9                          FISHERIES Impact

9.1                    Introduction

9.1.1               This section identifies and evaluates the potential impacts on capture and culture fisheries in the assessment area resulting from proposed dredging works in the Project.  This assessment is based on desktop review of the latest relevant literatures to describe the baseline condition, identify and evaluate potential direct, indirect, residual and cumulative impacts on fisheries resources during the proposed dredging works.  Mitigation measures and monitoring programme would be recommended, if necessary.

9.2                    Environmental Legislation, Standards and Guidelines

9.2.1               This fisheries impact assessment is conducted according to criteria and guidelines set out in the EIAO-TM Annex 9 and Annex 17 in order to provide complete and objective identification, prediction and evaluation of potential fisheries impacts arising from the Project.

9.2.2               Other local legislation that applies to fisheries and is relevant to this fisheries impact assessment includes the following:

l            Fisheries Protection Ordinance (Cap. 171) – aims to promote the conservation fish and other forms of aquatic life within the Hong Kong waters by regulating fishing practises to prevent detrimental activities to the fisheries industry.  The Ordinance came into effect on 30 June 1997.

l            Marine Fish Culture Ordinance (Cap. 353) – regulates and protects marine fish culture by designating areas of fish culture zone, granting license, prohibiting unauthorized vessels and any deposition of chemicals or other substance which are likely to cause injury to fish in a fish culture zone.  The list of designated fish culture zones was last revised in January 2000.

l            The Water Pollution Control Ordinance (Cap.358) – aims to control water pollution in the waters of Hong Kong.  Water control zones are designated with individual water quality objectives to promote the conservation and best use of those waters in the public interest.  The most updated water quality objectives for the Victoria Harbour Water Control Zone were revised in June 1997.

9.3                    Assessment Methodology

9.3.1               Baseline fisheries conditions are elucidated via a review of relevant literatures including the latest fisheries data presented in the AFCD Port Survey Report 2001-2002 and other relevant information available in other reports and publications listed below.  No necessary field survey is identified and conducted in this assessment.

l            Agreement No. CE 42/2001, Environmental and Engineering Feasibility Assessment Studies in Relation to the Way Forward of the Harbour Area Treatment Scheme – Water Quality, Ecological and Fisheries Impact Assessment (HATS EEFS Report).

l            Agreement No. CE 87/2001, Further Development of Tseung Kwan O – Feasibility Study (TKOFS EIA)

9.3.2               Potential impacts on capture and culture fisheries resources arising from the Project are identified and evaluated using the EIAO-TM evaluation criteria listed in Annex 9 and guidelines presented in Annex 17.  Results of the water quality modelling were used to assess the extent and severity of indirect impacts during the capital and maintenance dredging works, and in the formulation of mitigation measures, if required.

9.4                    Description of the Environment

9.4.1               The assessment area for the fisheries impact assessment included all areas within 500 m from the boundary of the Project area, i.e. Kowloon Bay, eastern Victoria Harbour, Kwun Tong Typhoon Shelter (KTTS), To Kwa Wan Typhoon Shelter (TKWTS) and Kai Tak Approach Channel (KTAC).  Based on the review on the available literature, no important nursery or spawning area is identified within the assessment area.  The nearest mariculture areas identified are the Tung Lung Chau Fish Culture Zone and Ma Wan Fish Culture Zone which are 8 km and over 10 km away from the Project area respectively.

Capture Fisheries

9.4.2               In Hong Kong, the capture fishing industry produced an estimated 162,000 tonnes of fisheries produce valued at $1,600 million in 2005 (AFCD, 2007a).  The industry consists of about 4,150 fishing vessels and 9,200 fishermen working abroad.  Fishing activities are mainly conducted in the waters of the adjacent continental shelf in the South China Sea.  The majority of the fishing vessels are manned by family members with the assistance of hired crew.  Main fishing methods include trawling, long-lining, gill-netting, and purse-seining with the majority of the total catch obtained through trawling.  Some recent data on local capture fisheries industry are summarised in Table 9.1.

Table 9.1                        RecentHong Kong Capture Fisheries Industry Figures

Parameter

2005

2004

2003

2002

2001

2000

Fishing fleet size (No. of vessels)

4,150

4,300

4,600

4,470

5,100

5,250

Portion of fishing fleet comprising sampans (P4) and non-mechanised vessels

No data

No data

No data

53%

54%

51%

Local fishermen engaged in capture fisheries

9,170

9,700

10,100

10,860

11,560

11,900

Mainland deckhand employed

No data

No data

3,908

4,100

4,560

5,200

Production (tonnes)

162,000

167,500

157,400

169,790

174,000

157,010

Value of produce (HK$ million)

1,600

1,600

1,500

1,600

1,700

1,600

Note: no data = data were unavailable at time of reporting

Source: AFCD Annual Reports, 2000 - 2006

 

9.4.3               The latest AFCD Port Survey 2001-2002 provides the most updated and detailed information on capture fisheries in Hong Kong waters, including both fishing operation and fisheries production (adult fish and fry).  The fishing operation within the assessment area was supported by vessels less than 15 m only.  Sampans were the dominant fishing vessels but other vessels such as Gill Netters, Long Liners, Hand Liners, Purse Seiners and miscellaneous crafts were also operated within the assessment area.  The capture fisheries data by vessels less than 15 m in the assessment area are summarised in Table 9.2.

Table 9.2                        Summaryof Capture Fisheries Data in Assessment Area by Vessels<15m

Parameter

Kowloon Bay

Eastern Victoria Harbour

KTTS

TKWTS

KTAC

No. of vessels

100-400

100-400

100-400

10-50

0

Adult fish production in terms of weight (kg/ha)

100-400

100-400

200-400

> 0 and    < = 50

0

Fish fry production in terms of weight (kg/ha)

0

0

0

0

0

Fisheries production (adult and fry) in terms of value (HK$ /ha)

5,000-10,000

5,000-10,000

5,000-10,000

1,000-2,000

0

Source: AFCD, 2007at (http://www.afcd.gov.hk)

 

9.4.4               The latest Port Survey did not record any fishing operation or fisheries production in the KTAC, showing that this area has no or very limited value in capture fisheries.

9.4.5               The scale of fishing activities in terms of number of fishing vessels operating in the Kowloon Bay, eastern Victoria Harbour and KTTS are considered to be moderate (100-400 vessels) as compared with other fishing grounds in Hong Kong.  In contrast, fisheries operation in the TKWTS is very limited with only 10-50 vessels recorded.

9.4.6               In terms of weight, fisheries production for adult fish in the Kowloon Bay, eastern Victoria Harbour and KTTS were moderate with yield of 100-200, 100-400 and 200-400 kg/ha respectively while very low adult fish production with yield of less than 50 kg/ha were recorded at the TKWTS.

9.4.7               Important nursery grounds can be identified from the main areas of fry collection for the mariculture industry.  Fry collection in Hong Kong has been much reduced in scale in recent years and the latest interview studies (AFCD, 2003) report that fry collection only occurs in a few areas.  These areas are mostly eastern inshore waters, such as Crooked Harbour, Double Haven, Long Harbour and Port Shelter, all outside the Assessment Area.  This indicates that there are no important spawning or nursery grounds for fish recruitment within the Assessment Area (ERM, 1998).

9.4.8               The most common capture fish in the Assessment Area was Rabbitfish (Siganidae).  Very high production of over 60 kg/ha of this species was recorded in the Kowloon Bay, eastern Victoria Harbour and KTTS while moderate yield of 20-40 kg/ha was recorded in TKWTS. This species is fast-growing fish of relatively low commercial value.

9.4.9               Other medium-valued species such as Seabream (Sparidae) and crab produced moderate yield of about 20-40 kg/ha annually in Kowloon Bay, eastern Victoria Harbour and KTTS but less than 5 kg/ha in TKWTS.  Other species such as Sardine (Clupeidae), Croaker (Sciaenidae), Threadfin Bream (Nemipteridae), Squid and Shrimp were scarcely reported (less than 5 kg/ha) in Kowloon Bay, eastern Victoria Harbour and KTTS, except Croaker and Threadfin Bream which produce 10-20 kg/ha and 5-10 kg/ha respectively in KTTS and part of eastern Victoria Harbour.

9.4.10           Overall, in terms of their capture fishery production values, fishing areas in Kowloon Bay, eastern Victoria Harbour and KTTS are ranked moderate to high value with production value of HK$5000-10000/ha annually whereas TKWTS produced about HK$1000-2000/ha every year and is considered as moderate-valued as compared with other fishing grounds in Hong Kong.

 

Culture Fisheries

9.4.11           Culture fisheries, on the other hand, included 26 fish culture zones (FCZs) located in various sheltered coastal areas in Hong Kong marine waters and occupied about 209 ha of marine area with about 1,100 licensed operators (AFCD, 2007b).  Majority of the licensed farms are small, family-based and consisting of one to two rafts with average total area of around 260m2.

9.4.12           Mariculture areas including marine fish culture and oyster culture were absent in the Assessment Area.  The nearest fish culture zones (FCZs) identified in the vicinity of the Project area are Tung Lung Chau FCZ (8 km from the Project area) and Ma Wan FCZ (over 10 km away).

9.4.13           Although no figures are available on the individual production of these FCZs, it was estimated that culture fisheries production in 2006 was about 1,488 tonnes valued at $89 million which catered about 7.9 per cent of local demand for live marine fish. (AFCD, 2007b).  Some recent figures on marine culture fisheries are presented in Table 9.3.

Table 9.3                        RecentHong Kong Culture Fisheries Industry Figures

Parameter

2006

2005

2004

2003

2002

2001

2000

Licensed operator

1,080

1,100

1,125

1,155

1,237

1,320

1,418

Production (tonnes)

1,488

1,539

1,540

1,490

1,210

2,470

1,770

Value (HK$ million)

89

76

79

76

57

136

102

Source: AFCD Annual Reports, 2000 – 2006 and (AFCD, 2007b)

 

9.4.14           The species cultured changed gradually over the recent years depending on the availability of imported fry.  Common species under culture include green grouper, brown-spotted grouper, giant grouper, Russell's snapper, mangrove snapper, red snapper, star snapper, and pompano (AFCD, 2007b).

9.5                    Identification, Prediction and Evaluation of Environmental Impacts

9.5.1               Impacts to fisheries resources may occur during the implementation of the Project, including the capital dredging and the regular maintenance dredging.  The impacts may be derived from direct loss of fishing area or indirect disturbance through changes to key water quality parameters.

Loss of fishing grounds

9.5.2               Potential direct impacts on fisheries resources arising from the Project would include loss of fishing area in Kowloon Bay and eastern Victoria Harbour near the southern tip of the former Kai Tak Airport runway.  The proposed dredging activities are considered to be of a relatively moderate scale and would result in temporary loss of 57 ha of fishing ground.

9.5.3               Although fisheries importance in Kowloon Bay and eastern Victoria Harbour are considered as moderate to high in terms of adult fish production and commercial fishing activities as compared with other fishing locations in Hong Kong, the affected fisheries area only constitute a very small portion of the total fishing area in Hong Kong.  The loss of fishery production would be temporary and insignificant as compared with the total fishery production in Hong Kong.

9.5.4               Fishing activities in the affected area constitutes only a small proportion of total fishing operations in Hong Kong in terms of vessel number, and most of the vessels operating there were non-mechanised crafts such as Sampan. 

9.5.5               The most common capture fish in the affected area was confined to Rabbitfish which is of relatively low economic value (FMO 2007).  No important nursery or spawning area was identified within the assessment area (ERM, 1998).

9.5.6               In view of the small size of the affected area, temporary and insignificant loss of fisheries production and low impact on fishing activities, such fisheries impacts due to capital and maintenance dredging are expected to be minor and acceptable.

Changes in water quality

9.5.7               Potential indirect impacts to the fisheries resources would include changes in water quality due to capital and maintenance dredging activities of seabed sediment and potential site run-off from land-based construction works.

Elevation of suspended solid (SS)

9.5.8               Dredging activities would temporarily elevate the suspended sediment level and create sediment plumes.  Possible indirect impact on fisheries resources may be resulted during the dredging activities.  Effects could be lethal or sublethal through reduction in survivalship, 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 in oxygen.  Fish egg and larval fish (fry) are more susceptible to deleterious impacts from sedimentation through smothering and clogging of their respiratory systems.  Adult fish is generally less sensitive to effects from suspended sediments.

9.5.9               Suspended sediment plume occurs naturally in the marine environment by wave action and vertical flux of water current.  Fish has evolved behavioural adaptations to sudden turbid water, including clearing their gills by flushing water or simply avoiding movement to turbid waters.

9.5.10           Based on the prediction of the sediment plume modelling for the unmitigated scenarios under the water quality impact assessment (see Section 5), potential water quality impact due to elevation of SS would occur at coastal waters of the Kowloon Bay.  It is predicted that impacts to fisheries resources immediately outside of the dredging area would occur because the elevation of SS is predicted to significantly increase from ambient levels at several locations (Water Quality Section, Appendix 5.4 to Appendix 5.9).  A number of mitigation measures to control water quality are therefore recommended to confine sediment plume within the proposed dredging area and to minimize the SS elevation during dredging operations.  With the implementation of the proposed mitigation measures as suggested in the water quality impact assessment, the water quality modelling results indicate that the SS elevation arising from this Project could be effectively reduced.  In view of the temporary nature of such impact, only minor impact on capture fisheries is anticipated.

9.5.11           Impact is not expected to occur at the far field fisheries sensitive receivers such as Tung Lung Chau FCZ and Ma Wan FCZ as they are located outside the influence zone of the predicted sediment plumes (Water Quality Section, Appendix 5.4 to Appendix 5.9). Thus, no adverse impacts on these FCZs would be expected from the proposed dredging works.

Contaminant Release During Dredging

9.5.12           Dredging activities can potentially cause the release of contaminants from marine mud. Potential impacts on fisheries resources include the accumulation of contaminants in the tissues of fish, resulting in sublethal effects which may alter behaviour, reproduction and increase susceptibility to disease.  Eggs, larvae and juveniles are particularly susceptible to the sublethal effects of contaminants, and elevated levels may lead to increased mortality. Bioaccumulation in commercially important fish species may ultimately impact human health. 

9.5.13           In-vitro laboratory assessment of sediment samples indicated that the concentrations of cadmium, copper, nickel, mercury, unionised ammonia and total inorganic nitrogen contaminants exceeded the assessment criteria.  However the laboratory tests do not take into account the dilution factor after the contaminants are released.  Water quality modelling results predict that levels of contaminants would be much lower than the relevant standards at monitoring sites nearby the source.  This is because any contaminants released during dredging are immediately diluted by the large volume of marine water within the dredging site.  Thus, it is considered that long-term off-site marine water quality impact is unlikely and any local water quality impact will be transient (see Water Quality Section 5 para. 5.8.8 – 5.8.18 for more details).

Decrease of dissolved oxygen (DO)

9.5.14           The relationship between SS and DO are complex.  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, lower the photosynthetic rate of phytoplankton and so lower the rate of oxygen production in water column.  Also, the release of inorganic substances from the dredged 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. 

9.5.15           The WQO standard for the Victoria Harbour that the average-depth and bottom water DO should remain above 4 mg/L and 2 mg/L respectively for 90% of the time is adopted in this assessment.  Based on results of the water quality modelling (refer to Table 5.24 to Table 5.26), the concurrent dredging activities would cause a maximum DO depletion of less than 0.02 mg/l in the Victoria Harbour.  Therefore no adverse impact on fisheries resources would be expected from the Project.

Maintenance Dredging

 

9.5.16           Maintenance dredging will be required during operation of the proposed cruise terminal at a frequency of about once every 5 to 10 years. The approximate time to complete maintenance would be <6 months for each berth. The maximum dredging rate during maintenance dredging (2,000 m3 per day) would be lower than that during the capital dredging (total of 8,000 m3 per day during Stage 1 dredging and 4,000 m3 per day during Stage 2 dredging). As only minor adverse impacts are predicted during capital dredging (12 months), maintenance dredging (<6 months) is not expected to have any significant adverse effect on fisheries resources with the implementation of the water quality mitigation measures recommended for capital dredging.

9.6                    Mitigation of Environmental Impacts

9.6.1               Following EIAO-TM Annex 17, mitigation measures are discussed in this section to avoid, minimize, and compensate for identified fisheries impacts.

9.6.2               The mitigation measures recommended in the water quality impact assessment to control water quality would serve also to protect fisheries resources from indirect impacts and ensure no adverse impact on fisheries resources would result from the Project. Those measures should also be strictly implemented during maintenance dredging.

9.7                    Evaluation of Residual Environmental Impacts

9.7.1               The only residual impact would be the temporary loss of 57 hectares of fishing area.  In view of the small size of affected area, negligible loss of fisheries production and low impact on fishing activities, direct loss of fishing area within the dredging area is considered as minor and acceptable. 

9.8                    Evaluation of Cumulative Environmental Impacts

9.8.1               There is a number of construction activities planned for other projects that would be conducted in and within the vicinity of the Project area such as construction of Central Kowloon Route, Road T2 and submarine gas main relocation.

9.8.2               As dredging and filling activities would be also included in the above projects, the most concerned cumulative impact would be the cumulative effect on the deterioration of water quality in the Victoria Harbour.  Water quality modelling (see Section 5) predicted that the dredging and filling works undertaken for these concurrent projects would result in elevation of SS level of more than 30 % of ambient level at several locations under the worse case scenario.

9.8.3               Cumulative potential impacts on fisheries resources would be the same as the potential impacts predicted above.  However with the implementation of proper mitigation measures recommended in the water quality impact assessment, cumulative impact on water quality parameters in the Project area could be effectively minimized and the associated fisheries impacts are thus expected to be acceptable.

9.9                    Environmental Monitoring and Audit

9.9.1               No unacceptable fisheries impacts would be expected from the Project.  No monitoring programme specific for fisheries would be required.

9.10                 Summary

9.10.1           Literature reviews of existing information indicated that identified fishing area in Kowloon Bay, eastern Victoria Harbour and KTTS are of moderate to high fisheries values while that in TKWTS and KTAC are of relatively low value.  There are no fish culture zones and important spawning or nursery grounds identified in and within the immediate vicinity of the Project area.  The nearest mariculture areas are FCZs at Tung Lung Chau and Ma Wan which are 8 km and over 10 km away, respectively, of the Project area.

9.10.2           Direct and indirect impacts on fisheries resources arising from the Project were identified and evaluated.  The Project will result in the temporary loss of approximately 57 hectares of fishing area.  In view of the small size of affected area, temporary and insignificant loss of fisheries production and low impact on fishing activities, fisheries impacts due to direct loss of fishing area within the dredging area is considered as minor and acceptable. 

9.10.3           Indirect impacts of change of water quality arsing from the Project would be temporary and insignificant based on the predictions from water quality modelling.  Mitigation measures suggested in the water quality impact assessment to control water quality would also serve to protect fisheries resources from indirect impacts.  No significant adverse impact on fisheries resources would be expected from the Project and therefore no necessary fisheries-specific mitigation measures would be required.

9.11                 References

Agriculture and Fisheries Department. (2003). Port Survey 2001/2002, Capture Fisheries Division.

Agriculture and Fisheries Department. (2007a). Fisheries: Capture Fisheries. http://www.afcd.gov.hk/

Agriculture and Fisheries Department. (2007b). Fisheries:  Aquacullture.  http://www.afcd.gov.hk/

CDM (2004). Environmental and Engineering Feasibility Assessment Studies in Relation to the Way Forward of the Harbour Area Treatment Scheme, Working Paper No.3 & 9.

 

Environmental Resources Management, ERM (1998).  Fisheries resources and fishing operations in Hong Kong waters. Final Report. Submitted to AFCD. 7 March 1998.

Fish Market Organisation. (2007). Wholesale Price of Fresh Marine Fish / Live Marine Product on 24/4/2007. http://www.fmo.org.hk/page4contenteng.asp

Maunsell (2005). Agreement No. CE 87/2001 (CE) Further development on Tseung Kwan O feasibility study EIA final report.