8.1.1
This section presents the findings of an assessment of potential
impacts on existing capture and culture fisheries, including fisheries
resources, fishing operations and fish culture activities, from the
construction and operation of the proposed Project. It summarizes baseline information on
fisheries production around Mirs Bay Water Control Zone (WCZ) and its vicinity
gathered from literature review. The
assessment of fisheries impacts is based on the Project Description (Section 2) and the findings of the Water
Quality Assessment (Section 5).
8.2.1
Technical Memorandum
The criteria for evaluating fisheries impacts are stated in the EIAO-TM.
Annex 17 of the EIAO-TM
prescribes the general approach and methodology from assessing fisheries
impacts caused by a project or proposal, to allow a complete and objective
identification, prediction and evaluation of the potential impacts. EIAO-TM
Annex 9 recommends the criteria that
are to be used for evaluation of fisheries impacts.
8.2.2
Other Legislation
Other legislation which applies to fisheries includes:
·
Fisheries Protection Ordinance (Cap. 171),
which provides for conservation of fish and other aquatic life, regulates
fishing practices and prevents activities detrimental to the fishing industry.
·
Marine Fish Culture Ordinance (Cap. 353),
which regulates and protects marine fish culture and other related activities
and requires all marine fish culture activity to operate under license in
designated Fish Culture Zones.
·
Water Pollution Control Ordinance (Cap. 358),
which aims to control water pollution in Hong Kong waters. Water Control Zones (WCZs) are designated
with individual water quality objectives to promote the conservation and best
use of those waters in the public interest.
·
Environmental Impact Assessment Ordinance (Cap. 499),
Section 5(7) – Environmental Impact Assessment Study Brief No. ESB-253/2012 Section
3.4.7 and Appendix G which outline the key fisheries impacts to be reviewed and
assessed in the EIA Report.
The Study Area for fisheries is the same as that for the Water
Quality Impact Assessment (see Section 5)
and includes other areas likely to be impacted by the Project, particularly
area with significant fisheries resources and fishing activities, spawning and
nursery grounds, and the Fish Culture Zones.
A desktop review of existing information on commercial fisheries
resources and fishing operations in waters of the Study Area has been
undertaken, and the most up-to-date information was obtained primarily from the
Agriculture, Fisheries and Conservation Department (AFCD). For a detailed description of the physical
and biological characteristics of the marine environment of the Study Area
please refer to Sections 5 and 7
respectively.
8.3.1
Overview of Hong Kong Fisheries
Marine-based commercial fishing operations in Hong Kong are
broadly classified into capture and culture fisheries.
Capture
Fisheries
Capture fisheries is primarily concentrated in the waters of Hong Kong, the Pearl River Estuary and the adjacent continental shelf of the South and East China Seas ([1]). The AFCD reported that in 2014 an estimated 160,789 tonnes of fish was produced, which was equivalent to an economic value of about HK$2,530 million ([2]). In addition, 9,400 local fishermen with approximately 4,500 vessels were servicing in the fishing industry ([3]). Most fishing vessels are manned by family members with the assistance of hired crew. The major fishing methods include trawling, long-lining, gill-netting and purse-seining with the majority of the total catch obtained through trawling. Recent data on local capture fisheries industry are summarized in Table 8.1.
Table 8.1 – Hong
Kong Capture Fisheries Industry Summary Statistics 2002 – 2014 (source: AFCD)
|
Year |
Fishing
fleet size (no. of vessels) |
No.
of Local fishermen engaged in capture |
Production
(tonnes) |
Value
of capture produce (HK $M) |
|
2002 |
4,770 |
10,860 |
169,790 |
1,600 |
|
2003 |
4,630 |
10,130 |
157,440 |
1,600 |
|
2004 |
4,330 |
9,770 |
167,540 |
1,600 |
|
2005 |
4,150 |
9,170 |
162,000 |
1,600 |
|
2006 |
3,950 |
8,500 |
155,000 |
1,600 |
|
2007 |
4,000 |
8,500 |
154,000 |
1,530 |
|
2008 |
3,800 |
7,900 |
158,000 |
1,780 |
|
2009 |
3,700 |
7,600 |
159,000 |
2,000 |
|
2010 |
3,900 |
8,200 |
168,000 |
2,100 |
|
2011 |
4,026 |
8,500 |
170,720 |
2,358 |
|
2012 |
3,992 |
8,800 |
155,230 |
2,317 |
|
2013 |
3,988 |
8,800 |
170,129 |
2,338 |
|
2014 |
4,500 |
8,800 |
160,789 |
2,530 |
Based on the latest data from AFCD Port Survey 2006, the highest
fisheries production (600 to 1,000 kg ha-1) in Hong Kong was
recorded in the vicinity of the eastern
and northeastern coasts including Ninepin Island Group, Po Toi and Tap Mun ([4])
and these areas also recorded the highest number of fishing vessels. The top 10 families captured in Hong Kong
waters were: Scad (Carangidae), shrimp, rabbitfish (Siganidae), squid, croaker
(Sciaenidae), crab, mullet (Mugilidae), sardine (Clupeidae), seabream
(Sparidae) and anchovy (Engraulidae).
Previous
studies indicated that fry collection has become very limited throughout Hong
Kong waters ([5]). Fish fry production was concentrated in the
eastern waters, although a minor production was also reported in the East Lamma
Channel and Po Toi.
To promote the sustainable development of fishing industry and to
conserve fisheries resources in Hong Kong waters, AFCD has implemented a number
of fisheries management and conservation measures. On 31 December 2012, an outright trawling ban
was put into effect in an attempt to restore the seabed and the depleted
fisheries resources ([6]). To complement the trawl ban and bring local fisheries
industry back to a sustainable path, the government seeks to implement other
fisheries management measures through legislative amendments to the Fisheries
Protection Ordinance (Cap. 171). These
measures include:
1.
Setting up a registration system for
local fishing vessels;
2.
Limiting new entrants and maintaining an
appropriate level of fishing effort;
3.
Restricting fishing activities of
non-fishing vessels and prohibiting fishing activities of non-local fishing
vessels;
4.
Designation of fisheries protection
areas;
5.
Habitat enhancement and restoration (i.e.
artificial reefs); and
6.
Fish restocking exercises.
Since 1999, Mainland Authorities (The Bureau of Fisheries
Management and Fishin Port Superintendence of the Ministry of Agriculture in
the Mainland) have implemented a fishing moratorium for South China Sea fishing
grounds for about 2.5 months during mid-summer (between 16 May to 1 August). The moratorium prohibits fishing activity by
the Hong Kong fleet outside of Hong Kong waters using trawl net, purse-seine,
hang trawl and cage trapping in order to conserve fisheries resources and
promote sustainable development of the fishing industry ([7]).
Culture Fisheries
Marine fish culture operations occur at 26 Fish Culture Zones
(FCZs) which altogether occupy about 209 ha of Hong Kong waters with some 968
licensed operators. They involve rearing
of marine fish from fry or fingerlings to marketable size in cages suspended by
floating rafts usually in sheltered coastal areas/ embayments. Most licensed fish farms are typically small
scale, family-based operations comprising only one or two rafts with average total
area of about 290 m2.
With effect from June 2002, the marine fish culture licence is
transferable. The existing moratorium
for FCZs has been reviewed and the following new measures are proposed to
promote the sustainable development of the local fisheries industry, including ([8]):
1.
Issue new marine fish culture licences in
three FCZs (i.e. O Pui Tong, Wong Wan and Sham Wan FCZs) with approximately 30
new marine fish culture license to be issued at the initial stage;
2.
Expand the existing FCZ at Yim Tin Tsai
to rearrange and spread out the existing rafts within the expanded zone with no
net increase in the total licensed raft area;
3.
Identify any potential sites for
designation of new FCZs; and,
4.
Impose licensing conditions and provide
appropriate support to encourage the mariculture industry to adopt new
technologies and management practices.
In 2014, the marine fish culture industry produced about 1,255
tonnes of fish valued at HK$115 million which accounts for about 6 % of local
demand for live marine fish. The
fish species commonly cultured in FCZs are of high commercial value including the green grouper (Epinephelus coioides), brown-spotted grouper (Epinephelus chlorostigma), giant grouper (Epinephelus
lanceolatus), Russell's snapper (Lutjanus
russellii), mangrove snapper (Lutjanus
argentimaculatus), goldlined seabream (Rhabdosargus
sarba) and star snapper (Lutjanus
stellatus). Some recent figures on the local marine
culture fisheries are presented in Table
8.2 below.
Table 8.2 –
Marine Culture Fisheries Summary Statistics 2002 – 2014 (source: AFCD)
|
Year |
Licensed
Mariculturists |
Production
(tonnes) |
Value
(HK$ million) |
|
2002 |
1,237 |
1,210 |
57 |
|
2003 |
1,157 |
1,490 |
76 |
|
2004 |
1,125 |
1,540 |
79 |
|
2005 |
1,104 |
1,540 |
76 |
|
2006 |
1,081 |
1,490 |
89 |
|
2007 |
1,072 |
1,530 |
99 |
|
2008 |
1,060 |
1,370 |
82 |
|
2009 |
1,050 |
1,437 |
92 |
|
2010 |
1,035 |
1,512 |
118 |
|
2011 |
1,010 |
1,185 |
94 |
|
2012 |
1,008 |
1,299 |
117 |
|
2013 |
987 |
1,005 |
94 |
|
2014 |
968 |
1,255 |
115 |
8.3.2
Capture Fisheries in the Study Area
Fishing
Operations
The area and number of vessels operating in the Study Area during
2005 are presented in Figure 8.1. It should be noted that trawling was still
allowed at time when the Port Survey was conducted in 2005. Small numbers of fishing vessels (10 – 100
vessels), mostly sampans and purse seiners, operated in waters around the
proposed STKSTW expansion and submarine outfall in 2005. Elsewhere within the Study Area, moderate
number of vessels (100 – 400 vessels) were recorded near Ap Chau, Kat O, Yan
Chau Tong, Lai Chi Wo and Wong Wan. The
vessels, which are less than 15 m in length, are the major type of fishing
operation vessels in northeastern waters.
Fishing
Production
The level of fisheries production in the waters around Sha Tau Kok
Area in 2005 is presented in Figures 8.2 and 8.3.
Data from the AFCD Port Survey 2006 indicated that fisheries
production in waters around the submarine outfall of the proposed STKSTW ranged
0 – 100 kg ha-1 for adult fish (Figure 8.2) accounting for HK$ 1,000 – 5,000
ha-1 in value (Figure 8.3). Key fish families recorded by Port Survey
2006 include Siganidae (Rabbitfish), Engraulidae (Anchovy), Sciaenidae
(Croaker) and Sparidae (Seabream).
In comparison to other areas of the Hong Kong fishing ground,
fisheries production in the waters around Sha Tau Kok Area is low. Other areas of high fisheries production
include areas around Cheung Chau, Lamma Island, the Ninepin Island Group, the
Soko Islands, the Po Toi Island Group and Tap Mun.
Fish Fry
Production
As presented in Figure 8.4, there is no record of fish
fry catches within the direct footprint of the submarine outfall
pipelines. Other areas of fish fry
production outside of the direct footprint of submarine outfall pipeline area
include the Po Toi Island Group, Port Shelter and Tap Mun.
8.3.3
Culture Fisheries in the Study Area
Six AFCD designated Fish Culture Zones (FCZs) are located in the
northeastern part of Hong Kong in the Mirs Bay in the vicinity of the Study
Area (Figure
8.5):
1.
Sha Tau Kok FCZ (1.17 km from the diffuser
of the proposed submarine outfall);
2.
Ap Chau FCZ (3.25 km from the diffuser of
the proposed submarine outfall);
3.
Kat O FCZ (5.17 km from the diffuser of
the proposed submarine outfall);
4.
O Pui Tong FCZ (6.29 km from the diffuser
of the proposed submarine outfall);
5.
Sai Lau Kong FCZ (5.17 km from the diffuser
of the proposed submarine outfall);
6.
Wong Wan FCZ (8.08 km from the diffuser
of the proposed submarine outfall).
There are no pond culture resources and activities in the
northeastern part of Hong Kong where the Project is located.
8.3.4
Spawning Areas
The northeast waters were identified in 1998 as fisheries spawning
grounds for high value commercial species (Figure 8.5) ([9]). The key species recorded spawning in the northeast
waters include Leiognathus brevirostris (shortnose
ponyfish), Konosirus punctatus (gizzard
shad) and Metapenaeopsis palmensis (southern
velvet prawn). The recognized spawning
grounds at the northeast waters are located > 2 km east of the proposed
submarine outfall.
8.3.5
Nursery Areas
Nursery areas in Hong Kong waters that are
important habitat area for a number of commercial juvenile fish and crustacean
species have been previously identified along northeast waters, across southern
waters from Lantau Island to Lamma Island and within Port Shelter waters ([10]),
whilst no nursery ground was identified within the direct footprint of the
submarine outfall of the proposed STKSTW (Figure 8.5). The identified nursery grounds are located
> 2 km east of the proposed submarine outfall.
8.3.6
Artificial Reef Deployment
The AFCD has been undertaking a programme to
enhance existing marine habitats and fisheries resources through the siting,
construction and deployment of artificial reefs (ARs) since 1996. Generally ARs provide hard bottom, high
profile habitat in areas without natural cover and may potentially act as fish
enhancement devices. The Yan Chau Tong
Marine Park and O Pui Tong ARs were deployed with the key objective of
enhancing the marine habitat quality and fisheries resources (Figure
8.5). A total of 19,820 m3
consisting of boat, tyre, concrete-coated tyre, quarry rock, pre-cast concrete
and biofilter core have been deployed on the seabed from 1998 to 2003 in Yan
Chau Tong Marine Park. For O Pui Tong, a
total of 4 units with volume of 200 m3 tyre modules were deployed in
2000. They are located at least 5.88 km
away from the proposed submarine outfall.
8.3.7
Sensitive Receivers
Based on the preceding review of the available information on the capture and culture fisheries of the waters in the vicinity of the proposed Project, the fisheries sensitive receivers that may potentially be affected by the Project activities are identified as follows:
·
Fish Culture Zones at Sha Tau Kok, Ap
Chau, Kat O, O Pui Tong, Sai Lau Kong and Wong Wan (at least 1.17 km away from
the diffuser of the proposed submarine outfall);
·
Recognized spawning and nursery ground of
commercial fisheries resources at northeast waters (at least 2 km away from the
diffuser of the proposed submarine outfall); and
·
Artificial reefs at Yan Chau Tong Marine Park
and O Pui Tong (at least 5.88 km away from the diffuser of the proposed
submarine outfall).
The locations of the sensitive receivers are
shown in Figure 8.5.
8.3.8
Fisheries Importance
Based on the baseline information provided above, the importance of the fisheries within the Study Area is evaluated. The fishing areas within and in the vicinity of the Project’s footprint are considered to be of low to moderate commercial value. Also considering the small size of these areas at Starling Inlet (464 ha), the Project Area is considered as of low importance to the Hong Kong fishing industry.
According to Annex 9 of the EIAO-TM, spawning and nursery grounds can be regarded as an important habitat type as they are critical to the regeneration and long-term survival of many organisms and their populations. However, no spawning and nursery area has been identified within the footprint of the proposed submarine outfall of the Project. The closest recognized spawning area is located at least 2 km east of the Project site. The closest artificial reefs are also over 5 km from the Project site. Considering the separation distances between the Project and these fisheries sensitive receivers, it is considered that the Project Area is of low importance to fisheries resources.
The waters surrounding the Project’s footprint and its vicinity support mariculture activities with six designated FCZs located in northeast waters. The closest FCZ is about 1 km away from the diffuser of the proposed submarine outfall. It is considered that the Project Area is of moderate importance to culture fisheries.
Results from the review indicate that fisheries importance of the
Project Area and its vicinity is low when compared to other waters of Hong
Kong. Therefore, it is
considered that further fisheries field surveys around the Project area are not
necessary for the impact assessment given the small scale of the marine
construction works with temporary loss of 1 ha fisheries habitat and fishing
ground.
A desktop literature review of baseline fisheries conditions was conducted for the purpose of establishing the fisheries importance of the waters in the vicinity of the proposed expansion of STKSTW at Sha Tau Kok. Information from the water quality impact assessment (Section 5) was examined to refine the size of the Study Area as that is potentially affected by perturbations to water quality parameters. This area, refined to within 7 km from the Project facilities, became the main focus for this fisheries impact assessment. The importance of potentially impacted fisheries resources and fishing operations, and aquaculture activity within this area was studied. The potential impacts due to the construction and operation of the Project were then assessed (with reference to the EIAO-TM Annex 17) and the impacts evaluated (with reference to the criteria in EIAO-TM Annex 9).
8.5.1
Construction Phase
·
Direct disturbances of fisheries habitat,
fishing ground, fishing operations and aquaculture activity; and,
·
Perturbations to key water quality
parameters.
Disturbance
to fisheries habitat, fishing ground, fishing operations and aquaculture
activity
Direct impacts to fisheries resources, habitats and fishing operations include disturbance caused by marine construction works (i.e. the construction of discharge outfall and the construction of diffusers).
As trenchless construction technique (i.e. HDD) will be used for the construction of submarine discharge outfall which does not require dredging along the submarine outfall alignment, it is anticipated that seabed sediments would not be disturbed and disturbance to fisheries habitat and fishing ground is hence not expected.
The submarine outfall diffuser will be installed within the cofferdam to be constructed at Starling Inlet. It is expected to cause temporary loss of approximately 1 ha of fisheries habitat and fishing ground which will last for approximately 27 months (September 2018 – November 2020), including the works area for work vessels. In addition, there will be 0.042 ha permanent loss of fishing ground due to the construction of the diffuser erected above the seabed and the loss of fishing ground has been minimised using HDD method for the construction of submarine outfall. Owing to the very small area of the fisheries habitat and fishing ground lost to the marine construction works when compared to the 464 ha sea area at Starling Inlet and due to its low fisheries importance, unacceptable impacts to local fisheries resources, habitats and fishing operations are not expected. Fisheries resources are expected to return to the area following the cessation of marine construction activities. Issuance of Marine Department Notice or other notification is expected to reduce the risk of collision of increased marine traffic and fishing vessels to within acceptable levels.
Perturbations
to key water quality parameters
Indirect impacts to fisheries resources, habitats and fishing operations during the construction phase are primarily associated with the suspension of sediments due to the marine works. Potential impacts to water quality from sediment release due to the installation of sheetpiles (and removal after the completion) for cofferdam installation at submarine outfall, decommissioning of existing submarine outfall, vessel discharges and land-based site runoff from construction workforce as described in the water quality impact assessment in Section 5. Potential impacts to water quality from sediment release are as follows:
·
Increased concentrations of suspended
solids (SS);
·
Decreased dissolved oxygen (DO)
concentrations;
·
An increase in nutrient concentrations in
the water column; and
·
Elevation of heavy metals and
micro-organic pollutants.
During construction period, discharges and runoff from the site, particularly during excavation and backfilling works, will contain SS which could be a source of water pollution. Drill cuttings (rock debris from drill hole) would be separated from used HDD drilling fluid and be disposed of as fill material onsite while used drilling fluid would be reconditioned (if required) and be reused as far as practicable. Spent drilling fluid which is no longer fit for reuse would be dewatered and disposed at landfill. Uncontrolled disposal of debris and rubbish such as packaging, construction materials and refuse and spillages of chemicals stored on-site, such as drilling fluid, oil, diesel and solvents would also result in contamination of construction site runoff. However, it is anticipated that no unacceptable water quality impacts would arise from the land-based works if standard site practices and mitigation measures, described in Section 5.9.4, are in place and properly implemented.
Sediment or SS could be lethal or sublethal to fish and other fisheries resources through reduction in survivorship, growth rate and reproductive potential due to stress incurred by the need to constantly flush out deposited material. High SS level may clog gill structure of fish and cause physical damage and hinder transfer of oxygen. Fish egg and larval fish (fry) are more susceptible to deleterious impacts from sedimentation through burial and clogging of their respiratory systems. Adult fish are more likely to move away when they detect certain SS level and therefore less sensitive to effects from SS.
Increase in SS in water column combining with a number of other physical or biotic factors would reduce DO in water column. Elevated SS reduces light penetration, lowers the photosynthetic rate of phytoplankton and eventually would lower the rate of oxygen production in water column. Also, the release of inorganic substances from the sediments may cause eutrophication and algal bloom. Oxidation of dead algae may use up some of the oxygen in the water. If oxygen levels are depleted to low levels, fish, especially those in early life stages may be unable to tolerate such conditions and suffer hypoxia-induced mortality and / or stress including reduced feeding and growth rate.
Sediment-bounded nitrogenous compounds could also be released into the water column and result in an increase of nutrients (total inorganic nitrogen - TIN and unionized ammonia - UIA). High levels of nutrients may potentially cause rapid increase in phytoplankton population, on occasions to the point that an algal bloom occurs. An intense algal bloom can cause sharp decrease in the levels of DO. This decrease in DO would initially occur in the surface water, and then spread to deeper water as dead algae fall through the water column and decompose on the seabed.
Aside from the effects of SS, DO and nutrient release on the water column, the Project works have the potential for release of heavy metals and micro-organic pollutants which may impact fisheries in terms of:
·
accumulation of contaminants in the
tissue of fish and invertebrates resulting in sublethal effects which may
affect behaviour, reproduction and increasing susceptibility to disease; and;
·
increased mortality, and sub lethal
effects to, eggs, larvae and juvenile species, as these are particularly
sensitive to elevated contaminant concentrations.
According to the
water quality impact assessment in Section
5, sediment release due to the installation of sheetpiles (and removal
after the completion) for cofferdam installation at submarine outfall,
decommissioning of existing submarine outfall, vessel discharges and surface
runoff from land-based construction activities near the coastal waters would
not cause any significant change in sediment, SS, organic and inorganic water
pollutants. It is also predicted that
the construction of submarine outfall diffuser under this Project would be in
compliance with the corresponding SS, DO, TIN and UIA criteria of WQO. Therefore, it is unlikely to cause
unacceptable impact on the aquatic environment from an ecotoxicological point
of view. Moreover, all important
fisheries resources, such as fish spawning and nursery grounds, FCZs, and
artificial reefs are at large distances (> 1km) away from the proposed works
area. With the implementation of
mitigation measures proposed in water quality impact assessment in Section 5, such as the use of silt removal
facilities, and effective site drainage would minimize any impacts to the
marine environment resulting from land-based construction activities. No unacceptable impact associated with water
quality change is expected on fisheries resources during the construction phase.
8.5.2
Operation Phase
As the cofferdam will be removed after the
completion of proposed submarine outfall construction, permanent loss of fishing
ground will be limited to the location of the submarine outfall diffuser
erected above the seabed, which is of 0.042 ha size. There will be no loss of habitat in the water
column. From the evaluation of the
productivity and value of the local fisheries in Section 8.3, the affected area
is considered as of low fisheries importance.
Overall, the very small size and low fisheries importance of the
affected area suggest that unacceptable impacts to fisheries caused by
permanent loss of fishing ground are not expected to occur. The potential impact of the operational phase
of the Project on the fisheries of the Study Area would be the change in the hydrodynamic regime and water quality
due to the operation of TSTP (interim scenario) and the expanded STKSTW
(operation scenario).
Based on the TSTP
design, there would not be a net increase in pollution loading from the
operation of the TSTP as compared with the operation of the STKSTW at
present. Therefore, it is
predicted that the TSTP operation would not result in the change in levels of
TIN, UIA, SS, DO and E. coli for the Sha
Tau Kok FCZ (420 m away from the diffuser of the existing submarine outfall). All other important fisheries resources, such
as fish spawning and nursery grounds, FCZs, and artificial reefs are at large
distances (> 2 km) away from the outfall, and no unacceptable change in
water quality is predicted at these sensitive receivers. With the operation of the expanded STKSTW,
treated effluent would be discharged at the proposed new submarine outfall
located further away from the Sha Tau Kok FCZ at the opening of the Starling
Inlet embayment which favours the effluent dispersion and material
exchange. Although there is an increase
in effluent flow rate (1,660 m3/day to 10,000 m3/day), it
is predicted that the levels of DO, TIN, UIA, SS and E. coli would comply to the WQO criteria at STKFCZ (1.17 km away
from the diffuser of the new submarine outfall) and all other sensitive
receivers (> 2 km away from the diffuser of the new submarine outfall). There would be no unacceptable impact from the
operation of the expanded STKSTW on the fisheries resources and fishing
operations.
Therefore, the impact due to discharge of treated effluent under both interim and operation scenarios on fisheries resources is considered acceptable.
As discussed in Section 5.8, precautionary measures have been taken into account in
the design and initial commissioning of the TSTP and expanded STKSTW to
minimize the risk of discharge of untreated or incompletely-treated sewage into
the marine water of Starling Inlet under emergency situation. In
the event that such situation occurs, it is predicted that the change in
levels of DO, SS, UIA and E. coli is
localised around the safety outlet of the TSTP and expanded STKSTW after a 2-hour
emergency discharge. The change in levels
of DO, SS, UIA and E. coli at the
FCZs, including the nearest Sha Tau Kok FCZ, is limited and would not result in
unacceptable change in levels of DO, SS, UIA and E. coli at the FCZs. No
unacceptable impact to the aquaculture activities at the FCZs is thus expected from
such emergency situation. In addition,
it is predicted that the water quality would recover to ambient levels within a
short period of time (3 to 10 days) after such emergency discharge (see Section 5). Therefore, the impact from the emergency
discharge of the TSTP and the expanded STKSTW on fisheries resources is
considered to be temporary and insignificant.
Given the unlikely occurrence of emergency discharge with the
application of the precautionary measures and the temporary change in water
quality after an emergency discharge, there would be no unacceptable impact
from such situation on the fisheries resources and fishing operations.
From the information presented above, the fisheries impact associated with the Project is not considered to be significant. An evaluation of the impacts accordingly to Annex 9 of the EIAO-TM is presented below.
8.6.1
Nature of Impact
Permanent impacts are predicted to occur as a result of the loss of fishing
ground in the 0.042 ha area to be used for installation of submarine outfall
diffuser. Temporary disturbance to
fishing grounds in the Project’s marine works area is expected. Temporary and localized impacts to pelagic
and demersal fisheries resources as a result of perturbations to water quality
are predicted to occur only in the immediate vicinity of the works area.
8.6.2
Size of Affected Area
The construction and operation of the Project is predicted to result in
the permanent loss of approximately 0.042 ha of fishing ground on the seabed only. In addition, the construction of the Project
is predicted to result in the temporary loss of approximately 1 ha of fisheries
habitat and fishing ground, including the works area for work vessels. This loss is considered to be insignificant
for local fishery resources and fishing operations given the very small size of
fisheries habitat and fishing ground loss and low fisheries importance in these waters.
8.6.3
Loss of Fisheries Resources/Production
The value of the fisheries resources/ production of the marine waters
around the submarine utilities is low in comparison to other waters in Hong
Kong. The area affected is very small.
8.6.4
Destruction
and Disturbance of Nursery and Spawning Grounds
No important spawning or nursery grounds have been identified within the
Project Area. The recognized spawning
and nursery grounds at Mirs Bay lie at least 2 km from the proposed
Project. As the water quality modelling
results have indicated that impacts to water quality are predicted to be
localised and short-term, impacts to the identified nursery and spawning
grounds are not expected to occur.
8.6.5
Impact
on Fishing Activity
Due to the small size of the affected area and the low fisheries
importance, impacts on fishing activity are expected to be negligible.
8.6.6
Impact
on Aquaculture Activity
No unacceptable impact has been identified on the FCZs as SS elevations,
DO depletion as well as nutrient and contaminant release from marine
construction works for cofferdam installation at submarine outfall would be
minimal. The closest FCZ is Sha Tau Kok FCZ
which is located at least 420 m from the diffuser of the existing submarine
outfall for TSTP or 1 km from the diffuser of the proposed submarine outfall
for expanded STKSTW, and no unacceptable change in water quality would be
predicted from the operation of the TSTP and expanded STKSTW, including the
presence of emergency discharge situation.
Therefore, no unacceptable impact on aquaculture activity is expected.
In accordance with the guidelines in the EIAO-TM Annex 17 on fisheries impact assessment, the policy adopted
in this EIA for mitigating impacts to fisheries, are:
·
Avoidance:
Potential impacts should be avoided to the maximum extent practicable by
adopting suitable alternatives;
·
Minimisation:
Unavoidable impacts should be minimised by taking appropriate and
practicable measures such as confining works in specific area or season,
restoration (and possibly enhancement) of disturbed fisheries resources and
habitats as well as establishing a communication plan to relevant stakeholders
regarding emergency discharge situation at STKSTW;
·
Compensation:
When all possible mitigation measures have been exhausted and there are
still significant residual impacts or when the impacts are permanent and
irreversible, consideration shall be given to compensation. It may include enhancement of fisheries
resources and habitats elsewhere.
Construction impacts to fisheries resources, habitats and fishing
operations have largely been avoided (i.e. important spawning and nursery area
of commercial fisheries resources, fish culture zones, artificial reefs) and
reduced through proper planning and design of the works, in particular those
associated with the marine construction activities for the submarine outfall
(e.g. adoption of trenchless method to avoid the needs of dredging and
backfilling along the submarine outfall alignment such that the seabed and
aquatic ecosystem are not disturbed, location of the outfall diffuser to allow
better mixing, and optimisation of project construction schedule). The main works have been designed to confirm
compliance with the assessment criteria at sensitive receivers and control
water quality impacts to within acceptable levels and water quality mitigation
measures will be implemented to further avoid/ reduce potential impacts (see Section 5). These measures are expected to control and
reduce potential impacts to fisheries resources as well, and no
fisheries-specific mitigation measures or compensation are thus required during
construction.
No significant impacts to fisheries resources and fishing operations is
expected to occur during the operation phase of the Project. Compliance with the relevant discharge
standards to control water quality impacts to within acceptable levels is also
expected to control impacts to fisheries resources. As a good practice, it is recommended to
establish a communication plan as a precautionary approach to inform the
mariculturists, relevant stakeholders (e.g. Sha Tau Kok District Rural
Committee) and relevant government departments (e.g. AFCD, EPD, MD) of the
emergency discharge situation at STKSTW such that appropriate response actions
can be formulated.
Impacts to fisheries resources, habitats and fishing operations during
construction and operation phase are considered to be within acceptable
level. As the cofferdam will
be removed after the completion of proposed submarine outfall construction, permanent
loss of fishing ground will be limited to the location of the diffuser erected
above the seabed, which is of 0.042 ha size.
The magnitude of residual impact is considered to be within acceptable
levels given the small size and low fisheries importance of the area being lost.
Information from publicly available sources suggested that the
construction/ implementation programmes of the major projects listed in Section 2.10 would coincide with the
construction of the Project. In
particular, the sediment removal project at Sha Tau Kok FCZ, Boat Shelter and
Approach Channel (tentative without confirmed programme) could be the concurrent marine
construction works that involves dredging operation inside Starling Inlet which
is scheduled to commence in the 1st half of 2017 for completion in the 1st half of 2018
tentatively, which would potentially be concurrent with the marine construction
period under this Project. During the dredging operation, the fish rafts of
the Sha Tau Kok FCZ would be relocated to two proposed temporary relocation
zones ([11]). One of the relocation zones is about 800 m
east to the existing Sha Tau Kok FCZ (FCZ7 shown in Figure 8.5) and the other
would be about 250 m south to the existing Sha Tau Kok FCZ (FCZ8 shown in Figure
8.5). Under the interim scenario
of the TSTP operation, as the two relocation sites are located further away
from the existing outfall of the existing STKSTW/TSTP, higher mean and 10th-percentile
DO levels as well as lower TIN, UIA SS, E.
coli levels are predicted. No
exceedance in WQO criteria would be predicted from the operation of the TSTP.
The fisheries impact assessment has considered the
cumulative effects of different activities of this Project on fisheries
resources and fishing operations. The
worst-case scenarios of concurrent construction of all Project facilities have
been assessed in the Water Quality Impact Assessment (Section 5) and thus the cumulative impacts of this specific Project
have been accounted for. As discussed in
Section 5, the cumulative impacts of
the various project-specific construction activities are not predicted to cause
unacceptable impacts to water quality.
Consequently, unacceptable cumulative impacts to fisheries resources are
not expected to occur.
Given that no operational impacts on fisheries resources are anticipated
from this project, operational cumulative impacts with other developments in
and around Starling Inlet are not predicted to occur.
As no unacceptable impacts have been predicted to occur during the
construction and operation of this Project, monitoring of fisheries resources
during these project phases is not considered necessary.
Monitoring activities designed to detect and mitigate any unacceptable
impacts to water quality during construction phase are also expected to serve
to protect against unacceptable impacts to fisheries. The details of the water quality monitoring
programme are presented in the EM&A
Manual attached to this EIA.
A literature review of baseline information on commercial fisheries
resources and fishing operations surrounding the waters of the proposed Project
has been undertaken. Results from the
review indicate that fisheries importance of the Project Area and its vicinity
is low when compared to other waters of Hong Kong. Sensitive receivers including spawning
ground, nursery ground, artificial reefs and Fish Culture Zone areas have been
identified; however, the assessment of water quality impacts demonstrated that
these areas will not be significantly affected.
During construction of the Project, direct impacts arising from the
proposed marine works include temporary loss of approximately 1 ha of fisheries
habitat and fishing ground. Given the
small size of the fishing ground and temporal nature (within 27 months) of the
marine works, no significant direct impacts on fishing operations are expected
to occur. Indirect impacts to fisheries
resources related to perturbations to key water quality parameters are also
expected to be insignificant as the predicted changes in water quality are
short term and localised to immediate vicinity of the works area. Marine construction works have been designed
to reduce potential impacts on the water quality which will, in turn, reduce
impacts on fisheries resources. No
fisheries-specific mitigation measures are required during construction.
There will be loss of 0.042 ha of fishing ground during operation due to
the installation of diffuser erected above the seabed. Given the small size and low fisheries
importance of the area being lost, unacceptable operational phase impacts to fisheries resources and
fishing operations are not expected to occur.
Unacceptable impacts from discharge of treated sewage are not
anticipated to occur. Compliance with
the relevant discharge standards to control water quality impacts to within
acceptable levels is also expected to control impacts to fisheries
resources. As a good practice, it is
recommended to establish a communication plan as a precautionary approach to
inform the mariculturists, relevant stakeholders (e.g. Sha Tau Kok District
Rural Committee) and relevant government departments (e.g. AFCD, EPD, MD) of
the emergency discharge situation at STKSTW such that appropriate response
actions can be formulated.
All of the potential construction and operational fisheries impacts
identified are deemed acceptable.
([1]) Sumaila, U. R, Cheung, W. and I. Teh (2007) Rebuilding Hong Kong’s Marine Fisheries: An Evaluation of Management Options. Fisheries Centre Research Reports 15 (3). pp.112.
([2]) AFCD (2015), available on: https://www.afcd.gov.hk/english/fisheries/fish_cap/fish_cap.html
([7])
AFCD (2000). Information Note on
Fishing Moratorium in the South China Sea.
Paper presented in Legislative Council Panel on Health Services.