7 FISHERIES IMPACT ASSESSMENT

7 FISHERIES IMPACT ASSESSMENT

7.1 INTRODUCTION

This Section of the EIA Report presents the findings of a desk-top assessment of the impact of installation and operation of the Project on existing fisheries resources, fishing operations and fish culture activities.

7.2 LEGISLATIVE REQUIREMENTS AND EVALUATION CRITERIA

7.2.1 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.

7.2.2 Other Legislation

Other legislation which applies to fisheries include:

* Fisheries Protection Ordinance (Cap 171) 1987 which provides for the conservation of fish and other aquatic life and regulates fishing practices; and

* Marine Fish Culture Ordinance (Cap 353) 1983 regulates and protects marine fish culture and other related activities.

7.3 BASELINE CONDITIONS AND FISHERIES SENSITIVE RECEIVERS

The Study Area was defined in the EIA Study Brief as the same as that for the Water Quality Impact Assessment (Figure 7.3a). Consequently, this assessment of impacts has focussed on the fisheries resources of this area.

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 information on the Hong Kong fishery was consulted (1). Information from other relevant studies within the Study Area were also reviewed in order to determine if the areas are important nursery and spawning grounds for commercial fisheries (2). Updated mariculture information was obtained from the Agriculture, Fisheries and Conservation Department (AFCD).

7.3.1 Capture Fisheries

Results of most recent surveys (3)(4) showed that Tolo Harbour supports fish assemblages of low diversity, dominated by fast growing low-value species which appear to thrive in the heavily eutrophic waters. Information from the Port Survey Data of AFCD (5), based on interviews with fishermen during the period 1996-1997, has revealed that one of the fishing zones in proximity to the pipelines alignment is ranked as recording high production (Tolo Channel North 4th of the 179 zones that reported a catch), four recorded medium ranked catches (Yim Tin Tsai West 60th, Yim Tin Tsai East 74th, Port Island 93rd and Ngo Mei Chau 113th), the remaining two zones recorded very low catches as Ping Chau was ranked as lowest of all of the fishing zones that reported catches (ie 179th of 179) and Mirs Bay was ranked as 176th (Annex D - Table 2.2). Two of the fishing zones reported no fry catch (Yim Tin Tsai East and Ping Chau) and of the remainder that did report fry catches, only Tolo Channel North was ranked as medium (56th of 89) whilst the others were ranked as low (Port Island 65th, Ngo Mei Chau 79th, Yim Tin Tsai W 87th and Mirs Bay 88th)..

The main fish species reported in catches from the Study Area are of low commercial value including, mixed species (juveniles of trash fish species such as pony fish, scad, rabbitfish and sardine) (Annex D - Table 2.3). Only the sea breams, rock fish and chicken grunt are regarded as being of medium value.

The catches in Tolo Channel are derived mainly from night operating bright light purse seine vessels. As a consequence, the catches are composed of low commercial value fish species and are often sold as fish feed to mariculturists. For the Northeast offshore fishing zones, the fisheries production is moderate but sampan (P4/7) fishing vessels are particularly dependent upon the area.

The findings of fisheries surveys, fishermen's interviews and accompanying literature reviews (6) conducted for AFCD's Fisheries Resources and Fishing Operations in Hong Kong Waters Study have determined that commercial fish species reproduce throughout the year, though spawning for the majority of species appears to be concentrated during the period from June to September. Northeast waters are known to be the spawning grounds for many fish species. Information showed that the fry of high value species (mainly the red pargo Pagrus major) have been found most abundant during February and March, whereas juveniles of other commercial species were found abundantly from July to August. Waters in Tolo Channel and northeastern Mirs Bay are known as important nursery areas for high value species such as red pargo (Pagrus major) and goldlined seabream (Rhabdosargus sarba).

7.3.2 Culture Fisheries

The closest AFCD designated FCZ to the Study Area are located at Yim Tin Tsai, Yim Tin Tsai (East), Yung Shue Au, Lo Fu Wat, Kau Lau Wan, Sham Wan and Tap Mun. Although there are other FCZs in the northeast New Territories they are located sufficiently remotely from the pipelines alignment as to not be affected by the works. There are no figures available for individual production at these FCZs. Annex D presents details of the areas of each of the FCZs.

The main species cultured in Hong Kong are the spotted grouper (Epinephelus coioides), gold-lined seabream (Rhabdosargus sarba), mangrove snapper (Lutjanus argentimaculatus) and the pompano (Trachinotus blochii).

7.3.3 Proposed Fisheries Protection Areas

A fisheries protection area has been proposed under the Fisheries Protection Ordinance within Tolo Channel and Long Harbour. Although designated to provide specific controls on fishing activities, the area can be regarded as a sensitive water body and any impacts should be minimised as far as possible during construction to achieve compliance with the Water Quality Objectives.

7.3.4 Identification of Sensitive Receivers

Based on the preceding review of the available information on the fisheries resources of the waters of the Study Area and its immediate vicinity, the sensitive receivers which may be affected by the proposed works associated with the Project are identified as follows:

* Fish Culture Zones at Yim Tin Tsai, Yim Tin Tsai (East), Yung Shue Au, Lo Fu Wat, Kau Lau Wan, Sham Wan and Tap Mun.

* Proposed Fisheries Protection Area within Tolo Channel and Long Harbour.

* The seasonal spawning and nursery grounds in Tolo Channel and Inshore Mirs Bay.

The location of the sensitive receivers identified above are shown in Figure 4.3a. The separation distance of all the sensitive receivers identified in the vicinity of the proposed pipelines alignment is presented in Table 4.5. The separation distance of the FCZs is also provided below:

Table 7.1 Shortest Separation Distance of Fish Culture Zones to the Pipelines Alignment

Fish Culture Zone	Shortest Separation Distance (m)
Yim Tin Tsai	1,160
Yim Tin Tsai (East)	1,050
Yung Shue Au	3,600
Lo Fu Wat	880
Kau Lau Wan	5,110
Sham Wan	6,500
Tap Mun	4,000

7.3.5 Fisheries Importance

The importance of the fisheries within the Study Area is addressed based on the baseline information provided above. The Fishing Zones within the Study Area, along the alignment are characterised as generally of high commercial value within Tolo Harbour and Channel and low commercial value in Mirs Bay. The catches from these zones are composed of juvenile mixed species, which are used as fish feed in mariculture. The size and subsequent value of the catches characterises these Fishing Zones as of high importance to the Hong Kong fishery.

The EIAO-TM (Annex 9) states that nursery areas 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. Published literature identified the Tolo Channel and inshore waters of Mirs Bay as a spawning and nursery area for many commercially important species (Annex D).

7.4 FISHERIES IMPACT ASSESSMENT METHODOLOGY

A desktop literature review was conducted in order to establish the fisheries importance of the area within and surrounding the pipelines alignment assessment area. 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 based on information from the water quality impact assessment (Section 4). This area became the focus for this fisheries impact assessment. The importance of potentially impacted fishing resources and fisheries operations identified within the Study Area was assessed using the EIAO-TM. The potential impacts due to the construction and operation of the Project and associated developments were then assessed (following the EIAO-TM Annex 17 guidelines) and the impacts evaluated (based on the criteria in EIAO-TM Annex 9).

7.5 IDENTIFICATION OF ENVIRONMENTAL IMPACTS

7.5.1 Construction Phase

The gas pipelines will be submerged and embedded in a 3 m deep trench in the seabed. The pipelines will be armoured with rockfill cover in sections near shipping zones (see Section 3 for more details). Impacts to fishing operations are expected to occur only during the deployment phase of the pipelines. These impacts are predicted to be small scale and localised and may occur through the following mechanisms.

Direct Impacts

No long term direct impacts are expected to occur through the deployment of the gas pipelines. Short term impacts are predicted to occur as a result of the jetting and dredging operations associated with the deployment of the pipelines; although once these operations have ceased, fisheries resources dependent on the affected area are expected to return due to recolonisation of the seabed by the supporting benthic fauna. The natural seabed will be reinstated as indicated in Section 3. As discussed in Section 3 the design of the piggable wye (subsea tee) is such that it will be completely submerged in the seabed and hence will not interfere with fishing operations.

Indirect Impacts

Indirect impacts to fisheries resources and fishing operations during the construction phase, include sediment release associated with the jetting/dredging 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; and

* an increase in nutrient concentrations in the water column.

Suspended Solids

Suspended sediment (SS) fluxes occur naturally in the marine environment, consequently fish have evolved behavioural adaptations to tolerate increased SS load (eg, clearing their gills by flushing water over them). Where SS levels become excessive, fish will move to clearer waters. This level is defined as the tolerance threshold, which varies from species to species and at different stages of the life cycle. If SS levels exceed tolerance thresholds, fish are likely to become stressed, injured and may ultimately die. Susceptibility generally decreases with age, with eggs the most vulnerable and adults the least sensitive to effects from sediments. The rate, season and duration of SS elevations will influence the type and extent of impacts upon fish.

It is noted that, despite the very conservative nature of the assessment, the predicted increases in suspended solids concentrations do not exceed tolerance thresholds established in the literature. Literature reviews indicate that lethal responses had not been reported in adult fish at values below 125 mg L-1 (7). However, guideline values have been identified for fisheries and selected marine ecological sensitive receivers as part of the recent study for AFCD, Consultancy Study on Fisheries and Marine Ecological Criteria for Impact Assessment (CSFMEC)(8) that have been based on international marine water quality guidelines for the protection of ecosystems. The AFCD study recommends a maximum concentration of 50 mg L-1 (based on half of the no observable effect concentrations). Although a maximum concentration value is recommended, the study acknowledges that site-specific data should be considered on a case-by-case basis.

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. 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 to support high metabolic rates.

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 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.

The results of the water quality assessment sediment concentrations have shown that the predicted maximum sediment concentrations are localised to within and around the pipeline and restricted to the lower layers of the water column (ie close to the seabed). It is expected that the concentrations within the Study Area as a whole will be maintained at environmentally acceptable levels (ie compliant with the Water Quality Objectives, see Section 4).

Impacts to the sensitive receivers listed above are predicted, as a result of the construction of Project, to be within environmentally acceptable levels (as defined by compliance with the Water Quality Objectives).

Fish Culture Zones (FCZs): As discussed in Section 4, elevated concentrations of suspended sediments in excess of 10 mg L-1 as a result of the dredging works at the Tai Po Landing Point are not predicted to occur at a distance greater than 190 m from the dredging operations. With the implementation of a silt curtain around the dredging operation which will reduce the loss of materials and the elevated concentrations of suspended sediments in excess of 10 mg L-1 would not occur at a distance greater than 50 m from the dredging operations. Therefore, adverse impacts to the closest FCZ, Yim Tin Tsai which is located > 1 km from the alignment are not anticipated.

Water quality modelling results showed that elevations in SS as a result of the jetting and dredging operations of the submarine pipelines are below the tolerance threshold for culture fish (50 mg L-1). The maximum depth averaged SS elevations at each of the FCZs is less than 3 mg L-1, which is well within the acceptable range and is not expected to cause unacceptable impacts.

Reductions in DO as well as increases in nutrient levels as a consequence of SS elevations are anticipated to be small and compliant with the WQO. Therefore, severe impacts on the FCZs due to the proposed works are not expected to occur. Due to the low severity of predicted impacts it is not expected that growth of fish in the FCZs will be affected by the construction activities associated with the jetting and dredging operations.

Therefore, impacts to the Fish Culture Zones as a result of the jetting and dredging works are unlikely to be severe, as the increase in SS near the closest FCZ (Yim Tin Tsai) is expected to be small. As discussed in Section 4, elevations in SS are predicted to be in the order of 5 mg L-1 under a worse case scenario, which are compliant with the WQO.

Fisheries Protection Areas (FPAs): Impacts to the FPA in Long Harbour are not anticipated have been avoided through the routing of the pipelines. Minor impacts to the Fisheries Protection Area in Tolo Channel are likely to occur within the area of jetting and dredging works and their immediate vicinity due to the elevated levels of suspended solids (depth averaged < 25 mg L-1). However, in the surface layer, where most fish larvae, eggs and fry are likely to be found post-spawning, the concentrations within the plumes arising from the works are less than 10 mg L-1 (Section 4 and Annex B - Figures 2.1a-d). Consequently, the impacts to the Fisheries Protection Area through elevated SS levels are considered to be of low severity and of short duration.

Reductions in DO as well as increases in nutrient levels as a consequence of SS elevations are anticipated to be small and compliant with the WQO. Therefore, severe impacts on the FPAs due to the proposed works are not expected to occur. Due to the low severity of predicted impacts it is not expected that fisheries resources in the FPAs will be affected by the construction activities associated with the jetting and dredging operations.

Seasonal Spawning and Nursery Grounds: Minor impacts to the seasonal spawning and nursery grounds in Tolo Channel and Inshore Mirs Bay are likely to occur within the area of jetting and dredging works and their immediate vicinity due to the elevated levels of suspended solids (depth averaged < 25 mg L-1). However, in the surface layer, where most fish larvae, eggs and fry are likely to be found post-spawning, the concentrations within the plumes arising from the works are less than 10 mg L-1 (Section 4 and Annex B - Figures 2.1a-d). Consequently, the impacts to the spawning and nursery grounds through elevated SS levels are considered to be of low severity and of short duration.

There is a resident spawning aggregation of the snapper fish Lutjanus johnii on the Artificial Reefs near the border of the Hoi Ha Wan Marine Park facing Tolo Channel. Provided that all recommended mitigation measures are met, adverse environmental impacts arising from the construction to the ARs would be considered indirect and secondary.

7.5.2 Operational Phase

As discussed in Section 3.2.2 and Section 4.6.3, the pipelines are designed to be maintenance free and should they require inspection this will be done using a remotely operated intelligent pipe inspection gauge (PIG). This type of maintenance will occur once every ten years and will be within the gas pipes. Consequently, there will be no need to disturb the seabed sediments during maintenance and therefore water quality will not be affected.

The only operational impacts from the gas pipelines would be if repairs were required. The impacts from this would be of reduced severity that those during the construction phase as the work would take place in a specific and confined small area. Therefore, unacceptable impacts to capture and culture fisheries during the operational phase of the Project are not envisaged.

7.6 ASSESSMENT OF ENVIRONMENTAL IMPACTS

From the information presented above, the fisheries impact associated with the Project is considered to be low. An evaluation of the impact in accordance with Annex 9 of the EIAO-TM is presented below.

* Nature of impact: Short term impacts will occur to fisheries resources in the Study Area as a result of the jetting and dredging activities for the pipelines installation operations. Temporary impacts to pelagic and demersal fisheries resources as a result of minor perturbations to water quality are predicted to occur only in the vicinity of the jetting/dredging operations.

* Size of affected area: Although the pipelines are long (28.5 km in HKSAR waters) the affected area of fisheries resources is predicted to be very small and localised to the works involved in installation of the pipelines.

* Size of fisheries resources / production: Due to the size of the Study Area, the fisheries resources and production rates range from high to low in terms of catch weight and value.

* Destruction and disturbance of nursery and spawning grounds: The Tolo Channel and Inshore Mirs Bay sections of the pipeline route pass through previously identified spawning and nursery grounds for commercially important species and a proposed Fisheries Protection Area. The impacts associated with the installation of the gas pipelines will be of low magnitude, short term and restricted to within a close distance to the pipelines alignment. Therefore, impacts to these important areas are expected to be small and short term.

* Impact on fishing activity: The pipelines pass through two distinguishable areas: a high fisheries production and activity area in Tolo Channel, and a low production area in Mirs Bay. Impacts to fishing activities in either area are not expected to be of concern due to the small area physically disrupted during installation of the pipelines and the short time frame of disturbance.

* Impact on aquaculture activity: Based on the Water Quality Objectives and AFCD criteria, the FCZs in the Study Area are not predicted to be impacted by either SS elevations, DO depletions or nutrient elevations as a result of the Project.

7.7 MITIGATION OF ADVERSE ENVIRONMENTAL IMPACTS

In accordance with the guidelines in the EIAO-TM on fisheries impact assessment the general policy for mitigating impacts to fisheries, in order of priority, are avoidance, minimization and compensation.

Impacts to fisheries resources and fishing operations have largely been avoided during construction through constraints on the works operations for installation of the pipelines. These constraints were recommended in Section 4 to control water quality impacts to within acceptable levels and are also expected to control impacts to fisheries resources. Hence, no fisheries-specific mitigation measures are required during construction.

7.8 RESIDUAL ENVIRONMENTAL IMPACTS

The only residual impact identified that may affect commercial fishing operations is the disturbance to fishing activity during the pipeline laying and jetting operations. The magnitude of this residual impact is low since the operations move at a rate of 1.08 to 1.6 km per day and thus any impacts to specific fishing grounds will be of a very short duration.

7.9 ENVIRONMENTAL MONITORING AND AUDIT

The dredging and jetting operations include constraints which act as appropriate mitigation measures to control environmental impacts to within acceptable levels. Actual water quality impacts from these activities will be monitored. Monitoring and audit activities designed to detect and mitigate any unacceptable impacts to water quality will serve to protect against unacceptable impacts to fisheries resources.

The water quality monitoring programme will provide management actions and supplemental mitigation measures to be employed should impacts arise, thereby ensuring the environmental acceptability of the project. As impacts to the fisheries resources and fishing operations are small and of short duration, the development and implementation of a monitoring and audit programme specifically designed to assess the effects of these activities on commercial fisheries resources is not deemed necessary.

7.10 CONCLUSIONS

Reviews of existing information on commercial fisheries resources and fishing operations located within the Study Area have been undertaken for this impact assessment. Information from a study on fishing operations in Hong Kong indicates that fisheries production values from along the pipelines alignment are highly variable.

Potential impacts to fisheries resources and fishing operations may arise from disturbances to benthic habitats on which the fisheries resources depend for food, or through changes to key water quality parameters, as a result of the installation of the gas pipelines. As impacts arising from the proposed dredging or jetting works are predicted to be largely confined to the specific works areas and of short duration, they are not expected to cause adverse impacts to any fishing grounds or species of importance to the fishery. While no special mitigation measures are required for fisheries resources, constraints on jetting and dredging operations recommended to control impacts to water quality to within acceptable levels are also expected to mitigate impacts to fisheries resources.

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(1) Agriculture, Fisheries and Conservation Department (1998) Port Survey 1996 - 1997.

(2) ERM (1998) Fisheries Resources and Fishing Operations in Hong Kong Waters, Final Executive Summary, for Agriculture, Fisheries and Conservation Department.

(3) Leung A W Y (1997). The epibenthic ichthyofauna of Tolo Harbour and Hong Kong's Northeastern waters: a long term record of change. In: The Marine Flora and Fauna of Hong Kong and Southern China IV, Proceedings of the Eighth International Marine Biological Workshop 1995, B Morton (ed), pp. 463-487, Hong Kong University Press, Hong Kong.

(4) ERM Hong Kong Ltd (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Final Report to AFD, HKSAR.

(5) Agriculture and Fisheries Department (1996-1997) Port Survey Data. Capture Fisheries Division, AFD, August 1998.

(6) ERM Hong Kong Ltd (1998) op cit.

(7) References cited in BCL (1994) Marine Ecology of the Ninepin Islands including Peddicord R and McFarland V (1996) Effects of suspended dredged material on the commercial crab, Cancer magister. in PA Krenkel, J Harrison and JC Burdick (Eds) Dredging and its Environmental Effects. Proc. Speciality Conference. American Society of Engineers.

(8) City University of Hong Kong, Final Report, Agreement No. CE 62/98, Consultancy Study on Fisheries and marine Ecological Criteria for Impact Assessment, AFCD, July 2001.