6 mCD). Pavona decussata was observed to be
abundant at shallow water while Goniopora
columna were observed to be
common at deeper water. |
|
T3 |
-3 to -6 mCD |
The seabed was mainly composed of rocks, rubbles, sand and hard corals
in shallow water (-3 to - 4 mCD) with sandy substrate in deep water (-5 to -6
mCD). Favites flexuosa was observed to be common at shallow and deep
waters. |
Transects
are located at West natural shores of Tap Mun (T1, T2 & T3) (Figure
B2.1 of Appendix 4B). The site
mainly comprised of large boulders, rocks and sand. On the hard substrata, sessile benthos
primarily comprised of isolated barnacles.
At most transects, relative low to moderate coverage of hard coral
colonies (5% - 50%) and other benthos (<5% - 30%), such as sea anemones,
zoanthids and sponges were identified (Table 4C.3 of Appendix 4C).
A total of thirty-five hard coral species, one species of black coral, four species of
sea anemones, one zoanthid species and one sponge species were identified (Table 4C.4 of Appendix 4C). The majority of coral recorded were common and
widespread species in Hong Kong, abundant or common species included hard
corals Pavona decussata,
Plesiastrea versipora and Goniopora columna. Small amount of black coral Antipathes curvata were recorded at transect T1. Pavona decussata was recorded with relatively higher abundance at
shallow water of transect T2. Other corals
and benthos were generally present in isolated colonies. Representative photos of the seabed and coral
conditions during the surveys are presented in Figure 4.1.
Overall, results of the dive surveys indicated that the subtidal hard substrate of the Assessment Area showed relatively low to moderate sessile taxa. Common and widespread hard corals were recorded in low to moderate percentage cover (5% - 50%) in general, with relatively higher coral coverage recorded at shallow water of transect T2.
Drop camera surveys were conducted
at Outer Tap Mun at survey locations shown in Figure B2.1 of Appendix 4B. A total of five stations were surveyed within
the Project site with the use of a drop camera system to record the benthic
attributes by positioning the system ~1 m above the seabed. The results showed that the seabed at the
survey locations (~-16mCD) consisted of silty mud without any hard substrate
and benthic organism recorded.
Representative photographs are presented in Figure
4.2a and Figure 4.2b.
The key findings of the literature
review and field surveys are summarised below.
Recognised sites of
conservation importance within the Assessment Area include Country Parks, Marine Parks,
and Sites of Special Scientific Interest (SSSI). No Special Area is located within the
Assessment Area. Some of these that are
relevant to marine ecology and are located in the Assessment Area are discussed
below.
The existing country parks in
the Assessment Area include the Sai
Kung East Country Park, Sai Kung West Country Park and Sai Kung West Country
Park (Wan Tsai Extension). However, as
all three country parks are of terrestrial conservation interest, it
is considered that the impact of the Project on these country parks are not
anticipated.
Locations of the country parks are provided in Figure
4A.2.1 of Appendix 4A ([1]).
Hoi Ha Wan Marine Park (HHWMP) is
the existing marine park within the Assessment Area. No proposed or potential marine parks are
identified within the Assessment Area.
Details of HHWMP is provided in Table 4A.2.1 of Appendix 4A. Location of HHWMP is provided in Figure
4A.2.1 of Appendix 4A ([2]).
The
SSSI which is considered relevant to the marine works of the Project is the Hoi Ha Wan SSSI.
Details of
Hoi Ha Wan SSSI are provided in Table 4A.2.1 of Appendix 4A.
Location of Hoi Ha Wan SSSI is provided in Figure 4A.2.1 of Appendix 4A ([3]).
According to the latest AFCD Marine
Mammal Monitoring Report 2021/22, no records of Hong Kong’s resident marine
mammal species, the Finless Porpoise, Neophocaena
phocaenoides and the Chinese White Dolphin (CWD) Sousa chinensis were reported in the Assessment Area. Considering the Project site located at the
northeastern waters in Outer Tap Mun while CWDs in Hong Kong are mainly
distributed at western and southwestern Lantau waters and FPs are mostly
distributed in the southern and eastern waters of Hong Kong, the impact to
marine mammals from the Project is therefore not anticipated. The distribution of FPs in Hong Kong waters
is provided in Figure 4A.2.4 of Appendix 4A ([4]).
Two species of horseshoe crab, Tachypleus tridentatus and Carcinoscorpius rotundicauda, have
previously been recorded around Hong Kong waters. Based on the abundance of juveniles, Luk Keng
and Sha Tau Kok are identified as the key nursery grounds for C. rotundicauda and T. tridentatus. Adult
horseshoe crabs are not recorded in the northeastern waters of Hong Kong. The nearest records of occurrence were from
the beaches in Lai Chi Wo in Yan Chau Tong Marine Park which is located out of
the Assessment Area (Figure 4A.2.1 of Appendix 4A), therefore, the impact of the
Project on horseshoe crabs is not anticipated.
Three mangrove stands are found in
the Mirs Bay FCZ and two mangrove stands are found in the Tolo Harbour and
Channel WCZ within the Assessment Area.
No mangrove stands were found at the Project site. The nearest mangrove stand from the Project
site is located at Hoi Ha Wan which is 2.6 km away. The site is considered to be far away from
the Project site and the impact of the Project on mangroves is therefore not
anticipated. Locations of the mangroves
are provided in Figure 4A.2.1 of Appendix 4A ([5]).
Coral
communities in the eastern waters of Hong Kong generally have a higher
diversity and abundance as the surrounding marine environment is less
influenced by the Pearl River outflow compared to the western waters of Hong
Kong with lower salinity and higher turbidity.
Literatures have reported that hard coral, octocoral and black coral
were recorded within the Assessment Area, with a wide range of hard coral
coverage recorded in HHWMP (10- 50% to >50%) and in Port Island (Chek Chau)
(30-75%) in some early studies. Recent
surveys including those conducted during Reef Check 2021 have also recorded
19.3% and ~50% coral coverage at Port Island and HHWMP respectively. Locations of the coral communities are
provided in Figure 4A.2.1 of Appendix 4A
([6])
([7])
([8])
([9]).
Results of
the Feasibility Study of this Project has revealed that coral communities
mainly composed of scattered hard coral colonies with high hard coral coverage
(76 – 100%) recorded at shallow water region of one transect. A total of 29 hard coral species and 1 black
coral species were identified in at the eastern shoreline of Tap Mun during
these surveys. The species identified
during the survey were generally regarded as common and widespread species in
Hong Kong waters, such as Pavona decussata, Favites chinensis,
Dipsastraea speciosa and Platygyra acuta.
Field surveys were
conducted to fill in the information gap of the Feasibility Study, with
findings showing that the majority of corals recorded were common and
widespread species in Hong Kong, including hard corals Pavona decussata, Plesiastrea versipora
and Goniopora columna. Small amount of black coral Antipathes curvata was also recorded. Overall,
the surveyed areas showed low to moderate coral coverage in shallow waters
(<5% - 50 %) and deep waters (5% - 10 %) and low to moderate sessile taxa coverage on the
subtidal hard substrate. Results of drop camera survey showed that the
seabed of this site (~-16 mCD) was dominated by silty mud without any hard
substrate or benthic organisms.
Amphioxus are mostly present within Hong Kong’s
eastern waters, with densities ranging from 10 to 400 ind / m2
predominantly at sites in Tai Long Wan, Nam She Wan, Long Ke Wan and Pak Lap
Wan off the Sai Kung Peninsula ([10]).
However, no studies have been conducted at the Project site
previously. Field surveys were conducted
to fill in this information gap. The
baseline subtidal benthos surveys reported that no records of amphioxus was
found at the Project site, therefore, the impact of the Project on
amphioxus is not anticipated.
Other intertidal and
subtidal benthos species reported in the Assessment Area from the field surveys
and literature review are common and widespread in Hong Kong with no species of
conservation importance. As the Project site is located away from the shorelines,
the assessment on intertidal hard bottom assemblages is considered not
necessary. Potential marine ecological
impact would occur mostly on the subtidal environment and the impact on
intertidal habitats is not anticipated.
There are studies
which showed that benthic communities at northeastern waters, Tolo Channel and
western Mirs Bay which overlaps with the Assessment Area are impoverished. None of these species is unique to a
particular location of the Assessment Area, and many of these species were also
reported elsewhere in Hong Kong waters. Seagrass (Halophila
minor), with high
ecological value was reported to be present
at To Kwa Peng, however, as it is located at 4.3 km away from the Project site,
the impact of the Project on the seagrass is therefore not anticipated. Location
of the seagrass bed is provided in Figure 4A.2.1 of Appendix 4A
([11]).
Findings of
white-bellied sea eagle (WBSE) was spotted on Port Island within the Assessment
Area, located ~2.7 km away from the Project site. It was reviewed from literature and previous
field surveys that the species is uncommon but widespread in Hong Kong. As the nesting grounds of WBSE is far away
from the Project site and that the foraging distance generally reaches 2 km
from their nesting location, the impact of the Project
on the WBSE is therefore not anticipated.
Locations of the WBSE nesting grounds are provided in Figure
4A.2.1 of Appendix 4A ([12]).
The existing conditions of the
marine ecological habitats and resources within the Assessment Area have been
assessed. These baseline conditions have
been based on available literature and, where considered necessary, focused
field surveys and data review to update and supplement the data. Based on this information presented in Section 4.3.2, Section 4.3.3, Appendices 4A and 4C the ecological importance of each habitat has been determined
according to the EIAO-TM Annex 8
criteria.
Within the Assessment Areas
(mainly marine ecology) of this EIA, which covers quite a large areal extent,
variations in the ecological characteristics of habitats across different
locations (which are kilometres apart) are likely to be present. To provide information of key relevance to
the marine ecological assessment, the ecological importance of habitats
presented in this baseline is therefore primarily focused on the vicinity of
the works areas of the Project site.
The ecological importance of
the habitats was determined through reference to the following:
n
Literature review;
n
Findings of the field surveys;
n
Comparison with other areas in
Hong Kong; and
n
Annexes 8 and 16 of the EIAO-TM.
Outcomes of the evaluation of
ecological importance of the marine habitats and species within the Assessment
Areas are presented in Tables 4.5 to 4.9.
Table 4.5 Marine Ecological Importance of Existing Marine Parks and SSSI within the Assessment Area
|
Criteria |
Hoi
Ha Wan Marine Park (HHWMP) |
Hoi
Ha Wan SSSI |
|
Naturalness |
Natural intertidal and subtidal hard and
soft bottom habitat and marine waters |
Natural intertidal and subtidal hard and
soft bottom habitat and marine waters |
|
Size |
~260 ha |
~278 ha |
|
Diversity |
Moderate |
Moderate |
|
Rarity |
Habitat and species are uncommon in the
northeastern water of Hong Kong.
Species of conservation importance including numerous species of
hermatypic hard coral, ahermatypic cup coral, black coral, and octocoral |
Habitat and species are uncommon in the
northeastern water of Hong Kong.
Species of conservation importance including numerous species of
hermatypic hard coral, ahermatypic cup coral, black coral, and octocoral |
|
Re-creatability |
Not re-creatable |
Not re-creatable |
|
Fragmentation |
Unfragmented |
Unfragmented |
|
Ecological Linkage |
Linked to the intertidal and subtidal
habitats |
Linked to the intertidal and subtidal habitats. |
|
Potential Value |
Already designated as marine park |
Already designated as a SSSI |
|
Nursery / Breeding Area |
Nursery grounds for juvenile of fishes and
other marine invertebrates |
Nursery grounds for juvenile of fishes and
other marine invertebrates |
|
Age |
Designated as marine park in July 1996 |
Designated as SSSI in January 1989 |
|
Abundance |
Historically high abundance of hard
coral. Old coral colonies and regarded
as location of considerable carbonate accumulation |
Historically high abundance of hard coral. Old coral colonies and regarded as location
of considerable carbonate accumulation |
|
Ecological
Importance |
High |
High |
Table 4.6 Ecological Importance of Intertidal Habitats within and in the vicinity of the Project site
|
Criteria |
Soft Bottom Intertidal Habitat |
Hard Bottom Intertidal Habitat |
Artificial Intertidal Habitat |
|
Naturalness |
Natural habitat |
Natural habitat |
Artificial |
|
Size |
Small, only small patches of sandy shore recorded |
Large, majority of the shoreline within and in the vicinity of the Project site |
Small, comprise of small piers and seawall |
|
Diversity |
Low |
High |
Low |
|
Rarity |
Ghost crab (Ocypode cordimana,
previously known as Ocypode cordimanus),
oligochaete worms (Heronidrilus bihamis) and fiddler crabs (Uca lactea) were recorded. No rare species found |
Common rocky shore flora and fauna were recorded e.g. bivalve Perna viridis, and short-spined sea
urchin Heliocidaris crassispina |
Not surveyed in the literature reviewed, it is assumed that the
assemblages comprise common
and widespread intertidal species in Hong Kong like Barnacle Balanus amphitrite, Bivalve Grafrarium
pectinatum, and snails Nassarius
festivus, Monodonta labio, Batillaria multiformis, B. zonalis |
|
Re-creatability |
Re-creatable; substrata may be re-colonised by intertidal and subtidal
organisms |
Not re-creatable |
Re-creatable; substrata may be re-colonised by intertidal and subtidal
organisms |
|
Fragmentation |
Fragmented |
Unfragmented |
Fragmented |
|
Ecological Linkage |
Not functionally linked to any high value habitat in a significant way |
Not functionally linked to any high value habitat in a significant way |
Not functionally linked to any high value habitat in a significant way |
|
Potential Value |
Unlikely to become an area of conservation value |
Unlikely to become an area of conservation value |
Unlikely to become an area of conservation value |
|
Nursery / Breeding Area |
No significant records identified |
No significant records identified |
No significant records identified |
|
Age |
N/A |
N/A |
N/A |
|
Abundance |
Lower abundance compared to natural rocky shore habitat |
Low abundance |
Lower abundance compared to natural rocky shore habitat |
|
Ecological
Importance |
Low |
Low |
Low |
Table 4.7 Ecological Importance of Subtidal Hard-Bottom Habitats within and in the vicinity of the Project site
|
Criteria |
West of Tap Mun |
Hoi Ha Wan
Marine Park and SSSI |
West of
Port Island |
Mirs
Bay |
|
Naturalness |
Natural |
Natural |
Natural |
Natural |
|
Size |
Large. The natural rocky shore at Outer tap Mun is
about 1.5 km in length. |
~260 ha for marine park and 278 ha for SSSI |
Large. The natural rocky shore at the West of Port
island is about 1 km in length. |
Large. About 4.8 km across waters between Kung Chau and Nam She Wan. |
|
Diversity |
Low to Moderate |
High |
Low
to Moderate |
Moderate |
|
Rarity |
Assemblages mainly comprise typical
common and widespread species in Hong Kong.
Coral communities of high ecological concern were not identified
within and in the vicinity of this site |
Habitat and species are uncommon in the
northeastern water of Hong Kong.
Species of conservation importance including numerous species of
hermatypic hard coral, ahermatypic cup coral, black coral, and octocoral |
Assemblages is
considered to mainly comprise typical common and widespread species in Hong
Kong, except Montipora mollis |
Assemblages comprise typical common and widespread species in Hong
Kong, except for some uncommon coral species
identified. Coral communities of high
ecological concern identified at Nam She Wan |
|
Re-creatability |
Not re-creatable |
Not re-creatable |
Not
re-creatable |
Not re-creatable |
|
Fragmentation |
Unfragmented |
Unfragmented |
Unfragmented |
Unfragmented |
|
Ecological Linkage |
Not functionally linked to any high value habitat in a significant way |
Not functionally linked to any high value habitat
in a significant way |
Not functionally linked to any high value
habitat in a significant way |
Functionally linked to amphioxus habitat at Nam She Wan |
|
Potential Value |
One particular site at the mid of
west shore of Tap Mun has higher hard coral coverage which exhibit higher
ecological value |
Already designated as marine park and SSSI |
Habitat has some potential value for a few
uncommon coral species |
Habitat is relatively undisturbed which might exhibit some potential
value. |
|
Nursery / Breeding Area |
No significant records identified |
Nursery grounds for juvenile of fishes and other marine
invertebrates |
No significant records identified |
No significant records identified |
|
Age |
N/A |
Designated as marine park in July 1996 and as
SSSI in January 1989 |
N/A |
N/A |
|
Abundance |
Low coverage of coral is present in
general, except at the mid of west shore of Tap Mun where higher coral
coverage was recorded |
Historically high abundance of hard coral. Old
coral colonies and regarded as location of considerable carbonate
accumulation |
Moderate to high hard coral cover was recorded in literatures, however, low coverage of coral is recorded in recent
studies |
Low coverage of coral is present in general with higher coral coverage
identified near shores at Nam She Wan |
|
Ecological
Importance |
Low to Moderate |
High |
Low to Moderate |
Low to Moderate |
Table
4.8 Ecological
Importance of Subtidal Soft Benthos Assemblages within the Project site
|
Criteria |
Outer Tap Mun |
|
Naturalness |
Natural |
|
Size |
~55 ha |
|
Diversity |
Low |
|
Rarity |
The assemblages are typical of similar habitats in the Hong Kong
waters, which are dominated by polychaetes
|
|
Re-creatability |
Re-creatable; substrata may be recolonised by benthic organisms |
|
Fragmentation |
Unfragmented. |
|
Ecological Linkage |
Not functionally linked to any high value habitat in a significant way |
|
Potential Value |
It is unlikely that the habitat could develop conservation importance |
|
Nursery / Breeding Area |
No significant records identified |
|
Age |
N/A |
|
Abundance |
In comparison to other parts of the eastern waters the assemblages are
of low to moderate abundance and biomass |
|
Ecological
Importance |
Low |
Table 4.9 Ecological Importance of Marine Waters
|
Criteria |
Waters in Outer Tap Mun and in the vicinity |
|
Naturalness |
Natural |
|
Size |
~55 ha |
|
Diversity |
Potential sighting of FP but rarely present |
|
Rarity |
FP is a resident species in Hong Kong. Commonly observed in eastern waters
but not in northeastern waters of Hong Kong |
|
Re-creatability |
Not re-creatable |
|
Fragmentation |
Unfragmented. |
|
Ecological Linkage |
Linked to FP and marine habitat nearby |
|
Potential Value |
It is unlikely that the habitat could develop conservation importance |
|
Nursery / Breeding Area |
No significant records identified |
|
Age |
N/A |
|
Abundance |
Very low density of FP in comparison to other waters of Hong Kong |
|
Ecological
Importance |
Low |
In accordance with EIAO-TM Annex 8 criteria, an
evaluation of species of conservation importance recorded from the Assessment
Area is presented in Table 4.10.
Table 4.10 Species of Conservation Importance within the Assessment Area
|
Common Name |
Scientific Name |
Protection Status |
Distribution, Rarity and Other Notes |
Literature |
Surveys |
Recorded Location |
|
Hard
Corals (>40 spp.) |
Duncanopsammia peltata Oulastrea crispata Porites sp., etc. |
Protection of
Endangered Species of Animals and Plants Ordinance (Cap.586) |
Common
and widely distributed in the eastern waters of Hong Kong |
ü |
ü |
In the vicinity of the Project site at
the western coastline of Tap Mun and throughout northeastern waters of
Hong Kong, such as Port Island located at ~2 km from the Project site |
|
Black
corals |
Antipathes curvata, Cirripathes sinensis, Antipathes sp., Cirripathes sp. |
Protection of
Endangered Species of Animals and Plants Ordinance (Cap.586) |
Common
but sparsely distributed in the north-eastern waters of Hong Kong |
ü |
ü |
One
species is recorded in the vicinity of the Project site and one species is
recorded at Mirs Bay. Mostly present
throughout the northeastern waters of Hong Kong, e.g. Port Island, Fung Wong
Wat, Gruff Head |
|
Cup
corals |
Balanophyllia sp. |
Protection of
Endangered Species of Animals and Plants Ordinance (Cap.586) |
Common
and widely distributed in the Hong Kong, especially in western waters |
ü |
|
In
the vicinity of the Project site |
|
Amphioxus |
Branchiostoma belcheri |
Listed as “Grade
II National Key Protected Species” in China Listed as
“Endangered” in the China Species Red List |
Recorded
from across Hong Kong waters, but major records were found in eastern waters |
ü |
|
Mostly
present within Hong Kong’s eastern waters, present more than >3 km from
the Project site, including Nam She Wan and Tai Long Wan |
|
Seagrass |
Halophila minor |
Considered
as important habitats in Environmental Impact Assessment Ordinance |
Uncommon
/ rare in Hong Kong |
ü |
|
Mainly
in To Kwa Peng, ~4.3 km from Project site |
|
White-bellied Sea Eagle |
Haliaeetus
leucogaster |
Listed
in Wild Animals Protection Ordinance (Cap. 170) Listed
in Protection of Endangered Species of Animals and Plants Ordinance (Cap.
586) Class II
Protected Animal of PRC Listed as
Regional Concern in Fellowes et al. (2002) |
Uncommon resident. Widely distributed in coastal
areas throughout Hong Kong |
ü |
|
Port
Island, ~2.7 km away from the Project
site |
Based on the review of available
information within the Assessment Area, marine ecological sensitive receivers
have been identified in accordance with the EIAO-TM
criteria. These sensitive receivers and
their distance from the Project site are listed in Table 4.11. Locations
of sensitive receivers can be referred to Figure 4A.2.1 of Appendix 4A.
Table 4.11 Approximate Shortest Distance to Marine Ecological Sensitive Receivers (SRs) around the Project site
|
|
Name |
Shortest Separation
(Geodesic) Distance (km) |
|
Corals |
Port Island (CR3) |
2.0 |
|
Wong Wan Tsai (CR8) |
4.7 |
|
|
Fung Wong Wat (CR9) |
4.0 |
|
|
Gruff Head (CR10) |
3.0 |
|
|
South Wong Wan Tsui (CR11) |
3.1 |
|
|
Wong Chuk Kok Tsui (CR12) |
3.5 |
|
|
Hoi Ha Wan Moon Island (CR13) |
1.5 |
|
|
Hoi Ha Wan Coral Beach (CR14) |
1.7 |
|
|
Heung Lo Kok (CR16) |
2.4 |
|
|
Mangrove Stand / Intertidal Habitat |
Fung Wong Wat (M5) |
4.5 |
|
Hoi Ha Wan (M6) |
2.6 |
|
|
Tai Tan (M7) |
3.3 |
|
|
To Kwa Peng (M8) |
4.3 |
|
|
Chek Keng (M9) |
4.5 |
|
|
Designated Marine Park |
Hoi Ha Wan Marine Park and Artificial Reef
within the Marine Park (MP2) |
0.7 |
|
Artificial Reef |
Long Harbour (AR1-AR6) |
0.7 |
|
Designated SSSI |
Hoi Ha Wan SSSI (SSSI1) |
0.7 |
The Method Statement on Marine
Ecological Impact Assessment for Outer Tap Mun Fish Culture Zone under this
assignment was approved on 12 October 2020 and is presented in Appendix 4B. A desktop literature
review and supporting field surveys were conducted in order to establish the
ecological profile of the area within and surrounding the Project. The
importance of potentially-impacted marine ecological resources identified
within the Assessment Areas was evaluated using the methodology defined in the EIAO-TM.
Potential
impacts to these resources due to the construction and operation of the Project
were assessed (following the EIAO-TM Annex 16 guidelines) and the
impacts evaluated (based on the criteria in EIAO-TM Annex 8). Findings of water quality modelling are used,
where appropriate, to assess potential impacts on the identified marine
ecological resources.
The
construction of the proposed Project will mainly involve the setup of fish farm
structures, including fish rafts / cages, auxiliary facilities and mooring
system. No dredging work is required
during the construction phase.
The scale
of construction work on-site is relatively small. Main components of the rafts / cages are
manufactured off-site and will be towed to the Project site using tug
boat. On-site assembly and anchoring of
the fish rafts / cages will be assisted by a small number of marine vessels
such as sampans and small speed boats for up to a few trips per day. Anchoring of these vessels might be
required. No heavy construction plant
would be used. Fish rafts / cages and
auxiliary facilities, such as storage space and shelters, would be positioned
by anchor lines attaching to the anchorage points on the seabed. Use of winch might be required during the
assembly and anchorage of fish rafts / cages.
All construction activities shall be conducted during daylight hours.
Potential impacts
to marine ecological resources arising from these works may be divided into
those related to:
n
Disturbance of marine habitats; and
n
Underwater sound from marine
construction activities and marine vessels.
Direct impacts to
marine ecology include disturbance caused by assembly and installation
activities on-site. The installation of fish farm structures are expected
to be completed within a few weeks for each fish raft, and would
cause temporary disturbance to marine habitats, such as marine waters with an
area of approximately 55 ha and small area of benthic habitats. Fish farm structures, such as fish cages will
occupy a section of the water column and the disturbance of seabed due to the anchorage
of fish farm structures will be confined to a thin
surface layer (<0.5 m) within a small area.
It should be noted that only a small number of vessels will be used and
the frequency / trip of these vessels would also be relatively low. No disturbance to other marine
ecological sensitive receivers, including HHWMP which
is located ~0.7 km away, is expected.
Within the Project site,
the seabed composition was found to mainly consist of silty mud without any
hard substrate with benthic assemblages dominated by polychaete
worms and characterised by similar species diversity and biomass as elsewhere
in Hong Kong. Species of
conservation importance, such as amphioxus, marine mammals and horseshoe crabs
were not observed within the Project site.
The overall coral coverage within and in the vicinity of the Project
site is considered to be low to moderate and other species recorded are
considered to occur frequently in Hong Kong.
Overall, the subtidal habitats within the Project
site were considered as of low ecological importance. Similar habitats are present in
the surrounding areas and the disturbance would represent a very small fraction
of the widely available habitat.
Considering
the temporary nature of the disturbance (a few weeks for each fish raft /
cage), the small extent of area affected and low ecological importance of the
affected area, impacts are considered to be of minor significance and
unacceptable impacts on marine ecological resources are not expected. Marine
ecological resources are expected to return to the area following the cessation
of fish farm construction activities.
Construction activities, such as during the assembly of fish raft, would
generate noise, glare and dust which may affect marine ecology. Potential impacts to marine life, mostly fish
species, would include temporary avoidance of areas in the vicinity of works
area or close to the source of disturbance. Considering the temporary nature of
the construction works, impacts from the generation of noise, glare and dust on
marine habitats are considered negligible, and unacceptable impacts on the
marine ecological resources are not anticipated. Major lighting sources will be pointed inward
and downwards to avoid disturbance to wildlife, unacceptable impacts on the
marine ecological resources are not anticipated.
Intermittent sounds, which occur during assembly
and installation activities on-site and marine vessel movement, may have an impact on marine
ecological resources. Potential effects
of increased underwater sound include physiological stress, avoidance and
injury (at high pressure levels). The
level of impact is however dependent upon background sound, number and type of
species affected, proximity of organism to the sound source, attenuation
properties of seabed sediments and hearing capabilities of the species
affected, etc.
Most marine invertebrates do not possess air-filled space
and thus it is generally considered that sound would have limited physiological
or behavioural effects on marine invertebrates, except if they are located
within a few metres of the sound source.
Therefore, underwater sound generated from marine works is expected to
have negligible impact on marine invertebrates in the Assessment Area.
The impact of underwater sound generation from
construction activities on fish is highly depended upon the hearing
capabilities of the different species present in the area, with the hearing
specialists being of greatest concern.
The significance of these effects is dependent upon the proximity of
fish to the sound source. Considering
that a small number of marine vessels would be present temporarily at the
Project site during fish farm construction, fish species that are sensitive to
the generation of sound are likely to instinctively avoid the area once works
commence and would be temporarily displaced to other areas where similar
habitat conditions are present.
Fishes are
expected to return to the area following the cessation of fish farm
construction activities.
Waters within the Assessment Area
and its vicinity is subject to moderate to high levels of marine traffic by
similar types of vessels. It is
reasonable to assume that marine organisms are habituated to background level
of underwater sound, and a small increase in vessel activity associated with the
construction of this Project is not anticipated to result in unacceptable
impacts on marine organisms at and in the vicinity of the Project site. Overall, unacceptable impacts on marine
ecological resources are not expected.
Mariculture
activities, such as management of fish raft / cages and fish stocks within the
Project site will be undertaken during operational phase. Limited numbers of small power generators
will be used on fish rafts to support daily mariculture activities. The transportation of fish stocks, fish feed,
fish raft equipment and workforce as well as occasional visitors will make use
of mainly small marine vessels such as sampans and speed boats for a few trips
a day. No maintenance dredging or
sediment removal is anticipated during FCZ operation. All operation activities shall be conducted
during daylight hours. The potential
impacts on marine ecology of the Assessment Area include:
n
Changes in marine habitats (marine
waters and benthic habitat);
n
Temporary relocation of rafts under
typhoons or algal blooms;
n
Underwater sound from daily
operations and marine vessels;
n
Perturbations to key water quality
parameters during fish farm
operation, including fish feed wastage, fish excretion and dead fish; and
n
Introduction of invasive species.
As
discussed in Section 4.5.1.1, the fish farm structures will not fully occupy
all of the Project site area but mainly a section of the water column and a
small area of seabed confined to a thin surface
layer (<0.5 m), the area of marine ecological habitat affected is
<55 ha. The small extent of area affected which is of low ecological importance,
impacts are considered to be of minor significance and unacceptable impacts on
marine ecological resources are not expected.
Fish rafts
/ cages and anchoring equipment would provide hard substrate for the settlement
of epifaunal organisms that would not otherwise be successful in colonising the
area. Where permitted, colonisation of
the structures over time is expected to lead to the development of a marine
fouling community. Effects associated
with creation of artificial habitat may include increased biological
productivity and increased diversity of habitats. Overall, the structures of the fish farm are
expected to result in potential positive effect on marine ecological resources
of the waters within and in the vicinity of the Project site.
All the
fish rafts / cages will be floating with permeable nets to allow water
exchanges with the marine environment.
Consequently, it is predicted that no unacceptable changes in
hydrodynamics will occur.
Operational
activities, such as cleaning of
fish cages and the use of lighting, would generate noise, glare and dust
which may affect marine ecology.
Potential impacts to marine life, mostly fish species, would include
temporary avoidance of areas in the vicinity of works area or close to the
source of disturbance. Considering the temporary nature of the cleaning
activities, impacts from the generation of noise, glare and dust on marine
habitats are considered negligible, and unacceptable impacts on the marine
ecological resources are not anticipated.
Major lighting sources will be pointed inward and downwards to avoid
disturbance to wildlife, unacceptable impacts on the marine ecological
resources are not anticipated.
In general,
relocation of fish rafts adopting advanced mariculture technologies are not necessary
under adverse weather (e.g. typhoon) given the framework of fish cages would
use weather-resistant and durable materials (e.g. HDPE cages, steel truss
cages). For other potential
circumstances (e.g. red tide event, outbreak of fish disease), the licensees
will review the need of fish raft relocation and propose the fish raft
relocation plan as necessary for agreement with AFCD on a case-by-case basis,
depending on the type of algal bloom (any toxicity to fish), expected duration
of such circumstances, feasibility for early harvesting of fish stock,
feasibility of implementing onsite control measures etc. In case fish raft relocation is considered
necessary, the fish rafts will be relocated away from the areas of
circumstances, avoid marine fairways and utilities and at some distance away
from ecological and fisheries sensitive receivers (e.g. about 200 m away from
established coral communities) to minimise potential impacts to these sensitive
receivers. Such relocation will be
temporary (e.g. a few weeks) and the fish rafts will return to the Project site
upon the cease of the circumstances. The
mobilisation of the fish rafts will cause temporary disturbance to marine
habitat. Increased operation of marine
vessels will occur due to the towing of fish rafts to the new location, and the
re-anchoring of fish rafts will cause temporary disturbance to the water column
and seabed. The corresponding impacts
would be similar to those occurred in the construction phase (Section
4.5.1). Overall, impacts are considered to be of minor significance and unacceptable
impacts on marine ecological resources are not expected.
Operation of the fish farm would produce underwater sound from the
management of fish rafts / cages and fish stocks, and operation of marine
vessels. The daily operations of mainly
small marine vessels, such as sampans or speed boats would be temporary which
the underwater sound characteristics of these vessels are similar to the operations
at Tap Mun FCZ and marine traffic at ferry routes nearby. Marine organisms in these waters are
habituated to the background level of underwater sound, and a small increase in
mariculture and vessel activities associated with the operation of this Project
are not anticipated to result in unacceptable impacts on marine ecological
resources and also marine habitats within HHWMP which is located ~0.7 km away.
Mariculture activities would
result in an increase in water quality pollutants primarily
from fish feed, feed wastage, fish excretion and dead fish. The increase in pollution load would affect the water quality in the receiving waters and the potential impacts on marine ecological resources are as follows:
n
Suspended solids (SS)
dispersion;
n
Dissolved oxygen (DO)
depletion; and
n
Elevated nutrient levels.
To estimate the impacts on marine ecological
sensitive receivers of the Assessment Area, computer modelling of changes in water quality were conducted under two scenarios:
n
Baseline scenario, which covered
the “without-project” condition in 2023; and
n
Project scenario, which took
into account the additional pollution load from the mariculture activities at
the Project site, as well as the other nearby proposed new fish culture zones
at Outer Tap Mun and Mirs Bay (each at their carrying capacity).
Relevant assessment criteria, i.e. Water Quality
Objectives (WQOs) in the Mirs Bay and Tolo Harbour and Channel WCZs, were then
used to assess potential impacts on marine ecological resources.
Fish farm operation are expected to generate SS within
the water column as a result of fish feed, fish feed wastage and fish
excretion, contributing to an increase in sediment deposition in close
proximity of the Project site.
The water quality modelling results have indicated
that at all marine ecological sensitive receivers, SS elevations as a result of
fish farm operation are predicted to be compliant with the relevant WQOs for
both wet and dry seasons. Impacts to
subtidal assemblages, such as fish, corals and benthic assemblages within and
in the vicinity of the Project site are expected to occur temporarily as the
modeling results indicate that the mariculture activities would only result in
short-term, localised elevations of SS.
The habitats affected are expected to be generally confined to the
Project site and subtidal assemblages in proximity to the Project site are
considered to be of low ecological value.
As the areas affected are predicted to have limited or no change of SS
levels between baseline and project scenarios, organisms are expected to be
exposed under similar environmental conditions as the fish farm operates. Based on the assumption that eventually the
affected areas will be recolonised by fauna typical of the area, the temporary
impact on these low ecological assemblages is not considered to be
unacceptable. Unacceptable impacts to
ecological assemblages, including species of conservation importance such as
amphioxus, marine mammals and horseshoe crabs, if present in the vicinity of
the Project site arising from elevated SS levels are not anticipated. Other marine ecological sensitive receivers
are predicted to be unaffected (as defined by the WQO and tolerance criterion).
With the fish farm standing stock kept within the
Project site’s maximum carrying capacity and the use of pellet feed within fish
farms, potential impacts to marine ecological resources will be well
managed. The Project site only occupies
a very small proportion of the habitats and supported ecological assemblages of
low ecological value, whereas areas which supported marine ecological resources
of moderate to high values are recorded at HHWMP which is located at ~0.7 km
from the Project site. Consequently,
unacceptable impacts on marine ecological resources are not expected to occur.
The relationships between SS and DO are complex, with
elevated SS in the water column together with a number of other factors to
reduce DO concentrations. Elevated SS
(and turbidity) reduces light penetration, lowers the rate of photosynthesis by
phytoplankton (i.e. primary productivity) and thus lowers the rate of oxygen
production in the water column.
Furthermore, the decomposition of organic matter in fish feed, fish
excretion and dead fish in the water column may consume DO in the receiving
waters. The resulting overall DO
depletion has the potential to cause an adverse effect on marine organisms,
especially to sessile organisms, such as corals, which cannot escape from the
hypoxia zone and could potentially cause mortality.
The water quality modelling results have indicated that DO
depletion associated with fish farm operation are predicted to be low and
remain compliant with the relevant WQO DO criteria at all marine ecological
sensitive receivers. Lower DO levels
recorded at the northern areas are likely a result of relatively high pollution
loading from dry weather load and treated sewage effluent from the Starling
Inlet (also known as Sha Tau Kok Hoi), as well as pollution load from Yantian area
of Guangdong. In general, the levels of DO are predicted to remain rather
stable in the Long Harbour embayment with and without fish farm operation. Outside of the Long Harbour embayment, no
unacceptable change in DO level is predicted at other marine ecological
sensitive receivers in both baseline and project scenarios.
Overall, there is limited change in the predicted DO levels
at baseline and project scenarios and unacceptable impacts to marine ecological
resources are not expected to occur.
High levels of nutrients released from fish feeds,
fish excretion and dead fish to the water column may potentially cause rapid
increases in phytoplankton population, on occasions to the point that an algal
bloom occurs. An intense bloom of algae can lead to sharp decreases
in the levels of DO. This decrease will initially occur in the
surface water, and then spread to deeper waters as dead algae fall through the
water column and decompose on the seabed. Anoxic conditions may result
if DO concentrations are already low or are not replenished. This
may result in mortality of marine organisms due to oxygen deprivation.
The water quality modelling results have indicated
that the levels of nutrients as a result of fish farm operation are expected to
be low in general within the Assessment Area.
Predicted levels of Total Inorganic Nitrogen (TIN) and unionized ammonia
at the Project site and all marine ecological sensitive receivers are below the
corresponding assessment criterion.
Overall, the increased levels of nutrients in the water column as a
result of fish farm operation are considered to be of minor significance and
unacceptable impacts to marine ecological resources are not expected to occur.
Chlorophyll-a
is a photosynthetic pigment of phytoplankton and is commonly used as a direct
indicator of algal biomass. As mentioned
above, increased levels of phytoplankton due to nutrients released from fish
farms could potentially trigger algal blooms, in which could reduce DO levels
in the water column and result in mortality of marine organisms.
The water
quality modelling results have indicated that the levels of chlorophyll-a vary
spatially across the Assessment Area and are generally higher at the surface
level and areas with shallower water depth.
The predicted change of chlorophyll-a levels
between baseline and project scenarios at the Project site and all other marine ecological sensitive receivers within
the Assessment Area is limited and below the corresponding assessment
criterion. Therefore, fish farm
operation is not expected to result in significant increase of chlorophyll-a
and unacceptable impacts to marine ecological resources are not expected to
occur.
The new fish stocks to the Project site will have
potential risks in introducing invasive species to the marine environment if
invasive species are cultivated and escaped from the fish farms. Invasive species may result in increased
biological interactions (e.g. competition and predation) with native marine
species, and therefore may pose threats to the local marine biodiversity.
Regular
maintenance of fish farm equipment, typically the condition of fish cages and
fish nets would be performed by the fish farm owner, to minimise the potential
risk of fish escape to the nearby marine environment. Details of these operation measures and
practices are presented in Appendix 2A.
Upon implementation of these measures, unacceptable
impacts on the marine ecological resources are not anticipated.
Based upon the information presented in Section
4.5, the significance of marine ecological impacts associated with the
construction and operation of the Project has been evaluated in accordance with
the EIAO-TM (Annex 8,
Table1). The outcomes of this
evaluation are summarised in Table 4.12.
Table 4.12 Significance of Marine Ecological Impacts Associated with the Construction and Operation of the Project Evaluated in accordance with EIAO-TM
|
Potential
Impact |
Source |
Receiver |
Nature
of Impact |
Overall
Impact Significance |
Mitigation
/ Precautionary Measures Required |
|||||
|
Habitat Quality |
Species Affected |
Size |
Duration |
Reversibility |
Magnitude |
|||||
|
Construction phase |
||||||||||
|
Habitat
disturbance |
Construction of fish farm structures (including the production of noise, glare and dust). |
Marine waters and benthic habitats within and in
the vicinity of the Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
All of the Project site (~55 ha). |
Temporary and short term (a few weeks) in the
active works area |
Reversible |
Small |
Minor |
No |
|
Underwater sound |
Construction of fish farm structures and marine vessels. |
Marine
waters within and in the vicinity of the Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
Localised to sound-generating activities, e.g. assembly of fish rafts,
installation of mooring system, marine vessels. |
Temporary and short-term (a few weeks) in the
active works area. |
Reversible |
Small |
Minor |
No |
|
HHWMP |
High |
Rare and
common fish species. |
Localised to sound-generating activities, e.g. assembly of fish rafts,
installation of mooring system, marine vessels; mostly affect area near the marine park
boundary. |
Temporary
and short term (a few weeks) in the active works area |
Reversible |
Small |
Minor |
No |
||
|
Operation phase |
||||||||||
|
Changes in
marine habitat |
Fish farm operational activities (including the production of noise, glare and dust). |
Marine
waters and benthic habitat within and in the vicinity of the Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
Localised to the vicinity of fish farm structures (<55 ha). |
Long-term over Project duration |
Reversible |
Small |
Minor |
No |
|
Temporary
relocation of fish rafts / cages |
Fish farm |
Marine waters and benthic habitats within and in
the vicinity of the Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
Localised to the immediate vicinity of the area
of fish rafts / cages relocation. |
Temporary |
Reversible |
Small |
Minor |
The
licensees will review the need of fish raft relocation and propose the fish
raft relocation plan as necessary for agreement with AFCD. |
|
Underwater sound |
Operational activities of fish farm and marine vessels |
Marine waters within and in the vicinity of the
Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
Localised to the immediate vicinity of the
sound-generating activities e.g. maintenance of the fish cages and marine
vessel movement. |
Long-term over Project duration but reversible. |
Reversible |
Small |
Minor |
No |
|
HHWMP |
High |
Rare and
common fish species |
Localised to the immediate vicinity of the sound-generating activities
e.g. marine vessel movement; potential affect areas near the marine park
boundary. |
Long term over
Project duration but
reversible. |
Reversible |
Small |
Minor |
No |
||
|
Changes in water quality due to fish farm operational activities |
Fish farm operational activities (e.g. fish feed,
fish drugs, waste water, etc.) |
Marine
waters, intertidal natural shores and benthic habitat within and in vicinity
of the Project site. |
Low |
Common fish species and benthic fauna dominated by polychaetes. |
Localised to the vicinity of the fish farm. |
Long-term over Project duration. |
Reversible |
Moderate |
Minor |
Water quality mitigation measures would further reduce impacts. |
|
HHWMP |
High |
Rare and
common fish species and corals |
Localised to the
vicinity of the fish farm;
potentially affect areas near the marine park
boundary. |
Long term over
Project duration. |
Reversible |
Small |
Minor |
Water quality
mitigation measures would further reduce impacts. |
||
|
Introduction of invasive species |
Fish stock in fish farm |
Marine waters within and in vicinity of the
Project site |
Low |
Common fish species. |
Within and in the vicinity of Project site (~55 ha). |
Long-term over Project duration. |
Reversible but with difficulty |
Small |
Minor |
Operation
measures and Practices in Appendix 2A would further reduce
impacts. |
|
HHWMP |
High |
Rare and
common fish species. |
Within the
HHWMP. |
Long-term over
Project duration. |
Reversible but
with difficulty |
Small |
Minor |
Operation
measures and Practices in Appendix 2A would further reduce
impacts. |
||
As there are no other existing or committed
non-FCZ projects identified in the vicinity of the Project site, the Water Quality Impact Assessment
conducted is based on the worst-case scenarios of concurrent operation of all
existing and planned FCZs as sources of pollution. It is expected that all FCZs will be operated
within the maximum carrying capacity and therefore, unacceptable impacts to
water quality are not anticipated.
Consequently, unacceptable cumulative impacts to marine ecological
resources are not predicted to occur.
As
other marine organisms, including amphioxus, marine mammals and horseshoe crabs
are not found within and in the vicinity of the Project site, potential
cumulative impacts on these animals are not anticipated and these impacts are
expected to mainly affect fishes and benthic assemblages if identified. Potential operational impacts
presented in Section 4.5.2 were examined to evaluate potential cumulative
impacts with other operations / developments in the northeastern Hong Kong
waters. Outcomes of this evaluation,
excluding the impact on water quality are summarised as follows:
n
Changes in Marine Habitat: In the
northestern waters, the changes in habitat would
be approximately be 500 ha in total, including the Project site (55 ha), the
proposed Wong Chuk Kok Hoi FCZ (35 ha) and the proposed Mirs Bay FCZ (410
ha). Although the area affected covers a
certain extent of Hong Kong waters, the provision of the proposed FCZs would support more mariculture
operations in Hong Kong and thus providing more fisheries resources to the
local and global fisheries market.
Considering that the marine
ecological resources in the northeastern waters where the Project site is
located are generally regarded as of low ecological value, the overall impacts
are minor, it is unlikely that the
construction of the Project would exert an unacceptable cumulative effect on
the marine environment.
n
Underwater Sound: This Project is located ~0.3 km and 0.9 km away
from Tap Mun FCZ and Kau Lo Wan FCZ respectively, while other existing and
planned FCZs are >2 km away. The
cumulative effect of underwater sound will therefore consider the impact from
the nearby Tap Mun FCZ and Kau Lau Wan FCZ.
For this Project, mainly small marine vessels e.g. sampans and speed
boats operated by fishermen would be used during FCZ operation. The underwater acoustic profiles generated by
works vessels of this Project would therefore be similar to the daily
operations of the nearby Tap Mun and Kau Lau Wan FCZ as well as marine traffic
near the Tap Mun pier. Cumulative
effects of works vessels operational sound, if any, are anticipated to be
negligible. It is not expected to result
in significant cumulative impact to the marine ecological resources within the
Assessment Area.
n
Marine Traffic: This Project is located at sufficient distance from
other FCZs in the vicinity. It is
expected to involve a relatively small number of mainly small marine vessels,
such as sampans and speed boats that travel to and from the Project site during
daily operations. Given that existing
marine traffic is present within Tap Mun from Tap Mun FCZ and nearby ferry
routes, and that the waters off northeastern Hong Kong have moderate levels of
existing marine traffic, such as the ferry route between Ma Liu Shui to Lai Chi
Wo / Kat O and Ma Liu Shui to Tap Mun, the cumulative effects of marine traffic
disturbance to the nearby marine ecological resources are anticipated to be
negligible.
Overall, the
cumulative impacts on marine ecological resources within the Assessment Area are
predicted to be minor and acceptable.
In accordance with the guidelines
in the EIAO-TM on marine ecology impact assessment, the general policy
for mitigating impacts to marine ecological resources, in order of priority,
are:
n
Avoidance:
Potential impacts should be avoided to the maximum extent practicable by
adopting suitable alternatives;
n
Minimisation:
Unavoidable impacts should be minimised by taking appropriate and practicable
measures such as confining works in specific area or season; and
n
Compensation:
The loss of important species and habitats may be provided for elsewhere as
compensation. Enhancement and other
conservation measures should always be considered whenever possible.
To summarise, this assessment of
impacts demonstrates that impacts will largely be avoided and minimised during
the construction and operation of the proposed Project, particularly to the key
marine ecological sensitive receivers, such as corals, mangroves, intertidal
habitats, ARs, nearby marine parks and SSSIs.
Impacts to marine ecological
resources and habitats have largely been avoided and minimised through proper
planning and design of the works. The
Project site is selected to be at a distance from key marine ecological
habitats, such as coral habitats in HHWMP and ARs in Long Harbour, such that
impact to these habitats are avoided.
The construction work of the FCZ is properly designed such that no
dredging work is required. To minimise
the impacts to the vicinity of the Project site, it is designed to have minimal
construction work on site. The scale of
construction work on-site is relatively small, and the number of vessels
operating concurrently are limited to a small number. The installation time of fish farm structures
is minimised and is expected to be completed within a few weeks for each fish
raft which would only cause temporary disturbance to marine ecological
habitat. Main components of the rafts /
cages are manufactured off-site and will be towed to the Project site using tug
boat. On-site assembly and anchoring of
the fish rafts / cages will be mainly assisted by a small number of marine
vessels such as sampans and small speed boats for up to a few trips per
day. No heavy construction plant would
be used. To minimise change of marine
habitat, the fish farm is designed to occupy minimal space which will only
occupy a thin surface layer (<0.5 m) within a small area. These measures are expected to control and
reduce potential impacts to marine ecological resources, and no marine ecology-specific
mitigation measures are thus required during construction.
The mitigation measures proposed to
mitigate water quality impact would also mitigate the potential impact to
marine ecological resources during construction and operation phase. Detail of the relevant mitigation measures
proposed are presented in Section 3.9.
Taking into consideration the impact assessments in
the previous sections and with effective implementation of the proposed
mitigation measures, the significance of residual impacts on marine ecological
sensitive receivers such as marine park (Table 4.12) have been evaluated in
accordance with Annex 8 of the EIAO-TM.
Residual impacts occurring as a result of the proposed Project have been
determined and are discussed as follows:
n
<55 ha of marine ecological
habitat will be affected during operation of the FCZ. While the design of fish
farm will only occupy a section of the water column and a small area of seabed,
with the small extent of affected habitat and the overall low marine ecological
value in the context of surrounding similar habitat, the impact due to the
change in marine habitat is considered to be of minor significance and
acceptable. Furthermore, with the implementation of the proposed mitigation
measures, the potential impact on marine ecological resources will be further
minimised. No unacceptable residual marine ecological impacts during the
construction and operation of the Project are therefore anticipated.
n
In addition, the fish farm
structures, which would provide artificial substrates for forming habitat and
shelter for juveniles or adult fisheries, would provide positive effects on
marine ecological resources within and adjacent to the Project Site.
Overall, the residual impacts of the
Project would be considered to be minor and acceptable.
As no
unacceptable impacts have been predicted to occur during the construction and
operation of this Project, monitoring of marine ecological resources during
these project phases is not considered necessary.
A review of baseline information on marine ecological
resources surrounding the waters of the proposed Project from available
literatures and field surveys has been undertaken, covering the intertidal,
subtidal soft bottom and hard bottom habitats, and marine waters. Results of the review and field surveys
indicated that marine ecological resources in the vicinity to the Project site
are generally regarded as of low ecological value, whereas further afield
habitats and sensitive receivers of ecological value, including the corals and
artificial reefs within existing marine park (i.e. HHWMP) are located at some
distance from the Project site. Species
of conservation importance such as horseshoe crabs and marine mammals are not
reported within the Assessment Area.
During
the construction of the Project, direct impacts arising from the proposed marine
works include disturbance to the marine habitat (i.e. ~55 ha, including the
water column and a small area of seabed confined to
a thin surface layer (<0.5 m)). Considering the temporary nature of the
disturbance and the overall low ecological value of marine ecological resources
at and in the vicinity of the Project site, unacceptable impacts on marine
ecological resources are not expected.
Impact of elevated levels of underwater sound as a result of construction
activities are considered acceptable with the presence of existing underwater
sound from the nearby Tap Mun FCZ, Kau Lau Wan FCZ, as well as nearby ferry
routes. No marine ecological-specific
mitigation measures are required during construction.
During FCZ
operation, there will be changes in marine habitat at the location of fish farm
structures (<55 ha). The structures
mainly occupy a section of the water column and a small area of seabed confined to a thin surface layer (<0.5 m). The presence of fish farm structures will
also provide hard substrates that could be colonised by a variety of marine
organisms and bringing potential positive effect on marine ecological
resources. Considering the relatively
small area affected in the context of surrounding similar habitat and the
overall low marine ecological importance at and in the vicinity of the Project
site, unacceptable impacts on marine ecological resources are not
expected. Potential impacts of elevated
levels of underwater sound generated from the marine vessels in the vicinity of
the Project site are considered acceptable with the presence of existing
underwater sound from the nearby Tap Mun FCZ, Kau Lau Wan FCZ, as well as
nearby ferry routes. Temporary
relocation of fish rafts due to potential circumstances
may occur over a short time, therefore, unacceptable impacts are not
anticipated. Impacts of changes in water
quality arising from FCZ operation are predicted to be largely confined in the
vicinity of the Project site within the maximum carrying capacity. No unacceptable change in water quality is
predicted at all marine ecological sensitive receivers in both baseline and
project scenarios. Impact on the
introduction of invasive species would be considered minor with regular
monitoring of mariculture facilities. No
marine ecology-specific mitigation measures are required during operation.
Overall, no unacceptable impacts to marine ecological resources and species of
conservation importance are expected to occur.
All of the potential construction and operational marine ecological
impacts identified are deemed acceptable.
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NF, Switzer AD, McCorry D, DeVantier L, True JD, Hughen KA, Angeline N, Yang TT
(2011) Coral communities of Hong Kong: long-lived corals in a marginal reef
environment. Marine Ecology Progress Series. 426:185-196.
([8]) Fabricius,
KE, McCorry D (2006) Changes in
octocoral communities and benthic cover along a water quality gradient in the
reefs of Hong Kong. Marine Pollution Bulletin, 52(1), 22–33.
([9]) ERM
(2003) The Proposed Submarine Gas Pipeline From Cheng Tou Jiao Liquefied Natural
Gas Receiving Terminal, Shenzhen to Tai Po Gas Production Plant, Hong Kong. EIA
Study (EIA-089/2003). Prepared for The Hong Kong and China Gas Company Limited.
([10]) Chen Y
(2007) The Ecology and Biology of Amphioxus in Hong Kong. PhD. Thesis. The City
University of Hong Kong.