10.1
Introduction
This
Section of the EIA Report presents the findings of an impact assessment on
existing fisheries resources, fishing operations and fish/oyster culture
activities from the construction and operation of the proposed LNG terminal at
Black Point. The assessment is
based on the Project Description (Part 3
Section 3) and the findings of the
Water Quality Impact Assessment (Part 3
Section 6).
10.2
Legislative Requirements and Evaluation Criteria
10.2.1
Technical
Memorandum
The criteria for evaluating fisheries
impacts are laid out in the EIAO-TM. Annex
17 of the EIAO-TM prescribes the
general approach and methodology for the assessment of fisheries impacts
arising from 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 evaluating
fisheries impacts.
10.2.2
Other
Legislation
Other legislation which applies to
fisheries includes:
·
Fisheries
Protection Ordinance (Cap 171) 1987 which provides for the conservation of fish and other
aquatic life and regulates fishing practices.
·
Marine
Fish Culture Ordinance (Cap 353) 1983 regulates and protects marine fish culture and other
related activities.
·
Environmental
Impact Assessment Ordinance (cap. 499), Section 5(7) - Environmental
Impact Assessment Study Brief no. ESB-126/2005 Section 3.4.6 which outlines
the key fisheries impacts to be reviewed and assessed in the EIA Report.
10.3
Baseline Conditions and Fisheries Sensitive Receivers
The
fisheries Study Area was the same as that for the Water Quality Impact
Assessment (see Part 3 Section 6). Consequently, this assessment of impacts
has focussed solely on the fishing operations and fisheries resources within
the Study Area. For a description
of the physical and biological characteristics of the marine environment of the
Study Area please refer to Part 3
Sections 6 and 9 respectively.
In Hong Kong, the commercial marine fishing industry is
divided into capture and culture fisheries. To assess the capture fishery within the
Study Area, the most up-to-date (i.e. 2001/2002) information on the Hong Kong fishery was utilised (). Information from other relevant studies
(i.e. 1998) was also reviewed in order to determine if the Study Area presents
important nursery and spawning grounds for commercial fisheries (). Updated mariculture
information was obtained from the Agriculture, Fisheries and Conservation
Department (AFCD).
In
2005, the estimated fisheries production in Hong Kong waters from both capture
and culture fisheries amounted to 165,531tonnes, valued at HK$ 1,686 million (). Capture fisheries accounted for 98% by
weight (93.3 % by value) of total production while the remaining 2% (6.7% by
value) corresponded to the culture sectors of the industry. Within Hong Kong waters, the highest
yields for local fisheries were mainly derived from the eastern and northeastern coasts.
The five most abundant fish species landed from the capture sector were
golden thread (Nemipterus virgatus, 14%
of total biomass of landed fish), lizardfish (Saurida sp 9%), big-eyes (Priacanthus sp
5%), scads (Decapterus
sp 5%) and yellow belly (Nemipterus bathybius 4%)().
10.3.1
Culture
Fisheries
No
Fish Culture Zones (FCZ) are located close to the proposed Black Point
LNG terminal. The closest AFCD designated FCZ is
located at Ma Wan (over 20 km from the proposed site) and thus is not expected
to be affected by the development.
As
shown in Figure
10.1, there are no gazetted oyster farming locations in Hong Kong;
however, oyster farming has long been practiced on the Deep Bay
mudflats. The oyster production
areas located along the shore from Tsim Bei Tsui to Ha Pak Nai are also unlikely to be affected by the development due
to the large separation distance from the Black Point LNG terminal (>5 km).
10.3.2
Capture
Fisheries
Based
on the latest (i.e. 2001/2002) AFCD Port Survey data ([5]),
the highest fisheries production (600 to 1,000 kg ha-1) was recorded
near Cheung Chau, Penny’s Bay, Kau
Yi Chau, Po Toi, Ninepin
Group and Tap Mun. The top 10 families captured in Hong
Kong were rabbitfish (Siganidae),
sardine (Clupeidae), croaker
(Sciaenidae), scad (Carangidae), squid, shrimp, anchovy (Engraulidae),
crab, seabream (Sparidae)
and threadfin bream (Nemipteridae).
Deep
Bay produced an estimated annual catch of 73 tonnes of adult fish and zero fry
with reference to AFCD’s information provided in 1998(). The area and number of vessels operating
during 2001/2002 in the waters around the proposed LNG terminal at Black Point
are presented in Figure 10.2 ().
Approximately 100 to 400 vessels were recorded around Black Point in
2001/2002. The majority of fishing
vessels were small in size with lengths not exceeding 15 metres. The fishing vessels observed throughout
the Study Area were mainly sampans, gill-netters and shrimp trawlers.
With reference to the grid system developed by AFCD (Figure 10.3),
less than 50 kg ha-1 of adult fish production was recorded around
Black Point in 2001/2002 ([8]). The overall adult fish production within
the Study Area was relatively low when compared with areas in the eastern
waters. Fishermen recorded zero
fish fry production in the waters around the proposed LNG terminal (Figure 10.4).
Deep
Bay waters, in the area where the proposed LNG terminal is to be located,
ranked 12th of the 12 fishing sectors in Hong Kong waters, in terms
of production of adult fish and value of catch (). Deep Bay is not considered to be a key
fishing area due to the shallow water depths which constrain vessel navigation
and the abundance of cargo vessels that ply the waters between the Shenzhen
River and the Pearl River. The catch value of the waters surrounding the proposed LNG terminal
at Black Point range from HK$1,000 to HK$2,000 ha-1, which is
relatively low in comparison to other areas in Hong Kong
waters (Figure
10.5). The recent
AFCD survey indicated that the waters surrounding the proposed LNG terminal at
Black Point do not support a fish fry industry with no records of juvenile
catch (Figure
10.4).
From
the available fisheries information for the Study Area, it is concluded that
the adult fish production is relatively low in comparison to elsewhere in Hong
Kong waters. Low numbers and size
of fishing vessels, low fish catch value and production characterise the waters
in the vicinity of Black Point, highlighting its low productivity.
Fisheries Resources - Spawning Areas
The northern Lantau
waters were previously identified in 1998 as fisheries spawning grounds for
high value commercial species (Figure
10.1) ().
The main commercial fish species reported in the north Lantau spawning area included Leiognathus brevirostris (ponyfish),
Lateolabrax japonicus
(sea bass/ perch) and Clupanodon punctatus (gizzard
shad).
The majority of commercial species
recorded in Hong Kong aggregate and spawn in the open water during the period
from June to September ().
Some fish species reported for the spawning grounds, including Platycephalus indicus
(flathead) and Clupanodon punctatus
(gizzard shad), spawn in the late winter/early spring (i.e., February to April)
and a few are known to spawn in January.
Caranx kalla (shrimp
scad) spawns in the early summer (around June) whilst
Leiognathus brevirostris (ponyfish) and croakers were found to be reproductive
throughout most of the year from May to December. The spawning period of most of the
crustacean species, including Metapenaeus joyneri was found to be from April to November ().
A recognised spawning area is located
2.7 km south of the proposed LNG terminal (Figure 10.1). This area is approximately 10 km long
(from Tai Mo To island to Lung Kwu Chau Island) and 5 km wide (from Castle Peak to the
northernmost tip of the Airport) and has been identified as an important area
for commercial species ([13]).
10.3.3
Artificial
Reef Deployment
The AFCD is undertaking a programme to enhance
existing marine habitats and fisheries resources through the siting, construction and deployment of artificial reefs (ARs). ARs provide hard bottom, high profile habitat in areas
without natural cover and potentially act as fish enhancement devices. The Sha Chau AR (Figure 10.1)
was deployed in March 2000 with the primary aim of enhancing the marine habitat
quality and fisheries resources ([14]). Forty
two concrete-coated containers with a total volume of 940 m3 have
been deployed. They are located
approximately 6.4 km away from the proposed Black Point LNG terminal and are
considered too remote from the project to be affected by the works.
10.3.4
Fisheries
Importance
The
importance of the fisheries within the Study Area is addressed based on the
baseline information discussed above.
The fishing areas within the Study Area are characterised as being
generally of low commercial value.
The catches from these areas are composed of juvenile mixed
species. The size and subsequent
value of the catches characterises these waters as of comparatively low importance
to the Hong Kong fishing industry.
The
EIAO-TM (Annex 9) states that
spawning 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. No spawning area has
been identified within the footprint of the LNG terminal at Black Point. The closest recognised spawning area is
located approximately 2.7 km south of the LNG terminal site at Black Point.
10.3.5
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 LNG terminal, the potential
sensitive receivers that may be affected by the proposed works associated with
the Project are identified as follows:
·
Spawning ground of commercial fisheries
resources in north Lantau (2.7 km from the LNG
terminal);
·
Artificial reefs in the Sha Chau & Lung Kwu Chau Marine Park (located 6.4
km from the proposed LNG terminal).
The
locations of the sensitive receivers are shown in Figure 10.1. Due to their distances from the proposed
Black Point LNG terminal, oyster production areas and FCZs
are not considered to be sensitive receivers and are not expected to be
affected by the Project.
10.4
Fisheries Impact Assessment Methodology
A
desktop literature review was conducted in order to establish the fisheries
importance of the area surrounding the proposed Black Point LNG terminal. Information from the water quality
assessment was used to refine the size of the Study Area as that potentially
affected by perturbations to water quality parameters (Part 3 Section 6). This
area became the focus for this fisheries impact assessment. The importance of potentially impacted
fishing resources and fisheries operations within the Study Area was
assessed. The potential impacts due
to the construction and operation of the Project and associated developments
were then assessed (with reference to the EIAO-TM
Annex 17 guidelines) and the impacts evaluated (with reference to the
criteria in EIAO-TM Annex 9).
10.5
Identification of Fisheries Impacts
10.5.1
Construction
Phase
As
discussed in Part 3 Section 3 the
construction of the proposed LNG terminal at Black Point will involve dredging
and reclamation works.
Dredging
and Reclamation
Construction
phase impacts to fisheries resources and fishing operations arising from the
construction works may be divided into those due to direct disturbances to that
habitat and those due to perturbations to key water quality parameters.
Direct Impacts
Direct
impacts to fisheries resources and fishing operations include habitat loss due
to the dredging and reclamations works.
Construction will lead to the permanent loss of approximately 16 ha and
a temporary interference of approximately 47 ha, due to the dredging of the
approach channel and turning circle.
Temporary loss of less than 1 ha of fishery habitat will also be
associated with the installation of the intake pipe.
Due
to the relatively small area of the fishing grounds permanently lost to
reclamation and due to its low fisheries value no significant adverse impacts
to local fisheries resources are predicted.
Though
a larger surface area is impacted by the dredging activities of the approach
channel and turning basin, it is expected that the temporary nature of the
interference will not cause significant impacts on the fishery resources and
activities. Fisheries resources are
expected to return to the area following the cessation of dredging. The potential impacts of maintenance
dredging are discussed below.
In
view of the small area and the short term nature of the loss of fisheries
habitat, no significant impacts are expected to be associated with the
installation of the seawater intake pipe.
Indirect Impacts
Indirect
impacts to fisheries resources and fishing operations during the construction
phase include sediment release associated with the marine works. Potential impacts to water quality from
sediment release are listed below:
·
Increased concentrations of suspended
solids (SS);
·
A resulting decrease in dissolved
oxygen (DO) concentrations;
·
An increase in nutrient concentrations
in the water column.
The
reclamation activities for the LNG terminal will involve dredging of the
existing marine sediments along the line of the seawalls. The existing marine sediments in areas
defined for the turning basin and approach channel with a depth less than 15 m,
will be dredged to allow the safe navigation of the LNG carrier.
Suspended Solids: Suspended solid (SS) fluxes occur
naturally in the marine environment and consequently fish have evolved
behavioural adaptations to tolerate changes in SS load (e.g., clearing their
gills by flushing water over them).
However, the increase in suspended solids concentrations that would
arise from the dredging would be uncharacteristic of the normal variable marine
conditions. Concentrations of SS
generated via dredging are expected to be greater, particularly in the
immediate vicinity of the dredger.
Beyond the active dredging area, dispersion will cause a rapid decrease
in the suspended solids concentrations.
Larvae
and post-juvenile fish are more susceptible to variations in SS concentrations
than more mature fish since their sensory system is less developed. Adult fish are more likely to move away
when they detect sufficiently elevated suspended solids concentrations and
therefore are unlikely to be significantly impacted. Larvae and post-juvenile fish are more
likely to be impacted as they may not be able to detect and avoid areas with
elevated levels of SS.
The
SS level at which fish move into clearer water is defined as the tolerance
threshold and varies from species to species at different stages of the life
cycle. If SS levels exceed
tolerance thresholds and the fish are unable to move away from the area, the
fish are likely to become stressed, injured and may ultimately die. Susceptibility to SS generally decreases
with age such that eggs are the most vulnerable and adults the least sensitive
to the effects of high SS concentrations.
The rate, timing and duration of SS elevations will influence the type
and extent of impacts upon fish and potentially crustaceans ()
().
Literature
reviews indicate that lethal responses had not been reported in adult fish at
values below 125 mg L-1 ([17])
and that sublethal effects were only observed when
levels exceeded 90 mg L-1 ([18]). However, guideline values have been
identified for fisheries and selected marine ecological sensitive receivers as
part of a study for AFCD, Consultancy
Study on Fisheries and Marine Ecological Criteria for Impact Assessment. The values are based on international
marine water quality guidelines for the protection of ecosystems ([19]). The AFCD study recommends a maximum SS
concentration of 50 mg L-1 (based on half of the no observable
effect concentrations).
Temporarily
elevated levels of SS are likely to occur in the immediate vicinity of the
marine works (see Part 3 Section 6 -
Water Quality Assessment).
These predicted increases do not exceed the tolerance threshold of 50 mg
L-1 established by AFCD and therefore impacts to fisheries resources
as a result of potential elevations of SS are not expected to occur. The water quality assessment has also
shown that unacceptable water quality impacts due to the release of heavy
metals and organic micro-pollutants associated with suspended sediments are not
expected to occur (see Part 3 Section 6.6).
Finally
it should be noted that the Black Point site is at the mouth of Deep Bay on the
eastern bank of the Pearl River Estuary.
As a result of discharges from the Pearl River and the Shenzhen River in
Deep Bay, the background variation in SS is acknowledged as being high. Water quality data gathered by EPD has
indicated that in the vicinity of the Black Point site SS values can reach over
200 mgL-1 (Part 3 Section 6). Therefore, impacts to fisheries
resources as a result of potential elevations of SS from the construction works
are not expected to occur.
Dissolved Oxygen: The relationships between SS and DO are
complex, with increased SS in the water column combining with a number of other
effects to reduce DO concentrations.
Elevated SS (and turbidity) reduces light penetration, lowers the rate
of photosynthesis by phytoplankton (primary productivity) and thus lowers the
rate of oxygen production in the water column. Furthermore, the potential release of
sediment contaminants into the water column may consume the DO in the receiving
water. The resulting overall DO
depletion has the potential to cause an adverse effect on the eggs and larvae
of fish and crustaceans, as at these stages of development high levels of
oxygen in the water are required for growth to support high metabolic growth
rates.
The
results of the water quality assessment (Part
3 Section 6) examining dispersion
of sediment plumes associated with the LNG terminal’s marine works have shown
that the predicted maximum levels of SS are localised. Aside from the immediate vicinity of the
dredging works, SS concentrations within the Study Area as a whole will remain
compliant with the Water Quality Objectives (WQOs). The subsequent effect on dissolved
oxygen within the surrounding waters is, therefore, predicted to be
minimal. Unacceptable impacts to
fisheries from the reduction of DO concentration are not expected to occur.
Nutrients: High levels of
nutrients in seawater can cause rapid increases in phytoplankton, on occasions
to the point where an algal bloom occurs.
An intense bloom of algae can lead to sharp decreases in the levels of
dissolved oxygen. This decrease
will initially occur in the surface water, and then deepen as dead algae fall
through the water column and decompose on the seabed. Anoxic conditions may result if DO
concentrations are already low or are not replenished. As discussed above, reduced levels of DO
can impact the eggs and larvae of fish and crustaceans which require high
levels of oxygen for development.
Significantly low levels of DO may also result in mortality to fish.
As
with dissolved oxygen, the effect of the localised increases in suspended solid
concentrations on nutrients within the surrounding waters is expected to be
minimal (see Part 3 Section 6). Unacceptable impacts to fisheries are
therefore not anticipated.
Impacts
on Sensitive Receivers
·
Seasonal Spawning Grounds: No impacts to the seasonal spawning
grounds in North Lantau are likely to occur due to
elevated levels of suspended solids (depth averaged < 1 mg L-1)
since they are compliant with the assessment criterion (Part 3 Section 6).
Reductions in DO and increases in nutrient levels as a consequence of SS
elevations are not expected to occur.
Adverse impacts on the seasonal spawning grounds due to the proposed
works are not expected to arise.
Introduction of environmental contaminants desorbed from suspended sediment
particles can have damaging effects on fisheries resources. As discussed in the water quality
assessment (Part 3 Section 6)
contaminant release from dredging of contaminated sediments is expected to be
minimal and not predicted to exceed environmental standards. Consequently, unacceptable impacts to
fisheries resources from contaminant release during dredging are not predicted
to occur.
·
Artificial Reefs (ARs)
in Marine Park: Impacts to the ARs in the Sha Chau & Lung Kwu Chau Marine Park (located 6.4 km from the proposed LNG
terminal) are not expected to occur, as elevated levels of suspended solids
(depth averaged < 1 mg L-1) are compliant with the WQO.
Contaminant Release
Another potential impact on fisheries
resources associated with disturbance of bottom sediment that require
assessment in accordance with Clause
3.4.6.5 of the Study Brief, are release of potential toxic
contaminants. The potential for
release of contaminants from dredged sediments has been assessed in Part 2 Section 6, whereas, a
comprehensive set of data on the quality of marine sediment is provided in Part 2 Section 7 – Waste Management.
As discussed in Part 2 Section 6, unacceptable water quality impacts due to the
potential release of heavy metals and micro-organic pollutants from the dredged
sediment are not expected to occur, impacts on fisheries resources due to
bioaccumulation of released contaminants from dredged sediments are also not
expected to occur.
10.5.2
Operational
Phase
The
potential impacts of the operational phase of the Project on the fisheries of
the Study Area can be divided into three main categories:
·
Impacts arising from the loss of
fisheries habitat and the alteration of the marine hydrodynamic regime;
·
Impacts arising from the alteration of
the benthic habitat due to maintenance dredging of the approach channel and
periodical disturbance caused by the LNG carrier’s passage;
·
Impacts arising from the uptake,
treatment and discharge of the seawater used in the vaporization process,
mainly physical damage to marine organisms and the alteration of the physical
and chemical parameters of the seawater.
Habitat Loss
From
the overview of the importance and value of the local fisheries performed in Part 3 Section 10.3 and the outcome of the
assessment of the coastal habitat in Part
3 Section 9 it is evident that the quality of the existing littoral habitat
of the Study Area is low. The
potential impacts associated with the loss of 600 m of natural coastline (Marine Ecological
Impact Assessment, Part 3 Section 9) are estimated to be low. Furthermore, it is deemed that the
enhancement effect of the new seawalls will reduce the impacts to the local
fish populations by providing habitat and shelter for juveniles or adult
fisheries resources as ecological assemblages may eventually colonise and grow
on the boulders. This will, in the
longer term, counteract the initial loss to the natural environment.
Marine Hydrodynamic Regime
Impacts to fisheries resources could potentially occur if the
shape of the reclamation causes a change to the hydrodynamic regime of the
Black Point coastline. Impacts of this nature could lead to
increased seabed current velocities which may cause seabed scour thus impacting
subtidal assemblages, or conversely, the current
velocities may drop affecting flushing and water exchange of an area.
Inadequate flushing could lead to a reduction in dissolved
oxygen (DO), an increase in nutrients and consequent impacts to fisheries
resources. The hydrodynamic modelling (Part 3 Section 6) has indicated that the reclamation in Black Point will have
an overall minimal effect on current velocity. Adverse impacts from changes to the
hydrodynamic regime and also water quality are, therefore, not expected to
occur.
Maintenance Dredging
To
the maximum extent possible, the selection of the fairway transit and approach
channel for the LNG carrier was based on the availability of the required
charted water depth (approximately -15mPD) in order to reduce the dredging
quantities and hence impacts to water quality. These will in turn serve to reduce
impacts to fisheries resources.
Maintenance dredging is anticipated to be required at a frequency of
once every four years. No long term
direct impacts are expected from the maintenance dredging works. As a result,
the fisheries resources are not predicted to be adversely affected by the maintenance
dredging.
Carrier Passage
Carrier passage in the dredged approach channel can potentially
lead to sediment re-suspension due to the turbulence created by the carrier’s
propellers and thrusters. The
disturbance of the substrate may potentially increase the recovery time of the
benthic communities which colonize the channel, reducing their productivity. Due to the low frequency of the LNG
carriers passage (once every five to eight days) and the low quality of the
existing benthic community it is expected that the overall impact due to
reduced productivity of the channel’s benthic community will be minimal (see Marine Ecological Impact Assessment, Part 3
Section 9).
Water Intake,
Treatment and Discharge
Stored
LNG will need to be re-gasified in order for it to be
transported by pipeline to the point of use. This will be accomplished via
vaporisers, which will either utilise piped seawater (in open rack vaporisers)
or hot combustion gases (referred to as submerged combined vaporisers) to raise
the temperature of the LNG to its gaseous state.
·
Open Rack Vaporisers (ORVs) – ORVs are heat exchangers
where seawater flows downward over the exterior vaporizer panels while
high-pressure LNG flows internally upwards. This counter current flow between the
warm seawater and cold LNG results in the vaporization or heating of the
LNG. The seawater falls over the
external panels to a trough and is then discharged back to the sea. The seawater will pass through a series
of screens to remove debris to prevent blockage or damage to the seawater
pumps. Upon leaving the vaporisers,
the (cooled) seawater will be collected in a sump and discharged back to the
sea via a submarine outfall. The
design seawater temperature drop is 8.5°C at the discharge point.
·
Submerged
Combined Vaporisers (SCVs) –In SCVs, the LNG is heated by flowing through tubes that are
submerged in a heated water bath.
The
present design for the LNG terminal calls for ORVs as
the primary vaporization method with a SCV unit as back-up.
The
intake volume and velocity of the ORV system may have potential impacts,
namely:
·
Physical alterations of the seawater
due to the heat exchange process which delivers cooler water at the outfall
location. Cooler water potentially
can impact the physiology of marine organisms (e.g. changes to natural
development and growth rates),
·
Potential physical damage to marine
organisms, particularly fish eggs and larvae, due to impingement on the intake
pipe’s protection screen and entrainment into the vaporizing system; and,
·
Chemical alteration of seawater due to
the antifouling additives (e.g., sodium hypochlorite) which can causes stress
and potentially death to marine organisms, particularly fish eggs and larvae,
zooplankton and phytoplankton.
The
potential fisheries impacts of the ORV process are discussed in the following
sections.
Discharge of Cooled Water
Induced
temperature changes to natural aquatic habitats have been proven to have
detrimental effects on the physiology of fishes. The decline in temperature has the
potential to alter the rate of development of fish embryos, larvae and gonad
maturation. A slower growth rate
means that fish larvae remain longer in the delicate early development stages,
potentially increasing mortality (). The altered development of gonad
maturation could ultimately reduce the spawning success of fish species and the
altered mechanism of muscle development ()
could potentially reduce the chance of survival of juvenile fish.
Cooled
water with a temperature of approximately 12.5°C
below ambient will be discharged at the LNG terminal’s seawater outfall,
located near the bed layer of the water column. The results of the water quality
modelling presented in Part 3 Section 6
indicate that a temperature change of +/-2°C
(the Water Quality Objective) will remain within approximately 200m from the
outfall in the dry season and approximately 70m in the wet season.
The
results presented in Part 3 Section 6
indicate that the impacts to seawater temperature caused by the open circuit
process are predicted to be localised.
It is therefore expected that the cooled water discharge will not cause
unacceptable impacts to the fisheries resources.
Impingement and Entrainment
The
discharge and intake points for the seawater to be used in the proposed open
circuit system (i.e., Open Rack Vaporisers or ORVs)
will be separated to reduce the re-circulation of the cooled water and
therefore maximise the efficiency of the heat exchange process.
In
order to draw in the warmest water to the vaporisers for optimum efficiency in
the regasification process, the seawater intake will
be designed to be as high as possible within the water column. For this purpose the intake will be
installed through the revetment of the seawall structure. The intake will be
appropriately screened to reduce the uptake of marine organisms and suspended
material. From a fisheries perspective
the high volume and velocity of inflowing seawater may have negative effects on
fish, fish eggs and crustaceans (e.g., shrimp) due to the physical damage
caused by collisions with the screen (impingement) and due to their uptake and
exposure to the vaporization process (entrainment).
The
swimming speeds of juvenile and larval fishes vary greatly but are generally
less than the water velocity of the intake pipe. Owing to their larger size, juvenile
fish are generally more susceptible to impingement, whilst, fish and crustacean
larvae and eggs, zooplankton and phytoplankton are more exposed to entrainment,
as their small size enables them to pass through the screen ([22]) ([23]).
Whilst
it is acknowledged that the uptake of seawater for the open loop vaporization
process may minimally increase the natural mortality rate of fish larvae,
crustaceans and fish eggs due to impingement and entrainment, it has to be
noted that the significance of such impacts is strongly dependant on the
ecological sensitivity and productivity of the impacted area. From the assessment completed in Part 3 Section 10.3 it is evident that
the quality of the near shore marine ecosystem of the Study Area is low and
that there are no identified spawning areas in the proximity of the intake
pipe. In addition, the AFCD Port
Survey of 2001/2002 reported that zero fish fry production was found in the
waters around the proposed LNG terminal with no records of juvenile catch (Part 3 Section 10.3.2 - Figure 10.4).
By
virtue of the low value of the marine ecosystem of the Study Area and its low
fisheries production level, it is predicted that no unacceptable adverse
impacts to important fisheries resources will occur.
Antifoulants
There
are potential operational issues caused by the growth or encrustation of marine
organisms on the open loop vaporization system (i.e., pipes, valves etc.). Operationally, the colonization of
marine organisms such as algae, bryozoans, molluscs and cirripedes
within cooled water circuits could result in losses in thermal efficiency and
reduced reliability of the system (including total shutdown). To counteract settling and growth of
marine organisms, cooled water circuits are typically dosed with chemicals
(usually sodium hypochlorite). Such
chemicals are known as antifoulants and they inhibit
the growth of organisms within the circuit by creating unsuitable living
conditions. A secondary consequence
of this form of treatment is associated with the discharge of the treated
seawater into the marine environment.
Research
has been conducted internationally on the effects of chlorine discharges on
marine ecological and fisheries resources.
The international review provides data which can be used as a benchmark
to evaluate potential impacts. Work
on the toxic effects of chlorine on fish eggs and larvae has indicated that
abnormal development may occur at concentrations of 0.31 to 0.38 mg L-1 ([24]). However, behavioural studies have
indicated that adult fish will avoid areas where concentrations of free
residual chlorine in the water exceed 0.035 mg L-1 ([25]).
The
proposed LNG terminal is predicted to discharge residual free chlorine at a
concentration of < 1.0 mg L-1. This concentration is similar to that
found in the cooling waters of power stations operating in Hong Kong and is
below EPD’s discharge limit of 1.0 mg L-1 ([26]).
Concentrations
of residual chlorine have been shown to diminish rapidly with time and distance
from the discharge point (). A concentration of residual chlorine of
0.01 mg L-1 (daily maximum) at the edge of the mixing zone is the
criterion used in the Water Quality
Assessment (Part 3 Section 6). The modelling exercise conducted in the
assessment indicates that maximum residual chlorine concentrations exceeding
0.01 mg L-1 are only likely to occur within 300 m of the outfall and
are mainly confined to lower layers of the water column. These predicted increases do not exceed
tolerance thresholds established in the literature (0.02 mg L-1) and
are in accordance with those levels recommended in previous studies in Hong
Kong (0.01 mg L-1).
Consequentially,
significant impacts to fisheries resources as a result of the discharge of
chlorinated water are not expected to occur.
Sewage
Impacts due to operational sewage discharge
on fisheries resources would not be expected as the discharge should satisfy
the requirement of WPCO-TM effluent
discharge standard (details refer to Part
3 Section 6.7.5).
10.6
Assessment of environmental Impacts
From
the information presented above, the fisheries impact associated with the
Project is not considered to be significant. An evaluation of the impacts according
to Annex 9 of the EIAO-TM is presented below:
·
Nature
of Impact: Permanent impacts
will occur as a result of the loss of fishing grounds in the 16 ha area to be
reclaimed for the LNG terminal.
Short-term impacts will occur to fisheries resources in the Study Area
as a result of the dredging of seawall trenches and the dredging of the
approach channel and turning basin.
Temporary impacts to pelagic and demersal
fisheries resources as a result of minor perturbations to water quality are
predicted to occur only in the immediate vicinity of marine works. Maintenance
dredging activities are also not predicted to cause unacceptable impacts to
fisheries due to their localised and infrequent nature. Discharges of cooled water are not
predicted to pose adverse impacts to fisheries resources and discharges of
residual free chlorine are predicted to be in compliance with the EPD’s allowable discharge level. No significant adverse impacts to
fisheries resources are expected from the impingement and entrainment of fish
larvae or eggs in the open circuit’s vaporization system.
·
Size
of Affected Area:
The construction of the LNG terminal will result in the permanent loss
of approximately 16 ha of natural marine habitat. This loss is not considered to be
significant for the local fishery resources in view of the small portion of
habitat lost and due to the low fisheries production in these waters.
·
Size
of Fisheries Resources/production: The value of the fisheries
resources/production of the marine waters around the turning basin and approach
channel, and the proposed LNG terminal is low in comparison to other waters in
Hong Kong.
·
Destruction
and Disturbance of Nursery and Spawning Grounds: No spawning grounds have been identified
within the Study Area. A recognised
spawning area for fisheries resources lies 2.7 km from the proposed LNG terminal. As the water quality modelling results
show, impacts to water quality will be localised and hence impacts to spawning
grounds are not expected to occur.
·
Impact
on Fishing Activity:
Due to the small size of the affected area and the low intensity of the
fishing operations, impacts on fishing activity are expected to be minimal.
·
Impact
on Aquaculture Activity:
No impact has been identified on fish and oyster culture activity as SS
and total residual chlorine elevations are compliant with the relevant standards,
and the Fish Culture Zones and oyster production areas are too remote to be
affected by the Project.
10.7
Mitigation Measures
In
accordance with the guidelines in the EIAO-TM
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;
·
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
off-site compensation. It may
include enhancement of fisheries resources and habitats elsewhere.
Construction
impacts to fisheries resources and fishing operations have largely been avoided
(ie spawning area of commercial fisheries
resources) and minimised through
the planning and design of the works; in particular those associated with the
backfilling and dredging. The main
works have been designed to control water quality impacts to within acceptable
levels and hence are also expected to control and minimise impacts to fisheries
resources. No fisheries-specific
mitigation measures or compensation are required during construction.
Significant
impacts to fisheries resources and fishing operations are not expected to occur
during the operational phase of the LNG terminal. Compliance with the relevant discharge
standards to control water quality impacts to within acceptable levels is also
expected to control impacts to fisheries resources. Furthermore, entrainment of fisheries
resources will be reduced through the appropriate design of the intake screens
on the seawater intake. No additional
fisheries-specific mitigation measures or compensation are required during
operation.
10.8
Environmental Monitoring and Audit (EM&A)
10.8.1
Construction
Phase
As
no unacceptable impacts have been predicted to occur during the construction of
the LNG terminal at Black Point, monitoring of fisheries resources during the construction
phase is not considered necessary.
10.8.2
Operation
Phase
As
no unacceptable impacts have been predicted to occur during the operation of
the LNG terminal at Black Point, monitoring of fisheries resources during the
operation phase is not considered necessary.
10.9
Residual Environmental Impacts
The
identified residual impact occurring during the construction phase is the
permanent loss of approximately 16 ha of seabed required for the LNG terminal
reclamation. The construction of
rubble mound seawalls on the edges of the LNG terminal’s reclaimed land has the
potential to provide habitat and shelter for juveniles or adult fisheries
resources as ecological assemblages may eventually colonise and grow on the
boulders. The enhancement effect of
the seawalls will further reduce the potential impacts of the reclamation works
on the local fishing and will not adversely affect the fishery as a whole.
The
combination of very limited habitat loss, the small-scale nature of fishing
operations and the potential environmental benefits of the seawall combine to
reduce the magnitude of this residual impact to within acceptable levels.
10.10
Cumulative Impacts
At
present there are no committed projects that could have cumulative impacts with
the construction of the terminal at Black Point. No projects are planned to be
constructed in sufficient proximity to the Project to cause cumulative effects
and hence, cumulative impacts are not expected to occur.
10.11
Conclusions
Reviews
of existing information on commercial fisheries resources and fishing
operations surrounding the waters adjacent to the proposed LNG terminal have
been undertaken. Information from a study on fishing operations in Hong Kong
and the AFCD Port Survey 2001/2002 indicate that fisheries production values in
the vicinity of the assessment area are low. Sensitive receivers such as
spawning grounds, artificial reefs, fish culture zones and oyster production
areas have been identified; however, the water quality modelling results show
that these areas will not be affected.
Adult
capture fisheries resources are unlikely to be adversely impacted by the LNG
terminal as they will likely avoid the works areas. Although impacts to fish fry may occur
through the permanent loss of habitat, the small size of the reclaimed area and
the low fisheries and fish fry value of the habitat lost greatly reduce the
significance of the impact to a level that is acceptable.
Impacts
arising from the proposed dredging works are predicted to be largely confined
to the specific works areas and to be temporary in nature. The predicted elevations of suspended
sediment concentrations due to the Project are not predicted to exceed the
assessment criteria over large areas or at sensitive receivers and they are not
expected to cause adverse impacts to water quality or to any fishing grounds or
species of importance to the fishery.
Dredging operations have been designed to minimise potential impacts on
the water quality which will, in turn, reduce impacts on fisheries
resources. No fisheries-specific
mitigation measures are required during construction.
Significant
operational phase impacts to fisheries resources and fishing operations are not
expected to occur. Entrainment of
fisheries resources will be mitigated through the appropriate design of the
intake screens. Unacceptable impacts from discharges of cooled water are not
anticipated to occur as the effects from these discharges will be
localised. Compliance with the
relevant discharge standards to control water quality impacts to within acceptable
levels is also expected to control impacts to fisheries resources. No
additional fisheries-specific mitigation measures are required during
operation.
All
of the potential construction and operational fisheries impacts identified are
deemed acceptable
