4 MARINE ECOLOGY

4.1 INTRODUCTION

Dive surveys were undertaken by ERM as part of the EIA at a series of locations parallel to the pipelines alignment. The survey results indicated that there were areas of coastline that should be regarded as of high ecological value due to the abundance and diversity of coral assemblages.

Although adverse impacts to corals are not predicted to occur during jetting of the pipelines in proximity to the areas of high ecological value, Towngas has decided that coral monitoring be undertaken. The monitoring will be focussed on the jetting works in the vicinity of the high ecological value areas within Tolo Channel and Tung Ping Chau during dredging on the Mainland side within 1 km of the HKSAR boundary, to verify that the project will have no adverse ecological impact on the corals.

4.2 SAMPLING METHODOLOGY

The objective of the coral monitoring will be to detect if any adverse impacts occur to corals in the vicinity of the project works during jetting and, where such impacts are identified and are found to be associated with the jetting works, to ensure appropriate action is undertaken to effectively reduce such impacts.

The coral monitoring will be reviewed in conjunction with the water quality monitoring results, which will detect concentrations of suspended solids generated during jetting.

4.2.1 Monitoring Locations

The monitoring programme includes undertaking dive surveys at both impact and control stations. The impacts to corals during works can then be inferred through a comparison between these two sets of stations and the water quality monitoring results.

Tolo Channel: The impact stations comprise representative coral communities situated along the northern coast of Tolo Channel, closest to the jetting works, and the control stations will comprise representative coral communities situated on the western coast of Chek Chau. An indicative area of monitoring is shown in Figure 4.2a.

Tung Ping Chau: The impacts stations comprise representative coral communities situated along the northeastern coast of Tung Ping Chau. A control station will be established within A Ma Wan on the southeastern part of Tung Ping Chau (Figure 4.2b).

The rationale for the monitoring stations is presented in Table 4.1:

Table 4.1 Marine Ecology Monitoring Stations

Monitoring Station	Location	Rationale	Coordinates X	Coordinates Y
Impact - I1	Wong Wan Tsui West	High ecological value corals (hard, soft and black)	847936.38	837181.28
Impact - I2	Wong Wan Tsui East	High ecological value corals (hard, soft and black)	848513.76	837677.23
Impact - I3	Fong Wang Fat	High ecological value corals (hard, soft and black)	850223.70	838639.53
Impact - I4	Gruff Head	High ecological value corals (hard, soft and black)	851089.77	837869.69
Impact - I5	Wong Chuk Kok South West	High ecological value corals (hard, soft and black)	850875.10	839098.48
Impact - I6	Wong Chuk Kok	High ecological value corals (hard, soft and black)	851741.17	840053.37
Impact - I7	Wong Chuk Kok North	High ecological value corals (hard, soft and black)	852555.42	840719.58
Control - C1	Chek Chau	High ecological value corals (hard, soft and black)	854598.46	840164.41
Impact - TPC1	Tung Ping Chau South	High ecological value corals (hard, soft and black)	861678.74	845446.33
Impact - TPC2	Tung Ping Chau North	High ecological value corals (hard, soft and black)	861880.86	845819.95
Control	A Ma Wan	High ecological value corals (hard, soft and black)	862966.97	844858.75

The control station area at Chek Chau (Zone B) and A Ma Wan (Zone C) are considered to be appropriate, as they are known to comprise extensive coral assemblages. The assemblages are considered to be outside of the potential impact zone as they are not expected to be affected by the jetting or dredging works. Any effects noted at the control sites will be due to other environmental perturbations and therefore will act as a check against which effects at the impact sites will be compared.

The number and location of the corals to be monitored at the impact and control stations (the corals to be tagged) shall be identified in the field and will comprise a minimum of 20 hard coral colonies and 20 soft/black coral colonies in each of 2 depth zones, to enable statistical evaluation. The corals shall be tagged randomly at each site. The coral colonies to be monitored at the control stations shall be located at similar depths as those identified for the impact stations.

4.2.2 Monitoring Techniques

The coral monitoring work shall be undertaken by observers hired by the ET that are experienced in the field identification of sessile benthic taxa using SCUBA gear. The observers shall be qualified marine biologists with a postgraduate degree in marine biology and specialist knowledge of corals. As the amount of monitoring work within Tolo Channel is high the ET should retain the services of a minimum of two coral specialists for the survey works. The same coral specialists shall be used for each dive survey to maintain consistency in the documentation of the tagged coral condition and shall be approved by AFCD in advance of undertaking the monitoring work.

It is expected that five surveys will be required at the impact stations and control stations. These will include one survey before jetting works commence (for the Baseline Survey and coral tagging), one survey during each of the three jetting passes on the pipelines (Impact Monitoring) and one survey upon completion of the jetting works (Post Project Monitoring). The baseline survey is a comprehensive quantitative survey that will provide the final tier of highly precise quantitative estimate of coral cover and abundance of common benthic taxa to the survey programme. It will also provide data that identify the most suitable hard coral species to be tagged during a follow-up dive and monitored during the works programme. The approach to undertaking this work is described as follows.

4.2.3 Baseline Survey/Coral Tagging

A comprehensive quantitative baseline dive survey will be undertaken at the impact station and control station areas prior to commencement of the jetting works. The dive survey will include a general reconnaissance survey to gain information on the coral abundance in the area for identification of the number of coral colonies to be tagged and update the detailed survey gathered as part of the EIA. At each site shallow, fringing hard coral communities (for fringing hard corals) and deeper mixed coral communities (for soft and black corals) will be sampled and recorded. Two field procedures shall be followed:

Shallow hard coral communities

Each site should be delineated by natural physical features and the survey area standardised to ~200 m (shoreline length) by ~10 m width. Ten 10 m long replicate transects should be laid haphazardly within the boundaries of each site. Transects should be orientated parallel to the shore where possible. Representative photographs will be taken along each transect.

Deeper coral communities (black and soft corals)

Quantitative estimates for black/soft coral colonies should be conducted in situ as photographic or video techniques (2-D images) may not be suitable for sampling. It is recommended, however, that a video record is made of each transect.

Two, 20m transects should be laid down haphazardly within each of the impact and control stations following a fixed depth (determined on the dive) and orientated parallel with the shoreline. Along each transact ten 1 x 1 m quadrats should be placed either side of the transect. A video record should be collected first then individual benthic taxon counted and recorded. Along each transect a minimum of twenty black/soft coral colonies should be examined in detail. Maximum height and condition will be recorded.

Parameters

General information shall be provided on the diversity, abundance and health status (bleaching, live/dead coral ratio and siltation coverage) of the corals in the general area. The corals to be tagged in a follow-up survey, and subsequently monitored, shall be identified and agreed with AFCD in advance of tagging. Priority shall be given to tagging the largest, undamaged colonies, as these colonies are likely to be the most prone to sediment damage and the recording of the condition of the corals will be more clearly identified in colonies not damaged in prior incidents. At each site, the most suitable coral species and growth forms of corals will be tagged. Corals of long polyp should be avoided as far as possible as they tend to have a higher tolerance response on sedimentation. The tagging plan will be reviewed by the ET Leader when more updated information has been collected prior to the construction works.

As the corals are generally coral heads of 'massive' form, there is no feasible way of using a ring tag, as is used for table corals. The corals shall, therefore, be tagged using small stones, which shall be painted a bright orange or green colour and marked with mahjong tags. At each tagged colony a numbered stone shall be placed next to the coral head and a matching numbered tag nailed into an adjacent piece of hard substrate (boulder or bedrock). A fine rope trail shall also be laid down linking all tagged colonies to aid future re-locations at both the impact and control stations.

Each of the tagged coral colonies shall be identified to genus or species levels and photographed. Information on the coral colonies shall be recorded, including their specific location, size and general condition of their environment. Other information shall also be recorded such as the survey date, time, atmospheric, sea and tidal conditions. All tags must be removed after the study, including those installed at the control and impact stations.

The sediment cover of each tagged coral colony shall be recorded including the percent of coverage, colouration and texture of the sediment and the approximate thickness of the sediment layer both on the colony and on adjacent bedrock or boulder substrate. Any contiguous patches of sediment cover >10% shall be counted. The health status of each tagged coral colony, including bleaching effect and live/dead ratio, shall also be recorded. Three parameters are to be recorded for each tagged coral and these are:

* Percentage sediment cover (hard corals only)

* Percentage bleached tissue (hard corals only)

* Percentage dead - total or partial mortality (hard corals, soft corals and black corals)

Each parameter will be assessed as a percentage of the total colony area. To aid percentage cover estimates a 50 x 50 cm quadrat (with a ten cm2 lined grid) will be used.

Sediment cover - it will be important to note the colouration and texture of the sediment and the approximate thickness of the sediment layer both on the colony and on adjacent bedrock or boulder substrate. All sediment areas must be documented. Contiguous patches of sediment cover >10 % must be counted and accumulated patches documented with time.

Bleaching - two bleaching categories will be recorded:

* Blanched or pale - a loss of zooxanthellae or photosynthetic pigments.

* Bleached - a total loss of zooxanthellae and coral tissue still present. White colouration as skeleton is visible through transparent coral tissue. It is possible that lower portions of the coral remain unbleached and therefore help to differentiate bleaching as opposed to partial mortality where tissue is absent.

All bleached tissue must be noted and percentage cover estimated for both blanched and bleached areas. Contiguous patches of bleached tissue >10 % cover must be counted and accumulated patches documented with time.

Total or partial mortality - coral tissue death may be through sediment deposition, bleaching, bacterial infection etc and this may lead to rapid algal overgrowth and colonisation of exposed skeleton by fouling organisms. Dead skeletal areas will appear white if recently dead and within a few days sediment settlement and algal overgrowth will change the appearance of such areas to a duller colouration. Partial mortality must be recorded and contiguous patches of dead tissue >10 % must be counted and accumulated patches documented with time.

Upon relocation of the tagged colony the condition of the coral will be assessed by noting areas of settled sediment, bleaching or partial/total mortality on a pre-printed sheet of underwater paper. The extent and location of such measurable parameters will be sketch by chinagraft pencil (or equivalent) on laminated photographs of the tagged colony. These sketch outlines will be redrawn over the scanned images to verify field notes when compiling the data. Other observations will also be noted.

Physical damage to colonies, tissue distension, mucous production and any other factors considered relevant will be noted in the field and included in the survey report. The coral observation data highlights the need for:

* Re-location of all tagged coral colonies on each dive survey assessment.

* A diver with specialist hard coral knowledge and a diver with specialist knowledge of soft/black corals must be employed to carry out the survey work.

* The same coral specialist must be used for each dive survey to maintain consistency in the documentation of the tagged coral condition.

* Photographs of each tagged coral from each survey assessment must be included in the reports. These photographs should be of each whole colony when conditions permit and this may mean complementing video footage with still photography (use of a Nikonos V or equivalent).

For soft corals, gorgonians and black corals the number of branches should be counted and the percentage affected by partial/full mortality recorded.

4.2.4 Impact Monitoring - Tolo Channel (Zone B)

The focus of the impact monitoring will be to determine whether impacts are occurring to corals during jetting works in the area from sedimentation or elevated SS levels. The results of the coral monitoring will be reviewed in association with the water quality monitoring results. The water quality data reviewed should be from the stations corresponding to the relevant coral stations (refer to Table 3.2 for the stations). Impact monitoring will be undertaken daily during each of the three jetting passes in the Tolo Channel (i.e. the green zone indicated in Figure 4.2a), and the Proforma report together with evidentiary photographs would be submitted to EPD, AFCD and other concerned parties within 2 days for scrutiny.

he information to be obtained will be as for the Baseline Monitoring, including information on: the health status of the corals, condition of their environment survey date, time, atmospheric, sea and tidal conditions during the survey and sediment cover in terms of percentage of coverage and approximate thickness. Each tagged coral colony shall also be photographed.

The jetting machine will be moving at a rate of no faster than 1.08 km day-1 and consequently the locations of the coral monitoring will change on a daily basis as illustrated on Figure 4.2a. The method will be such that the jetting machine approaches the first Kilometre Point (KP presented on Figure 4.2a) either in Mirs Bay (if the jetting machine is approaching from the NE) or in Tolo Channel (if the jetting machine is approaching from the SW) and this triggers coral monitoring along a section of coastline. As the machine moves along and approaches the next KP the subsequent section of coastline is monitored for impacts to corals. This process continues until the jetting machine is clear of Zone B.

The KP's are set 2 km apart as the water quality modeling indicated that the effects of the jetting machine may extend 1km either side of the jetting machine (as a result of the ebb and flood tides along Tolo Channel). The following stations will be monitored along the Tolo Channel Section (Table 4.2).

Table 4.2 Sequence of Monitoring Along the Tolo Channel Section

Location	Sequence of Monitoring	Control Station
KP0 E = 846975.82 N = 836107.91	I1 and I2	C1
KP2 E = 848675.42 N = 837136.72	I1 and I2	C1
KP4 E = 850383.25 N = 838190.23	I2, I3, I4	C1
KP6 E = 851914.13 N = 839490.65	I3, I4, I5	C1
KP8 E = 853432.65 N = 840799.30	I5, I6, I7	C1

4.2.5 Impact Monitoring - Tung Ping Chau Marine Park

The focus of the impact monitoring will be to determine whether impacts are occurring to corals within the Tung Ping Chau Marine Park during dredging works in the area from sedimentation or elevated SS levels. The results of the coral monitoring will be reviewed in association with the water quality monitoring results. Impact monitoring will be undertaken during dredging on the Mainland side within 1 km of the HKSAR boundary as shown on Figure 4.2b. Although there will be additional pipeline landing works at the Shenzhen approach the works will be sufficiently remote not to cause an effect on the Marine Park and hence monitoring is not required on the Hong Kong side.

The information to be obtained from the monitoring will be as for the Baseline Monitoring, including information on: the health status of the corals, condition of their environment survey date, time, atmospheric, sea and tidal conditions during the survey and sediment cover in terms of percentage of coverage and approximate thickness. Each tagged coral colony shall also be photographed.

The dredging works on the Mainland side are expected to take approximately 8 days. It is considered that at this working rate the corals should be monitored every two days. Should the dredging works take place at a slower rate then the monitoring frequency can be reduced following agreement with AFCD and EPD. The Contractor will notify the ET Leader two days before entering the zone marked on Figure 4.2b (1).

A Proforma report together with evidentiary photographs would be submitted to EPD, AFCD and other concerned parties within 2 days for scrutiny.

4.2.6 Post Project Monitoring

Within Tolo Channel the post project monitoring will comprise one survey within two weeks after completion of the final jetting pass. For the Tung Ping Chau area one survey should take place within one week of completion of dredging works within the section on the Mainland side that is within 1 km of the boundary of the HKSAR.

The Post Project Monitoring should consist of the video transect work conducted during the Baseline Monitoring (see Section 4.2.3 for details).

4.3 MARINE ECOLOGY COMPLIANCE - ACTION EVENT PLAN

The main focus of the ecological monitoring will be to determine whether impacts are occurring to the high ecological value assemblages (as identified in Table 6.1 of the EIA report) of hard corals, soft corals and black corals along the Tolo Channel coastline during the jetting works and at Tung Ping Chau during dredging works in Mainland waters. The detection of ecological impacts will be considered as significant and lead to a comprehensive review of the installation operations and mitigation measures. The ecological monitoring is focussed on the responses of tagged corals (hard corals, soft corals and black corals) to the installation works. The monitoring has focussed on tagged corals because changes in percentage cover or abundance of corals would not be apparent over the short timeframe within which the works occur. As discussed in Section 1 of this EM&A Manual the jetting works will proceed at a rate of 1.08 km day-1 (within Tolo Channel) and consequently will likely complete one pass of jetting in the north-eastern section of Tolo Channel where the corals are located in 8-10 days. Similar construction time will also be experienced in Tung Ping Chau during dredging works on the Mainland side.

Changes in percentage cover or abundance of corals would only be apparent after a period of two weeks or more. Because of this, the action plan for the introduction of mitigation measures has been prepared based on the assessment of changes from the baseline in the following parameters:

Hard Corals: Sediment Cover (% of coral surface);

Bleaching (% of surface bleached white);

Partial Mortality (% of surface exhibiting mortality).

Soft/Black Corals: Partial Mortality (% of total number branches

exhibiting mortality).

Decision points for the Action Limit Levels have been based on protocols adapted from monitoring on the Great Barrier Reef in Australia, Sai Kung and West Po Toi in Hong Kong (2) (3) (4). EM&A results from the studies in Hong Kong have demonstrated that these protocols have successfully prevented impacts to corals. The stepwise approach to the application of the Action Event Plan is detailed below:

Step 1 Commence tagged coral (hard, soft and black) monitoring at the impact site following methodology described in Section 4.2.2. If no increase in sedimentation cover/ bleaching/partial mortality is observed on the hard corals or partial mortality on the soft/black corals no action is required. The coral survey specialist should present this information to the ET Leader at the end of each survey day for verification (Proforma report presented in Annex D). Monitoring should continue the following day at the appropriate impact stations (dependent on the location of the jetting machine/dredging works). If an increase in sedimentation cover/ bleaching/ partial mortality is observed on the hard corals or partial mortality on the soft/black corals at one or more impact monitoring stations Step 3 should be enacted, if not, Step 2.

Step 2 If no actions are triggered a formal report should be issued to the Contractor, Towngas, EPD and AFCD and the IEC along with evidentiary photographs the day following completion of the survey (second). Meanwhile monitoring work and installation works should continue uninterrupted. If no actions are triggered for the reminder of the installation works the ET Leader should issue a formal report every two days to all parties detailing the findings of the previous 2 days of monitoring.

Step 3 Hard Corals: If during the Impact Monitoring a 15% increase in the percentage of sedimentation on the hard corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations that is not reported at the Control Monitoring Station, then the Action Level is exceeded (Step 4).

If during the Impact Monitoring a 15% increase in the percentage of bleaching of hard corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Action Level is exceeded. (Step 4)

If during the Impact Monitoring a 15% increase in the percentage of partial mortality of corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Action Level is exceeded (Step 4).

Soft/Black Corals: If during the Impact Monitoring a 15% increase in the percentage of partial mortality of corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Action Level is exceeded (Step 4). If the Action Level is not exceeded Step 2 is enacted.

Step 4 If the Action Level is exceeded the ET Leader should inform all parties (Contractor, Towngas, EPD, AFCD and IEC). The data from the water quality monitoring should also be reviewed. If the water quality monitoring shows no attributable effects of the installation works, then the Action Level is not triggered. If the water quality data indicate exceedances (for SS and/or turbidity) the ET Leader should discuss with the Contractor the most appropriate method of reducing suspended solids during jetting/dredging (eg reduce speed/volume of water used during installation). The water quality data reviewed should be from the stations corresponding to the relevant coral stations (refer to Table 3.2 for the stations in Zone B and WQ1-4 for the Tung Ping Chau area). This mitigated method should then be enacted on the next working day.

Step 5 Monitoring should proceed the following day as per Step 1.

Hard Corals: If during the Impact Monitoring a 25% increase in the percentage of sedimentation on the hard corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations that is not reported at the Control Monitoring Station, then the Limit Level is exceeded (Step 6).

If during the Impact Monitoring a 25% increase in the percentage of bleaching of hard corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Limit Level is exceeded (Step 6).

If during the Impact Monitoring a 25% increase in the percentage of partial mortality of corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Limit Level is exceeded (Step 6).

Soft/Black Corals: If during the Impact Monitoring a 25% increase in the percentage of partial mortality of corals occurs at more than 20% of the tagged coral colonies at one or more Impact Monitoring Stations which is not recorded at the Control Monitoring Station, then the Limit Level is exceeded (Step 6).

If the Limit Level is not exceeded Step 2 is enacted and work continues according to the mitigated method.

Step 6 If the Limit Level is exceeded the ET Leader should inform all parties (Contractor, Towngas, EPD, AFCD and IEC) immediately. Should the Limit Level be exceeded, the contractor should stop works immediately and work out the solution according to the requirements of EPD and AFCD. The ET Leader should inform the Contractor to suspend jetting/dredging operations until an effective solution is identified. Once the solution has been identified and agreed with all parties jetting/dredging works may commence.

It should be noted, that for the success of the monitoring programme there should be an element of review and revision throughout the ecological monitoring aspects of the programme as more data are gathered. This will ensure that the programme takes account of the data as they are collected and allow for full utilisation of the available information. Once the first pass of jetting has been completed the monitoring results should be reviewed. If no actions have been triggered then the ET Leader may proposed to reduce the scale of the monitoring works for agreement by Towngas, EPD, AFCD and the IEC.

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(1) The start point of the zone illustrated on Figure 4.2b is 861836 (E), 847941 (N) (HK GRID).

(2) Benson L J, Holdworthy PM, Buttler IR, and Oliver J (1994) Townsville Port. Authority Capital Dredging Works 1993; Environmental Monitoring Programme. ISBN O 646 2155 965

(3) ERM - Hong Kong, Limited (2001) Water Quality and Control Monitoring Plan for the Proposed 132 kV Cable Circuits From A Kung Wan to Sai Kung Pier, Final Report for CLP Power.

(4) ERM - Hong Kong, Limited (2001) Focussed Cumulative Water Quality Impact Assessment of Sand Dredging at the West Po Toi Marine Borrow Area. Environmental Monitoring and Audit Manual. Updated Manual 9 July 2001 for HAM Dredging and Marine Contractors.