7 PREDICTED ENVIRONMENTAL IMPACTS AND POTENTIAL MITIGATING MEASURES

Transcription

1 7 PREDICTED ENVIRONMENTAL IMPACTS AND POTENTIAL MITIGATING MEASURES 7.1 IMPACT IDENTIFICATION The most common methods or tools for impact identification are 26 : professional and technical experience checklists matrices networks overlays and geographic information systems (GIS) expert systems The impact identification carried out for the proposed project:- is based on the Matrices of aquaculture activities, impacts and mitigation measures No3 for Coastal cage or pen culture appended to the Composite Guidelines for the Environmental Assessment of Coastal Aquaculture Development, i.e. fish farms at sea and land-based infrastructure; has been amended in the light of the present project o which refers to the sea-based activities only, i.e. new fish farms, o the land-based activities already exist and are excluded from the project o the present project refers to low density aquaculture (i.e. is NOT intensive aquaculture). (e.g. sections D3, D4, etc. referring to the land activities have been omitted; the numbering has not been modified to remain in line with the Matrices of aquaculture activities of the Composite Guidelines) Actions Affecting Environmental Resources and Values A. Site selection Potential Environmental Impacts 1. Conflicts with other site users and On and off-site damage to natural resources and interference in livelihoods of local communities social conflicts 2. Selection of ecologically sensitive site Potential loss of biodiversity. 3. Hazards to aquaculture from nearby pollution Water pollution from industry, agriculture sources (e.g. agriculture, industry) affecting sustainability of aquaculture 4. Typhoons, flooding, hurricanes Damage to physical facilities and loss of fish stock. 5. Water quality Water quality deterioration caused by self-pollution from aquaculture effluent 6. Fish seed Potential impacts on biodiversity caused by overharvesting of wild stocks. Lack of sustainability of aquaculture due to insufficient seed supply. Introduction of exotic species may impact on indigenous species 7. Disease problems Potential impacts caused by presence of serious pathogens/ disease problems 26 (UNEP 1996) 7-1

2 Actions Affecting Environmental Resources and Potential Environmental Impacts Values B. Farm design B. Poor design can lead to a variety of environmental problems 1. Attention to problems A (1) to A(7 ) above As above. 2. Socio-economic impacts Social inequities leading to social unrest 3. Interference with navigation, traditional users Impacts on existing uses 4. Aesthetics Aesthetic impacts C. Farm construction Poor construction practices can lead to various environmental problems 1. Siting Impacts on benthos during construction and disturbance of wildlife D. Farm operation and management 1. Solid waste disposal Impacts on benthos, wildlife 2. Waste water/effluent discharge Impacts on local water quality and sediments 5. Use of chemicals Potential impacts on workers health Water pollution Impacts on aquaculture product quality 6. Seed collection/supply Loss of biodiversity caused by harvesting of wild stocks. Impacts on wild stocks through escapes of farmed stocks. 9. Disease outbreaks and disposal of mortalities Economic impacts on stock, product quality and native populations. 10. Operational failures caused by storms Sudden impacts caused by loss of fish stock. 11. Boats, infrastructure support Water pollution from boat engines 13. Predators and wildlife Wildlife disturbance Predators causing damage to fish stocks. Table 7-1: Matrix of Impacts applied to FMM Coastal Fish Farms Most of the potential effects and interactions of a fish farm with its surrounding environment are represented in the diagram shown on Figure 7-1 below. Figure 7-1: Overview of actual and potential ecological effects from marine finfish farms 7-2

3 7.2 IMPACTS EVALUATION AND MITIGATION MEASURES Methodology Each of the above-listed potential impacts has been evaluated based on the significance of the impact on the environment. There are a number of criteria that are incorporated into the determination of the significance of potential impacts, comprising: Magnitude or severity of an impact (Negligible/ Moderate/ Critical); Spatial extent (local/large scale); Duration (short term, intermediate or long term); Reversibility; Probability of occurrence (rare/occasional/frequent); Confidence in the impact prediction; and The margins by which set values are exceeded (e.g. air or water quality standards). In addition, in order to classify the significance of predicted impacts, and in an effort to provide a consistent framework for considering and evaluating impacts on different environmental parameters, the terminology presented in Table 6-2 below has been adopted. IMPACT Negligible Minor adverse Moderate adverse Major adverse Minor beneficial Moderate beneficial DEFINITION The impact is not of concern The impact is undesirable but of limited concern The impact gives rise to some concern but it is likely to be tolerable (depending on its scale and duration) The impact gives rise to serious concern; it should be considered as unacceptable The impact is of minor significance but has some environmental benefit The impact provides some gain to the environment Major beneficial The impact provides a significant positive gain Table 7-2: Terminology for classifying and defining environmental impacts Impacts Evaluation and Where potentially significant adverse impacts have been identified, mitigating measures have been examined and recommended in order to reduce residual impacts, as far as possible, to environmentally acceptable levels. The sections below refer to those of the matrix presented in Table 6-1 above. A/ Site Selection A1. Conflicts with other site users and interference in livelihoods of local communities Aquaculture activity on activities of in-lagoon fishermen and boat operators Activities of in-lagoon fishermen and boat operators on aquaculture activity 7-3

4 Aquaculture activity on activities of in-lagoon fishermen and boat operators o Disturbance of the artisanal fisheries as the fish farming zones are no-go areas o Disturbance to boat operators as the fish farming zones are no-go areas Activities of in-lagoon fishermen and boat operators on aquaculture activity o Disturbance of the fish farming activity o Risk of damaging the cages and release of fish Impact caused by the aquaculture activity. As discussed in section 6.9 hereof, no artisanal fishing occurs in the muddy silty bassin and plain where the fish farms zones are located (refer figure 6-5: sensitivity map); fishermen usually place their casiers on the shoals which are sensitive areas. The fish farming zones are located on the eastern side of Anse Jonchee channel; boat operators and pleasure craft use a route which is rather in the middle of the channel, i.e. west of the fish farming zones. Based on the above, the risk of conflict with in-lagoon fishermen and boat operators can be assessed as minor adverse. Impact caused to the aquaculture activity. As discussed previously, the fish farm zones act as artificial reefs; previously void of such amounts of marine life. They have become populated with fish living around the cages or visiting the cages such as dolphins and therefore attract fishermen and operators as an easy point to make an extra living. Damages to the cages and destruction of the fish stock would have a major adverse impact on the economy as FMM would witness substantial losses The potential mitigations are in the form of implementation of legal provisions and good site practices: (i) Appropriate regional land use planning. Section 8 of the Fisheries and Marine Resource Act sets the legal framework for fish farming activities and the First Schedule lists the fish farming zones as part of the regional land use planning. (ii) Generally, the shoals are sensitive areas where fishermen usually place their casiers. In order to avoid any conflict with fishermen, the fish farms shall be located away from any shoal. In the present case, shoals are located to the west of East Bambous Point 1; the fish cages shall hence be located eastward. (iii) Consultation process. For the purpose of its expansion, Ferme Marine de Mahebourg has carried out a first public meeting with all stakeholders of the area, i.e. coastal users of the region including fishermen. Regular meeting shall be held thereafter to inform stakeholders of the area of the activities of FMM. Tripartite with the competent authority should also be set up to sensitise fishermen to Section 8 of the Fisheries and Marine Resource Act and its consequences on the land use planning. (iv) Participation of local people in aquaculture projects. Ferme Marine de Mahebourg is the only medium scale economical activity in the coastal area of the district which has not witnessed any major new employment generators in recent years. FMM currently employs 102 persons from the area. With its proposed expansion, FMM will reach a direct employment capacity of around 250 persons from the area. With the resolution of any conflicts with other site users and interference in livelihoods of local communities, there would be no residual impact. 7-4

5 A2. Selection of ecologically sensitive site Operation of a fish farm within an ecologically sensitive area e.g. shoals Disturbance of/damages to the ecologically sensitive area Disturbance of/damages to the ecologically sensitive area would have a major adverse impact on any coral colonies, moderate adverse on seagrases meadow and other benthic life (i) Careful site selection and integration of aquaculture into integrated coastal management. The Aquaculture Master Plan has identified the area of Grand Port Channel as a suitable area for fish farming activities given that the channel is rather protected as within the lagoon and yet constantly flushed as located in between two active passes. (ii) Management plan which identifies ecologically sensitive sites. In line with its commitment for a sustainable aquaculture, FMM has set up a full management plan which includes monitoring plan and audits on its existing farms and careful planning and selection of the three new farms. The ecology of the area is monitored as part of the regular audits and eco-sensitivity maps have been established following extensive dive surveys of the area of the three new farms. (iii) Maintain buffer areas around farm. A minimum distance of 500m between the farms and 250 m to the edge of the sandy plateau around half a mile have been recommended in the context of FMM s Fish Farming activities (refer section ) (iv) Prior assessments of impacts. The environmental monitoring plan and regular audits implemented by FMM along with the present EIA report and associated studies serve the purpose of the requirement for prior assessments of impacts. With the avoidance of ecologically sensitive area, there would be no residual impact. A3. Hazards to aquaculture from nearby pollution sources (e.g. agriculture, industry) Seawater pollution caused by runoff water from the river and the coast Seawater pollution caused by other users of the lagoon Hazards to aquaculture that can induce a high level of mortality Hazards to aquaculture would have: 7-5

6 a major adverse impact on the aquaculture and on the revenues of FMM (i) Careful site selection. The location of all the fish farming zones close to the reef and away from the coast and rivers mouths reduces the risk of pollution of the coastal water induced by runoffs from agriculture and industrial activities. In the present context, run offs from industrial activities have not been identified; run off from domestic on site wastewater treatment plants is more of concern together with runoff from intensive agricultural practices. (ii) Pressure from aqua-culturists to reduce pollution from other sectors. In addition to runoffs from the coast, pollution caused by other users of the lagoon, e.g. fuel spillage from boats, etc. are of concern as this pollution could cause massive contamination and mortality in the fish stock. Accordingly it should be ensured that all activities allowed in the lagoon are compatible with fish farming. With a proper site selection and good site practices from other lagoon users which indeed beyond FMM s control the residual impact would be minor adverse A4. Typhoons, flooding, hurricanes Natural catastrophes such as cyclones, swells and to a lesser extent tsunamis Disturbance of the fish farm activity Risk of damaging the cages and release of fish Natural catastrophes could have: a major adverse impact on the aquaculture with losses of fish (mortality or escapes if nets are damaged) and on the revenues of FMM The potential mitigations are in the form of engineering design and good site practices: (i) Careful site selection. As mentioned in section 1.((i) above, the Aquaculture Master Plan has identified the area of Grand Port Channel as a suitable area for fish farming activities given that the channel is rather protected from cyclonic waves and winds and swells. (ii) Pond design taking account of extreme climatic events (e.g. cyclones). As detailed in section 4.2, the fish farms are made of a complex structure of anchors, weights, etc. The structure of the cages can withstand winds of 180km/hr. In case of stronger winds forecast, the cages are sunk 5m below sea level where they are protected from the wind. With a proper site selection, good engineering design of the cages and an emergency response plan in case of bad weather, the residual impact would be negligible 7-6

7 A5. Water quality Water pollution due to nearby pollution source (see A3) Water pollution due to the fish farm itself Improper water quality leading to fish mortality Improper water quality could have: a major adverse impact on aquaculture with losses of fish (mortality) and on the revenues of FMM The potential mitigations are in the form of engineering design and good site practices: (i) Careful site selection in relation to carrying capacity. The area needs to be flushed regularly with fresh water intake from the ocean so that the water quality remains within standards for aquaculture (ii) Management practices and effluent controls. As discussed in section 5.4, the quality of the feed used, the size of the fish, the feed conversion and the feeding method are of importance to minimise the waste. (iii) Strategic planning to keep number of farms within carrying capacity. The aquaculture master plan has defined a number of fish farms zones in the lagoon of Anse Jonchee, part of which have been proclaimed under schedule one of the Act. With a proper site selection and the implementation of good site practices, the residual impact of fish farms of water quality would be minor adverse to negligible. A6. Fish Seed Uncontrolled sources of fingerlings including harvesting of wild stock Changes in the marine ecosystem Non viable fish farms Harvesting of wild stock and over exploitation Introduction of fish species which if escaped would impact of the marine ecosystem Improper selection fish species and fingerling sourcing could have: a major adverse impact on the marine ecosystem if introduced fish have the capacity to reproduce in open waters a major adverse impact on the socio-economic aspects of fish farming if not viable 7-7

8 The potential mitigations are in the form of engineering design and good site practices: (i) Careful assessment of requirements prior to farm development. Technical and financial feasibility studies have been carried out to assess not only the requirements but also the technical and financial viability of the fish farm (ii) Development of hatcheries. FMM has developed its hatchery in Fingerlings from the hatchery shall be placed in the fish farms for growing (iii) Sustainable harvesting practices for wild stocks. FMM does not harvest wild stocks (iv) Prior assessment of impacts from introductions of new species. The Red Drum (Ombrine) is an introduced species and the first species of fish recommended in the Aquaculture Master Plan as having an important zoological interest and excellent aquaculture skills. The European Seabass (Bar) is an introduced species that has also been approved. None of these species can reproduce in the tropical context and even in case of escape would not harm the marine ecosystem With a proper selection fish species and fingerling sourcing, the residual impact of fish farms o water quality would be minor adverse to negligible. A7. Disease problems Disease outbreaks at the fish farm Mortality at the fish farm Spreading of possible disease to the wild fish populations Improper selection fish species and fingerling sourcing could have: a major adverse impact on the marine ecosystem if introduced fish have the capacity to reproduce in open waters a major adverse impact on the socio-economic aspects of fish farming if not viable The potential mitigations are in the form of good site practices: (i) Disease surveys of existing farms to assess risk. As discussed in section , in order to prevent any occurrence of disease outbreak, sanitary evaluations of the livestock are undertaken by qualified fish pathologists of FMM; evaluations by third parties are also carried out: the latest evaluation by an external fish pathologist was carried out in February During this examination the juveniles and adult fish were examined for internal and external parasites, bacteria and viruses. No pathological organisms were detected. (ii) Introduction of risk management strategies to reduce risk. As discussed in section , routine inspections are carried out twice daily. Abnormal behaviour of fish would be observed at the onset of any disease. The competent authority would be informed forthwith and a management plan set up for disposal of the dead fish in sanitary manner on shore and quarantine measures for other cages. 7-8

9 With the introduction of necessary surveys and risk management strategies, there would be no residual impact. B/ Farm Design B1. Attention to problems A (1) to A (7) above. See above potential mitigation strategies for negative environmental impacts. B2. Socio-economic impact Socio-economic impact on stakeholders of the area Negative impact in case FMM is not allowed to expand and, not being viable, is forced to terminate its operations and thus lay off employees and disengage itself from the socio-economic life of the area Positive impact if FMM is allowed to expand, becomes viable and contributes further to the socioeconomic life of the area Closure of FMM as the only industry in the area would have a major adverse impact on stakeholders of the area Expansion and viability of FMM as the only industry in the area would have a major beneficial impact on stakeholders of the area (i) Participation of local people in aquaculture projects. As mentioned in section A/1.(iii) above, FMM currently employs 102 persons from the area; some appropriate training is provided as detailed in chapter 5 hereof. (ii) Understand socio-economic conditions prior to project, and ensure developments do not negatively impact local people. The project consists in the expansion of an existing activity. The socioeconomic conditions have been captured over the years of operation. The expansion will create further direct employment opportunities (up to 250 persons) and indirect employment such as in the transport, sales and export sectors. A first public presentation was held on 23 rd December 2013 to inform the stakeholders of the area and obtain the views of the local community on the project. Other meetings shall be set up as the project progresses. With the expansion of the fish farming activity to reach a viable stage, there would be a positive beneficial impact. 7-9

10 B3. Interference with navigation, traditional users Operation of a fish farm within a lagoon used by other operators such a tourist boats and traditional users such a in lagoon fishermen Interference with lagoon users damages to the fish farms leading to potential looses of revenues and accidents at sea Interference with navigation, traditional users would have a moderate to major adverse impact on both aquaculture concessionaries and lagoon users if other users are not informed and sensitised to the fish farming zones being a no go area around which a buffer needs to be established and maintained (i) Site farms in ways which do not impact traditional users. Grand Port channel is traditionally used by fishermen and pleasure crafts that do not have a formal and imposed navigational path; as briefly discussed in section in section A1 above, the fish farming zones are located on the eastern side of Anse Jonchee channel; boat operators and pleasure craft use a route which is rather in the middle of the channel, i.e. west of the fish farming zones. Users of the lagoon would not be impacted by the fish farming zones. (ii) It should also be reminded that the siting of the fish farming zones is based on the location of appropriate sites defined in the Aquaculture Master Plan and enacted in the legislation. (iii) Lastly, it shold be reminded that the project consists in the expansion of an existing activity; the two first fish farming zones leased by FMM have not caused any impact on navigation and traditional users, rather it has attracted these people. The next three ones would similarly not cause any impact. (iv) Maintain buffer areas between farms and other uses. The fish farms are clearly and visibly marked in accordance with section 8D of the Fisheries and Marine Resource Act. The fish farms zone should also be indicated in the navigational charts to increase safety upfront; this is presently not the case. The Fish Farm Zones are no-go areas and yet this does not prevent boat operators and other sea users such as fishermen to enter the restricted area; this trespassing should be discouraged by the authorities at the least by sensitisation of the other sea users. With a proper siting of the fish farms (as dictated by law) and maintenance of an adequate buffer around the fish farms, the residual impact on navigation and traditional users would be minor adverse to negligible. B4. Aesthetics Fish cages which structures does not blend in the natural landscape 7-10

11 Visual intrusion into the local context and inadequacy with the surrounding landscape and land use Non aesthetic cages which do not blend with the surrounding environment would have Minor to moderate adverse impact as likely to be tolerable (i) Low profile cages, minimise use of unsightly structures. The new fish farms shall be alike the existing ones which are indeed low profile cages. Figure 4-3 below shows the existing visible structure With the use of low profile cage, the residual impact of fish farms on te aesthetic would be negligible. C/ Farm Construction C1. Siting Impacts associated with the construction of the cages Disturbance to the local navigation and traditional users during construction Disturbance to the local navigation and traditional users during construction would have a minor adverse impact on the sea users given that as indicated below the construction are within a wider fish farm zone which is a no-go area (i) Maintain buffer areas. During construction or rather assembling of the cages, temporary buoys shall be placed to mark the concession; permanent marking shall be done thereafter in accordance with the Act. (ii) Ensure site disturbance is limited to immediate area. The installation methodology as provided in section above clearly shows that that site disturbance is limited to the immediate construction area With a proper siting of the fish farms (as dictated by law) and maintenance of an adequate buffer around the fish farms, the residual impact during construction on navigation and traditional users would be minor adverse to negligible. 7-11

12 D/ Farm Operation and Management D1. Solid Waste Disposal Non-organic waste generated during the operation stage. Pollution of the marine and coastal environment in the absence of a solid waste management plan Pollution of the marine environment with solid waste would have a major adverse impact on dolphin and other marine life eating the waste such as plastic bags or getting caught in discarded nets. The potential mitigations are in the form of adherence to an already existing Solid Waste Management Plan: (i) Non-organic, solid waste materials should be disposed of safely. Non-organic solid waste generated by the fish farm consists exclusively of the bags containing the feed. These bags are brought back to the premises and handled as domestic waste as currently no plastic recycler is interested by the low volumes. With the expansion and standardisation of the bags, it is expected that plastic recyclers will find an interest to collect these bags for recycling. With the setting up and adherence to a Solid Waste Management Plan, there would be no residual impact. D2. Waste water/effluent discharge Operation of a fish farm in an inadequate manner that would cause alteration of the water quality Excess of fish feed or inappropriate feeding method that would result in a loss of food that deposits at the bottom Insufficient natural circulation of the water column that would result in waste (excess of food/excrements) not being flushed Decaying of dead fish left in the cages that would affect the water quality Inadequate operation of a fish farm that would cause alteration of the water quality would have a major adverse impact on the surrounding marine environment (ii) Efficient feeding practices (optimise use of fish food). As discussed in section 6.4 hereof, fish feeding is a sensitive issue that has been carefully evaluated by FMM in order to find the adequate Food Conversion Ratio 7-12

13 (iii) Site farms in areas with adequate tidal flow. As discussed in section 6.9 hereof, the primary and secondary currents assist to a rapid flushing of the lagoon and dispersal of nutrients (iv) Disposal of dead/diseased animals in sanitary manner on shore. As discussed in section 4.2 hereof, the type of aquaculture carried out is of an artisanal and ecological type with low densities in the cages. This reduces the risk of dead/diseased animals. Nonetheless natural death occurs and when this happens dead fish are removed from the cages (mainly to avoid attracting sharks), collected by a dedicated boat, kept in an air tight container at low temperature in a dedicated room and disposed of at the sanitary landfill of Mare Chicose. There has been no significant disease outbreak at FMM; nonetheless should this happen the procedures set up under the contingency plan would be adopted and fish disposed of in accordance with requirements of the competent authority. (v) Minimise leaks from water pumps, boat engines, generators etc. in order to avoid leakages, engines are services in accordance with the manufacturer s requirement, boats are checked before use and aging engines would be replaced forthwith. (vi) Secondary aquaculture, e.g. of filter feeding molluscs, seaweeds in vicinity of cages. There is no need for an artificial secondary aquaculture in the vicinity of the cage as a natural marine life has develop around the cages (as discussed in section 6.7 hereof) and feed promptly on any excess of feed. With the adoption of good site management practices, with artisanal and ecological type with low densities in the cages, there would be negligible residual impact to minor adverse impact that would disappear within a week after stopping the activity. D5. Use of chemicals Use of chemicals that could be released directly or indirectly into the marine environment, e.g. copper based anti-fouling treatments of fish cage nets ( refer chapter hereof) Disturbance of/damages to the ecologically sensitive area Release of copper into the environment by use of copper based anti-fouling treatments Disturbance of/damages to the ecologically sensitive area would have a moderate to major adverse impact on the marine life depending on types of chemicals used (i) Ban of chemicals in the aquaculture. FMM does NOT use any chemicals in its fish farms in accordance with its self-adherence to the aquaculture product quality standards implemented and certification by Friends of the Sea. (refer chapter hereof) (ii) Reduce disease problems through preventative management, not chemicals. According to the above, a preventive management plan has been set up to reduce disease problems as briefly spelt out in section 4.2 hereof. 7-13

14 With the ban of chemical use, there would be no residual impact. D6. Seed collection/supply Impact associated with seed collection in open waters (wild stock) Depletion of wild stock of finger lings and thus depletion of adult fish Disturbance of/damages to the ecologically sensitive area would have a major adverse impact on the wildlife (i) Improved fishing techniques that reduce damage to non-target stocks. FMM does not harvest wild stock. (ii) Development of hatcheries. The development of FMM s hatchery in 2002 as mentioned above, avoids the loss of biodiversity caused by harvesting of wild stocks. (iii) Siting in ways that minimise storm damage. As discussed above, the fish farms have been located in areas rather protected from cyclonic waves. The siting is based on site studies and confirmed by surveys of the hydrodynamics characteristics of the area. The mortality due only to storm damages is difficult to assess; the mortality due to farm operations including weather is in the range of 5%. (iv) Prior assessments of introductions of exotics. The impact on wild stocks through escapes of farmed stocks is negligible as although the Red Drum and the European Seabass are predators of the Mauritian wild stock, they have predators such as dolphins, and other larger marine mammals and above all fishermen and would be caught very rapidly. The Red Drum and the European Seabass cannot reproduce naturally in Mauritius as these species need seasonal variations and cold water. As regards the Red Drum, no natural reproduction has been observed in Mauritius since 10 years. The introduction of exotics has been licensed by the competent authority. (v) Adherence to ICES/FAO Codes of Practice. FMM adheres to Code of practices and has obtained certifications as detailed in section of this EIA report With the careful selection of exotic fish species adapted to the local context the wild stock is not effected; there is therefore no residual impact. D9. Disease Outbreaks and Disposal of Mortalities Disease outbreak and inappropriate handling of mortalities that could cause contagion to the wild stock 7-14

15 Contagion to/depletion of the wild stock Transmission to human beings Disturbance of/damages to the ecologically sensitive area would have a major adverse impact on the ecosystem (i) Implement preventative health management strategies. As discussed in section 4.2 hereof, a series of contingency plans are in place as preventative health management strategies (ii) Sanitary disposal of mortalities. As discussed in section D2. (Iv) above. (iii) Quarantine procedures/health certification for introduced fish stocks. As discussed in section 4.2, the fingerlings used in the fish farms originate from the hatchery. In the event that introduction of eggs is required, FMM seeks the authorisation from and follow the requirements of the competent authorities. With the setting up of preventive measures to avoid any Disease Outbreaks and the proper Disposal of Mortalities, there would be no residual impact. D10. Operational failures caused by storms Storms, cyclones hitting the south eastern coast of Mauritius Disturbance of/damages to the fish farms with escapes of fish Disturbance of/damages to the fish farms would have a moderate to major adverse impact on the revenues of FMM a moderate to major adverse impact on the marine life with release of exotic fishes (i) Accommodating operational failures in management procedures. (Sudden impacts caused by loss of fish stock). As discussed in section D6. (iv) above, both fish species cannot reproduce in the Mauritian waters so no second generation of escapees would be possible. Although they are predators, they also have larger predators and the escapees would soon be caught and removed from the chain. (ii) Routine checking of nets, moorings & Farm structures designed to withstand storm events. These aspects have been discussed in section 4.2 hereof. 7-15

16 With the adoption of good engineering design and best site practices, the residual impact would be negligible to minor adverse in case of escapes (and rather positive on the feed of larger predators!) D11. Boats, infrastructure support Operation of a fish farm within inappropriate equipment Water pollution from oil leaks Disturbance of the marine life with noise/vibration from engines Disturbance of/damages to the ecologically sensitive area would have moderate adverse on the marine life on the navigational path between land based activities and the fish farms and around these (i) Use of appropriate fuel and maintenance of engines. As discussed in section D2. (v) above, appropriate equipment is sued and engines are serviced in order to avoid pollution such as fumes, vibrations and noise, etc. (ii) Minimise leakage from oil, petrol. As discussed in section D2. (v) above, appropriate equipment is sued and engines are serviced in order to avoid oil leak With the use of adapted equipment, there would be no residual impact. D13. Predators Operation of a fish farm which attracts unwanted predators such as sharks, barracudas, tuna and adversely impact the ecosystem Unwanted predators such as sharks and adversely impact the ecosystem and safety of sea users. From the external audits carried, it should be noted that over 10 years of operations, predator attacks have occurred some 60 times, half of which were by sharks. Disturbance of/damages to the ecologically sensitive area would have a moderate adverse impact on the ecosystem and safety of sea users; impact would disappear as soon as activities would stop 7-16

17 (i) Select sites with low numbers of predators. As discussed in section 6.3 hereof, the biodiversity in the Anse Jonchee Channel is not very rich; no predators have been noticed during the baseline dive surveys for the three new fish farms. On the over hand around the existing fish farms the biodiversity is high as these act as artificial reefs. Predators such as sharks are attracted by dead fish; other predator attack life fish. (ii) Implement management systems to reduce impacts (e.g. guards, double nets). As discussed in section hereof, anti-shark nets are installed below the fish cage net. Twice daily inspections and removal of any dead fish are programmed to reduce the risk of attracting sharks. With a siting of the farm away from predator zones and by adopting good site practices, the residual impact would be negligible to minor adverse. 7.3 SUMMARY OF POTENTIAL IMPACTS AND MITIGATION STRATEGIES Table 7-3 below summarizes the potential impacts identified and mitigation strategies adopted for the present project as defined in the Matrices of aquaculture activities, impacts and mitigation measures No3 for Coastal cage or pen culture appended to the Composite Guidelines for the Environmental Assessment of Coastal Aquaculture Development. Actions affecting environmental resources and values Potential impacts environmental Potential mitigation strategies for negative environmental impacts A. Site selection A. Appropriate site selection 1. Conflicts with other site users and interference in livelihoods of local communities 2. Selection of ecologically sensitive site 3. Hazards to aquaculture from nearby pollution sources (e.g. agriculture, industry) 4. Typhoons, flooding, hurricanes On and off-site damage to natural resources and social conflicts Potential loss of biodiversity. Water pollution from industry, agriculture affecting sustainability of aquaculture Damage to physical facilities and loss of fish stock. 5. Water quality Water quality deterioration caused by self-pollution from aquaculture effluent 6. Fish seed Potential impacts on biodiversity caused by over-harvesting of wild stocks. Appropriate regional land use planning Consultation process Participation of local people in aquaculture projects Careful site selection and integration of aquaculture into integrated coastal management Management plan which identifies ecologically sensitive sites Maintain buffer areas around farm Prior assessments of impacts Careful site selection Pressure from aquaculturists to reduce pollution from other sectors Careful site selection. Pond design taking account of extreme climatic events (e.g. cyclones). Careful site selection in relation to carrying capacity. Management practices and effluent controls Strategic planning to keep number of farms within carrying capacity Careful assessment of requirements prior to farm development Development of hatcheries instead of harvesting practices for wild stocks 7-17

18 Actions affecting environmental resources and values Potential impacts environmental Lack of sustainability of aquaculture due to insufficient seed supply. Introduction of exotic species may impact on indigenous species 7. Disease problems Potential impacts caused by presence of serious pathogens/ disease problems B. Farm design B. Poor design can lead to a variety of environmental problems 1. Attention to problems A As above. (1) to A(7 ) above Potential mitigation strategies for negative environmental impacts Prior assessment of impacts from introductions of new species. Disease surveys of existing farms to assess risk. Introduction of risk management strategies to reduce risk. B. Careful/appropriate design As above. 2. Socio-economic impacts Social inequities leading to social unrest 3. Interference with navigation, traditional users Impacts on existing uses Participation of local people in aquaculture projects. Understand socio-economic conditions prior to project, and ensure developments do not negatively impact local people Site farms in ways which do not impact traditional uses. Maintain buffer areas between farms and other uses 4. Aesthetics Aesthetic impacts Development of buffer zones Low profile cages, minimise use of unsightly structures. C. Farm construction Poor construction practices can lead to various environmental problems C. Careful/appropriate & proven construction practices adapted to tropical conditions 1. Siting Impacts on benthos during construction and disturbance of wildlife D. Farm operation and management 1. Solid waste disposal Impacts on benthos, wildlife 2. Waste water/effluent discharge Impacts on local water quality and sediments 5. Use of chemicals Potential impacts on workers health Water pollution Impacts on aquaculture product quality Maintain buffer areas. Ensure site disturbance is limited to immediate construction area Non-organic solid waste materials should be disposed of safely. Efficient feeding practices (optimise use of fish food). Site farms in areas with adequate tidal flow. Disposal of dead/diseased animals in sanitary manner on shore Minimise leaks from water pumps, boat engines, generators etc No use of chemicals Reduce disease problems through preventative management, not chemicals. 7-18

19 Actions affecting Potential environmental environmental resources and values impacts 6. Seed collection/supply Loss of biodiversity caused by harvesting of wild stocks. Impacts on wild stocks through escapes of farmed stocks. 9. Disease outbreaks and disposal of mortalities 10. Operational failures caused by storms 11. Boats, infrastructure support Economic impacts on stock, product quality and native populations. Sudden impacts caused by loss of fish stock. Water pollution from boat engines 13. Predators and wildlife Wildlife disturbance Predators causing damage to fish stocks. Table 7-3: Summary of Potential Impacts and Mitigation Strategies Potential mitigation strategies for negative environmental impacts Development of hatcheries. Siting in ways that minimise storm damage. Prior assessments of introductions of exotics. Adherence to ICES/FAO Codes of Practice. Implement preventative health management strategies. Sanitary disposal of mortalities. Quarantine procedures/health certification for introduced fish eggs Accommodating operational failures in management procedures. Routine checking of nets, moorings. Farm structures designed to withstand storm events. Use of appropriate fuel and maintenance of engines. Minimise leakage from oil, petrol Select sites with low numbers of predators. Implement management systems to reduce impacts (e.g. guards, double nets) 7-19