Introduction
8.1
This section of the EIA report
presents an assessment of potential impacts on the fisheries resources
associated with the improvement work at Castle Peak Road between Ka Loon Tsuen
and Siu Lam. The project will include
road widening between Ka Loon Tsuen and Tai Lam Kok, dredging (approximately
1.4 hectares), reclamation of seabed (approximately 0.8 hectares) and
construction of a road/ bridge between Tai Lam Kok and Siu Lam section. Based on the literature review of fisheries
information within the study boundary and in the vicinity of the project site,
this section provides a description of the physical environmental background
and fisheries baseline information, predicts and evaluate the significance of
impacts and recommends mitigation measures where appropriate. The impact assessment follows the criteria
and guidelines for evaluating and assessing fisheries impact as stated in
Annexes 9 and 17 of the EIAO-TM.
8.2
According to the EIAO-TM and the Study
Brief, the objectives of the fisheries assessment include:
·
establishment of the physical
environmental background;
·
description and quantification of
existing fisheries resources and activities;
·
identification of parameters and areas
important to fisheries;
·
prediction of potential fisheries
impacts;
·
evaluation of the significance of
impacts predicted;
·
recommendation of feasible mitigation
measures and implementation programme;
·
recommendation of appropriate
monitoring and audit programme.
8.3
Since the proposed works is expected
to involve some sediment dredging and minor reclamation during the construction
phase, the fisheries impact assessment should be conducted with reference to
the findings of the water quality impact assessment.
Legislation and Guidelines
8.4
This section makes reference to the
following Hong Kong government ordinances and regulations, guidelines and
standards and international convention when identifying fisheries activities,
evaluating and assessing impacts of the proposed development on the fisheries
resources and activities in and around the study area.
8.5
Fisheries Protection Ordinance (Cap.
171), which promotes the conservation of fish and other forms of aquatic life
within the waters of Hong Kong and regulates fishing practices to prevent
activities detrimental to the fishing industry.
8.6
Marine Fish Culture Ordinance (Cap 353),
which designates and protects fish culture zones (FCZs) from injury to fish and
pollution of waters.
8.7
Water Pollution Control Ordinance (Cap.
358), which sets limits to water
quality parameters in various zones.
8.8
Town Planning Ordinance (Cap. 131),
which makes provision for the systematic preparation and approval of plans for
the layout of areas of Hong Kong as well as for the types of building suitable
for erection therein. It makes provision for the preparation and approval of
plans for areas within which permission is required for development.
8.9
Technical Memorandum of the Environmental Impact Assessment
Ordinance (EIAO) (Cap 499), which provides guidance
on the methodology for fisheries impact assessment in Hong Kong. Annex 9 of the
Technical Memorandum sets out criteria for evaluating fisheries impact while
Annex 17 denotes the guidelines for fisheries impact assessment.
Physical Environment
8.10
The inshore waters of Hong Kong are
influenced by rainfall and freshwater input from the Pearl River estuary. The waters off the coast of Tai Lam Chung
falls within the eastern limit of the Pearl River Estuary influence and thus
the water can be considered to display an estuarine characteristic. This waters also forms part of the Urmston
Road Channel. Summer stratification of salinity in the water column can be
detected due to the waters of low salinity from the Pearl River flowing south-eastwards
over the denser, more saline oceanic water mass arriving from the
south-east. The waters off Tai Lam
Chung also experience moderate exposure with strong turbulence generated from
currents (Morton & Morton, 1983).
The maximum current speed recorded is estimated to be 94 cm/s (Hyder-Maunsell,
on-going).
8.11
The study area falls mainly within the
North Western Water Control Zone. The
Environmental Protection Department (EPD) conducts regular marine water quality
monitoring in the area and the most relevant monitoring stations to the study
area are NM2 and NM1. Based on EPD
regular marine water quality monitoring results for the period 1989 and 1998,
there is sign of an increasing nutrient enrichment for the station NM1. A significant rise in E. coli has also been recorded for the same period.
8.12
According to the 1998 EPD water
quality monitoring results, the water quality of the nearby waters was
generally turbid (annual turbidity means, 6.5 – 7.3 NTU, annual Suspended
solids means 4.0 – 6.3 mg/L), moderate surface dissolved oxygen level (annual
means, 5.5 – 6.2 mg/L), moderate in inorganic nutrients (annual means total
nitrogen in the nearby areas 1.14 –1.22 mg/L and annual means total phosphorus
of the nearby areas 0.05 – 0.06 mg/L), and low in both E. coli (annual geometric means, 110 – 300 cfu/100ml) and faecal
coliforms (annual geometric means, 600 – 1300 cfu/100ml).
Fisheries Activities and Fisheries Resources
8.13
Fisheries activities within the study
area and in the vicinity included for impact assessment in this study are as
follows:
·
Capture fisheries
·
Mariculture
·
Homeport
8.14
In addition to adult fish, fry
resources as well as nursery or spawning grounds existing in the area are
considered.
Capture Fisheries
8.15
The waters of Hong Kong is divided
into 189 fishing areas (AFD, 1998). Based
on AFD Port Survey 96/97, the fishing areas immediately in the vicinity to the
study area include Areas 38 (Tsing Lung Tau) and 39 (Tai Lam Chung). In view of the dredging and reclamation
activities and their scale of operations associated with the project,
assessment of far field fishing areas such as 23 (Yam O), 24 (Tsing Chau Tsai),
40 (Pearl Island) and 25 (Ma Wan) would also be considered depending on the
extent of potential impact predicted.
Apart from the Ma Wan and Tsing Chau Tsai, which belongs to the Western
harbour section, the other mentioned fishing areas belong to North Lantau
section (Figure 8.1).
8.16
There were approximately 320 fishing
vessels operating in the fishing areas concerned, compared with the territory’s
total of 2,619. Of the fishing vessels
operating in the fishing areas, only 12 or 3.8% were bigger than 15m (AFD,
1998).
8.17
With reference to the Port Survey
conducted by AFD in 96/97, in terms of production per hectare, some fishing
areas like Ma Wan and Tsing Chau Tsai are ranked within the top 25% of all
fishing areas indicating that these areas are rather productive. However, in overall terms, they only
contribute a minor proportion to Hong Kong’s total fish production (see Table
8.1). Breakdown of the top ten fish
caught in the fishing areas is presented in Table 8.2.
8.18
Fish fry capture activities were
reported from Ma Wan, Tsing Lung Tau.
However, none of these four zones can be regarded as important areas for
fry production. The main fish species
reported in catches from the fishing zones in the study area are of low
commercial value including, mantis shrimp, mixed species, croaker, crabs and
sole (Scott Wilson & ERM-HK, 2000a).
Table 8.1 Production by Fishing Area (all
fishing vessels)
|
Fishing Area
|
Area (Ha)
|
Adult fish production in kg
(% of total HK production), [production per ha]
|
Rank (Production * Ha-1)
|
Fry fish production (tails)
|
Rank (Production * Ha-1)
|
|
Yam O
|
529.94
|
63,009
|
82
|
-
|
-
|
|
Tsing Chau Tsai
|
170.31
|
38,943
|
39
|
7661
|
46
|
|
Ma Wan
|
418.82
|
81,988
|
48
|
7661
|
68
|
|
Pearl Island
|
286.83
|
27,182
|
97
|
-
|
-
|
|
Tsing Lung Tau
|
218.77
|
35,179
|
62
|
7661
|
58
|
|
Tai Lam Chung
|
370.36
|
7908
|
148
|
-
|
-
|
|
Total
|
1405.9 (0.77%)1
589.13 (0.32%)2
1995.03 (1.09%)3
|
211,122 (1.2%), [150.17]1
43,087 (0.24%),
[ 73.13]2
254,209 (1.5%), [127.42]3
|
-
|
22984 (0.36%)
|
-
|
|
Total of Hong Kong (189 fishing areas)
|
181790.97
|
17681243 [97.26]
|
-
|
6383437
|
-
|
Source: AFD, 1998
Note: 1 = total for far field fishing areas (Yam O, Tsing
Chau Tsai, Ma Wan and pearl Island)
2 = total for immediate
fishing areas (Tsing Lung Tau and Tai Lam Chung)
3 = total for all fishing
areas.
Table 8.2 Top Ten Adult Fish Caught by Fishing
Area
|
Name
|
Ranked by Adult Fish
Weight
|
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
Yam O
|
MIXSPP
|
SEBMAR
|
CLUPUN
|
MUGAFF
|
SPARID
|
SIGORA
|
ARGSPP
|
MURCIN
|
TRIHAU
|
MCRAB
|
|
Tsing Chau
Tsai
|
MIXSPP
|
SEBMAR
|
ARGSPP
|
MURCIN
|
SPARID
|
PSECRO
|
SIGORA
|
ILIELO
|
LATJAP
|
PLAIND
|
|
Ma Wan
|
SIGORA
|
SEBMAR
|
MIXSPP
|
ARGSPP
|
SPARID
|
CLUPUN
|
PSECRO
|
MURCIN
|
LATJAP
|
ILIELO
|
|
Tsing Lung Tau
|
MIXSPP
|
SEBMAR
|
ARGSPP
|
SIGORA
|
ACETES
|
SPARID
|
PSECRO
|
MURCIN
|
LATJAP
|
ILIELO
|
|
Tai Lam
Chung
|
ACETES
|
MURCIN
|
MIXSPP
|
SEBMAR
|
ARGSPP
|
PLAIND
|
ORAOA
|
MPRAN
|
ORASPP
|
METAFF
|
|
Pearl Island
|
MIXSPP
|
ACETES
|
STRARG
|
TRAJAP
|
ORAOA
|
ARGSPP
|
PLAIND
|
PARHUN
|
PSEANO
|
ELETET
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Source: AFD, 1998
Note: MIXSPP = mixed fish, SIGORA = Siganus oramin, ARGSPP = Argyrosomus
spp. , ACETES = Acetes spp., SEBMAR =
Sebasticus marmoratus, CLUPUN = Clupanodon punctatus, PLAIND = Platycephalus indicus, MUGAFF = Mugil affinis, TRIHAU = Trichiurus Haumela, MURCIN = Muraenosox cinereus, ILIELO – Ilisha elongata, MPRAWN = Mixed prawn,
METAFF = Metapenaeus affinis, LATJAP = Lateolabrax japonicus, PSEANO = Psenopsis anomala, ORAORA = Oratosquilla oratoria, TRAJAP =
Trachurus japonicus, ORASPP =
Oratosquilla spp. , ELETET = Eleutheronema
tetradactylus, MCRAB = mixed crab, PSECRO = Pseudosciaena crocea,
Culture Fisheries
8.19
Based on the literature review, the
nearest mariculture activities are located in the Ma Wan Fish Culture Zone
(Figure 8.1). The Ma Wan Fish Culture
Zone is located in three sheltered areas to the northwest of Ma Wan Island.
Bays on north Lantau to the west of Kap Shui Mun channel are known to be
nursery areas (MCAL, 1997). Mariculture
operators of Ma Wan also collect some fry locally. As of 31 January 2001, there are 132 licensed raft in the Ma Wan
FCZ with a total licensed area of 14,557 m2 (total gazetted area =
46,300 m2). The main species
cultured include the Spotted Grouper (Epinephelus
chlorostigma), Goldlined Seabream (Rhabdosargus
sarba), Mangrove Snapper (Lutjanus
argentimaculatus) and the Pompano (Trachinotus
blochii) (Mott Connell Ltd, 1999).
8.20
In March and April 1998, widespread
red tide algal blooms killed many fish of the FCZs in Hong Kong but Ma Wan FCZ
was the least affected FCZ due to the fast currents in the vicinity (Scott
Wilson & ERM-HK, 2000a).
Homeport
8.21
The homeport most relevant to the
present study is P009 (Ma Wan/Tsing Lung Tau/Yam O (Figure 8.1).
8.22
The Ma Wan/Tsing Lung Tau/Yam O
homeport adult fish and fry production for 1996/97 was 333,546.14 kg and
91,935.48 kg respectively. In overall
terms, its contribution to Hong Kong’s total fish (adult and fry) production is
relatively minor (1.8%) (AFD, 1998).
According to the Fishing Vessel Count conducted by AFD in 1997, there
were 294 vessels in the Ma Wan port combined with Tsing Lung Tau and Yam O
ports; compared with the territory’s total of 4857. Most of the operators concerned were P4/7 operators (for
mariculture) (ERM, 1998). Top ten adult
fish caught by homeport is presented in Table 8.3.
Table 8.3 Top
Ten Adult Fish Caught by Homeport (Ma Wan/Tsing Lung Tau/Yam O)
|
Ranked by Adult Fish Weight
|
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
MIXSPP
|
SEBMAR
|
ARGSPP
|
SIGORA
|
SPARID
|
PSECRO
|
LATJAP
|
PLEPIC
|
ILIELO
|
SILSIH
|
Source: AFD, 1998
Note: MIXSPP = mixed fish,
ARGSPP = Argyrosomus spp.,
SEBMAR = Sebasticus marmoratus,
SIGORA = Siganus oramin , ILIELO – Ilisha elongata, LATJAP = Lateolabrax japonicus, , SPARID = Sparidae
spp., PSECRO = Pseudosciaena crocea,
SILSIH = Sillago sihama, PLEPIC = Plectorhynchus pictus
Fry Fish Resource
8.23
According to the “Fisheries Resources
and Fishing Operations in Hong Kong Waters” (ERM, 1998), spawning grounds of
commercial fisheries resources identified which would be of relevance to the
present project include the Northeast Lantau spawning ground. It is believed the areas around North Lantau
are important fish fry harvesting grounds for a number of commercial species
(CES, 1997).
8.24
Surveys on fisheries, fish fry and
dolphins were carried out by CES for the Lantau Port Development Studies for
Container Terminals 10 & 11 from December 1995 to January 1997. Fish fry surveys were carried out in waters
north east of Lantau Island and monthly observations of vessel activities were
conducted. Major families of fry fish
collected in the survey include Sparidae
(commercially important for the fry fisheries), Slangidae, Mugilidae, Siganidae, Leiognathidae, Carangidae and Sillaginidae. Fisheries information on FCZ can be obtained from the Port Survey
by AFCD. It is also found that rocky
substrate around Ma Wan provides important fisheries habitat, especially as
nursery and spawning grounds (Mott Connell, 1999).
8.25
In general, historical studies of
local fisheries resources indicated that fisheries yields were high in the
eastern and northeastern areas of Hong Kong waters and low in the western
waters of Hong Kong. However, spawning
grounds of commercial fisheries resources were found north of Lantau. Species observed in these waters include Liognathus brevirostris, Lateolabrax
japonicus and Clupanodon
punctatus. Nursery areas of
commercial fisheries were not found in the immediate vicinity of the works area
(ERM, 1998).
8.26
The commercial value of the fishes
concerned is assessed by reviewing the monthly trade statistics from the
wholesale fish market (from the Fish Marketing Organisation). Available data on fish prices are presented
in Table 8.4.
Table
8.4 Average Price of Fresh Marine Fish
sold at Wholesale Fish Market in Hong Kong (March 2000)
|
Species Name
|
Common Name
|
Average Price ($/kg)
|
|
Psenopsis anomala
|
Melon Seed
|
21.88
|
|
Trachurus japonicus
|
Scad
|
3.83
|
|
Muraenosox cinereus
|
Conger-pike eel
|
9.78
|
|
Trichiurus Haumela
|
Hair-tail
|
13.36
|
|
Argyrosomus spp.
|
Croaker
|
9.09
|
|
Pseudosciaena crocea
|
Yellow Croaker
|
25.66
|
|
-
|
Grouper
|
26.09
|
|
-
|
Bream
|
31.50
|
|
-
|
Snapper
|
15.87
|
|
-
|
Other fishes (mixed)
|
8.44
|
|
-
|
Shrimp – large
|
118.50
|
|
-
|
Shrimp - small
|
25.00
|
Source:
Fish Marketing Organisation, AFCD
Assessment
Methodology
8.27
A desktop literature review was
conducted in order to establish the baseline conditions of the physical
environment and the fisheries resources involved. Information from the water quality assessment and ecological
impact assessment also provide input for the fisheries impact assessment.
8.28
Parameters to be considered in the
assessment include:
·
size of the fisheries habitats
(including possible nursery and spawning grounds)
·
richness of fisheries resources
·
degree of fisheries activities
·
fish production
·
commercial value of fish
8.29
The fishing areas concerned include Ma
Wan, Yam O, Tsing Chau Tsai, Pearl Island, Tsing Lung Tau and Tai Lam
Chung. Since the site of road
improvement works is approximately 2.5 km from Ma Wan Fish Culture Zone,
potential impacts from the construction and operation phases on the fisheries
in this area are of major concern.
Relevant sensitive receivers within Ma Wan FCZ and in the vicinity have
been identified. Spawning areas are
known to exist in the vicinity.
Potential impacts on capture fisheries as well as aquaculture and other
existing fisheries activities will be assessed.
Identification of Impacts
Construction Phase
Direct Impacts
8.30
Direct
impacts to fisheries activities and resources include habitat loss due to
dredging and reclamation associated with the road improvement works. The area of reclamation, i.e., 0.8 hectares,
is attributed to about 0.2 % of the combined area of Tsing Lung Tau and Tai Lam
Chung fishing areas. Ranking of these
two fishing areas in terms of production per ha (from all vessels) is 25 and
153 respectively, implying medium importance overall. The scale of reclamation is considered to be minor thus the
direct impact on fisheries would not be significant.
Indirect Impacts
8.31
Indirect impacts to fisheries
resources and fishing operations during the construction phase include sediment
release associated with the construction activities. Potential impacts to water quality from sediment release are
listed below:
Increased concentrations of suspended solids (SS)
8.32
Suspended sediment fluxes occur
naturally in the marine environmental and consequently fish have evolved
behavioural adaptations to tolerance increased SS loads, including clearing
their gills by flushing water over them.
Where SS levels become excessive, fish will move to clearer waters. Susceptibility generally decreases with age,
with eggs the most vulnerable and the adults the least sensitive to effects
from sediments. Other factors such as
the rate, season and duration of SS elevations will interact with life stage
sensitivity to influence the type and extent of impact upon fish.
Decrease in DO concentrations
8.33
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 in the water column. 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. Elevated SS can also cause
increased energy retention from sunlight, resulting in higher temperatures, and
thus the potential for lower oxygen levels as oxygen is more soluble in cold
water. This has a particularly adverse
effect on the eggs and larvae of fish, as at these stages of development high
levels of oxygen in the water are required for growth due to high metabolic
rates.
Increase in nutrient concentrations in the water column.
8.34
High levels of nutrients in seawater
can cause rapid increases in phytoplankton often 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 bottom. Anoxic
conditions may result if DO concentrations are already low or are not
replenished. This may result in mortality
to fish, especially juveniles, due to oxygen deprivation.
Operation Phase
8.35
Since the proposed project will only
involve a small scale reclamation at Tai Lam Kok, and further reclamation will
not be required along the road alignment beyond Tai Lam Kok to Ka Loon Tsuen,
changes to existing shoreline within the study area is not expected. Thus, it would be unlikely that the project
would cause any significant changes to the hydrodynamic regime such as tidal
flows and flushing effects.
8.36
Fisheries impacts during the operation
phase also include site runoff to adjacent waters. Toxic chemicals/ oil spilt from vehicles may enter the marine
waters via the drainage system.
Impact Evaluation
Construction Phase (direct impact)
8.37
The permanent loss of fishing area is
only attributed to 0.2 % of the combined area of Tsing Lung Tau and Tai Lam
Chung fishing areas. Therefore, the
direct impacts to fisheries resources and fishing operation include habitat
loss due to the dredging and reclamation associated with the road improvement
works is regarded as low.
Construction Phase (indirect impact)
8.38
Fish Culture Zones have specific water
quality criteria. One of the main
parameters under consideration is suspended solids (SS) which at high levels
would clog gills and affect turbidity.
Eggs and fry fish are most susceptible to increased SS. Water quality data including dissolved
oxygen (DO) and nutrients obtained from the water quality impact assessment of
the area should also be considered for the fisheries impact assessment.
8.39
Fisheries resources in the affected
area include capture fisheries in the immediate fishing areas (Tai Lam Chung
and Tsing Lung Tau). The ranking of
such fishing areas in terms of fish production per hectare is medium and they
only contribute to 0.24 % of the territory’s total adult fish production (Table
8.1). Thus any impact on the sensitive
receivers in the area is expected to be minimal with little if any effect on
the fish production of the territory.
8.40
Potential impacts from the road improvement
works on the far-field sensitive receivers including Ma Wan and Tsing Chau Tsai
fishing areas, Ma Wan Fish Culture Zone and nursery ground off the north coast
of Lantau would unlikely be severe.
With the adoption of the mitigation measures recommended in Sections
5.48 – 5.54, the elevated SS concentration from the dredging works of the
project is predicted to be less than 0.6mgL-1 at a distance over
900m from the dredging area (Table 5.9 refers). With the minor increase in SS concentration, reductions in DO as
well as increases in nutrient levels are anticipated to be small and comply
with the WQO. In view of these
sensitive receivers are located far away from the dredging area (more than
900m), no insurmountable impacts associated with the proposed road improvement
work are expected.
Operational Phase
8.41
Fisheries impacts during the operation
phase also include site runoff to adjacent waters. Toxic chemicals/ oil spilt from vehicles may enter the marine
waters via the drainage system.
However, the design of the road and its safety management are expected
to prevent such oil spillage from vehicles, therefore, adverse impact to marine
ecology due to oil spillage is not anticipated.
Mitigation of Adverse Environmental Impacts
8.42
According to the EIAO TM, the order of
priority for mitigating impacts should be avoidance, minimization and
compensation. Fisheries impacts have
been avoided by minimising the reclamation area and scale of dredging. Since no insurmountable fisheries impacts
have been identified, mitigation measures are not necessary.
Environmental Monitoring and Audit
8.43
No environmental monitoring and audit
is required.
Conclusion
8.44
Preliminary literature review has been
conducted to establish the baseline conditions of the study area. Water quality monitoring records revealed
that nearby waters was generally turbid with moderate surface dissolved oxygen
level and inorganic nutrients.
Parameters such as suspended solids and dissolved oxygen have been
considered for fisheries impact assessment.
8.45
Fisheries resources and fisheries
activities sensitive to the project have been identified. Special attention is drawn to the Ma Wan
Fish Culture Zone, fishing areas of Ma Wan, Tsing Lung Tau, Tai Lam Chung, Yam
O, Tsing Chau Tsai and Pearl Island. In terms of fish production, the fishing
areas concerned contribute a small proportion to the territory’s total. With the adoption of the mitigation measures
recommended in Chapter 5 of Water Quality Impact Assessment, no insurmountable
impacts associated with the proposed road improvement work on these sensitive
receivers are expected. Hence, no
specific mitigation measure is necessary in the fisheries perspective.
1. AFD (1998). Port Survey 96/97
2. CES (1997). Lantau Port Development Stage 1 Fish Fry Survey and
Stage 2 Resources Survey.
3.
Hyder-Maunsell (on-going ). Update on
Cumulative Water Quality and Hydrological Effect of Coastal Developments and
Upgrading of Assessment Tool.
4. EPD (1999). Marine Water Quality in Hong Kong 1998.
5. ERM (1998). Fisheries Resources and Fishing Operations in Hong Kong
Waters.
6. MCAL (1999). Tsuen Wan Bay Further reclamation, Area 35 – Tang Lung
Chau dangerous Goods Anchorage EIA Final Assessment report.
7. Morton, B. & Morton, J. (1983). The Sea Shore Ecology of Hong Kong, Hong Kong University Press.
8. Mott Connell Ltd (1999). Route 10 Investigation and Preliminary
Design EIA Final Report.
9. Scott Wilson Ltd & ERM-HK (2000a). Theme Park and Associated
Developments Final EIA Report.
10. Scott Wilson Ltd & ERM-HK (2000b). Northshore Lantau Development
Feasibility Study Final EIA Report.