6.1.1.1 This section of the report identifies and evaluates the nature and extent of potential impacts arising from the construction and operation of the Project on marine ecological resources.

6.2 Environmental Legislation, Policies, Plans, Standards and Criteria

6.2.1.1 This Section makes reference to the following guidelines, standards, documents and the HKSAR Government ordinances and regulations when identifying habitats and species of ecological importance and evaluating ecological impacts:

· Wild Animals Protection Ordinance (Cap. 170)

· Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586)

· Marine Parks Ordinance (Cap. 476) and subsidiary legislation

· Town Planning Ordinance (Cap. 131)

· Hong Kong Planning Standards and Guidelines (HKPSG) Chapter 10

· Environmental Impact Assessment Ordinance (Cap. 499)

· EIAO Guidance Note Nos. 6/2002, 7/2002

· The IUCN Red List of Threatened Species

Wild Animals Protection Ordinance (Cap. 170)

6.2.1.2 Under the Wild Animals Protection Ordinance (Cap. 170), designated wild animals are protected from being hunted, whilst their nests and eggs are protected from injury, destruction and removal. All marine cetaceans and sea turtles are protected under this Ordinance. The Second Schedule of the Ordinance, which lists all the animals protected, was last revised in June 1992.

Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586)

6.2.1.3 The Protection of Endangered Species Animals and Plants Ordinance (Cap. 586) provides protection for certain plant and animal species through regulating the import, introduction from the sea, export, re-export, and possession or control of certain endangered species of animals and plants and parts and derivatives of those species. Certain types of corals are listed in Schedule of the Ordinance, including Blue coral (Heliopora coerulea), Organ pipe corals (family Tubiporidae), Black corals (order Antipatharia), Stony coral (order Scleractinia), Fire corals (family Milleporidae) and Lace corals (family Stylasteridae). The import, export and possession of scheduled corals, no matter dead or living, is restricted.

Marine Parks Ordinance (Cap. 476) and Subsidiary Legislation

6.2.1.4 The Marine Parks Ordinance (Cap. 476) and Subsidiary Legislation allows for designation, control and management of marine parks and marine reserves through regulation of activities therein to protect, conserve and enhance the marine environment for the purposes of nature conservation, education, scientific research and recreation. The Ordinance came into effect on 1 June 1995. The Authority administering marine parks and reserves is the Country and Marine Parks Authority.

Town Planning Ordinance (Cap. 131)

6.2.1.5 The amended Town Planning Ordinance (Cap. 131) provides for the designation of coastal protection areas, Sites of Special Scientific Interest (SSSIs), Conservation Area, Country Park, Green Belt or other specified uses that promote conservation or protection of the environment. The authority responsible for administering the Town Planning Ordinance is the Town Planning Board.

Hong Kong Planning Standards and Guidelines (HKPSG) Chapter 10

6.2.1.6 Chapter 10 of the HKPSG covers planning considerations relevant to conservation. This chapter details the principles of conservation, the conservation of natural landscape and habitats, historic buildings, archaeological sites and other antiquities. It also describes enforcement issues. The appendices list the legislation and administrative controls for conservation, other conservation related measures in Hong Kong and government departments involved in conservation.

Environmental Impact Assessment Ordinance (Cap. 499)

6.2.1.7 Annex 16 of the TM-EIA sets out the general approach and methodology for assessment of ecological impacts arising from a project or proposal, to allow a complete and objective identification, prediction and evaluation of the potential ecological impacts. Annex 8 recommends the criteria that can be used for evaluating habitat and ecological impact.

EIAO Guidance Note Nos. 6/2002, 7/2002

6.2.1.8 EIAO Guidance Note No. 6/2002 clarifies the requirements of ecological assessments under the EIAO. EIAO Guidance Note No. 7/2002 provides general guidelines for conducting ecological baseline surveys in order to fulfill requirements stipulated in the EIAO TM.

The IUCN Red List of Threatened Species

6.2.1.9 The IUCN Red List of Threatened Species is a comprehensive inventory of the global conservation status of plants and animals. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. There are seven Categories of Threat in the IUCN Red List System: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened and Least Concern. A species is listed as threatened if it falls in the Critically Endangered, Endangered or Vulnerable categories.

6.3 Assessment Methodology

6.3.1.1 The Marine Ecological Impact Assessment was conducted in accordance with the Technical Memorandum of Environmental Impact Assessment Ordinance (EIAO TM) Annex 8 and Annex 16.

6.3.1.2 In accordance with the EIA Study Brief, the Assessment Area for the purpose of the Marine Ecological Impact Assessment should be the same as the Assessment Area for Water Quality Impact Assessment, covering Deep Bay, Northwestern and Western Buffer Water Control Zones WCZs. For this EIA study, the ecological characteristics of the Assessment Area were elucidated through a desktop study of literatures. A review of the ecological information of the Assessment Area indicates that the existing data is extensive and comprehensive. The data from the on-going AFCD dolphin monitoring programme will provide detailed Chinese White Dolphin distributional data. For the HATS EEFS (Environmental Protection Department (EPD), 2004), a comprehensive ecological literature review as well as ecological surveys to fill in identified data gaps including juvenile fish sampling (August 2002), subtidal and intertidal survey (October 2002), and coral survey (January 2003), were conducted. Additionally, more recent relevant journals and publication as well as relevant EIA studies are used in this EIA report to supplement the marine ecological baseline information in the Assessment Area. Therefore, no information gap is identified and no further field surveys are considered neccessary for this EIA study. A list of the key relevant literature is presented at the end of this section.

6.4 Description of Environment

6.4.1.1 The ecological baseline condition of the Assessment Area is described below, comprising:

· Benthic community

· Coral community

· Intertidal community

· Marine mammal (Chinese White Dolphin) and Horseshoe crab

· Marine Park, Nature Reserve and Site of Special Scientific Interests (SSSIs)

· Artificial Reefs

6.4.1.2 A location map of the ecological resources within the Assessment Area is shown in Figure 6.1. Photographs of representative habitats and species of conservation interest are shown in Appendix 6.1.

6.4.2 Benthic Community

6.4.2.1 In Agriculture Fisheries, and Conservation Department, (2002), “Consultancy Study on Marine Benthic Communities in Hong Kong” report, polychaete annelids, crustaceans, and bivalves were the most abundant groups recorded in the Assessment Area, comprising of 46.9% polychaeta annelids, 18.2% crustaceans and 11.1% bivalves of the total species. They were well presented components of the soft bottom community (CED, 1995). The common, ubiquitous species included the polychaetes Mediomastus sp., Sigambra hanaokai, Aglaphamus dibranchis, Prionospio malmgreni, Paraprionospio pinnata, Ophiodromus anustifrons, Prionospio ehlersi and Otopsis sp., the crustacean (crab) Neoxenophthalmus obscures, the echinoderm (brittle star) Amphiodia obtecta, and the sipunculan Apionsoma trichocephalus. Some of these species are known to be adapted well to organic pollution. The sampling locations are indicated in Figure 6.2.

6.4.2.2 Most of the sediments in the Assessment Area except the area near the Sha Chau and Lung Kwu Chau Marine Park are composed of very fine sand and silt or clay and are unlikely to provide high interstitial niches for benthic infauna (Shin, 1998). From Wade (1972), a diverse community structure in the tropics, has high values of species richness (d) over 10, diversity (H’) over 3 and evenness (J) over 0.8.

6.4.2.3 Based on AFCD (2002), the Assessment Area generally had d < 10, H’ <2 and J<0.8. Lower species diversity and evenness were found in Deep Bay as compared to the eastern and southern waters. The indices thus reflect the response of benthic communities to local hydrographic or water quality conditions. In Deep Bay, a large variation of salinity is noted owing to the discharge of freshwater outflows from the Shenzhen River, high trawling pressure and influence of the Pearl River (Morton et al., 1996). All these areas are thus relatively environmentally disturbed, leading to lower species diversity and evenness in the benthic communities.

6.4.2.4 According to the survey in the “Consultancy Study on Marine Benthic Communities in Hong Kong”, the Sha Chau and Lung Kwu Chau Marine Park had higher species, individuals and biomass. In summer (species 13-33 per 0.5 m², individuals 66-220 m^-2, biomass 3.66-25.38 g m^-2) and winter (species 52-57 per 0.5 m², individuals 328-484 m^-2, biomass 6.08-9.88 g m^-2). The polychaete Mediomastus californiensis was dominant in both surveys. Other species common in the summer were the polychaete Lumbrineris nagae, Mediomastus sp., Otopsis sp. and Aglaophamus dibranchis, and the bivalve Potamocorbula laevis. In the winter, other polychaetes were also dominant, including Paraprionospio pinnata, Prionospio malmgreni, Prionospio pygmaea, Prionospio sp. and Sigambra sp.. However, no rare and protected benthic species were recorded.

6.4.2.5 With reference to the “Construction of Lung Kwu Chau Jetty EIA Study”, the macro-epifauna comprised larger organisms (typically > 1mm) that tend to live on or in close association with the sediment surface. Trawl surveys were conducted near the Marine Park. A total of 69 invertebrate species were recorded including 19 species of crab and 13 shrimp species and the area was considered biologically diverse. There were also numerous mollusc species present although in accordance with many other studies conducted in the Northwestern waters, there were few echinoderms.

6.4.2.6 The “Permanent Aviation Fuel Facility for Hong Kong International Airport, EIA (2002)” by CED reviewed the findings from “Environmental Monitoring and Auiditing for Contaminated MudPit IV at East Sha Chau by CED (2001a, 2002) in Northwestern WCZ. Macro-infauna invertebrates surveys were carried out in wet seasons only (May and August, 2001). The results showed that in terms of families present, the annelids (~50%), arthropods (~20%) and molluscs (~15%) were the top three dominant families among the total number of identified families. These three families usually comprised the majority of individuals present. However, the infaunal diversity in this study was low H’<2. These results are consistent with the study findings from AFCD (2002). The benthic macroinvertebrate epi-fauna invertebrates survey was carried out in May, 2001 from the “Environmental Monitoring and Auditing for Contaminated Mud Pit IV at East Sha Chau by CED (2002) for the Northwestern WCZ from demersal trawls. Numerous mollusca species, especially gastropod snail and sea slugs (~22%) and crustacean, especially crab (~33%) were the top two dominant species in term of total number of species recorded. However, the diversity is still considered to be low (H’<2) in the Northwestern WCZ which may reflect both the naturally-occurring stressors such as periodic fluctuations in the physico-chemical environment associated with Pearl River run-off and anthropogenic impacts such as trawling pressures.

6.4.2.7 The surveys carried out for the Habour Areas Treatment Scheme Environmental Engineering Feasibility Study (HATS EEFS) (EPD, 2004) provided further information on existing marine benthic community. The Study Area of the HATS EEFS WP9 covered the Western Buffer WCZ. The subtidal benthic field surveys were conducted at Sandy Bay in September and October 2002 and presented in Figure 6.3.

6.4.2.8 A summary of findings from the HATS EEFS is presented below:

· Mollusca was the dominant taxa in terms of abundance in Sandy Bay (Appendix 6.2 refers)

· In terms of biomass (wet weight) (Appendix 6.3 refers), echinoderms were dominated at Sandy Bay (66.2%).

· The relative abundance of the five most dominant species from each site is summarized in Appendix 6.4. Although the sites were different in terms of dominant species, it is very clear that the dominant species from each site belongs to the same trophic levels, either filter feeding epifaunal organisms or infaunal deposit feeders.

· The relative biomass of the five most dominant spcies from each site is summarized in Appendix 6.5. Again, although the sites were different in terms of dominant species, it is very clear that the dominant species from each site belongs to the same trophic level, either filter feeding epifaunal organisms or infaunal deposit feeders.

Community diversity in sampling sites within Western Buffer WCZ

· In order to get a whole picture of community diversity, Appendix 6.6 shows the findings of means for number of individuals, weight of biomass, number of family and genera of each grab and the mean of species diversity (H’) and richness (d) were both around 0.6. The sampling sites within Western Buffer WCZ are considered to have low ecological value and community diversity, based on the criteria from Wade (1972).

· The infaunal benthic community in Sandy Bay is characterized by relatively high abundance, very high biomass, and high biodiversity. The infaunal community is equally represented by common polychaetes, crustaceans and echinoderms in terms of number, but over dominated by echinoderms in terms of biomass. Again, large variation in benthic community structure was detected among stations at this site.

6.4.2.9 A subtial benthic survey was conducted near Ngau Hom Shek and Sheung Pak Nai inside the Deep Bay WCZ in both dry season (October 2001) and wet season (January 2002) for the “Shenzhen Western Corridor EIA Study”. No rare species was found in the samples. Polychaete and phoronida were the two main component fauna in the grab samples collected. Organisms of these two taxa constituted about 90 % of all organisms recorded. The number of species in each sample was low. None of them exceed 10. Diversity index (H') of all six sites in wet and dry seasons ranged from 0.76 to 1.56. In terms of species number and diversity index, the benthic fauna was not diverse. The density of organisms was also low, given that only 618 organisms were found in 36 samples in two samplings.

6.4.2.9 Based on the above, a summary on benthic community baseline condition within the Assessment Area is presented below:

· The benthic community in Northwestern and Western Buffer WCZs generally support low species richness and eveness for benthic invertebrates. Witn an exception in Sandy Bay at the southern end of the Western Buffer WCZ, where supports relatively high abundance and high biomass of benthic invertebrates.

· The Deep Bay WCZ supports low species richness and low diversity of benthic community.

· The dominant species in the Assessment Area are generally polychaetes, mollusca, echinoderms and mullusca in terms of abundance. No rare and protected benthic species recorded. All species are common and widespread in Hong Kong.

· The ecological value of the Assessment Area for benthic community is therefore considered as low.

6.4.3 Coral Community

6.4.3.1 Corals are usually adversely affected by reduced salinity (hyposalinity) and the high levels of suspended solids discharged by the Pearl River (and hence low light penetration). The general absence of many hermatypic corals from the Assessment Area is therefore not unexpected.

6.4.3.2 The coral communities of the Assessment Area are sparse compared to rocky reefs of similar depth and exposure in the higher saline oceanic eastern and southern waters of Hong Kong, although some of ahermatypic cup corals (thought to be Balanophyllia or Phyllangia sp.), pale-blue gorgonian Guaiagorgia, Dendronephthya sp. colonies, isolated sea pens (Virgularia or Pteroides sp.) and one hermatypic coral Oulastrea crispata were recorded in June 2001 in the far eastern Northwestern WCZ. All gorgonians exhibited high partial mortality, as also prevalent in the wider gorgonian populations of Hong Kong generally.

6.4.3.3 According to AFCD surveys for the study of “Ecological Status and Revised Species Records of Hong Kong’s Scleractinian Corals (2004)”, no rare and uncommon coral species were recorded in the Assessment Area. The western waters are not considered as a coral richness hotspot. The turbidity in summer associated with heavy monsoonal rains and the influence of the Pearl River Delta have restricted coral recruitment, growth and reef development. Furthermore, recent trawling pressure has caused coral injuries in these areas.

6.4.3.4 Coral surveys were performed in the Western Buffer WCZ for the HATS EEFS in 2003 at the waters around Sandy Bay and Ap Lei Chau. The areas surveyed for corals are presented in Figure 6.4 and the surveyed coral species list and their conservation status is shown in Appendix 6.7. A summary of the coral communities and their ecological values is presented below:

Ap Lei Chau (in Western Buffer WCZ)

· At Ap Lei Chau, the soft coral coverage is <5%, Echinomuricea spp., and Dendronephthya spp. were the two most common soft coral species. Fourteen species of hard corals were recorded with <5% coverage. Faviids were the most abundant. The survey location at Ap Lei Chau had moderate high hard coral diversity but low in both soft and hard coral coverage.

Sandy Bay Area (in Western Buffer WCZ)

· The Sandy Bay area is a highly disturbed environment with recreated shoreline habitats. From spot-check dives to a maximum depth of 12 metres, both hard coral (14 taxa) and soft coral (5 taxa) were observed from this survey located at Sandy Bay Area. The most ubiquitous taxa were the soft corals Echinomuricea spp. and the bryozoan Schizoporella errata.

· In east Sandy Bay, there was little soft coral cover (<5%) and no hard coral recorded. Only small isolated Echinomuricea colonies were observed. Nine hard corals species were observed in shallow transect with <5% cover. Psammocora superficialis and Porites lobata were the most abundant species and the Faviids were also well represented.

· In west Sandy Bay, at both deep and middle transects, soft corals were present and had a percentage cover 10-50%. Seven genera were recorded with Echinomuricea spp. being dominant. At a shallow depth zone, soft corals were present with a percentage cover <10% with Echinomuricea spp. again being the most abundant taxa; 11 hard coral species with <5% cover of which Faviids were the most abundant hard corals.

· The percentage cover for soft corals in Sandy Bay was low but medium in West Sandy Bay. However the percentage cover for hard corals was low for Sandy Bay Area. The species diversity was low compared with East Lamma.

6.4.3.5 A dive survey was conducted for the “Construction of Lung Kwu Chau, Jetty EIA (2002)” between the period February 2001 and February 2002 at southeast bay of Lung Kwu Chau in side Northwestern Buffer WCZ. It was noted that the waters in the bay were highly turbid making the area especially unsuitable for hermatypic corals. The salinity of marine waters at Lung Kwu Chau was also heavily influenced by discharge from the Pearl River. Common blue coloured gorgonian short seawhip soft coral (Euphexaura sp.) was discovered growing attached to the shipwreck structure past the north of the bay. Also attached to the shipwreck were 2 colonies of the ahermatypic coral Tubastrea sp.. These were both dead. The same blue coloured Euphexaura sp. gorgonians were also observed growing on rusting steel bars in the southern section of the bay of the existing jetty. These colonies were small and numbered only 6 in total. No scleractinian corals were encountered within the bay.

6.4.3.6 Coral community surveys for the “Castle Peak Road Improvement between Area 2 and Ka Loon Tsuen, Tuen Wan Design and Construction Consultancy EIA (2001)” from Highways Department (2001) were conducted in June 2001 along the coastal area in Castle Peak Road near Tsing Lung Tau and Dragon Beach (within Western Buffer WCZ). The results of the surveys are described below:

Sham Tseng (East)

· A species of ahermatypic cup-coral was recorded (positive identification not presently available but thought to be either Balanophyllia or Phyllangia sp.). The percentage cover along transect was low (<1%), and a pale blue gorgonian (Euplexaura sp.) was recorded. Another zooxanthellate scleractinian species Oulastrea crispate was recorded at 2 m depth. The cup coral and octocorals (gorgonians and Dendronephthya spp.) were most abundant at the shallow depths of 2 and 5 m. The very common and widespread gorgonian Echinomuricea sp. was also recorded at 2 m depth. In summary, 2 hard coral species were recorded, Oulastrea crispate and Balanophyllia or Phyllangia sp. which are common and widespread in Hong Kong.

Sham Tseng (West)

· The same hard and octocorals as recorded at the Sham Tseng East Site were also recorded at Sham Tseng West. The abundance was much lower at all depths surveyed. Isolated sea-pens (Virgularia or Pteroeides sp.) were recorded.

Tsing Lung Tau

· An unknown isolated cup-coral was recorded. Pale blue gorgonian Euplexaura sp. was recorded as a common species. Occasional small Dendronephthya sp. colonies, encrusting sponges, the old sea-pen and a colony of the scleractinian species Oulastrea crispate were recorded. To summarize, 2 hard coral species were recorded, Oulastrea crispate and Balanophyllia or Phyllangia sp. which are common and widespread in Hong Kong. There were 3 octocoral species (Euplexaura sp., Dendronephthya sp. and sea pens) present along the coastline.

6.4.3.7 A summary on coral community baseline condition within the Assessment Area is presented below.

· In the Western Buffer WCZ, a few soft coral species were found at Tsing Yi waters nearest to the Stonecutters Island sewage outfall. Further to the south, at Ap Lei Chau and West Lamma (within Sandy Bay Area) a moderate high hard coral species number were recorded reaching 14 taxa. However, the percentage cover was low (<5%). The highest percentage of soft coral cover was recorded from West Lamma (10-50%). Also, both soft and hard coral occurring in low abundance were recorded including Euplexaura sp. and Oulastrea crispate respectively around Sham Tseng and Tsing Lung Tau. No rare species were recorded. In terms of species richness and biodiversity, the ecological value for the coral community in this WCZ is considered as low to moderate.

· In the Northwestern WCZ, corals were only recorded in Sha Chau and Lung Kwu Chau Marine Park. No hard coral was recorded in this Marine Park. Only soft croals were recorded and dominated by common coral species Euphexaura sp.. The number of colony was 6 in total and it was considered to be a low abundance. The ecological value of coral community is considered to be low.

· In the Deep Bay WCZ, the salinity was much reduced and the water was highly turbid under continuous influence of effluent discharged from Pearl River Delta, restricting the coral recruitment. No coral was recorded inside Deep Bay WCZ. There is no ecological value on coral community in the Deep Bay WCZ.

6.4.4 Intertidal Community

6.4.4.1 Intertidal surveys for the HATS EEFS (2004) were conducted at Sandy Bay in September 2002. The study area for HATS EEFS covered the Assessment Area of this EIA Study in the Western Buffer WCZ at Sandy Bay. The survey areas are presented in Figure 6.3. Key relevant findings are presented below.

Sandy Bay (in Western Buffer WCZ)

· In total, 15 species of invertebrates were found in the intertidal rocky zone; with 2 species in high intertidal zone, 9 species in mid intertidal zone and 13 species in low intertidal zone. Among all invertebrates identified, grazing snail N. vidua was the most dominant and made up of 22.2% of total individuals found in the intertidal zones. Other abundant invertebrates include grazing snail N. trochoides (15%), M. labio (10.85%) and limpet S. siria (11.7%) and chiton A. japonica (12.4%) of the total invertebrate individuals. A summary of abundant invertebrates recorded in vertical zonation of intertidal rocky shore will be presented in Table 6.4.1.

Table 6.4.1 The vertical zonation of abundant invertebrates recorded in Sandy Bay intertidal rocky shore

Vertical Zonation	Dominant Species in terms of abundance
High Intertidal Zone	N. trochoides N. vidua
Mid Intertidal Zone	M. labio Siphonaria siria N. vidua
Low Intertidal Zone	Cellana grata S. siria A. japonica Patelloida pygmaea

6.4.4.2 Morton and Morton (1983) suggested that common ‘biofouling’ organisms previously recorded on artificial seawalls and wharfs in Hong Kong include barnacles (Tetraclita squamosa, Capitulum mitella and Balanus amphitrite), polychaete tube-worms (Hydroides elegans, Spirobis foraminosus), mussels and oysters (Perna viridis, Septifer virgatus, Saccostrea cucullata), bryozoans (Bugula neritina), ascidians (Ascidia sydneiensis, Ciona intestinalis, Styela plicata) and various macro-algae (Ulva fasciata, Enteromorpha prolifera, Codium cylindricum, Colpomenia sinuosa).

6.4.4.3 Almost all the recorded species in HATS EEFS (2004) were herbivorous grazers and filter feeders in intertidal rocky shore. The artificial seawall supported the bio-fouling species. Most of the species recorded in HATS EEFS (2004) were common and widespread in Hong Kong rocky shores and no rare species were recorded.

6.4.4.4 Information on intertidal shores in the Western Buffer WCZ is available from the “Improvement to Castle Peak Road between Ka Loon Tsuen and Siu Lam, EIA (2001)” are highlighted below:

· The coastal waters near Tai Lam Chung were low in salinity with moderately wave exposure (Morton and Morton, 1983). The marine ecological habitats in the study area are categorized into natural boulder coast, artificial seawall and beach. The artificial seawall was mainly located between Siu Lam and area near Ka Loon Tsuen, while the natural boulder coastline and sandy beach were located in Ka Loon Tsuen. Field surveys were conducted on the natural boulder coastline and the artificial seawall at Ka Loon Tsuen in May 2000.

Natural Boulder Coastline

· The natural boulder coastline is a typical sheltered rocky shore with little exposure to strong-waves. The field survey indicated that the assemblages were of sheltered shore communities with high quantities of winkles, Nodilittorina radiata, dominating the lower shore. Other intertidal species including common whelk, Thais spp., limpet, Cellana toreuma, smooth limpet, Notoacmea spp., false limpet, Siphonaria spp. and barnacles Tetraclita japonica were recorded. No rare species was recorded in the survey.

Artificial Seawall

· The artificial seawall had been constructed over 20 years and small marine fauna had colonized along this old reclaimed sea-edge (Highways Department, 1996). Species composition was identified at the artificial seawall in Ka Loon Tsuen. The field survey indicated that the assemblages were of moderate exposed rocky shore communities with high quantities of Littoriaria articulata dominating the higher shore and Monodonta spp. dominating the lower shore. Other intertidal species included Nodilittorina radiata, Cellana toreuma, Notoacmea spp., Nerita albicilla and Thais spp..

Beach

· Species composition was identified at the beach in Ka Loon Tsuen. Five cores (diameter about 10cm, length about 40cm) were sampled at high and low shores. The samples were sieved and stained with rose bengal. No macro-invertebrate was recorded in the present field survey.

6.4.4.5 The “Siu Ho Wan Water Treatment Works Extension EIA (2004)” provides recent information on intertidal community in the Northwestern waters WCZ as summarized below:

· Ecological surveys covering the wet season were conducted from July 2003 to October 2003 in Pui O Bay. In addition, ad hoc observations of fauna (primarily avifauna) were made during site visits conducted in the 2003/2004 dry season.

Sandy Shore

· Sandy shore habitat supported ghost crabs (Ocypode ceratophthalmus, Ocypode gaimardi) with frequent burrows at the high shore. Sand-bubbler crabs (Scopimera globosa) were also occasionally recorded. Hermit crabs (Clibanarius sp.) were infrequently recorded usually inhabiting Turitella shells. Surf clams (Donax sp.) were occasionally recorded on the low shore. At the backshore, the common sesarmine crab Perisesarma bidens was commonly recorded particularly in a small pool area behind the western end of Pui O gazetted beach.

Rocky Shore

· Rocky shore habitat was identified in the southwest corner of the Assessment Area fringing Pui O Bay. The rocky shore comprised moderate to large rocky boulders with medium wave exposure. Rocky shore habitat supported typical and widespread species of moderately exposed rocky comprising rock oysters (Saccostrea cullculata), barnacles (Tetraclita sp., Capitulla mitella) sea slaters (Ligia exotica), small shore crabs (Hemigrapsus sanguineus), limpets (Notoacmea schrenkii) and snails (Monodonta labio, Nerita albicilla and Morula musiva). This semi-exposed rocky shore supported common and widespread species in Hong Kong and no rare species were recorded.

6.4.4.6 The intertidal survey for the “Tung Chung – Ngong Ping Cable Car Project EIA (2003)”, including sandy beaches (with small boulders) in Tung Chung Bay and mudflat communities at San Tau were conducted in June and July 2002. This information on intertidal communities in the Northwestern WCZ is available from this study, as summarized below.

San Tau Mudflat

· The mudflats beside the San Tau mangal found colonies of the rare seagrass Halophila ovata and Zostera japonica. The seaweeds Enteromorpha sp. and Colpomenia sinuosa were also seasonally abundant on the mudflat near the seagrass beds (Halophila ovalis and Zostera japonica). The epifauna and infauna communities were dominated by gastropods of the genera Batillaria, Littoraria, Cerithidea and Nerita. The mudflat was also an important habitat for the horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda. The mudskipper Periophthalmus cantonensis is widespread. Mudflat was dominated by the gastropods Cerithidea djadjariensis, Batillaria multiformis, Batillaria zonalis, Nerita striata and Clithon oualaniensis with these species entirely covering the mudflat in some areas. These species were also present in the infauna to a certain extent. Other occasional epifauna species were the mudskipper Periophthalmus cantonensis that was present wherever there were tidal pools and the crab Uca chlorophthalmus. The crab Uca lactea was locally dominant at open and elevated (well drained) areas of mudflat near the backshore.

Tung Chung Bay

· The Bay’s estuarine waters linked the coastal marine environment and the freshwater habitats of San Tau Stream and Tung Chung Stream. Due to the variable physio-chemical environment brought about by changing salinity in the Bay, the coastal waters supported a diversity of fish species. The most abundant species include Flathead Mullet Mugil cephalus and Tiger Fish Therapon jarbua. Most activity along the west of Tung Chung Bay where shells taken were predominantly rock oysters Sacostrea cucullata, the mangrove clam Gelloina erosa and various cockles (Cardiidae).

6.4.4.7 The intertial surveys for “Construction of Lung Kwu Chau Jetty, 2002” including rocky shore and sandy shore were conducted along southeast coast of Lung Kwu Chau Island in February 2001 to February 2002. This information on intertidal communities in Northwestern WCZ is available from this study, as summarized below.

Rocky Shore

· Littorinids were observed from this field survey to be most common higher up in the littoral zone, as were sea slaters, Ligia exotica. Patches of Kyrtuthrix cyanobacteria were also present on the high shore. Lower down the seashore were observed the grazing snails, Monodonta spp. and Nerita spp.. Also found on the mid shore was the crustose algae Hildenbrantia and the limpet T. squamosa which was attached to the exposed rocky surfaces, while the stalked barnacle Capitullum mitella was confined to the shelter crevices. On the lower shore several Saccostrea cucullata were observed. In winter, the rocky lower shore dominated by macro-algae species, Enteromorpha, Ulva and Sargassum.

Sandy Shore

· Low macro-invertebrates were recorded during the survey. The course sand grain size limits water retention leading to desiccation of macro-invertebrates, so resulted in very low biodiversity. Only large ghost crabs, Ocypode ceratophthalmus, were recorded in small number inside burrows in sandy shore.

6.4.4.8 Intertidal surveys were carried out in Sha Chau Island and Lung Kwu Chau Island rocky shores between October 2003 and November 2004 from “(Put O Ang, Jr. et al, 2005) Biological Monitoring in Sha Chau and Lung Kwu Chau Marine Park. Final Report submitted to the Agriculture, Fisheries and Conservation Department, HKSAR”. The dominant species included Littoraria articulata, Saccostrea cucullata, Balanus Amphitrite, Tetraclita squamosa, Nodilitorina trochoides, Septifer virgatus and juvenile snail (<1mm). In upper shore, it was dominated Littoraria articulata, Tetraclita squamosa, Nodilitorina trochoides, Septifer virgatus and juvenile snail (<1mm). In middle shore, it was dominated by Littoraria articulata, Saccostrea cucullata, Balanus Amphitrite and Tetraclita squamosa. In lower shore, it was dominated by Littoraria articulata, Saccostrea cucullata, Balanus amphitrite, Tetraclita squamosa and Septifer virgatus. In general, the middle shore supported the highest species diversity. The species recorded were typical semi-exposed shore species. No rare species were recorded. All were common and widespread in Hong Kong.

6.4.4.9 From the “Deep Bay Link EIA Study, 2002”, both dry and wet seasons field surveys for both epi-fauna and macro-infauna of the inter-tidal mudflat and mangrove at Ngau Hom Shek (within Deep Bay WCZ) were conducted in February to March 2000 and April to May 2000 respectively. The epi-fauna was dominated by mollusca. For macro-fauna, crab and mudskipper were the most dominated species found in the burrows of the mudflat. For benthic in-fauna, 719 macro-benthic animals belonging to 25 taxa were collected. Polychaete worms dominated the in-fauna collected. Two families of Polychaetes were the most abundant, namely Terebellidae and Nereidae (e.g. Nereis neanthes). No horseshoe crabs were recorded during this survey. However, a local fisherman interviewed from this study (who checked net traps set on the lower shore on a daily basis) reported an encounter with a group of juvenile horseshoe crabs about 6 years ago. This suggests the site could, at one time, serve as a breeding ground for the species. Several small patches of the seagrass Halophila beccarii occurred on the Ngau Hom Shek intertidal shore, forming a low mat of vegetation on slightly raised mounds of sandy sediment.

6.4.4.10 From the “Shenzhen Western Corridor EIA Study”, surveys were conducted in August 2001 to February 2002 on intertidal community in Ngau Hom Shek, Ngau Hom Sha, and Sheung Pak Nai (within Deep Bay WCZ). For the intertidal epi-fauna, mudskipper and crab (including Macrophthalmus and Grapsid crabs) species were dominated with occassionally rock oyster recorded in the study area. Annelids, bivalves and crustaceans were the dominant faunal groups in the specimens found. No rare species was found in the samples. Polychaete Neanthes glandicincta was the most common and abundant infauna in the samples. Seagrass Halophila beccarii on the south shore of Deep Bay, primarily on the seaward side of mangrove communities and also near stream mouths as shown in Figure 6.5.

6.4.4.11 Surveys on September 2002 to January 2003 at Yam O mudflat discovered an extensive seagrass bed estimated to cover an area of at least 0.8 ha from “Road P1 Advance Works at Yam O Engineering Design and Construction” from CED (2003). This seagrass bed was formed by a dense cover of the Spoon Grass Halophila ovata (sometimes called Paddle Grass and synonymous with Halophila minor). The seagrasses appeared to be in good condition with new growths appearing as sparsely arranged leaves fringing the dense beds.

6.4.4.12 From AFCD (2005), the coastal community working group of AFCD carried out seagrass survery in January 2002, Halophila beccarii was recorded in Sha Kwong Tsuen, Sheung Pak Nai and Ha Pak Nai, Halophila ovalis was recorded in Yam O, Sheung Pak Nai and San Tau and Zostera japonica was recorded in San Tau.

Mangrove communities

6.4.4.13 According to Tam and Wong (1997) and AFCD (2006), seven mangrove communities which situates at Mai Po, Lut Chau, Tsim Bei Tsui, Sheung Pak Nai, Tai Ho Wan, San Tau and Yi O are found including in the Assessment Area. The locations of the mangrove communities are shown in Figure 6.1 and the baseline information about the mangrove is summarized as below:

Mai Po

· The Mai Po Marshes mangrove, at 85 ha, is the largest remaining in Deep Bay (Tam and Wong 1997). This mangrove community was dominated by Kandelia candel, Aegiceras corniculatum, Avicennia marina and Acanthus ilicifolius, with Bruguiera gymnorrhiza and Excoecaria agallocha as secondary species (Irving and Morton 1988). According to AFCD (2006), a baseline ecological monitoring programme for Mai Po Inner Deep Bay Ramsar Site was performed from 2001 to 2002. The executive summary of the programme reported that the area of Mai Po interdal mangal increased by 18 ha (from 262 ha to 280 ha) approximately.

Lut Chau

· The area was about 56 ha and it was crossed by estuarine creeks. A total of 8 species of mangroves were recorded. The stand was dominated by a mixture of Aegiceras corniculatum and Kandelia candel with small patches of Acanthus ilicifolius. The benthis macrofauna consisted mainly of mudskippers (species unknown) and crabs, very few gastropods were recorded. Avifauna at the stand consisted of the usual egrets (Egretta garzetta) and gulls.

Tsim Bei Tsui

· The area was apporoximately 35.5 ha and spreaded over several kilometers of coastlines. A total of 10 species of mangrove and associate flora were recorded. The mangrove was dominated by Kandelia candel with a few individuals of Aegiceras corniculatum scattered in between. There were 7 species of benthic macrofauna recorded in the study. The study area had very large numbers of mudskippers (mainly Periophthalmus cantonensis) and some very large specimens of Ellobium chinensis. The mangrove floor was dominated by mud crabs (Helice sp.), with fiddler crabs (Uca sp.) only occur in the back-mangroves and where substrate was firmer.

Sheung Pak Nai

· The mangrove stand spreaded over 4 km of coastlines and had an area of about 6.3 ha. There were many polluted freshwater streams running through the mangroves into the sea. Nine species of mangrove and associate species were recorded, including the locally uncommon species Halophila ovata. The stand was dominated by Kandelia candel which was planted about 15 years ago. A total of 19 species of benthic macrofauna were recorded, dominated by cerithid gastropods, mud crabs (Helice spp.) and mudskippers (Periophthalmus cantonensis). Chinese Pond Herons (Ardea baccus), Grey Herons (Ardea cinerea), Night Herons (Nycticorax nycticorax), and Little Egrets (Egretta garzetta) were recorded.

Tai Ho Wan

· The mangrove had an area of 1.9 ha and consisted of 12 species of mangrove and associate flora. It was dominated by Aegiceras corniculatum with patches of Bruguiera gymnorrhiza interspersed. The benthic macrofauna at the stand is extremely sparse (only 15 species), dominated by crabs but at a low density.

San Tau

· It covered an area of 2.1 ha and had 18 species of mangrove and associate flora. Bruguiera gymnorrhiza occurred in substantial numbers in this stand. The foreshore had patches of two locally uncommon species, Zostera japonica and Halophila ovata. San Tau was dominated by a mixture of dense patches of Aegiceras corniculatum, Bruguiera gymnorrhiza and Kandelia candel. Some Avicennia marina were also present, mixing in with the other species but had a low density. The benthic macrofauna consisted mostly of gastropods, though large numbers of hermit crabs were also present. A total of 25 species of benthic macrofauna were recorded and the most common one was Cerithidea djadjariensis.

Yi O

· The area was about 1.2 ha and it had 14 species of mangrove and associate flora. The mangrove was dominated by Avicennia marina and Aegiceras corniculatum, through there were patches of Kandelia candel on the muddy substrate. A total of 40 species of benthic macrofauna were recorded. Terebralia sulcata and Cerithidea sp. were as common as the hermit crabs (Pagurus sp.). The mudskipper Periophthalmus cantonensis was also common on the banks of the river.

6.4.4.14 A summary of intertidal community baseline condition within the Assessment Area is presented below.

· The coastline in the Assessment Area comprises habitat types including sandy shore, boulder shore, mudflat, rocky shore, artificial seawall and mangrove communities.

· Most of intertidal habitats support low biodiversity dominated by common and widespread infauna in Hong Kong. Rare seagrasses including Halophila ovata was recorded in Yam O, Sheung Pak Nai and San Tau, Zostera japonica were recorded in San Tau mudflat. Seagrass and Halophila beccarii, was recorded in Tai Ho Wan (The University of Hong Kong 1999) and Ngau Hom Shek, Sha Kwong Tsuen and Sheung Pak Nai in Deep Bay water.

· Sandy shore is dominated by common species such as the large ghost crab, while rocky shore, is usually dominated by common grazing snails N. trochoides and N. vidua and grazing limpets C. toreuma. Artificial seawall, potential infauna composition would be biofouling species (Morton and Morton, 1983) and the species found in artificial seawall were common and widespread in Hong Kong. For mangrove communities, they are usually dominated by common flora species such as Kandelia candel and Aegiceras corniculatum. The benthic macrofauna recorded in the previous ecological study consists of mudskippers (e.g. Periophthalmus cantonensis), mud crabs (e.g. Helice sp.) and gastropods (e.g. Cerithidea djadjariensis).

· The intertidal shore in the Northwesten WCZ supports seagrass bed and nursery ground for horseshoe crab with high ecological value, whereas the rest of the intertidal shore with common and widespread in-fauna and epi-fauna species is considered to have low ecological value.

· All the epi-fauna and in-fauna species recorded in the interidal shore in the Western Buffer WCZ are common and widespread in Hong Kong with no rare and protected species are recorded. Therefore, the ecological value of this intertidal community is considered as low.

· The Deep Bay WCZ provides nursery ground for horseshoe crab and supports seagrass bed. The epi-fauna and in-fauna species in Deep Bay generally provide important food source for migratory bird species. Therefore the ecological value of the intertidal community is considered to be moderate to high.

6.4.5 Marine Mammal and Horseshoe Crab

6.4.5.1 Parts of the study area are frequented or may be traversed by cetaceans and horseshoe crab, which are species of conservation significance.

Marine Mammal (Chinese White Dolphin)

6.4.5.2 A total of fifteen species of cetaceans has been recorded from Hong Kong waters (Parsons et al., 1995), of which only two species are resident year round: the Indo-Pacific Humpback Dolphin, also known locally as the Chinese White Dolphin (Sousa chinensis) and the finless porpoise (Neophocaena phocaenoides). However, only Chinese White Dolphin was recorded in the Assessment Area for this Project.

6.4.5.3 Chinese White Dolphin is recognized internationally as of ecological importance and are listed in CITES Appendix I and as “Data Deficient” in the IUCN Red List of Threatened Species.

6.4.5.4 Furthermore, the Chinese White Dolphin is listed in China as a “Grade I National Key Protected Species”

Chinese White Dolphin (Sousa chinensis)

6.4.5.4 In Hong Kong, Chinese White Dolphins (Sousa chinensis) predominantly frequents the less saline brackish waters around the Pearl River Estuary although loss of habitat to numerous developments, fishing, shipping activity and pollution from various sources have reportedly placed increasing pressure on the local Chinese White Dolphin population (e.g., Liu and Hills, 1997; Jefferson, 2000a).

6.4.5.5 Comprehensive information on the population biology of the Chinese White Dolphin (Sousa chinensis) in Hong Kong waters are found in the “Monitoring of Indo-pacific Humpback Dolphin (Sousa chinensis) in Hong Kong Waters – Data Analysis Final Report, 2005” for AFCD (Jefferson, 2005) and also in the ‘Monitoring of Chinese White Dolphin (Sousa chinensis) in Hong Kong waters – Biopsy Sampling and Popuoation Data Analysis Final Report’ (AFCD, 2007), as highlighted below. Updated information on Chinese White Dolphin sightings made in 2005-06 as reported in “Monitoring of Chinese White Dolphins (Sousa chinensis) in Hong Kong Waters – Data Collection Final Report, 2006” for AFCD (Hung, 2006), is also discussed below.

Sightings and Distribution

6.4.5.6 Detailed sighting surveys were conducted from September 1995 to December 2004 to determine the abundance and habitat use for Chinese White Dolphin, which reported their distribution mainly in those western waters influenced by the Pearl River Estuary. The most important habitats were assessed based on the highest concentrations of sightings at the mouth of Deep Bay and the northern, western and southwestern Lantau Island as shown in Figure 6.6. A very few individuals were observed in the southern Hong Kong Island and Lamma and eastern Lantau Island. No individual was observed in Victoria Harbour. Hung (2006) reported that the distribution of dolphin sightings made in 2005-06 was similar to past distribution records (Figure 6.7), with most dolphins sighted in the northern and western waters off Lantau Island. Within the North Lantau region, high concentration of dolphin sightings could be found in waters to the west and northwest of Lung Kwu Chau, between Lung Kwu Chau and Black Point and around the Brothers Islands.

6.4.5.7 Jefferson (2005) reported that density varied dramatically among areas and seasons. By far, the highest density area was West Lantau, with exceptionally high densities in all four seasons of 96 to 219 individuals per 100 km². Autumn was the season with the highest density in West Lantau, 219 individuals per 100 km². High densities of over 75 individuals per 100 km² were found in Lingding Bay, Macau, and Northwest Lantau. Other areas had moderate to low densities of 5 to 75 individuals per 100 km², except for East Lantau and Lamma, which both had negligible densities of less than 3 individuals per 100 km². Density could change radically over very short distances. For instance, average seasonal densities of 185 individuals per 100 km² in West Lantau dropped to 1.3 individuals per 100 km² in East Lantau, over a distance of only about 20 km.

6.4.5.8 Hung (2006) calculated encounter rates of Chinese White Dolphins (number of on-effort sightings per 100 km of survey effort) for the four main survey areas (i.e. Northeast Lantau, Northwest Lantau, West Lantau and South Lantau) using dolphin sightings data collected during the study period of April 2005 to March 2006. The encounter rate was the highest in West Lantau (19.9 sightings per 100 km), which is 2.3 times higher than Northwest Lantau (8.8), 7.4 times higher than Northeast Lantau (2.7) and 12.4 times higher than South Lantau (1.6). Hung (2006) also reported that the encounter rates in West Lantau were much higher than the other three survey areas in all four seasons (which is also the case for the past three years), further confirming that West Lantau has consistently been the highest in dolphin density all year round and across different years, and is thus considered to be the most important area for Chinese White Dolphins in Hong Kong.

Abundance and seasonal variation

6.4.5.8 Abundance also varied extensively. The total of the estimates for Hong Kong waters were similar in three seasons (166 in winter, 162 in summer, and 193 in autumn). In spring, it dropped to only 103 individuals (AFCD, 2007). In the Hong Kong survey areas, abundance was the lowest in spring in every case.

6.4.5.9 When all the seasonal totals for all the survey areas (in Hong Kong and China) were compared, the totals were very similar in three seasons (1171 in winter, 1076 in spring, and 1139 in autumn). Only in summer, was the total dramatically different, with the sum adding to only 678 individuals.

6.4.5.10 In summary, the total abundance estimates for all the survey areas (Hong Kong and China, refer to Figure 6.6) during three of the four seasons (about 1080 -1170 in autumn through spring) is highly suggestive that the majority of the population was included in the estimates for these seasons. Therefore, the total population size should be about 1300-1500 individuals (ACFD, 2007).

Calving periods

6.4.5.11 Jefferson (2005) suggested the Chinese White Dolphin give birth in every month of the year, but with a peak in spring and summer months (from March to August). During this half of the year, 76.3% of calves are born. A peak in calving during the warmer months of the year may be typical for the species (Cockcroft 1989).

6.4.5.12 According to “(Put O Ang, Jr. et al, 2005) Biological Monitoring in Sha Chau and Lung Kwu Chau Marine Park, Final Report submitted to the Agriculture, Fisheries and Conservation Department, HKSAR“, calves were mostly observed in central Sha Chau and around Lung Kwu Chau Marine Park. There were totally 11 calves observed in the study area from October 2003 to September 2004.

Feeding habits

6.4.5.13 Feeding habits of Chinese White Dolphin are analysed based on stranding specimen. Croakers Johnius spp., lionhead Collichthis lucida, and anchovies Thryssa spp., were the most common prey. Little evidence shows that cephalopods or crustaceans are their major prey items.

Chinese White Dolphin Mortality In Hong Kong

6.4.5.14 A higher number of dolphin strandings was recorded in summer as compared with other seasons, but the reasons for stranding are still unknown. Mortality of cetaceans would be caused by incidental capture of fishing nets and vessel collisions. Tissue analyses of stranded dolphin and porpoise specimens conducted by a 2-year study entitled the Assessment of the Environmental Contaminants in Marine Mammals in Hong Kong (AFCD, 2008) showed that the levels of contminants measured in these stranded marine mammals in Hong Kong were not directly related to their cause of death. However, prolonged exposure to some pesticides and industrial contaminants might affect reproduction and immunity in these marine mammals. Further monitoring on such contaminants would be required to track their changes in dolphins' body burden and the associated ecological risks.

Horseshoe Crab

6.4.5.15 Horseshoe crabs are an ancient and taxonomically isolated group (Class Merostomata, sub-class Xiphosura) related to spider, ticks and mites. They are important in biomedical applications where the blood of horseshoe crabs is the source of compounds used to screen for pathogens in medical facilities and on medical equipment. Three species have been reported to occur in HKSAR waters: Tachypleus tridentatus, T. gigas and Carcinoscorpius rotundicauda. These represent all species known from the South China Sea (Sekiguchi 1988), and three of four species known world-wide. Information on abundance of these species is limited. The information and distribution of horseshoe crabs summarized below is based on Chiu and Morton (1999).

Distribution

6.4.5.16 At least 140 living horseshoe crab adults and 100 juveniles, and 17 dead adult specimens were recorded during the survey period from 1995 to 1998. They are distributed at Deep Bay (e.g. Ngau Hom Shek and Sheung Pak Nai) and Lantau Island (e.g. Yi O and Hau Hok Wan). Occasionally, they were fished up at Sai Kung and Lamma Island (AFCD, 2006). Adults largely occur in shallow to deep waters while juveniles were generally encountered on intertidal sandy-mud flats. Two horseshoe crabs, namely Tachypleus tridentatus and C. rotundicauda were recorded during the surveys. The locations where horseshoe crabs were either observed or recorded during the study period are shown in Figure 6.8.

T. tridentatus

6.4.5.17 Most identified during the survey period were from waters off Tai O, Yi O and Tung Chung Wan, Lantau Island (~ -5 m C.D.). Some of them were recorded from the East and West Lamma Channel, Lung Kwu Sheung Tan, Shek Kwu Chau, Silverstrand beach and Sharp Island, with a few recorded sporadically from Lau Fau Shan (Deep Bay) and Kau Pei Chau (southern waters).

6.4.5.18 Large dead specimens were collected around Tuen Mun, Shek Kwu Chau and Waglan Island, Pui O, Tung O Wan and Pak Nai.

6.4.5.19 Juveniles of Tachypleus tridentatus were mostly recorded from sand or sandy-mud flats at Shui Hau Wan, San Tau and Pak Nai, with a few occasionally recorded at Lung Kwu Sheung Tan, Nim Wan and Sha Lo Wan.

C. rotundicauda

6.4.5.20 This species occurs in Tai O, Yi O, Sham Wat Wan, Sha Lo Wan and Tung Chung Wan, Peng Chau and Sha Chau. Juveniles have been recorded in Ha Pak Nai.

6.4.5.21 Coastal surveys were conducted on June and July 2002 for the “Tung Chung – Ngong Ping Cable Car Project, 2003. Fifty seven juvenile individuals of the T. tridentatus and 2 juvenile individuals of C. rotundicauda were found in the San Tau mudflat and mouth of Tung Chung Stream.

6.4.5.22 From “Shenzhen Western Corridor EIA Study”, one partial carapace of a horseshoe crab was found along the Sheung Pak Nai shore during September 2001, and one juvenile Tachypleus tridentatus was found on the Ngau Hom Shek shore in October 2001. The location of horseshoe crab was shown in Figure 6.5.

6.4.5.23 These two species of horseshoe crabs appear to be in population decline and are thought to be under severe pressure in the South China Sea, including HKSAR waters, due to habitat loss and overexploitation (Huang 1997).

6.4.6 Marine Park, Nature Reserve and SSSIs

Sha Chau and Lung Kwu Chau Marine Park

6.4.6.1 The Sha Chau and Lung Kwu Chau Marine Park is situated in the open waters on the western side of Hong Kong. This marine park was designated for Chinese Whie Dolphin mainly on 22 November 1996. It covers a total sea area of about 1,200 hectares.

6.4.6.2 The marine environment of Sha Chau and Lung Kwu Chau Marine Park is, greatly influenced by the Pearl River freshwater run-off, with high organic loading and sediment loading. Marine organisms found in this region are highly adapted to low salinity and high turbidity marine environment.

6.4.6.3 Sha Chau and Lung Kwu Chau Marine Park has rich fisheries resources. Fishes of the Engrulidae, Scieanidae and Clupeidae families are important food for Indo-Pacific Humpback Dolphin (locally known as Chinese White Dolphin) which was found in this marine park. Therefore, this area provides an important feeding ground for Chinese White Dolphin.

6.4.6.4 Ecological data on Sha Chau and Lung Kwu Chau Marine Park from “(Put O Ang, Jr. et al, 2005) Biological Monitoring in Sha Chau and Lung Kwu Chau Marine Park. Final Report submitted to the Agriculture, Fisheries and Conservation Department, HKSAR” and relevant EIA studies have been reviewed for the information on ecological resources in Marine Park and have been presented in respective section above. Both benthic, intertidal and coral community are of low ecological value.

Mai Po Nature Reserve and Ramsar Site

6.4.6.5 The Mai Po Marshes Nature Reserve is approximately 380 ha in area, and consists of mangrove forest, gei wai and fish ponds. This Nature Reserve is a key part of the internationally important Deep Bay wetland, which is later listed as a Ramsar Site. The Mai Po Marshes, at 85 ha, is the largest remaining in Deep Bay (Tam and Wong 1997). This mangrove community was dominated by Kandelia candel, Aegiceras corniculatum, Avicennia marina and Acanthus ilicifolius, with Bruguiera gymnorrhiza and Excoecaria agallocha as secondary species (Irving and Morton 1988). The mangrove is considered well-established and expanding, the main body of it having remained mostly undisturbed since the 1940s (Peking University undated).

6.4.6.6 The Mai Po wetland and Inner Deep Bay region, which is about 1500 ha, was listed as a Ramsar Site on 4 September 1995. The Site has a shallow bay with extensive intertidal mudflats backed by mangal, tidal shrimp ponds (gei wais), fishponds and reedbeds. The mangal is the largest in Hong Kong while the reedbed is the largest in Hong Kong and Guangdong Province. The Site is a very important refueling station for the water birds during their migrations between the Arctic Russia and Australia (AFCD 2006).

SSSIs

6.4.6.7 Lung Kwu Chau, Tree Island and Sha Chau were designated as SSSI for its importance to night-time roosting Cormorants.

6.4.6.8 The international conservation importance of the Mai Po and Inner Deep Bay area has been acknowledged by the Mainland and the HKSAR for several decades. In the HKSAR, the area of mangroves and gei wai known as Mai Po Marshes was designated an SSSI in 1976 for its botanical and ornithological value (Anon. 1995a). The Inner Deep Bay SSSI, established in 1986 to protect the Inner Deep Bay mudflats, lies adjacent to the Mai Po mangroves at their seaward edge. The Inner Deep Bay SSSI is the HKSAR's largest, at 2,300 ha (ibid.). The Tsim Bei Tsui SSSI was established in 1986 to protect mangrove communities. The Tsim Bei Tsui Egretry SSSI was established in 1989 to protect an egretry. In 1999, the Town Planning Board established Wetland Conservation Area (WCA) and Wetland Buffer Area (WBA), around Mai Po and the Inner Deep Bay mudflats, with the goal of prohibiting development incompatible with conservation of the area's natural value (TPB 1999).

6.4.6.9 Pak Nai Site of Special Scientific Interest (SSSI No. 31). This coastal SSSI was designated in 1980 due to its importance as a high tide roost for gulls and terns (Anon. 1995a). The endangered Saunders' Gull Larus saundersi has been recorded there. It is an important foraging site for many wetland bird species and lies 2.5 km south west of the study area.

6.4.7 Artifical Reefs

6.4.7.1 There are two artificial reefs within the Assessment Area at Sha Chau and near the Hong Kong International Airport. The goal of the artificial reefs was to enhance marine ecological reources, rehabilitate degraded habitats, protect sprawning and nursery ground for marine life and enhances habitat quality of seabed.

6.5 Ecological Value

6.5.1.1 Based on the results from Water Quality Impact modeling, potential changes of water quality parameters as a result of this Project would be restricted to a zone of influence within the Western Buffer and NorthWestern WCZs. Therefore the following habitats and species evaluation focus only on ecological resources within these waters with potential impacts, and resources outside these waters would unlikely receive impacts and are not discussed further.

6.5.1.2 With reference to the detailed baseline description above, the ecological values of these two WCZs are assessed using criteria in EIAO TM Annex 8, as presented in Tables 6.5.1 to 6.5.4.

Table 6.5.1 Ecological value of marine benthos within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Benthos
Broad area of potential impact	Western Buffer WCZ	Northwestern WCZ
Naturalness	Habitats for benthic community have been subject to certain degree of disturbance from urban developments and are under the influence of water pollutants from Pearl River and Hong Kong urban discharges	Habitats for benthic community have been subject to high degree of disturbance from Pearl River discharges and moderate high trawling pressure for fisheries resources
Size	Moderate large	Large
Diversity	Species richness is low (d< 10) and diversity is low (H’<3)	Species richness is low (d< 10) and diversity is low (H’<3)
Rarity	All species recorded are common and widespread in Hong Kong	All species recorded are common and widespread in Hong Kong
Re-creatability	High, as habitats have been subject to certain level of disturbance	High, as habitats have been subject to high level of disturbance
Fragmentation	The benthic habitats were not fragmented	The benthic habitats were not fragmented
Ecological linkage	No. They are not linked to other high value habitats but would provide habitat for other marine fauna	Presence of Sha Chau and Lung Kwu Chau Marine Park within this WCZ which is considered as one of the major sighting habitats for the Chinese White Dolphin
Potential value	Low	Low
Nursery/breeding area	Possible but none documented	Possible but none documented
Age	N.A.	N.A.
Abundance	Low	Low
Ecological Value	Low	Low

Table 6.5.2 Ecological value of coral community in potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Corals
Broad area of potential impact	Western Buffer WCZ	Northwestern WCZ
Naturalness	Benthic habitats for coral community have been subject to certain degree of disturbance from urban developments and are under the influence of water pollutants from Pearl River and Hong Kong urban discharges	Benthic habitats for coral community have been subject to high degree of disturbance from Pearl River discharges and moderate high trawling pressure for the fisheries resources
Size	Only a very small/ negligible size of soft corals was recorded in south of Tsing Yi and no hard corals were recorded. In Ap Lei Chau, both low abundance of soft and hard corals were recorded. In Sandy Bay, a moderate size of soft coral communities and small communities of hard corals were recorded. In Sham Tseng and Tsing Lung Tau, both soft and hard corals were recorded in low abundance with <1% coverage	Only soft corals were recorded in this WCZ. Corals were recorded in Sha Chau and Lung Kwu Chau Marine Park. Only 6 colonies were recorded
Diversity	Low-moderate. Low soft coral diversity was recorded in south of Tsing Yi. Low soft coral diversity and moderate high hard coral diversity were recorded in Ap Lei Chau. Low soft coral diversity and moderate high hard coral diversity were recorded in Sandy Bay. Common soft and hard corals were recorded along Sham Tseng and Tsing Lung Tau with limited biodiversity	Limited diversity and only soft corals were recorded
Rarity	No rare species were recorded	No rare species were recorded
Re-creatability	Low. It takes long years for re-colonization	Low. It takes long years for re-colonization.
Fragmentation	The habitats were not fragmented	The habitats were not fragmented
Ecological linkage	No. They are not linked to other high value habitats but would provide habitat for other marine fauna	Presence of Sha Chau and Lung Kwu Chau Marine Park within this WCZ which is considered as one of the major sighting habitats for the Chinese White Dolphin
Potential value	Low	Low
Nursery/breeding area	Possible but none documented	Possible but none documented
Age	N.A	N.A
Abundance	Low-moderate. Low abundance was recorded in Tsing Yi, Ap Lei Chau, Sham Tseng and Tsing Lung Tau, but moderate abundance in Sandy Bay	Low. Low abundance of corals was recorded within this WCZ
Ecological Value	Low-moderate	Low

Table 6.5.3 Ecological value of intertidal community in potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Intertidal
Broad area of potential impact	Western Buffer WCZ	Northwestern WCZ
Naturalness	The coastline along Western Buffer contains a range of habitats from disturbed habitats such as artificial seawall (e.g. in Tsing Yi Island), and gazetted beaches (e.g. in Lido, Ting Kau), to natural rocky shore (e.g. in Sandy Bay)	The coastline along the Northwestern contains a range of habitats from natural mudflat (e.g. in San Tau), natural rocky shore (e.g in Pui O) and mangrove communities (e.g. in Tai Ho Wan). The coastline is also straightened with concrete lining and artificial seawall (e.g. in Ka Loon Tsuen)
Size	Moderate size of intertidal habitats in Western Buffer WCZ	The size of intertidal habitats are large
Diversity	Species richness of epi-fauna and in-fauna species is low	Species richness of epi-fauna and in-fauna species is low. However, horseshoe crab and seagrass are supported within this WCZ
Rarity	Low as habitats support common and widespread species in Hong Kong	Both epi-fauna and in-fauna species are generally common and widespread in Hong Kong. With an exception of the epi-fauna, horseshoe crab which is a species of conservation interest. Seagrass is also considered to have conservation interest
Re-creatability	Habitat can be recreated for sandy shore and artificial seawall. For natural rocky shore, it takes long time to allow species recolonization	Habitat can be recreated for sandy shore and artificial seawall. For natural rocky shore and mangrove communities, they take long time to allow species recolonization. And mudflat is difficult to recreate
Fragmentation	The habitats are not fragmented.	The habitats are not fragmented
Ecological linkage	No. They are not linked to other high value habitats but would provide habitat for other marine fauna	Presence of Sha Chau and Lung Kwu Chau Marine Park within this WCZ which is designated for the Chinese White Dolphin
Potential value	Low	Negligible
Nursery/breeding area	Possible but none documented	Nursery ground for horseshoe crab and seagrass
Age	N.A.	N.A.
Abundance	Low	Low
Ecological Value	Low	Low – High Low – Most interidal habitats within this WCZ are low ecological value. High – Horseshoe crab habitats recorded along the coast from Yi O to Tung Chung Bay in Lantau Island, and seagrass beds recorded at Yam O, Tai Ho Wan and San Tau

Table 6.5.4 Ecological value of Artificial Reefs in potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Artificial Reefs
Naturalness	Low as the artifical reefs are man-made and artificially deployed
Size	Small
Diversity	Species richness of fish is moderate within the artificial reef areas
Rarity	No rare species was documented
Re-creatability	High
Fragmentation	The habitats are not fragmented
Ecological linkage	Link to the marine habitat for Chinese white dolphin and possibly enhance its food availability.
Potential value	Moderate
Nursery/breeding area	Possible but none documented
Age	Since 2000
Abundance	Moderate
Ecological Value	Moderate

6.5.1.3 The only marine species of conservation interest recorded within the potential impacted areas would be the Chinese White Dolphin, Horseshoe crab and Seagrass. The evaluation on ecological value of Chinese White Dolphins, Horseshoe crab and Seagrass in accordance with EIAO Annex 8 Table 3 is presented in Table 6.5.5, Table 6.5.6 and Table 6.5.7 respectively.

Table 6.5.5 Ecological value of Chinese White Dolphin within potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Chinese White Dolphin
Protection status	Protected under the Wild Animals Protection Ordinance (Cap. 170); Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) and Marine Park Ordinance (Cap. 476) and Chinese White Dolphin is listed in CITES Appendix 1 and protected in the People Republic of China.
Distribution	Local population mainly distributed in estuarine habitat in Pearl River Delta and Northwestern WCZ within the Assessment Area. Western WCZ supports low occurrence of Chinese White Dolphin
Rarity	Over 1000 individuals recorded in Pearl River and Hong Kong waters. It is locally not uncommon.

Table 6.5.6 Ecological value of Horseshoe Crab within potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Horseshoe Crab
Protection status	No statutory protection status in Hong Kong and Mainland China
Distribution	Local population mainly distributed in estuarine habitat mainly in Deep Bay WCZ and Northwestern WCZ within the Assessment Area. Two, Tachypleus tridentatus and Carcinoscorpius rotundicauda, have been recorded within the Assessment Area
Rarity	Relatively local rare species of a taxonomically distinct and ancient class; rarity probably due to unsustainable harvest

Table 6.5.7 Ecological value of Seagrass within potentially impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Seagrass
	Halophila beccarii	Halophila ovalis	Zostera japonica
Protection status	No statutory protection status in Hong Kong and Mainland China	No statutory protection status in Hong Kong and Mainland China	No statutory protection status in Hong Kong and Mainland China
Distribution	Seagrass beds were recorded in Ngau Hom Shek, Sha Kwong Tsuen, Sheung Pak Nai and Nam Chung Yeung UK and Tai Ho Wan. Only Tai Ho Wan within Northwestern WCZ supports this seagrass beds. However, no such seagrass beds recorded in Western Buffer WCZ.	Seagrass beds were recorded in eastern waters in Hong Kong (AFCD, 2005) including Hoi Ha, Ham Tin and also distributed in eastern waters such as Sheung Pak Nai, San Tau, Yam O and Nim Yue Wan. Only San Tau and Yam O within Northwestern WCZ supports this seagrass beds. However, no such seagrass beds recorded in Western Buffer WCZ.	Seagrass beds were recorded in Lam Chung Yeung Uk, San Tau, Sheung Pak Nai, Sha Kwong Tsuen, and San Tau. Only San Tau within Northwestern WCZ supports this seagrass beds. However, no such seagrass beds recorded in Western Buffer WCZ.
Rarity	Locally rare	Locally rare	Locally rare

6.5.1.4 One sighting of Chinese White Dolphin was made in the East Lantau region during the study period of April 2005 to March 2006 (Hung, 2006). The past distribution of dolphin sightings in Hong Kong waters from 1996–2006 (Figure 6.7) indicates low concentrations of dolphin sightings in the waters of the Western Buffer WCZ on comparison to the other surveyed areas. As the waters of the Western Buffer WCZ supported very low occurence of Chinese White Dolphin, the ecological value of this WCZ to dolphins in the Assessment Area is considered low.

6.5.1.5 The northern and western waters of Lantau, however, are considered as one of the major sighting habitats for Chinese White Dolphins (Jefferson 2005 and Hung 2006), with calves observed near the Sha Chau and Lung Kwu Chau Marine Park (Put O Ang, Jr. et al, 2005). From Hung (2006), the calculated DPSE values (i.e. number of dolphins per 100 units of survey effort) using dolphin sightings data from the period 1996 to 2005 indicate the waters to the north of Lantau Island were utilized by dolphins to a significant extent. The waters around Lung Kwu Chau, along Urmston Road, at the northeast corner of the airport, and around the Brothers Islands were all identified as important areas to the dolphins in the North Lantau region. Therefore, the ecological value of the waters of the Northwestern WCZ to dolphins in the Assessment Area is considered to be high.

6.5.1.6 No records of Horseshoe crab were found in Western Buffer WCZ. The Western Buffer WCZ did not provide suitable habitat for this species. However, juvenile and adults horseshoe crabs were recorded in Northwestern WCZ. Therefore Northwestern WCZ provides nursery ground for horseshoe crabs.

6.5.1.7 Seagrass is not a protected species in Hong Kong, but is of locally rare and of conservation interest. No seagrass was recorded in the Western Buffer WCZ. Seagrass was recorded in the Northwestern WCZ with Halophila ovata recorded in Yam O and San Tau, Zostera japonica recorded in San Tau mudflat, and Halophila beccarii recorded in Tai Ho Wan. The Northwestern WCZ provides nursery ground for seagrass.

6.6 Identification and Evaluation of Environmental Impact

Construction Phase

6.6.1.1 The Project will involve minor land-based construction works within the existing Pillar Point Sewage Treatment Works (PPSTW), and therefore no ecological impact is expected within the PPSTW project area. This issue will not be addressed further in this Section.

Operation Phase

6.6.1.2 As discussed in Section 4, the key water quality issue of this Project would be the effect of disinfected CEPT effluent discharged from the PPSTW. Key parameters of concern would include E. coli, dissolved oxygen (DO), Biochemical Oxygen Demand (BOD₅), Suspended Solids (SS), Total Inorganic Nitrogen (TIN), Unionized Ammonia (UIA) and sedimentation rate.

6.6.1.3 According to the Water Quality Impact modeling results in Section 4, the levels of E. coli, BOD₅, SS and sedimentation rate decrease in the Northwestern WCZ while the TIN and UIA do not have significant change during the commissioning of the Project. This indicates that, with the implementation of the Project, the changes of water parameters would have a positive impact to the water quality and marine ecology in the Northwestern WCZ.

Evaluation of Environmental Impacts

6.6.1.4 The Water Quality Impact modeling results in Section 4 indicated that the potential impact zone would be restricted to the Northwestern and Western Buffer WCZs. Therefore, the impact assessment focuses on ecological resources including benthos, intertidal communities, coral communities, artificial reefs and Chinese White Dolphin, in these two WCZs.

6.6.1.5 The model results show that there would be a reduction of E. coli, BOD₅, SS and sedimentation rate in the Northwestern and Western Buffer WCZs and a slight increase in DO level localized at the PPSTW outfall after the Project completion. Therefore, the Project would have a positive impact on the affected marine habitats as well as the health of the Chinese White Dolphin and its prey (DSD 2003). In addition, the predicted Unionized Ammonia (UIA) level in the receiving water would fully comply with the WQO of 0.021 mg/l after the Project completion. Adverse impact to ecological resources including those habitats / species of conservation interest such as coral communities, artificial reefs and Chinese White Dolphin in Northwestern and Western Buffer WCZs is not expected.

6.6.1.6 Based on the Water Quality Impact Assessment, the predicted TIN (nutrient) levels, which failed to comply with the WQO for the 2 WCZs. The key issue in relation to the TIN exceedances would be the potential enhancement of algal bloom. The predicted TIN levels were subject to the influence from the background sources from the Pearl Estuary as well as other concurrent discharge such as the North-West New Territories (NWNT) outfall. Since the Water Quality modeling shows that the change of nutrient levels induced by this Project would be minor and localized near the PPSTW outfall, potential adverse impacts are not expected.

6.6.1.7 Based on the above, in accordance with the EIAO TM Annex 8 criteria, the potential ecological impacts on marine benthic community, coral community, intertidal community, artificial reefs and Chinese White Dolphin are presented in Tables 6.6.1 to 6.6.5.

Table 6.6.1 Potential ecological impacts on Benthos habitats within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Western Buffer WCZ	Northwestern WCZ
Habitat quality	Low	Low
Species	Common and widespread species in Hong Kong such as polychaetes and crustaceans, which dominate in this WCZ	Common and widespread species in Hong Kong such as polychaetes and crustaceans, which dominate in this WCZ
Size/ Abundance	Moderate size of benthic habitat would be impacted	Large size of benthic habitat would be impacted
Duration	Long term	Long term
Reversibility	No irreversible impacts on the composition and abundance of benthos community	No irreversible impacts on the composition and abundance of benthos community
Magnitude	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.
Potential Impact	Low	Low

Table 6.6.2 Potential ecological impacts on Coral community within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Western Buffer WCZ	Northwestern WCZ
Habitat quality	Low-Moderate	Low-moderate
Species	A very few soft coral but no hard coral species were recorded in waters at south of Tsing Yi. Low number of soft coral species and moderate high number of hard coral taxa (more than 14 taxa) was recorded in Ap Lei Chau and Sandy Bay.	Only 6 colonies of soft corals were recorded at Sha Chau and Lung Kwu Chau Marine Park in this WCZ
Size/ Abundance	Low abundance of soft coral and no hard coral community were recorded in south of Tsing Yi. Low abundance of both soft and hard corals was recorded in Ap Lei Chau. Moderate high abundance of soft corals and low abundance of hard corals were recorded in Sandy Bay	Only low abundance of soft corals were present in this WCZ
Duration	Long term	Long term
Reversibility	No irreversible impacts on the composition and coverage of coral community	No irreversible impacts on the composition and coverage of coral community
Magnitude	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.
Potential Impact	Low	Low

Table 6.6.3 Potential ecological impacts on Intertidal communities within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Western Buffer WCZ	Northwestern WCZ
Habitat quality	Low	Low
Species	The dominant species of herbivorous grazers and limpets are common and widespread in Hong Kong	Apart from common epi-fauna and in-fauna species, horseshoe crab and seagrass are species of conservation interest
Size/ Abundance	Low abundance of species recorded	Low abundance of species recorded
Duration	Long term	Long term
Reversibility	No irreversible impacts on the composition and abundance of intertidal community	No irreversible impacts on the composition and abundance of intertidal community
Magnitude	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.
Potential Impact	Low	Low

Table 6.6.4 Ecological impact on artificial reefs within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Artificial Reefs
Habitat quality	Moderate
Species	The fish species found within the artificial reefs are common and widespred in Hong Kong.
Size/ Abundance	Small
Duration	Long term
Reversibility	No irreversible impacts on the composition and abundance of reef-associated fish and other marine fauna.
Magnitude	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.
Potential Impact	Low

Table 6.6.5 Ecological impact of Chinese White Dolphin within potential impacted areas (Western Buffer and Northwestern WCZs)

Criteria	Chinese White Dolphin
Habitat quality for Northwestern and Western Buffer WCZs	Both habitats have been subject to certain degree of disturbance from urban developments and are under the influence of water pollutants from Pearl River and Hong Kong urban discharges
Species	Chinese White Dolphin is an ecologically important species listed under IUCN Red List of Threatened Species, CITES Appendix 1 and protected Animals under Hong Kong Legislation and in the People Republic of China
Size/ Abundance	One to 3 individuals of dolphins over 9 years surveying efforts were recorded in Western Buffer WCZ compared with total population in year round in Hong Kong with minimum 103 to maximum 193 individuals in Hong Kong Waters. However, the Northwestern WCZ is considered as one of the major sighting habitats for Chinese White Dolphins, with calves observed near the Sha Chau and Lung Kwu Chau Marine Park
Duration	Long term
Reversibility	No irreversible impacts on the distribution and abundance of dolphins
Magnitude	Low. Small and localized change of TIN at PPSTW outfall and the resulted ecological impacts would be insignificant. Positive water quality impact with reduction of E.coli, BOD₅, SS levels and sedimentation rates and increase in DO levels.
Potential Impact	Low

6.6.1.15 No adverse marine ecological impacts are anticipated from the implementation of the proposed upgrading works considering that there would be improvement in water quality with reduction in E. coli, BOD_5, SS levels and sedimentation rates and increase in DO levels in Western Buffer and Northwestern WCZs;

6.7 Mitigation of Environmental Impact

6.7.1.1 As discussed above there would be no adverse ecological impacts from the proposed PPSTW upgrading and therefore no mitigation measures would be required.

6.8 Evaluation of Residual Impact

6.8.1.1 Based on the above assessment, no residual impact from the Project on ecological resources is anticipated.

6.9 Environmental Monitoring and Auditing

6.7.1.2 As discussed above there would be no adverse ecological impacts from the proposed PPSTW upgrading and therefore no marine ecological monitoring would be required.

6.10 Conclusions

6.10.1.1 A literature review has been conducted to establish the ecological baseline condition of the Assessment Area and assessment of potential impacts conducted in accordance with the EIAO TM requirements.

6.10.1.2 The Water Quality Impact modeling results in Section 4 indicated that there would be a reduction of E. coli, BOD₅, SS and sedimentation rates in the Northwestern and Western Buffer WCZs and a slight increase in DO level localized at the PPSTW outfall after the Project completion. Therefore, the Project would have a positive impact on the identified marine ecological resources. On the other hand, the model predicted that the Project would cause an increase in the TIN level in the receiving waters. The key issue in relation to the TIN would be the possible enhancemeng of algal bloom. As the model predicted that the change of TIN would be minor and localized at the PPSTW outfall, no adverse ecological impacts are anticipated from the Project.

6.11 References

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