9A                                      Baseline Marine Ecological Resources

9A.1                                Introduction

This Annex presents the findings of ecological studies for the proposed wind farm development areas off Southwest Lamma and the surrounding Study Area.  Marine ecological habitats and resources have been identified and the ecological value of the Study Area evaluated.  The assessment has been based on a review of the available literature, as well as detailed field surveys to provide the most up-to-date information on existing conditions.  The rationale for surveys is presented, followed by the methodologies employed, results obtained and a discussion of the results and comparison with other similar studies where appropriate.  The findings enclosed within this Annex will form the basis of establishing the ecological importance of the different marine habitats within and around the proposed wind farm development areas.

9A.1.1                          Ecological Study Area

The Study Area for the ecological assessment covers a large area of open water of southern Hong Kong to ensure that potential marine ecological sensitivities that have been identified in the water quality impact assessment are considered.  This relatively wide Study Area also ensures that consideration is given to mobile species that are present in the area (e.g. marine mammals and sea turtles).  The Study Area for the marine ecology baseline has incorporated the footprint of the proposed wind farm site and the proposed alignment corridor for the submarine cable connection to the Lamma Power Station Extension.  The Study Area is shown in Figure 9A.1.

9A.2                                Legislative Requirements and Evaluation Criteria

9A.2.1                          Introduction

This section summarizes all legislative requirements and evaluation criteria for the protection of species and habitats of marine ecological importance in the Study Area.

9A.2.2                          Legislative Requirements and Evaluation Criteria

Legislative requirements and evaluation criteria relevant to the study are as follows:

1.        Marine Parks Ordinance (Cap 476);

2.        Wild Animals Protection Ordinance (Cap 170);

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

4.        Town Planning Ordinance (Cap 131);

5.        Hong Kong Planning Standards and Guidelines Chapter 10 (HKPSG);

6.        The Technical Memorandum on Environmental Impact Assessment Process under the Environmental Impact Assessment Ordinance (EIAOTM);

7.        United Nations Convention on Biodiversity (1992);

8.        Convention on Wetlands of International Importance Especially as Waterfowl Habitat (the Ramseur Convention);

9.        PRC Regulations and Guidelines; and,

10.     City University of Hong Kong (2001). Agreement No. CE 62/98, Consultancy Study on Fisheries and Marine Ecological Criteria for Impact Assessment, AFCD, Final Report July 2001.

9A.2.3                          Marine Parks Ordinance (Cap 476)

The Marine Parks Ordinance provides for the designation, control and management of marine parks and marine reserves.  It also stipulates the Director of Agriculture, Fisheries and Conservation as the Country and Marine Parks Authority, which is advised by the Country and Marine Parks Board.  The Marine Parks and Marine Reserves Regulation was enacted in July 1996 to provide for the prohibition and control certain activities in marine parks or marine reserves.

9A.2.4                          Wild Animals Protection Ordinance (Cap 170)

Under the Wild Animals Protection Ordinance, designated wild animals are protected from being hunted, whilst their nests and eggs are protected from destruction and removal.  All birds and most mammals including all cetaceans are protected under this Ordinance, as well as certain reptiles (including all sea turtles), amphibians and invertebrates.  The Second Schedule of the Ordinance that lists all the animals protected was last revised in June 1997.

9A.2.5                          Protection of Endangered Species of Animals and Plants Ordinance (Cap 586)

The Protection of Endangered Species of Animals and Plants Ordinance was enacted to align Hong Kong’s control regime with the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). With effect from 1 July 2006, it replaces the Animals and Plants (Protection of Endangered Species) Ordinance (Cap 187).  The purpose of the Protection of Endangered Species of Animals and Plants Ordinance is to restrict the import and export of species listed in CITES Appendices so as to protect wildlife from overexploitation or extinction.  The Ordinance is primarily related to controlling trade in threatened and endangered species and restricting the local possession of them.  Certain types of corals are CITES listed, 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 listed species, no matter whether dead or living, is restricted. 

9A.2.6                          Town Planning Ordinance (Cap 131)

The Town Planning Ordinance provides for the designation of areas such as “Coastal Protection Areas”, “Sites of Special Scientific Interest (SSSIs)”, “Green Belt” and "Conservation Area” to promote conservation or protection or protect significant habitat. 

9A.2.7                          Hong Kong Planning Standards and Guidelines Chapter 10

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 addresses the issue of enforcement.  The appendices list the legislation and administrative controls for conservation, other conservation-related measures in Hong Kong, and Government departments involved in conservation.

9A.2.8                          Technical Memorandum on Environmental Impact Assessment Process under the Environmental Impact Assessment Ordinance

Annex 16 of the EIAOTM 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 ecological impacts.

9A.2.9                          Other Relevant Legislation

The Peoples’ Republic of China (PRC) is a Contracting Party to the United Nations Convention on Biological Diversity of 1992.  The Convention requires signatories to make active efforts to protect and manage their biodiversity resources.  The Government of the Hong Kong Special Administrative Region (HKSAR) has stated that it will be “committed to meeting the environmental objectives” of the Convention ([1]).

The PRC in 1988 ratified the Wild Animal Protection Law of the PRC, which lays down basic principles for protecting wild animals.  The Law prohibits killing of protected animals, controls hunting, and protects the habitats of wild animals, both protected and non-protected.  The Law also provides for the creation of lists of animals protected at the state level, under Class I and Class II.  There are 96 animal taxa in Class I and 161 in Class II.  Class I provides a higher level of protection for animals considered to be more threatened.

9A.3                                Marine Ecological Resources – Background

9A.3.1                          Introduction

This section describes the baseline conditions of the marine ecological resources at the Study Area from existing information in available literature.  Baseline conditions have been assessed based on a review of the findings of relevant studies and the collation of available information regarding the marine ecological resources of this part of Hong Kong.

Based on this review, an evaluation of the information collected was conducted to identify any gaps that need to be filled and to conduct an assessment of ecological importance of the marine habitats.  Where information gaps were identified or where certain habitats or species were considered to warrant further attention, focussed field surveys have been conducted (see Section 9A.4).

9A.3.2                          Site History

The site for the proposed wind farm is located in the waters between Lamma Island and Cheung Chau, near the southern reaches of the West Lamma Channel.  The proposed submarine cable route will run from the north of the wind farm site and connect to the Lamma Power Station Extension.  The water depth at the wind farm site ranges from -18 mPD to -23 mPD.  The closest distance of the wind farm site to land is approximately 3.5 km to Lamma Island.

In terms of hydrography, the Study Area is located within a zone of transition in which, in the wet season, surface waters of reduced salinity, higher temperature and higher dissolved oxygen occur over the cooler, more saline oceanic waters with lower dissolved oxygen.  In the dry season, with a reduced flow from the Pearl River adjacent to western Hong Kong waters, vertical stratification is usually not observed ([2]).

9A.3.3                          Literature Review

A literature review was conducted to determine the existing marine ecological conditions within the Study Area to identify habitat resources and species of potential importance.

Based on the literature review the following habitats and/or organisms of ecological interest have been identified in the Study Area:

·            Hard Bottom Habitats

-      Intertidal Hard Bottom Habitats

-      Subtidal Hard Bottom Habitats

·            Soft Bottom Habitats

-      Intertidal Soft Bottom Habitats

-      Subtidal Soft Bottom Habitats

·       Epifaunal Assemblages

·       Infaunal Assemblages

·            Marine Mammals

·            Sea Turtles

Existing conditions of each of the above marine resources based on available literature are discussed in more detail in the following sections.

9A.3.4                          Hard Bottom Habitats

Intertidal Hard Bottom Habitats

Intertidal hard shores of Hong Kong display characteristic zonation patterns consisting of different algal and invertebrate species along the vertical gradient from terrestrial to marine environments.

The intertidal hard bottom habitat of southwestern Lamma Island contains mainly moderately-exposed to exposed natural rocky shores extending from Ha Mei Tsui to Sham Wan.  The proposed submarine cable landing site at the Lamma Power Station Extension consists of sheltered to moderately-exposed artificial sloping seawall which was constructed in 2001.

There is little published information describing the intertidal assemblages of the artificial seawall at the Lamma Power Station Extension.  A wet season intertidal survey was, however, conducted on the west coast of the Lamma Island adjacent to the power station as part of the environmental impact assessment for the navigation channel and jetty modification works at the Lamma Power Station ([3]).  Results of this survey indicated that the survey areas were regarded as of low ecological value and comprised low abundances of common grazing molluscs and filter feeders with no particular conservation value.

In contrast, focussed quantitative surveys have been conducted on the natural rocky shores along the west of Lamma Island during the wet season of 1998 for the Lamma Power Station Extension EIA ([4]).  A total of 18 to 29 species of intertidal fauna, including grazing molluscs, common dogwhelks and barnacles (the most abundant species being the limpet Patelloida saccharina, the chiton Acanthopleura japonica and the barnacle Balanus amphitrite), and some 4 to 8 species macroalgae, were recorded in the survey transects.  The assemblages recorded were considered to represent common and widespread species typical of natural rocky shores in Hong Kong.

For this EIA Study, it was considered appropriate to conduct intertidal surveys at the artificial seawall of the Lamma Power Station Extension in order to fill data gaps and provide up-to-date data on the ecological value of this habitat.  No surveys were considered necessary on the intertidal habitats in vicinity of the proposed submarine cable alignment as habitats are relatively distant.

Subtidal Hard Bottom Habitats

Coral communities are commonly regarded as the most ecologically important and valuable subtidal hard bottom assemblages.  The Agriculture, Fisheries and Conservation Department (AFCD) reported that there are over 80 species of hard corals recorded in Hong Kong waters ([5]).  The general trend for coral communities in Hong Kong is one of increasing abundance and diversity from west to east with the greatest diversity and abundance generally found in the northeastern waters of Hong Kong due to the optimal environmental conditions for settlement, growth and survival found in these waters.  It has been suggested that the distribution of hard corals is primarily controlled by hydrodynamic conditions, in particular salinity level, turbidity and light penetration.

The western and southern waters of Hong Kong are influenced by the Pearl River Estuary which reduces salinities, increases turbidity and therefore reduces light penetration.  Due to the requirements for coral growth, the cumulative effect of these conditions results in sub-optimal conditions for coral recruitment and survival in these waters.  Unlike the hermatypic hard corals, ahermatypic octocorals (generally include soft and black corals) which do not require light for zooxanthellae photosynthesis, are more widely distributed in Hong Kong waters and often occur at greater depths.

Ecology of the subtidal hard bottom habitats in the vicinity of the proposed cable landing site has been reported in two key studies conducted in 1998 and 2000 respectively.  In 1998, Remotely Operated Vehicle (ROV) surveys were conducted at the footprint of the extension reclamation site and the seawall of the Ash Lagoon as part of the EIA for the Lamma Power Station Extension ([6]).  Findings of the surveys showed that there was an abundant assemblage of soft corals and gorgonians, particularly the sea whip Euplexaura robusta and the soft corals Dendronephthya spp., localised within a 1 km length at a distance of approximately 50 – 100 m to the south and the west of the seawall of the Ash Lagoon.  The densities of the soft coral assemblages at the site surveyed (< 0.815 m^-2) were, however, considered as low in comparison with those found at other sites in Hong Kong.

A baseline marine ecological monitoring, which included quantitative Rapid Ecological Assessment (REA) dive surveys, was conducted in 2000 prior to the commencement of the reclamation works for the Lamma Power Station Extension to establish the status of the subtidal coral assemblages of the project site ([7]).  Results of the monitoring showed that a total of 11 to 12 species of corals, predominantly gorgonians and soft corals, were found at the Ash Lagoon seawall and the seabed about 10 – 20 m from the seawall.  As with the 1998 survey, the subtidal assemblages of these sites consisted mainly of gorgonians and soft corals, with Euplexaura sp. being particularly abundant.  The octocoral abundance at these sites ranged from 4.6 to 10.1 colonies m^-2.  Isolated colonies of the non-reef building hard coral species Tubastrea sp. were also present at the Ash Lagoon Seawall.

A number of studies have been conducted for the subtidal hard bottom habitats along the natural shores in the vicinity of the proposed cable alignment.  In the 1998 study, ROV and quantitative SCUBA dive surveys were conducted along the west coast of Lamma Island from Shek Kok Tsui to Hai Mei Tsui South ([8]).  Findings from the ROV survey at a depth range of 5-10 m indicated that while the seabed characteristics varied from flat sand to a steep rocky seabed comprised largely of boulders, the subtidal assemblages of the sites surveyed were dominated by gorgonians and soft corals (from the genus Dendronephthya) with only one hard coral species (Tubastrea sp.) recorded.  Results of subsequent quantitative SCUBA survey at shallower coastal region of the same sites revealed that these sites were generally covered by rocks and sand with shell debris and coral cover was very low (mean cover < 1.4 % of the transect).  Coral diversity was also very low, comprising hard corals from the family Faviidae and Psammocora superficialis, and the soft corals Dendronephthya spp.  The subtidal assemblages were dominated by sessile organisms such as mussels Septifer virgatus and Perna viridis and barnacle Balanus spp., and mobile fauna including gastropods, crabs, sea cucumber and urchins.  Overall, the ROV and SCUBA surveys concluded that the relative abundance and diversity of corals recorded at the sites surveyed was low in comparison with other areas in Hong Kong, and the subtidal assemblages were of low ecological value.

Another dive survey was conducted in 2001 which revisited half of the sites surveyed in the 1998 survey ([9]).  Similar findings were reported on the seabed conditions and low abundance of hard corals and octocorals, with two additional hard coral genera Cyphastrea and Goniastrea recorded.

As part of a study of the marine habitats of South Lamma, dive surveys were conducted along shoreline from Hung Shing Ye to Ha Mei Tsui ([10]), in areas over 1 km from the Project site.  The surveys found sparsely scattered coral colonies of encrusting faviids, interspersed with a few soft corals of the genus Dendronephthya.  Most colonies were small with sizes varying little amongst most colonies.  In comparison to other sites around Lamma Island, western Lamma supported fewer faviid corals than the eastern coast such as at Tung O Wan.  In comparison to other sites in Hong Kong, the coral communities were considered to be of low ecological value.

Dive surveys conducted around Yung Shue Wan, which is about 1 km away from the proposed cable landing point, concluded that the identified coral community was not of great significance in comparison to other areas in Lamma ([11]).

For this EIA Study, it was considered appropriate to conduct subtidal dive surveys at the artificial seawall of the Lamma Power Station Extension and at hard substrate(s) along the cable alignment in order to fill data gaps and provide up-to-date data on the ecological value of this habitat type.

9A.3.5                          Soft Bottom Habitats

Intertidal Soft Bottom Habitats

Sandy shores along the west coast of Lamma Island that faces the wind farm site include the sandy shore adjacent to the Lamma Power Station, Kat Tsai Wan, Tit Sha Long and two gazetted beaches at Hung Shing Yeh and Lo So Shing, which are at least 1.5 km from the cable landing point at the Lamma Power Station Extension.  Sandy shores generally appear almost devoid of marine life ([12]) and are hence of low ecological value.  Sham Wan, which is an intertidal sandy shore of ecological value to nesting Green Turtles, is located at least 4 km from the cable landing point and is discussed further in Section 9A.3.6.

There are no intertidal soft habitats within 500 m of the cable landing point, and as such, they are not considered further here and in the Impact Assessment.

Subtidal Soft Bottom Habitats

Epifauna

Subtidal soft bottom habitats, as well as supporting infaunal species, commonly support macro-benthic epifauna.  These organisms are generally > 1 mm in size and live either on or within the surface sediments.  Due to the nature of the Hong Kong’s fishery and the typical subtidal substratum in Hong Kong being soft bottom (sandy or silty) habitat, data on subtidal epifaunal assemblages in Hong Kong are primarily available from studies on benthic fisheries resources, collected by demersal trawling surveys.

Information on the epifaunal assemblages of the Study Area have been taken from the AFCD-commissioned study on Fisheries Resources and Fishing Operations in Hong Kong ([13]).  Trawl surveys undertaken as part of AFCD’s study indicated that that the highest biomasses recorded in the waters were contributed by Squillidae (mantis shrimp) for both south (waters outside Shek Kok Tsui) and north (waters outside Yuen Kok) Lamma Island, which is over 2 km away from the Project Site.  Other families such as Synodontidae (lizard fish) and Dasyatidae (stingrays) have been recorded in south Lamma and north Lamma, respectively.

Two species of horseshoe crab, Tachypleus tridentatus and Carcinoscorpius rotundicauda, have previously been recorded in AFCD surveys around Hong Kong waters (AFCD 2006) ([14]), including the mudflat of Shui Hau as the key nursery grounds for T. tridentatus ([15]).  The horseshoe crab nursery ground at Shui Hau is located far away from the proposed Wind Farm Site and cable route (at least 10 km), and is considered to be too remote to be affected by the Project works.

No surveys were considered necessary for epifaunal assemblages as a review of the available literature provided sufficient evidence of a low ecological value habitat in the waters surrounding the proposed wind farm and along the submarine cable route off Southwest Lamma.

Infauna

Subtidal infauna are organisms (> 0.5 mm in size) living either on or within the surface sediments of the seabed.  In order to provide an indication of the potential ecological value of the infaunal assemblages at the wind farm site and cable route in the context of seabed of Hong Kong waters, it is considered useful to review studies that have investigated infaunal assemblages in Hong Kong on a wide scale.  Where considered useful, studies of infaunal assemblages at specific locations have also been included in the review.

A number of studies have been carried out in the vicinity of the wind farm site and cable route, dating back to 1982 and mostly in the 1990s ([16]) ([17]) ([18]) ([19]) ([20]) ([21]).  In summary, these studies suggest that infaunal assemblages are polychaete-dominated, with mean abundance and mean biomass generally lower than the overall mean values (101.4 individuals m^-2and 35.2 g m^-2 respectively) for Hong Kong.  Average biomass of infauna from the studies listed above are summarised in Table 9A.1.

Table 9A.1      Biomass of Infaunal Assemblages from the Lamma Island Area & Elsewhere in Hong Kong ([22])

Study	Area/ Date	Biomass (g m-2)
Shin & Thompson 1992	West Lamma Channel	20.20
	Hong Kong Mean	35.20
APH Consultants 1994	APH-13 December 1993	14.68
	APH-13 June 1994	3.93
	APH-15 December 1993	13.13
	APH-15 June 1994	7.53
AXIS Consultants 1994	Navigation Channel September 1994	22.20
Mouchel 1998	S15 (West Lamma) – Mean	24.14
ERM 1996 – 1997 Seabed Ecology Studies	East Sha Chau (August)	7.50
	Basalt Island (August)	6.10
	East of Ninepins (August)	12.80
	Soko Islands (November)	35.70
	South Cheung Chau (November)	47.20
	Eastern Waters (April)	32.90
	Tathong Channel (April)	35.70
	South Lamma (April)	30.60
ERM 1998	Power Station Reclamation Site (September)	6.00

 

Territory-wide surveys of Hong Kong subtidal infauna assemblages were conducted at proposed wind farm location and in the vicinity of the proposed cable corridor in 2001([23]).  Nine sampling stations (Station Nos. 35 – 39, 55 – 57) are close to the proposed area of works and data extracted from them are considered to provide representative, up-to-date information of the assemblages within the Study Area.  Findings of the surveys indicated that the substratum of the nine sampling stations is covered by very fine sand (average median diameter of 5.83 phi unit).  Benthic assemblages found were typical of Hong Kong waters.  In summer, the average number of species was high (40 species 0.5 m^-2), while the average abundance (331 individuals per m^-2) and average biomass (32.33 g m^-2) were low when compared with average values of Hong Kong (33 species 0.5 m^-2, 540 individuals m^-2 and 71.2 g m^-2; Table 9A.2).  In winter, the average number of species (42 species 0.5 m^-2) and average biomass (35.17 g m^-2) were high, while the average abundance (344 individuals m^-2) was medium in comparison with average values of benthic assemblages in Hong Kong (34 species 0.5 m^-2, 450 individuals m^-2 and 28 g m^-2).  Concerning the species diversity, the sediments showed medium (H’ = 2 to 3) to high diversity (H’ >3), in comparison to other survey areas.  In both seasons, no species of conservation concern were found in all stations within the Study Area.

Table 9A.2      Summary Information from Grab Survey in 2001 ([24])

Proposed Project Area	Station No.	Summer (Wet Season)			Winter (Dry Season)
		No. of Sp.	Abundance	Biomass	No. of Sp.	Abundance	Biomass
Cable route	38	43	322	18.84	56	692	19.12
	39	39	284	54.70	34	142	81.20
Mean		41	303	36.77	45	417	50.16
Wind farm	35	34	330	8.70	39	264	6.82
	36	43	416	61.76	34	262	42.58
	37	42	330	13.20	41	288	11.14
Mean		40	359	27.89	38	271	20.18
Overall mean		40	331	32.33	42	344	35.17
Overall in HK		33	540	71.20	34	450	28.00

 

Based on the above, the infaunal assemblages in the proposed Study Area are not considered to have great abundance, diversity and biomass in comparison to other areas of Hong Kong.  However, it was considered appropriate to conduct benthic surveys to provide up-to-date data on such assemblages in the vicinity of the works areas of this Project.

9A.3.6                          Potential Marine Park at South Lamma

The general marine and coastal waters off south Lamma Island have been proposed for designation as Marine Parks as a result of the AFCD-commissioned feasibility study ([25]).  The proposed park is approximately 1 km away the wind farm development site.  The proposed designation primarily aims to protect one of the core habitats for finless porpoise and the nesting site in Sham Wan for green turtles.  A variety of studies have investigated the marine ecology of these two species in this area and the results are summarised in the following sections.

9A.3.7                          Other Protected Areas

The Cape D’Aguilar Marine Reserve, the potential Marine Park at Soko Islands and the potential Marine Park at Fau Lau, which are about 10 km, 10 km and 20 km away from the proposed Project Site respectively, are considered to be too remote to be affected by the Project works.

9A.3.8                          Marine Mammals

A total of 16 (and possibly up to 18) species of marine mammals (mostly cetaceans) have been recorded in Hong Kong waters, two of which are considered residents: the Indo-Pacific humpback dolphin (Sousa chinensis, locally called Chinese white dolphins) and the finless porpoise (Neophocaena phocaenoides) ([26]).  Whilst the distribution of Indo-Pacific humpback dolphins is limited to the western waters of Hong Kong, which are influenced by freshwater input from the Pearl River ([27]) ([28]), finless porpoises are common in the waters of southern and eastern Hong Kong and do not occur in Hong Kong’s northwestern waters (apart from very occasional strandings) ([29]).  Given the distinctive local distribution patterns of these two species, Neophocaena phocaenoides is considered as the key sensitive receptor of this Project and is discussed further below.  Sousa chinensis is, however, also discussed below to establish its status within the Study Area.

A long-term monitoring programme on humpback dolphins and finless porpoise in Hong Kong and adjacent waters has been undertaken since 1995 to provide broad knowledge on the distribution, abundance, habitat use, and life history of these species ([30]) ([31]) ([32]) ([33]) ([34]) ([35]).  Systematic databases established from this programme have been evaluated to form the basis of this review.

Indo-Pacific Humpback Dolphin

The Indo-Pacific humpback dolphin Sousa chinensis is a tropical/ sub-tropical cetacean widely distributed in the coastal and inshore waters of the Indian and western Pacific oceans ([36]).  It is protected locally by the Wild Animals Protection Ordinance (Cap. 170), and is listed as "Near Threatened" in the 2009 IUCN Red List of Threatened Species ([37]).  Sousa chinensis is also listed in CITES Appendix I (i.e. highest protection), and is listed as “Endangered” in the China Species Red List and a "Grade I National Key Protected Species" in China.  As such S. chinensis is considered a species of conservation interest/ concern, both locally in Hong Kong and regionally in China and across the Asia Pacific.

It has been reported that in 2006 at least 1,200 ([38]) individual dolphins were estimated to utilise the waters of the Pearl River Estuary and Hong Kong ([39]).  A more recent estimate using 2004 to 2006 survey data indicates that the total population size of this species in these waters is considered to be about 1,300 to 1,500 individual ([40]).  Of these individual dolphins, approximately 200 are thought to include waters within Hong Kong as part of their range ([41]).

Abundance of humpback dolphins in Hong Kong waters is the highest in the north and west Lantau areas (Figure 9A.2).  These areas are thus considered to be the major habitats for humpback dolphins in Hong Kong waters, where individuals of humpback dolphins have been consistently sighted throughout the year ([42]).  Seasonal and spatial variation of abundance of humpback dolphins is usually observed; this is thought to be due to the increased input of freshwater from the discharge of the Pearl River Estuary and the subsequent movements of estuarine prey species into Hong Kong from PRC waters ([43]) ([44]) ([45]).  AFCD reported that in 2006 the abundance of humpback dolphins in Hong Kong’s waters ranged from 103 in spring to 193 individuals in autumn ([46]).

The long-term monitoring study in the past 13+ years has shown that humpback dolphins do not regularly occur in eastern waters with higher salinity, as this species has a strong preference for waters with influence from the Pearl River freshwater input ([47]) ([48]).  Waters to the east of Lantau are rarely used by dolphins, and this area appears to comprise the eastern boundary of their range ([49]).  The long-term sightings database has revealed that there have only been four sightings of humpback dolphins in the eastern survey areas (i.e. including southwestern Lamma waters) since 2000 (Figure 9A.3).  Of note, all of these were solitary animals and were sighted only in winter months (in Jan 2000, Feb 2004, and Nov and Dec 2007) ([50]).  Their occurrence in these waters was thus considered to be extralimital.

Quantitative grid analysis (i.e. numbers of sightings standardised with survey effort) has been established to examine dolphin abundance and their fine-scale habitat usage.  Of the areas surveyed, standardised dolphin sighting densities and dolphin densities were the highest at West Lantau ([51]).  Such analysis was, however, not undertaken for the Lamma survey area since sightings were too low to allow a cost-effective monitoring and analysis.

On the basis of the review of long-term monitoring database and relevant literature, southwestern Lamma waters are not considered to be an important area for Indo-Pacific humpback dolphins.

Finless Porpoise

The finless porpoise Neophocaena phocaenoides is a tropical/ sub-tropical cetacean widely distributed in coastal marine waters, as well as some river mouths and estuaries, from the Persian Gulf eastwards around the rim of the Indian Ocean to the Taiwan Strait area in southern Japan.  It is protected locally by the Wild Animals Protection Ordinance (Cap. 170), and is listed as "Vulnerable" in the 2009 IUCN Red List of Threatened Species ([52]).  Neophocaena phocaenoides is also listed in CITES Appendix I (i.e. highest protection), and is listed as “Endangered” in the China Species Red List.  As such N. phocaenoides is considered a species of conservation interest/ concern, both locally in Hong Kong and regionally in China and across the Asia Pacific.

In Hong Kong, finless porpoise occur year-round, and they can be found primarily in the southern (i.e Po Toi, Lamma, Southeast and Southwest Lantau) and eastern (i.e. Mirs Bay, Sai Kung and Ninepins) waters of the territory ([53]) ([54]) ([55]) ([56]) ([57]) (Figure 9A.4).  The AFCD reported that in 2006 at least 217 ([58]) individual porpoises were estimated to utilise the waters of Hong Kong and in Chinese waters just south of Hong Kong ([59]).

The majority of porpoise sightings have been made in southern waters, with a high concentration of sightings near the Po Toi Islands, at the southwest corner of Lamma Island, in southeast Lantau (southern waters of Cheung Chau and southwest corner of Chi Ma Wan Peninsula) and southwest Lantau (near Shek Kwu Chau and the Soko Islands) (Figure 9A.5).  These areas are thus considered to be the main habitats for finless porpoises in Hong Kong waters.  They rarely occurred in West and North Lantau, which are heavily influenced by freshwater input from the Pearl River, and are the prime habitat of the Chinese white dolphin population ([60]) ([61]).  The only area where the two resident species showed substantial overlap in distribution was in South Lantau waters ([62]) ([63]).

Seasonal variation in distribution is evident for finless porpoises in Hong Kong ([64]) ([65]).  They are more commonly sighted in southern waters (i.e. South Lantau and Lamma) during winter and spring, while in summer and autumn they shift to the eastern waters to a great extent (i.e. Po Toi, Ninepins and Sai Kung), potentially as a result of the influx of freshwater in those months, and hence more estuarine conditions ([66]) ([67]).  Their abundance in Hong Kong waters ranges from a high of approximately 152 individuals in spring to approximately 55 in autumn ([68]).

Quantitative grid analysis on porpoise habitat use revealed that during 2004-08, standardised porpoise sighting densities (i.e Sightings Per Survey Effort (SPSE) values, representing the number of on-effort sightings per km², with the survey area mapped using a 1 km by 1 km grid) were higher at the waters just south of Soko Islands, the offshore waters in Southeast Lantau, at southwest corner of Shek Kwu Chau and Cheung Chau, near Stanley Peninsula and around Po Toi Islands than in other areas of Hong Kong waters ([69]).

Therefore based on the results of the information available from the long-term sighting data on marine mammals in the waters of Hong Kong, it appears that finless porpoises have been sighted regularly within the areas surrounding the proposed wind farm site and cable route.  In order to provide up-to-date and detailed comprehensive baseline information to supplement information from the literature, a programme of finless porpoise surveys was undertaken for this EIA Study.

9A.3.9                          Sea Turtles

Of the seven extant species of sea turtles, loggerheads (Caretta caretta), leatherbacks (Dermochelys coriacea), hawksbills (Eretmochelys imbricata), olive ridleys (Lepidochelys olivacea) and greens (Chelonia mydas) have been reported to occur in the waters of Hong Kong ([70]).  However, the green turtle is the only species confirmed to nest in Hong Kong ([71]).

Green turtle Chelonia mydas is protected locally by the Wild Animals Protection Ordinance (Cap. 170), and is listed as "Endangered" in the 2009 IUCN Red List of Threatened Species ([72]).  It is also listed in CITES Appendix I (i.e. highest protection), and is listed as “Critically Endangered” on the China Species Red List and a "Grade II National Key Protected Species" in China.  As such Chelonia mydas is considered a species of conservation interest/ concern locally, regionally and globally.

The major nesting site for green turtles in Hong Kong is at Sham Wan, southern Lamma Island, which is over 5 km from the proposed wind farm site ([73]) ([74]) ([75]) ([76]).  A small number of green turtles are known to nest at Sham Wan, although nesting does not occur every year ([77]).  In 1999, the 0.5 ha of sandy beach at Sham Wan was listed as a Site of Special Scientific Interest and a Restricted Area under the Wild Animals Protection Ordinance (Cap. 170).  Access to the beach is prohibited between 1 June and 31 October each year during the green turtle nesting season ([78]).

Satellite tracking of female green turtles nesting at Sham Wan beach has been undertaken since 2002 to examine their regional migration patterns.  Results of the tracking showed that the same nesting female (named “Hong Kong 2”) tracked in June 2003 and August 2008 used the waters close to Sham Wan, in the south and southeast of Lamma Island, between subsequent clutches (Figures 9A.6 and 9A.7).  She maintained a distance of within 10 km of the beach during inter-nesting periods for just over 2 months before migrating back to foraging grounds in the coastal waters of Dao Bach Long Vi, Vietnam ([79]).

Satellite tracking of on a foraging green turtle in the Gangkou Sea Turtle National Nature Reserve populations in China revealed that they moved from its foraging grounds in Daya Bay to Wanshan Archipelago ([80]), migrating past or through Hong Kong, by Basalt Island, Tung Lung Chau and other parts of Hong Kong waters, between nesting and foraging grounds (Figure 9A.8).  Another tracking study conducted on post-nesting green turtles populations in Taiwan also indicated that the turtles often utilise several coastal areas as temporal residential forging sites as far as to the east coast of China ([81]). 

There is no documented evidence of foraging activity by sea turtles in Hong Kong waters, though sightings of sub-adults green turtles that would not undertake long-distance migration may suggest foraging behaviour (AFCD, unpublished data).  Overseas studies have showed that green turtles may not feed during the nesting season and they normally forage on seagrass as primary food source ([82]) ([83]) but can also feed on algae ([84]) .  Of note, no seagrass beds that could be foraging areas for green turtles are located in vicinity to the proposed wind farm site and cable route.  In addition, the seabed at the Study Area is comprised of fine sediments which do not appear to support important foraging habitats for green turtles, either during the inter-nesting season, or as a more permanent foraging ground.  The Study Area is therefore unlikely to serve as foraging habitats for this species.

Due to the very occasional occurrence of green turtle in Hong Kong waters, systematic survey for the species was considered impractical and as such, baseline surveys were not undertaken as part of this EIA.

9A.4                                Baseline Marine Ecological Surveys

The literature review of the marine ecological habitats and resources of the waters within and in close proximity to the proposed wind farm and cable route has provided an indication of the ecological importance of the Project Site.  However, in order to provide up-to-date information on marine ecological baseline conditions, a number of field surveys were considered necessary and were undertaken in 2008 and 2009 (Table 9A.3).

Table 9A.3      Marine Ecology Baseline Surveys

Survey Type	Methodology	Season & Date
Intertidal Assemblages at Lamma Power Station Extension	Quantitative surveys of three 100 m belt transects (at high, mid and low intertidal zones) at artificial seawall, covering both wet and dry seasons	Wet Season: 28 Oct 2008 Dry Season: 27 Feb 2009
Subtidal Benthic Assemblages	Quantitative grab sampling surveys at 10 sites (three stations at each site).  Sites surveyed represented the wind farm site, cable route and reference sites	Wet Season: 19 Oct 2008 Dry Season: 19 Mar 2009
Subtidal Hard Bottom Assemblages (Coral)	Semi-quantitative (Rapid Ecological Assessment (REA) technique) and qualitative (recorded within Study Area and areas in the vicinity)	4 and 5 May 2009
Marine Mammal	Quantitative vessel-based survey using line transect methods around Lamma Island                     Qualitative vessel-based survey around Lamma Island	1 day per month for 6 months, from Dec 2008 to May 2009 (inclusive) (Winter / Spring) in the following dates: 24 Dec 2008 (Winter), 16 Jan 2009 (Winter), 13 Feb 2009 (Winter), 13 Mar 2009 (Spring), 15 Apr 2009 (Spring) and 11 May 2009 (Spring   3 days per month for 5 months, from July to October 2008 (Summer / Autumn), and in June 2009 (Summer), in the following dates: 24, 26, 28 July 2008 (Summer), 15, 21, 25 August 2008 (Summer), 4, 11, 26 September 2008 (Summer), 6, 17, 20 October 2008 (Autumn), and 10, 11, 17 June 2009 (Summer)

 

Survey methodologies have been selected to follow standard and accepted techniques for marine ecological surveys.  In addition, each methodology has been previously conducted as part of other Environmental Impact Assessments (EIA) studies, accepted under the Hong Kong Environmental Protection Department Environmental Impact Assessment Ordinance (EIAO).

Survey schedules have been undertaken in accordance with the Environmental Impact Assessment Ordinance, Cap.499 Guidance Note 7/2002 - Ecological Baseline Survey for Ecological Assessment, specifically in terms of the following:

·           Duration of Survey;

·           Seasonality;

·           Types of Survey Period; and

·           Survey Effort.

The following sections present the methodology and results for each marine ecological survey undertaken as part of the assessment of marine ecological baseline conditions.

9A.4.1                          Intertidal Hard Bottom Assemblages

Survey Methodology

Only one type of intertidal habitat, artificial shore, was identified in the vicinity of the proposed cable landing point   The artificial shore at the Lamma Power Station Extension consists of steep seawall of large boulders, and this habitat was examined for the intertidal surveys.

The intertidal surveys consisted of quantitative transect surveys at three locations (T1, T2 and T3, Figure 9A.9) along the artificial sloping seawall within the 500 m study boundary of the proposed landing point.  Intertidal surveys were conducted in both the wet and dry seasons.  Local tide tables were used to assess tidal height at the site and times of surveys.

At each of the three survey locations, three 100 m horizontal (belt) transects along the seawall were surveyed at each of the three shore heights: 2 m (high-shore), 1.5 m (mid-shore) and 1 m (low-shore) above Chart Datum (CD).  On each transect, ten quadrats (50 cm × 50 cm) were placed randomly to assess the abundance and diversity of flora and fauna.  All organisms found in each quadrat were identified and recorded to the lowest possible taxonomic level to allow density per quadrat to be calculated.  Sessile species, such as algae (encrusting, foliose and filamentous), barnacles and oysters, in each quadrat were also identified and estimated as percentage cover on the rock surface using a double-strung, 50 cm × 50 cm quadrat.

Survey Results

Wet Season Survey Results

A total of 18 faunal groups were recorded in the wet season survey.  At all three transect locations, dominant (in terms of abundance) organisms recorded included the littorinid snail Echinolittorina spp. in the high-shore, the topshell Monodonta labio and the limpet Cellana toreuma in the mid-shore, and the limpets C. toreuma and Patelloida saccharina and the common dogwhelk Thais clavigera in the low-shore.  Sessile species including the barnacle Tetraclita squamosa and the oyster Saccostrea cucullata are also present in the low-shore.  Both the abundance/ density of mobile species and percentage cover of sessile species were considered to be low (mean ~ 38 individuals m^-2 and ~ 13 % m^-2 respectively).  Only four species of algae and one species of cyanobacteria were recorded in the wet season survey, and the percentage cover by these species was very low (mean < 4 % m^-2).  The surveys results are summarised below:

 

Wet Season	Mean Abundance per m2
Species	High-shore	Mid-shore	Low-shore
Gastropods (individuals)
Acanthopleura japonica	0.27	0.93	3.47
Cellana toreuma	0.00	12.40	17.20
Chlorostoma argyrostoma	0.00	0.00	0.27
Echinolittorina radiata/ vidua	8.13	0.13	0.00
Echinolittorina trochoides	0.40	0.00	0.00
Monodonta labio	2.53	13.33	12.13
Nerita yoldii	0.00	1.07	4.00
Patelloida pygmaea	0.00	0.00	0.40
Patelloida saccharina	3.20	5.60	13.60
Siphonaria japonica	0.13	0.27	0.53
Thais clavigera	0.00	5.33	9.73
Grapsus albolineatus	0.00	0.00	0.40
Crustaceans
Isopod sp. (individuals)	0.00	0.00	0.80
Ligia exotica (individuals)	1.60	0.67	1.60
Capitulum mitella (%)	0.47	1.47	0.07
Tetraclita squamosa (%)	0.87	7.83	13.87
Tubeworms
Hydroides sp.	0.00	0.00	0.40
Bivalves
Saccostrea cucullata (%)	0.27	1.13	12.73
Algae (%)
Ralfsia expansa	0	0.67	0
Hildenbrandia sp.	0	2.33	3.00
Corallina sp.	0	0	3.27
Pseudulvella applanata	0	0	1.00
Cyanobacteria (%)
Kyrtuthrix maculans	0	0.83	0

 

Dry Season Survey Results

The species composition of the intertidal organisms during the dry season was similar to that of the wet season, with a total of 17 faunal groups, four algal species and one species of cyanobacteria.  Seasonal variation in intertidal assemblage pattern was attributed to higher abundance of grazing molluscs, particularly Echinolittorina spp., Cellana toreuma, Monodonta labio, Patelloida saccharina and Siphonaria japonica, lower abundance of Thais clavigera, lower percentage cover of Tetraclita squamosa and Saccostrea cucullata, and higher percentage cover of the encrusting algae Hildenbrandia sp., in the dry than the wet season.   Mean abundance of mobile species, sessile species and algae recorded in the dry season survey were 64 individuals m^-2, 3 % m^-2 ~ 21 % m^-2 and respectively.  The surveys results are summarised below:

 

Wet Season	Mean Abundance per m2
Species	High-shore	Mid-shore	Low-shore
Gastropods (individuals)
Acanthopleura japonica	0	3.33	2.27
Cellana toreuma	0.53	22.00	29.87
Chlorostoma argyrostoma	0	0	0.40
Echinolittorina radiata/ vidua	32.00	0	0
Echinolittorina trochoides	1.73	0	0
Monodonta labio	0	19.20	19.07
Nerita yoldii	0	0.93	1.07
Patelloida pygmaea	2.67	2.40	1.33
Patelloida saccharina	1.20	12.27	19.73
Siphonaria japonica	0.93	2.53	8.00
Siphonaria laciniosa	0.13	1.07	1.73
Thais clavigera	0.13	2.27	1.87
Crustaceans
Ligia exotica (individuals)	0	0.13	0.13
Capitulum mitella (%)	0.17	1.07	0
Tetraclita squamosa (%)	0.03	1.63	0
Bivalves
Saccostrea cucullata (%)	0	6.23	1.10
Septifer virgatus (%)	0	0.03	0
Algae (%)
Ralfsia expansa	0	0.07	0
Hildenbrandia sp.	0	19.07	32.77
Green algae	0	0	0.27
Encrusting coralline algae	0	0.33	8.83
Cyanobacteria (%)
Kyrtuthrix maculans	0.47	0.50	0

Overall, results of the seasonal intertidal surveys indicated that the artificial sloping seawall of the Study Area exhibited a low diversity of species.  The species recorded during the surveys are all very common and widespread species on artificial shores of Hong Kong.

9A.4.2                          Subtidal Soft Bottom Assemblages – Benthos

Survey Methodology

Sampling Locations

Benthic sediment samples were collected from 10 sites representative of the subtidal soft-bottom habitats of the potential wind farm site, cable route and the Study Area.  The sampling sites were as follows:

·           Proposed Wind Farm Location: S1 to S5;

·           Proposed Transmission Cable Alignment: SP1 and SP2; and

·           Reference Stations: SR1 to SR3.

The locations of each survey site are shown in Figure 9A.10.

The numbers of sampling stations within the wind farm and along the cable route were considered sufficient given the relatively homogeneous nature of sediments at the sites.  The reference stations have been identified in order to provide information on benthic ecology in areas that may be deemed more sensitive (eg close to Sham Wan of Lamma Island).

Field Sampling Methodology

At each of the 10 survey sites, three stations approximately 50 m apart were established and one grab sample was collected from each station.  Stations were sampled using a modified Van Veen grab sampler (960 cm² sampling area; 11,000 cm³ capacity) with a supporting frame attached to a swivelling hydraulic winch cable. 

Sediments from the grab samples were sieved on board the survey vessel.  The sediments were washed onto a sieve stack (comprising 1 mm² and 500 m² meshes) and gently rinsed with seawater to remove all fine material.  Following rinsing any material remaining on the two screens was combined and carefully rinsed using a minimal volume of seawater into pre-labelled thick triple-bagged ziplock plastic bags.  A 5% solution of borax-buffered formalin containing Rose Bengal in seawater was then added to the bag to ensure tissue preservation.  Samples were sealed in plastic containers for transfer to the taxonomy laboratory for sorting and identification.

Laboratory Techniques

The benthic laboratory performed sample re-screening after the samples had been held in formalin for a minimum of 24 hours to ensure adequate fixation of the organisms.  Individual samples from the 500 m² and 1 mm² mesh sieves were gently rinsed with fresh water into a 250 m² sieve to remove the formalin from the sediments.  Sieves were partially filled while rinsing a specific sample to maximize washing efficiency and prevent loss of material.  All material retained on the sieve was placed in a labelled plastic jar, covered with 70% ethanol, and lightly agitated to ensure complete mixing of the alcohol with the sediments.  Original labels were retained with the re-screened sample material.

Standard and accepted techniques were used for sorting organisms from the sediments.  Small fractions of a sample were placed in a petri dish under a 10-power magnification dissecting microscope and scanned systematically with all animals and fragments removed using forceps.  Each petri dish was sorted at least twice to ensure removal of all animals.  Organisms representing major taxonomic groups, such as Polychaeta, Arthropoda, Mollusca, and miscellaneous taxa, were sorted into separate, labelled vials containing 70% ethanol. 

Taxonomic identifications were performed by qualified and experienced specialist using stereo dissecting and high-power compound microscopes.  These were generally to the species level except for unidentified taxa, which were identified to genera as far as practical.  The careful sampling procedure employed minimizes fragmentation of organisms.  If breakage of soft-bodied organisms occurred, only anterior portions of fragments were counted, although all fragments were retained and weighed for biomass determinations (wet weight).

Survey Results

Survey Dates and Conditions

Grab samples were collected from all 10 sampling sites in both the dry (19 March 2009) and wet (28 October 2008) seasons.  In general, conditions during surveys were fine with relatively calm sampling conditions throughout. 

Dry Season Survey Results

A total of 173 individual organisms were collected from the 30 grab sampling stations at the 10 survey sites during the dry season survey in March 2009.  The specimens belong to eight Phyla with a total of 10 classes, 41 families and 49 species identified.  Table 9A.4 provides a summary on the abundance, biomass and taxonomic richness of infauna collected at each site.  A complete set of raw data is presented in Tables 1 & 2 of Annex 9A1.

Results of the dry season benthic survey showed that infaunal abundance, biomass and taxonomic richness (here represented by number of families and species of infaunal organisms) were very low at all sampling sites (Table 9A.4).  There was some variation in infaunal abundance, biomass and taxonomic richness among sampling sites.  Whilst the mean infaunal abundance and mean taxonomic richness per station were significantly higher at the Reference Site SR1 than other sites, infaunal biomass was significantly higher at the wind farm site S3 than other sites (Table 9A.4).  With the exceptions explained above, all sampling sites showed relatively similar infaunal abundance, biomass and taxonomic richness.  Variation within site (ie among sampling stations) was also considered to be small, as can be seen from the low standard deviation (SD) values (Table 9A.4).

In terms of infaunal abundance, the majority (71.7%) of organisms recorded were from the Phylum Annelida, followed by Arthropoda (12.1%) and Sipuncula (5.2%).  Each of the other recorded phyla contributed to < 3 % of the number of individuals recorded.  The polychaete worm Prionospio queenslandica, from the family Spionidae, was the most abundant species from the dry season survey (total abundance = 25 individuals), particularly at SR1 (total abundance = 16 individuals).  No rare or uncommon species were recorded in the survey.  The composition of infaunal assemblage at each site in terms of mean numerical abundance of organisms present (grouped by class) in the dry season survey is presented in Figure 9A.11.

In terms of infaunal biomass, organisms from the Phylum Mollusca contributed 41% of the total biomass recorded, while organisms from Chordata, Arthropoda and Annelida also contributed significant biomasses (25.3%, 22.4% and 10.2% respectively).  Each of the other recorded phyla contributed to < 5 % of the total infaunal biomass recorded.  High biomass of molluscs was contributed by a single individual of the bivalve Scapharca sp. at one sampling station of the S3 site.  The composition of infaunal assemblage at each site in terms of mean biomass of organisms present (grouped by class) in the dry season survey is presented in Figure 9A.12.

 

Table 9A.4      Composition of Infaunal Assemblages at the Sampling Sites for the Soft Bottom Habitat Surveys at the Southwest Lamma Study Area during the Dry Season Survey in March 2009

Location	Site	Number of Stations Sampled	Total Number of Infaunal Individuals	Mean Number of Individuals per Station (± SD)		Mean Number of Individuals per m2 (± SD)		Total Biomass (g wet weight)	Mean Taxonomic Richness (No. Families) per Station (± SD)		Mean Taxonomic Richness (No. Species) per Station (± SD)		Mean Biomass per Individual (g wet weight)
Reference	SR1	3	45	15.00	(± 6.00)	156.25	(± 62.50)	2.1081	8.33	(± 2.31)	8.67	(± 2.08)	0.0468
	SR2	3	16	5.33	(± 1.53)	55.56	(± 15.91)	3.3299	4.67	(± 1.53)	4.67	(± 1.53)	0.2081
	SR3	3	9	3.00	(± 1.00)	31.25	(± 10.42)	1.5615	2.00	(± 1.00)	2.00	(± 1.00)	0.1735
Wind farm	S1	3	19	6.33	(± 1.15)	65.97	(± 12.03)	0.4430	5.33	(± 0.58)	5.33	(± 0.58)	0.0233
	S2	3	13	4.33	(± 1.53)	45.14	(± 15.91)	0.8796	3.67	(± 1.15)	4.00	(± 1.73)	0.0677
	S3	3	14	4.67	(± 2.08)	48.61	(± 21.68)	9.2311	4.33	(± 2.52)	4.33	(± 2.52)	0.6594
	S4	3	10	3.33	(± 0.58)	34.72	(± 6.01)	0.6409	3.33	(± 0.58)	3.33	(± 0.58)	0.0641
	S5	3	10	3.33	(± 2.52)	34.72	(± 26.21)	6.1169	3.00	(± 2.00)	3.00	(± 2.00)	0.6117
Cable	SP1	3	14	4.67	(± 2.52)	48.61	(± 26.21)	1.3030	4.67	(± 2.52)	4.67	(±2.52)	0.0931
	SP2	3	23	7.67	(± 5.51)	79.86	(± 57.37)	0.2853	4.33	(± 2.08)	4.33	(± 2.08)	0.0124

 

Wet Season Survey Results

A total of 194 individual organisms were collected from the 30 grab sampling stations at the 10 survey sites during the wet season survey in October 2008.  The specimens belong to eight Phyla with a total of 10 classes, 34 families and 43 species identified.  Table 9A.5 provides a summary on the abundance, biomass and taxonomic richness of infauna collected at each site.  A complete set of raw data is presented in Tables 3 & 4 of Annex 9A1.

Results of the wet season 2008 benthic survey showed that, as with the results of the dry season survey, infaunal abundance, biomass and taxonomic richness were very low at all sampling sites (Table 9A.5).  Whilst the mean infaunal abundance and mean taxonomic richness per station were similar across sampling sites, with SP2 showing a slightly higher infaunal abundance, infaunal biomass was significantly higher at the wind farm site S2 than other sites (Table 9A.5).  Variation within site (ie among sampling stations) was also considered to be small, as can be seen from the low standard deviation (SD) values (Table 9A.5).

 

Table 9A.5      Composition of Infaunal Assemblages at the Sampling Sites for the Soft Bottom Habitat Surveys at the Southwest Lamma Study Area during the Wet Season Survey in October 2008

Location	Site	Number of Stations Sampled	Total Number of Infaunal Individuals	Mean Number of Individuals per Station (± SD)		Mean Number of Individuals per m2 (± SD)		Total Biomass (g wet weight)	Mean Taxonomic Richness (No. Families) per Station (± SD)		Mean Taxonomic Richness (No. Species) per Station (± SD)		Mean Biomass per Individual (g wet weight)
Reference	SR1	3	17	5.67	(± 2.52)	59.03	(± 26.21)	1.1714	4.00	(± 1.00)	4.33	(± 1.15)	0.0689
	SR2	3	11	3.67	(± 2.52)	38.19	(± 26.21)	2.3300	3.00	(± 1.73)	3.00	(± 1.73)	0.2118
	SR3	3	21	7.00	(± 2.65)	72.92	(± 27.56)	1.4495	5.67	(± 2.08)	5.67	(± 2.08)	0.0690
Wind farm	S1	3	19	6.33	(± 0.58)	65.97	(± 6.01)	2.1422	4.67	(± 1.15)	5.00	(± 1.00)	0.1127
	S2	3	21	7.00	(± 0.00)	72.92	(± 0.00)	12.2189	5.67	(± 0.58)	5.67	(± 0.58)	0.5819
	S3	3	22	7.33	(± 3.06)	76.39	(± 31.82)	2.5986	5.00	(± 1.00)	5.33	(± 1.53)	0.1181
	S4	3	20	6.67	(± 1.53)	69.44	(± 15.91)	1.5394	5.33	(± 1.53)	5.33	(± 1.53)	0.0770
	S5	3	12	4.00	(± 2.00)	41.67	(± 20.83)	0.3607	3.33	(± 1.15)	3.33	(± 1.15)	0.0301
Cable	SP1	3	22	7.33	(± 0.58)	76.39	(± 6.01)	1.9954	4.00	(± 1.00)	5.00	(± 1.00)	0.0907
	SP2	3	29	9.67	(± 6.43)	100.69	(± 66.97)	1.7443	6.00	(± 1.00)	6.33	(± 1.53)	0.0601

 

In terms of infaunal abundance, the majority (67.0%) of organisms recorded in the wet season were from the Phylum Annelida, followed by Arthropoda (12.4%) and Nemertinea (5.2%).  Each of the other recorded phyla contributed to < 5 % of the number of individuals recorded.  The polychaete worm Aglaophamus dibranchis, from the family Nephtyidae, was the most abundant species from the wet season survey (total abundance = 35 individuals), and it was present in most of the sampling sites.  No rare or uncommon species were recorded in the wet season survey.  The composition of infaunal assemblage at each site in terms of mean numerical abundance of organisms present (grouped by class) in the wet season survey is presented in Figure 9A.11.

In terms of infaunal biomass, organisms from the Phylum Echinodermata contributed 42% of the total biomass recorded, while organisms from Arthropoda, Chordata and Annelida also contributed significant biomasses (19.4%, 16.6% and 10.8% respectively).  Each of the other recorded phyla contributed to < 6 % of the total infaunal biomass recorded.  High biomass of echinoderms was contributed by a single individual of the sea cucumber Actinopyga echinites at one sampling station of the S2 site.  The composition of infaunal assemblage at each site in terms of mean biomass of organisms present (grouped by class) in the wet season survey is presented in Figure 9A.12.

Overall, results from the dry and wet season surveys undertaken as part of this EIA suggested that infaunal assemblages of the surveyed sites consisted of common and widespread species typical of disturbed environment, i.e. numerical dominance of low biomass, stress-tolerant and short-lived polychaete species.  Infaunal assemblage structure was largely similar between seasons, with slightly higher infaunal abundance, biomass and taxonomic richness in the wet than the dry season.  The abundance, biomass and taxonomic richness of infauna at and in the vicinity of the wind farm site and cable route off Southwest Lamma are very low in comparison with the average values reported by CityU Professional Services Limited (2002) for benthic assemblages in Hong Kong (34 species per 0.5 m², 450 individuals per m² and 28 g per m²).

9A.4.3                          Subtidal Hard Bottom Habitat – Coral 

Methodology

Subtidal dive surveys were undertaken at subtidal hard bottom habitats within and in close proximity to the footprint of the Project Area with a key focus at the proposed cable landing site and along the cable route where hard substrata were noted from the geophysical survey undertaken for this site (see Section 12).  The dive surveys comprised the following two components:

·       Qualitative spot dive survey; and

·       Semi-quantitative Rapid Ecological Assessment (REA) survey.

Each of these surveys is described further in the following sections.  Survey locations are presented in Figure 9A.13 and details of the surveys are summarised in Table 9A.6.

Table 9A.6        Survey Transects and Type of Survey Undertaken

Survey Site	Type of Survey	Total Length of Area Surveyed
T1	Semi-quantitative REA survey	100 m
T2	Semi-quantitative REA survey	100 m
T3	Semi-quantitative REA survey	100 m
T4	Semi-quantitative REA survey	100 m
T5	Semi-quantitative REA survey	100 m
T6	Semi-quantitative REA survey	100 m
T7	Semi-quantitative REA survey	100 m
T8	Semi-quantitative REA survey	100 m
Patch 4	Qualitative spot dive survey	5 m
Patch 6	Qualitative spot dive survey	5 m
Patch 7	Qualitative spot dive survey	5 m
Patch 8	Qualitative spot dive survey	5 m
Patch 9	Qualitative spot dive survey	5 m
Patch 10	Qualitative spot dive survey	5 m

 

Qualitative Spot Dive Survey

Recent geophysical surveys identified a number of small patches of hard substrate along the cable route.  These patches, identified as superficial dumped materials, occurred within the 150 m wide cable corridor and within approximately 10 m depth or less.  Whilst the age of the patches is unknown,   it was noted that some of the materials were located on top of trawl lines, which suggested that these could be introduced on to the seabed relatively recently.  The materials were also thought to be relatively mobile as displacement of the materials by trawling activity was seen on geophysical images (Figure 9A.14).

A series of targeted spot dive checks were carried out at selected patches of dumped materials along the proposed cable route to investigate if coral communities are present at these potential areas of hard substrate (Figure 9A.13).  Not all identified patches of dumped material were surveyed, but the hard substrate patches surveyed are thought to be representative of all patches of dumped material noted in the Study Area.  Representative ground-truthing of sessile assemblages at the selected hard substrate patches was thus used to characterise the biological nature of all patches of dumped material identified.

At each survey site, a spot dive reconnaissance check was conducted by qualified coral specialists by SCUBA to confirm the substrate type and associated sessile benthos, particularly the presence of coral communities (hard and soft corals).  The immediate seabed area around the patch (5 m radius around the centre point) was checked, and representative photographs of the seabed and associated fauna were taken.  Coral species encountered during the spot dive checks were identified to the lowest possible taxonomic level.

Rapid Ecological Assessment (REA) Survey Method

The Rapid Ecological Assessment (REA) technique was employed in order to investigate the presence of any coral communities (hard and soft corals) associated with subtidal hard bottom habitats at the cable landing point area at the Lamma Power Station Extension.  The REA technique allows semi-quantitative information on the ecological attributes of the subtidal habitat to be obtained in a relatively simple way without compromising scientific rigour.  This technique is the standard practices for EIA marine baseline surveys in Hong Kong and has been modified from the standardised REA survey technique established for the assessment of coral communities on the Great Barrier Reef ([85]) for marine environment of Hong Kong ([86]).

A series of REA surveys were conducted by qualified coral ecologists by SCUBA at a total of eight transects along the seawall of the Lamma Power Station Extension (Table 9A.6; Figure 9A.13).  The spatial coverage of the proposed REA transects included the zone of potential direct and indirect impacts, which encompassed the seawall at and in the vicinity of the proposed cable landing point.  These REA transects represented a 100 m stretch of seawall at two depth zones:

·       Shallow depth zone: -2 to -5 mCD (typically the depth range of coral colonies associated with seawall habitat); and

·       Deep depth zone: -6 to -10 mCD.

The depths of these transects might be adjusted slightly based on the substrate habitats, the presence or absence of hard and soft corals, and field conditions.

Field data of the REA survey were recorded by coral specialists who are experienced in the underwater identification of sessile benthic taxa.  REA surveys were carried out using 100 m long transects with the transect tapes laid out within a single ecological zone - habitat - depth range as bulleted above.

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

Tier I - Categorisation of Benthic Cover

Upon the completion of each survey transect, five ecological and seven substratum attributes were assigned to one of seven standard ranked (ordinal) categories (Tables 9A.7 and 9A.8).

Table 9A.7      Categories used in the REA Surveys - Benthic Attributes

Ecological	Substratum
Hard coral	Hard substrate
Dead standing coral	Continuous pavement
Soft coral	Bedrock
Black coral	Rubble
Macroalgae	Sand
Turf algae	Silt
	Large boulders (>50 cm) Small boulders (<50 cm)
	Rocks (<26 cm)

Table 9A.8      Categories used in the REA Surveys - Ordinal Ranks of Percentage Cover

Rank	Percentage Cover (%)
0	None recorded
1	1-5
2	6-10
3	11-30
4	31-50
5	51-75
6	76-100

Tier II - Taxonomic Inventories to Define Types of Benthic Communities

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

·            Scleractinian (hard) corals to species wherever possible;

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

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

Following the completion of each transect survey, each taxon in the inventory was ranked in terms of abundance in the community (see Table 9A.9).  These broad categories rank taxa in terms of relative abundance of individuals, rather than the contribution to benthic cover along each transect.  The ranks are subjective assessments of abundance, rather than quantitative counts of each taxon.

Table 9A.9      Ordinal Ranks of Taxon Abundance

Rank	Abundance
0	Absent
1	Rare (a)
2	Uncommon
3	Common
4	Abundant
5	Dominant
Note: (a)       The classification of “rare” abundance refers to low abundance (small quantity) on the transect, rather than in terms of distribution in Hong Kong waters.

 

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

(A)              The degree of exposure to prevailing wave energy was ranked from 1 - 4, where:

1 =    sheltered (highly protected by topographic features from prevailing waves);

2 =    semi-sheltered (moderately protected);

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

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

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

0 =    no sediment;

1 =    minor (thin layer) sediment deposition;

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

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

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

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

·           Species abundance data for each transect. 

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

Survey Results

The dive surveys were conducted on 4 and 5 May 2009.  The conditions during surveys were fine with calm conditions throughout.  The visibility was generally < 1.0 m.

Results of Qualitative Spot Dive Checks

Results of qualitative dive surveys at Patches 4, 6, 7, 8, 9 and 10 confirmed that the seabed at these locations was composed of sandy silts with sparse rock and rubble.  The hard substrate at Patches 4, 6 and 8 were sparsely colonised with the gorgonians Echinomuricea sp. and Menella sp., and substrate at Patch 8 showed sparse colonization of soft coral Dendronephthya sp., Echinomuricea sp. and black coral Cirripathes sp. (Table 9A.10).  The seabed at Patches 7, 9 and 10 showed no colonization of sessile taxa.  The communities identified during the survey were located on the hard substrate, but these areas only formed a small percentage of the seabed as the majority of the seabed comprised soft substrate.  Figure 9A.15 presents some images taken at the qualitative dive survey locations.

 

Table 9A.10    Coral Species Recorded at the Qualitative Spot-Check Patches

	Patch 4	Patch 6	Patch 7	Patch 8	Patch 9	Patch 10
Octocoral Species (a)
Dendronephthya sp.	0	0	0	1	0	0
Echinomuricea sp.	1	1	0	1	0	0
Menella sp.	1	1	0	1	0	0
Black Coral Species	0	0	0	1	0	0

Note:         (a). 0=absent, 1=present

 

 

Results of REA Survey

Along each transect the seabed composition was identified and conditions were noted as shown in Table 9A.11 and Table 9A.12.  The substrate of the REA transects was mainly large boulders.  Some images taken at the REA dive survey transects are presented in Figure 9A.16.

Octocoral species were not recorded in any of the REA transects at the Lamma Power Station Extension seawall.  Although this was contrary to the findings of the 2000 baseline marine ecological monitoring at the Ash Lagoon Seawall, this is not unusual as localised environmental conditions (e.g. current velocity and turbidity) at the sites may potentially affect the distribution and abundance of octocorals.

Hard coral coverage at the REA transects was very low (< 5 %), and hard coral was not recorded at T2 and T8.  A total of three hard coral species were recorded during the REA surveys (Table 9A.13).  The scleractinian coral Oulastrea crispata and ahermatypic cup corals were recorded in the majority of the transects, and a sub-massive Porites sp. was recorded at T5.  These results support the findings of the 2000 surveys that hard coral abundance and diversity was very low on artificial seawall of this area.

The predominant species recorded during the REA survey was Oulastrea crispata.  This coral species belongs to the Faviidae family of which all species are known to have high tolerance limits to sub-optimal physico-chemical conditions often associated with the Hong Kong nearshore environment, e.g. fluctuations in salinity and sea surface temperature (daily and seasonal), elevated sedimentation loading and total suspended sediment, and reduced light attenuation levels.  Oulastrea crispata is a common and ubiquitous coral species in Hong Kong, though typically not recorded in high abundance within established coral communities.  It is most often recorded in the most marginal conditions for corals, i.e. areas of high sediment loading, and represented by scattered, small colonies in shallow, subtidal areas with few other coral species.  This species is thus considered as a locally widespread, highly stress-tolerant species with little conversation concern.

Common subtidal species recorded at the REA transects included the barnacle Balanus sp., the bivalves Tridacna sp. and Perna viridis, the sea urchin Diadema setosum and some gastropods.

Overall, results of the dive surveys show that very sparse colonies of locally common, widespread coral species were present along the proposed cable route and the cable landing point, and their abundance and diversity were considered to be very low in the context of subtidal coral assemblages in Hong Kong.

 

Table 9A.11   Description of the Seabed Recorded along Each Transect and the Qualitative Surveys

Transect (T)/ Patch (P)	Depth	Description
T1	-3 m CD	The seabed was mainly composed of large boulders with sparse small boulders and rocks.  A few colonies of encrusting hard coral Oulastrea crispata were found along the transect.
T2	-6 m CD	The seabed was mainly composed of large boulders with sparse small boulders.  No hermatypic hard coral colonies were found.  Several ahermatypic cup coral colonies of the Family Dendrophyllidae were recorded.
T3	-4 m CD	The seabed was mainly composed of large boulders with sparse small boulders.  Several colonies of encrusting hard coral Oulastrea crispata were recorded along the transect.
T4	-6 m CD	The seabed was mainly composed of large boulders with sparse small boulders.  Several colonies of encrusting hard coral Oulastrea crispata and ahermaptypic cup coral colonies of the Family Dendrophyllidae were recorded along the transect.
T5	-4 m CD	The seabed was mainly composed of large boulders with sparse small boulders.  Several colonies of encrusting hard coral Oulastrea crispata and sub-massive Porites sp. were recorded.
T6	-6 m CD	The seabed was mainly composed of large boulders.  Several Oulastrea crispata colonies were recorded.  Ahermatypic cup corals of the Family Dendrophyllidae were common along transect.
T7	-4 m CD	The seabed was mainly composed of large boulders with sparse small boulders and rocks.  Colonies of encrusting hard coral Oulastrea crispata were found along the transect.
T8	-7 m CD	The seabed was mainly composed of large boulders with sparse large boulders and rocks.  Ahermatypic cup corals of the Family Dendrophyllidae were commonly found along transect.
P4	-10 m CD	The seabed was predominately covered by sand and silt with scattered and sparse rubbles.  Few colonies of the gorgonians Echinomuricea sp. and Menella sp. were recorded.
P6	-12.3 m CD	The seabed was composed of sand and silt with scattered and sparse rubbles.  Few colonies of the gorgonians Echinomuricea sp. and Menella sp. were recorded.
P7	-12.9 m CD	The seabed was mainly composed of silt with sparse rocks and rubble recorded.  No sessile organisms were observed.
P8	-13 m CD	The seabed was composed of sandy substrate with some sparse rocks and rubbles.  A number of coral colonies, including the gorgonians Echinomuricea sp., Menella sp., Echinogorgia sp., soft coral Dendronephthya sp. and black coral Cirripathes sp. were recorded.
P9	-12 m CD	The seabed was composed of silt with no sessile organisms found.
P10	-13 m CD	The seabed was composed of silt with no sessile organisms found.

 

Table 9A.12   Seabed Attributes along the Semi-Quantitative Survey Transects

	T1	T2	T3	T4	T5	T6	T7	T8
Transect depth (a)	s	d	s	d	s	d	s	d
Seabed attributes (b)
Bedrock	0	0	0	0	0	0	0	0
Boulders – large	4	6	5	6	6	6	6	6
Boulders – small	1	1	1	1	1	1	1	1
Rock	1	1	1	0	1	1	1	0
Rubble	1	0	0	0	1	0	1	0
Sand	1	1	0	0	0	0	0	0
Silt	0	1	1	1	1	1	1	2
Ecological attributes (b)
Hard coral	1	0	1	1	1	1	1	0
Dead standing coral	0	0	0	0	0	0	0	0
Soft coral	0	0	0	0	0	0	0	0
Black coral	0	0	0	0	0	0	0	0
Turf algae	1	1	1	1	1	1	1	1
Macroalgae	0	0	0	0	0	0	0	0
Coralline algae	3	2	3	1	2	1	2	1

Notes:       (a)        T1 to T8 = transect line; s= shallow water; d=deep water

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

Table 9A.13    Species Recorded along the REA Survey Transects

Type	Taxon/ Family	Species	T1	T2	T3	T4	T5	T6	T7	T8
Hard Coral	Hermatypic
	Faviidae	Oulastrea crispata	2	0	2	2	2	2	2	0
	Poritidae	Porites sp.	0	0	0	0	2	0	0	0
	Dendrophyllidae	Unidentified cup coral sp.	0	2	0	2	0	3	0	3
Others	Crustacea	Balanus sp.	3	4	3	3	3	3	3	0
		Crab (unidentified)	0	0	0	0	0	2	2	0
		Hermit crab (unidentified)	0	0	3	0	0	0	0	2
	Bryozoa	Schizoporella errata	0	0	0	2	0	0	0	2
		Unidentified sp.	2	0	0	0	0	0	0	0
	Bivalvia	Tridacna sp.	3	2	3	2	2	2	0	0
		Perna viridis	0	2	3	0	2	0	0	2
	Gastropoda	Gastropod (eg Topshell, Whelks)	2	3	3	0	2	2	3	0
		Cypraea arabica	0	0	2	0	2	0	0	0
	Echinodermata	Diadema setosum	3	3	4	3	3	3	0	0
		Anthocidaris crassispina	2	0	0	0	0	2	3	0
		Salmacis sphaeroides	2	0	0	0	2	0	2	0
	Cnidaria	Haliplanella lineata	0	0	0	0	2	0	0	0
		Sea squirt	0	0	0	0	0	0	2	2
	Porifera	Sponges	0	2	0	2	0	0	0	2
	Sabellidae	Fan worm	0	0	0	0	2	0	2	0

Note:         (a). 0=absent, 1=rare, 2=uncommon, 3=common, 4=abundant, 5=dominant.  Also note patches were surveyed by spot dive so that REA data were not collected for these sites.

The ranks shown in the Table above indicate the relative abundance of each coral in relation to other corals in the community. In other words, these broad categories rank taxa in terms of relative abundance of individuals, rather than the contribution to benthic cover along each transect.  The ranks are subjective assessments of abundance, rather than quantitative counts of each taxon. For instance, if a coral is ranked as ‘common’, it means it was more frequent than other coral species along the transect.  It should be borne in mind that coral cover along all of the transects where corals occurred was very low (<5% cover)