RANOBE MINE PROJECT, SOUTHWEST REGION, MADAGASCAR VOLUME 10: ICHTHYOLOGY AND AQUATIC HABITAT IMPACT ASSESSMENT

Transcription

1 RANOBE MINE PROJECT, SOUTHWEST REGION, MADAGASCAR VOLUME 10: ICHTHYOLOGY AND AQUATIC HABITAT IMPACT ASSESSMENT Prepared for: Prepared by: World Titanium Resources Ltd Anton Bok 15 Lovegrove Close, Mount Claremont Western Australia 6010 January 2013

2 TABLE OF CONTENTS 1. INTRODUCTION Objectives Terms of Reference (ToR) Assumptions and Limitations DESCRIPTION OF THE STUDY AREA Spatial Extent of the Study Area The Fiherenana River Ichthyofauna in the Study Area APPROACH AND METHODS Field Surveys Sampling Sites Fish Capture Methods RESULTS and DISCUSSION Catch Data Fish and Crustacean Species Conservation Importance Migratory Species Subsistence Fisheries Fishing gear and species utilized POTENTIAL IMPACTS RECOMMENDED MITIGATION MEASURES Nature of Potential Impacts Assessment of Potential Impacts Issue 1: Water Quality Issue 2: Water Quantity Issue 3: Barriers to migration CONCLUSIONS AND RECOMMENDATIONS REFERENCES APPENDIX A APPENDIX B LIST OF TABLES Table 3-1. The six fish sampling sites in the Fiherenana R. and the two sites on Lake Ranobe Table 4-1. Annotated checklist of fish & crustacea caught at the eight sampling sites within the Study Area. (Sites marked with asterix * = fish species reported present by local fishers) LIST OF PLATES Plate 2-2: Strong surface flow in the Fiherenana River approx. 28 km upstream of the road bridge on 13/06/ Plate 2-1: The dry Fiherenana River bed at the road bridge on 14/06/ Plate 2-4:. Local women washing clothes in fresh water in the Fiherenana R. about 3 m downstream of the road bridge on 14/06/ Plate 2-3: Excavations in Fiherenana River bed about 2 km upstream of the road bridge on 13/ Plate 3-1. The eight fish sampling sites in the Toliara Sands Study Area Plate 3-2: Google Earth image showing locality of fishing sties F1 and F Plate 3-3: Google Earth image showing location of sites F4 and F i

3 Plate 4-2: The seine net catch of crabs (Varuna litterata) and tilapia fish at Site F Plate 4-1: Fishers (young girls) seine netting at Site F2, as isolated flood channel of the Fiherenana R Plate 4-4: Dip net used by young girl at Site F4 in Fiherenana River Plate 4-3: Fish Trap used at Site F5 in the Andranofoty tributary of the Fiherenana River ii

4 1. INTRODUCTION 1.1 Objectives This study on the ichthyofauna and aquatic habitats potentially impacted upon by the proposed - Ranobe in south-western Madagascar, forms part of the revised Environmental and Social Impact Assessment study. A detailed description of the proposed mining project and the history and contents of the various environmental studies already undertaken, are given in previous reports and will not be repeated here. The proposed activities associated with the mining operation that could potentially impact on aquatic habitats and aquatic biota such as fish, are briefly outlined below. The various options under consideration in the revised project plan includes the potential location of the Heavy Mineral Concentrate (HMC) transfer station near the Fiherenana River and the possible location of the Mineral Separation Plant (MSP) near the Port at Toliara Town, instead of at the mine site. The net water requirement by the MSP will be about 10m 3 /hr which will be obtained from the Fiherenana River alluvial aquifer. When considering the above options, it will thus be necessary to assess possible impacts of the project on the Fiherenana River in terms of: a) Impact of lowering the water table in the alluvial aquifer of the Fiherenana River, b) potential impacts of increased sedimentation and pollution on aquatic habitats and biota dependent on the Fiherenana River. c) The potential impacts in terms of blocking natural migrations of aquatic biota, due to the construction of either a pipeline and/or a new bridge (or causeway) over the Feherenana River in order to transfer the HMC (or separated heavy minerals) to the Port of Toliara. Groundwater abstraction for mining activities in the Ranobe Permit Area could theoretically impact on the Ranobe Lake water levels, although studies already undertaken indicate this is highly unlikely. A brief look at the aquatic biota in Ranobe Lake in terms of biodiversity and utilization by adjacent communities was therefore considered warranted. 1.2 Terms of Reference (ToR) The specific ToR for the aquatic faunal study includes the following: Determination of the fish species present in the aquatic habitats potentially impacted upon by the proposed Toliara Sands Mining operation, namely the Fiherenana River and Lake Ranobe. Determination of the conservation importance and socio-economic value of these fish species in terms of utilization in the local fisheries. Assessing the migratory behaviour of fish species in the Fiherenana River, particularly in terms of the importance of maintaining connectivity between inland freshwater and estuarine/marine habitats. Assessing the potential impacts resulting from the proposed mining development and associated infrastructure and recommending appropriate and feasible mitigation measures that can be adopted to reduce negative impacts or enhance positive impacts for each phase of the project. 1

5 1.3 Assumptions and Limitations The absence of access roads in the upper reaches of the Fiherenana River, together with time constraints, restricted fish sampling to a limited variety of habitats and potential sampling sites. Thus additional fish surveys at more sites may have revealed additional fish species. This single fish survey was undertaken during the winter dry season, when there are naturally low flows in the Fiherenana River. The dry winter months may not be the optimum period to sample migratory fish species for the following reasons: a) There is normally no surface flow in the river channel for long distances on the coastal plain in winter, even at times when there is strong surface flow in the upper reaches of the Fiherenana River (see Chapter 2). However, in the dry season subsurface flow continues to take place in downstream reaches in the sandy river-bed sediments, i.e. in the hyporheos. Thus, in the dry season, no fish movements between the estuarine/marine and the inland freshwater riverine habitats is normally possible, and b) Migratory activity of catadromous fish species (i.e. fish that breed in estuarine or marine habitats and then migrate upriver to freshwater habitats) is often seasonal and restricted to the wet summer months when there is normally strong surface flow connecting inland and coastal river reaches. 2

6 2. DESCRIPTION OF THE STUDY AREA 2.1 Spatial Extent of the Study Area Rivers are longitudinal ecosystems and many fish species undertake extensive migrations both up and downstream at various stages during their life cycles. Previous fish surveys in the larger rivers of western coastal Madagascar have revealed the presence of numerous intrusive marine species (Kiener 1965 vide Sparks & Stiassny 2003). These include a number of catadromous fish species such as at least 3 mullet species (Mugilidae), as well as three species of Anguillid eels. These species breed at sea and then migrate as young fry (or elvers in the case of eels) high up coastal rivers in both Africa and Madagascar. No historical data on the fish distribution within the Fiherenana River system were available to the author. In reference to the Toliara Sands mining project, a poorly designed structure (e.g. causeway or pipeline) across the lower Fiherenana River could potentially disrupt continuity between coastal and inland habitats. Fish sampling for this project was therefore extended some 84 km upstream of the mouth to the inland reaches of the Fiherenana River in order to determine the extent of the penetration of migratory marine-spawning species. 2.2 The Fiherenana River The Fiherenana River rises to the mountains to north-east of Toliara near the town of Ambinany and flows some 175 km before discharging into the sea via a wide sandy delta just north of Toliara Port. Like most rivers within the sub-arid region of south-west Madagascar, there is often no surface flow in the lower reaches of the Fiherenana river channel during the dry winter months (April to November). During the field visit in mid-june 2012, there was no surface flow in the river at the road bridge (Plate 2-1), although shallow surface flow was visible at this time approximately 17km upstream, with strong surface flows seen some 28km upstream (Plate 2-2). Plate 2-1: The dry Fiherenana River bed at the road bridge on 14/06/2012 Plate 2-2: Strong surface flow in the Fiherenana River approx. 28 km upstream of the road bridge on 13/06/2012 It is thus apparent that during the dry season substantial sub-surface (or hyporheic) flow through the course, sandy bed material takes place in the lower Fiherenana River. The water table in the lower reaches is near the surface at this time, which allows local people to obtain water from the dry river bed by digging shallow excavations (Plate 2-3). Near the head of the Fiherenana estuary on the right (north) river bank on 14/06/2012, surface water was again visible and was flowing into the estuary (Plate 2-4). 3

7 Plate 2-3: Excavations in Fiherenana River bed about 2 km upstream of the road bridge on 13/ Ichthyofauna in the Study Area Plate 2-4: Local women washing clothes in fresh water in the Fiherenana R. about 3 km down-stream of the road bridge on 14/06/2012 In comparison to Madagascar s terrestrial vertebrates (particularly the lemurs) which have been studied in great detail, very little recent information is available on the distribution of indigenous freshwater fishes (Sparks & Stiassny 2003). No historical data on the freshwater fishes found in the Fiherenana River itself were available for this investigation. In a recent review of all the available information by Sparks and Stiassy (2003), a total of 49 freshwater fish species have been recorded in the Western basins of Madagascar, which includes the Fiherenana and rivers such as the larger Onilahi River to the south of Toliara and the Manombo River to the north of the Ranobe Permit Area. These 49 fish species include a high proportion of so-called intrusive marine species which are commonly found well inland and are mainly marine-spawning species that spend a significant portion of their life in freshwater habitats. As mentioned earlier, this includes widespread catadromous marinespawning species such as mullet (Mugillidae) and eels (Anguillidae), which often penetrate high up suitable rivers in large numbers. These migratory species contribute to both the ecological functioning of these rivers as well as form an important component of local subsistence fisheries. In addition, at least 3 species of Macrobrachium prawns and the catadromous swimming crab Varuna litterata that are found in this region have a similar life history, with the adults breeding in the sea or estuaries and the young larvae (megalopae) undergoing extensive migrations upriver (Plates 2-5 and 2-6). 4

8 Migrating crab megalopae Plate 2-5: Varuna litterata larva (megalopa) at Site F1 (14/06/2012) Plate 2-6: V. litterata megalopae (larvae) migrating upstream into freshwater reaches from the Fiherenana estuary (14/06/2012) 5

9 3. APPROACH AND METHODS 3.1 Field Surveys Sampling Sites A total of six sites were sampled in the Fiherenana River, with site F1 located at the tidal limit of the estuary and the most upstream site (F6) located some 84 km upstream from the mouth. In addition, both the north and south basin of Lake Ranobe was sampled. The co-ordinates and a brief description of these eight sites are given Table 3-1. Table 3-1: The six fish sampling sites in the Fiherenana R. and the two sites on Lake Ranobe Site River/water body Co-ordinates Description/comments No. South East F1 Fiherenana R At the tidal limit of the northern channel of the Fiherenana estuary F2 Fiherenana R Floodplain channel on right (northern) bank connected to main channel of Fiherenana R. only during high flows F3 Fiherenana R Main channel of Fiherenana R. at Ambolikira Village F4 F5 F6 Lake Andranofoty stream Andranoboaboaky trib. of Fiherenana Manandany trib of Fiherenana R Andranofoty tributary of Fiherenana R, 400m downstream of Andranofoty Lake Andranoboaboaky stream fed by spring, which flows into Andraofoty tributary at junction with Fiherenana R Manandany tributary at junction with of Fiherenana River RL1 Ranobe Lake Northern basin of Lake Ranobe RL2 Ranobe Lake Southern basin of Lake Ranobe A Google Earth image indicating the locality of the various sites within the Study Area is given in Plate 3-1 with more detail given of sites F1 and F2 in Plate 3-2 and Sites F4 and F5 in Plate 3-3. Further details of these 8 fish sampling sites, including photographs, habitat descriptions, fish catches made and water quality recorded (using an Eutec ph and conductivity meter), are given in Appendix A Fish Capture Methods Fish were captured using a 12V DC back-pack electro-fisher (Samus 725G), a 6m minnow seine net (4mm mesh) and a variety of dip nets. Details of the fishing gear used, the fishing effort and the fish captured at each site, as well as description of the habitats sampled, are given in Appendix 1. A representative sample of the captured fish were preserved in 10% formalin for further identification and photographing. All preserved fish samples were labeled and given to Mr. Roberto Jean Luc Komento of the INSTITUT HALIEUTIQUE ET DES SCIENCES MARINES of the UNIVERSITE DE TOLIARA, who kindly assisted with the field work, for record-keeping purposes and possible further study. 6

10 Manandany Tributary Fiherenana River Plate 3-1: The eight fish sampling sites in the Toliara Sands Study Area. 7

11 Fiherenana River Plate 3-2: Google Earth image showing locality of fishing sties F1 and F2 Andranoboaboaky Tributary Andranofoty Tributary Lower Andanofoty Lake Fiherenana River Plate 3-3: Google Earth image showing location of sites F4 and F5 8

12 4. RESULTS AND DISCUSSION 4.1 Catch Data Fish and Crustacean Species The fish catch data obtained during the field surveys were supplemented by questioning fishers that were encountered at the sites, as well as the local villagers living adjacent to the Fiherenana River and Ranobe Lake, regarding their fish catches. Colour plates of possible fish (and eel) species from the fish book Complete Guide to the Freshwater Fishes of Southern Africa (Skelton 2003) were used to assist in this process. An annotated list of the fish captured and/or present at the eight sampling sites according to local fishers, is given in Table 4-1. A total of eleven fish species and three crustacean species (crab, prawn and freshwater crayfish) were caught in freshwater habitats in the Fiherenana River and three fish species in Lake Ranobe (Table 4-1). Photographs of the fish species caught are given in Appendix B. Four of the total of twelve fish species found are alien to Madagascar and have been introduced by man. The relatively low number of fish species captured may be a reflection of the low sampling intensity as well as seasonal factors, i.e. sampling in the winter months. More comprehensive sampling in a greater variety of habitats in the wet summer months may reveal more species in the Fiherenana River. However, the survey did confirm the presence of marine-spawning fish species upstream in the Fiherenana River, the main objective of this study Conservation Importance None of the fish or crustracean species sampled are considered under threat in terms of the IUCN Red List of Threatened Species (IUCN 2012) Migratory Species All of the seven indigenous fish found in the Fiherenana River are thought migrate between freshwater and estuarine or marine habitats at some stage of their life cycle (Whitfield 1998; Skelton 2003, Heemstra & Heemstra 2004). Typically spawning takes place in salt water, after which the young fish migrate via the estuary high up into the freshwater zones of the Fiherenana River before returning to salt water to breed. However, some of these species such as the freshwater goby Awaous aeneofuscus, may be able to breed in both fresh and brackish water habitats and further research on this issue is required. The two indigenous crustacean species are also known to breed in marine or estuarine habitats and migrate upstream to freshwater habitats - i.e. have a catadromous life-style. 4.2 Subsistence Fisheries Fishing gear and species utilized Although the field survey was undertaken in winter during low river flows and cooler water temperatures when there is reduced fishing activity, useful information on the local subsistence fisheries and fishing gear used, was obtained. All communities living adjacent to the Fiherenana River and on the shores of Lake Ranobe appear to utilize the fish resources of these water bodies, using a variety of fishing gear 9

13 including seine nets, gill nets, fish traps and a variety of dip nets as shown in plates 4-1 to 4-4. During the interviews with fishers it emerged that virtually all species of fish and crustaceans that were captured were eaten. Table 4-1: Annotated checklist of fish & crustacea caught at the eight sampling sites within the Study Area. (Sites marked with asterix * = fish species reported present by local fishers) Fish & Crustacean Species Scientific Name Common Name MARINE/ESTUARNE-SPAWNING FISH SPECIES: Anguilla marmorata Madagascar mottled eel Sites Present F2*,F4*, F5*, F6 Anguilla mossambica Longfin eel F2*, F4*, F5*, F6* Mugilidae Mullet (at least 3 species) F1, F2*,F4*, F5* Comments Breeds at sea. An Adult caught at F6 over 80 km from river mouth, can negotiate water falls. Important food source. Breeds at sea. Known to migrate to headwaters of coastal rivers, can negotiate water-falls. Important food source. Breeds at sea. At least 3 species known to migrate up coastal rivers, but blocked by water-falls. Important food fish. Kuhlia rupestris Rock flagtail F4 Indigenous species, adults thought to move downstream to spawn in sea, but further studies on breeding requirements required. Good food fish. Eleotris fusca Dusky sleeper F4*; F5 Found in coastal lagoon, estuaries and in lower reaches of coastal rivers. Thought to breed in salt water. Food source. Awaous aeneofuscus Freshwater goby F6 Found in estuaries and freshwater, may breed in both saline and freshwater. Good food fish. Terapon jabua thornfish F1 Breeds at sea and does enter lower freshwater reaches of coastal rivers. Not considered important food source. MARINE-SPAWNING CRUSTACEAN SPECIES: Varuna litterata Macrobrachium sp. catadromous swimming crab Freshwater prawns F1, F2, F4*, F5* F1, F2*, F4*, F5* NON MIGRATORY FRESHWATER FISH SPECIES: Breed in marine habitats, small larvae migrate high up coastal rivers. Used as food-source. Early larval development in marine or estuarine habitats, migrates high up coastal rivers. Food source. Gobiidae Goby (unknown) F6 Species not yet identified. Small size may limit food value Oreochromis mossambicus Mozambique tilapia F2, F4, F5*, F6, Alien species introduced from Africa by man, important food fish Oreochromis niloticus Nile tilapia F2*, F4*, F5, F6, RL1* RL2 Alien species introduced from Africa by man. Cyprinus carpio Common carp RL2 Alien species introduced by man Gambusia holbrooki). Eastern F2, F3, F5, Alien fish from North America, too small for mosquitofish RL1, FL2 food source FRESHWATER CRUSTRACEAN SPECIES Procambaras sp. Marbled crayfish F6 Alien freshwater crayfish. Possible food source. Appeared 2 years ago in area. 10

14 Plate 4-1: Fishers (young girls) seine netting at Site F2, as isolated flood channel of the Fiherenana R Plate 4-2: The seine net catch of crabs (Varuna litterata) and tilapia fish at Site F2 Plate 4-3: Fish Trap used at Site F5 in the Andranofoty tributary of the Fiherenana River Plate 4-4: Dip net used by young girl at Site F4 in Fiherenana River In terms of the migratory species present, important food fishes utilized by the local fishing communities adjacent to the Fiherenana River included mullet, eels and gobies. The nature of this study did not allow the relative importance of locally captured fish, either as a food source or income (from local sales), to be determined. However, it is apparent that the locally captured fish and crustaceans form an important source of protein in the diet of these rural people. 11

15 5. POTENTIAL IMPACTS RECOMMENDED MITIGATION MEASURES 5.1 Nature of Potential Impacts The final choice regarding the various project options such as the location of the Heavy Mineral Concentrate (HMC) transfer station near the Fiherenana River and the possible location of the Mineral Separation Plant (MSP) south of the Fiherenana River at the Port of Toliara (instead of at the mine) has yet to be taken. This study will thus not attempt to assess details of the potential impacts associated with the location of the above infrastructure on aquatic biota. However, the sensitivity of the aquatic habitats potentially affected by the project will be assessed and the generic impacts associated with all the various options and general principles regarding mitigation measures to be implemented, will be proposed. The main potential impacts include: Issue 1: Water Quality Increased sedimentation & elevated turbidity in the Fiherenana River. Heavy mineral contamination Hazardous material contamination Issue 2: Water Quantity Lowering of the water table in the Fiherenana River in the dry season Lowering the regional water table and Lake Ranobe water levels. Issue 3: Barriers to migration Instream structures blocking natural migrations in Fiherenana R. (e.g. causeway, bridge). 5.2 Assessment of Potential Impacts This section attempts to describe and assess the significance of the individual potential impacts and to propose reasonable mitigation measures. A description of the rating criteria and qualitative assessments used to describe the likelihood, extent (spatial scale), duration, intensity and confidence attached to the prediction, as well as the environmental significance scale, is given in the main EIA Report and is similar to the protocol used in all the specialist studies for this project Issue 1: Water Quality Impact 1.1: downstream Increased sedimentation and elevated turbidity in the Fiherenana and Cause and comment Elevated turbidity in rivers, particularly due to mobilization of fine sediment, can have a significant and even lethal impact on aquatic biota, including fish. These impacts include reduced primary production, smothering of benthic organisms and fish eggs, clogging and abrading of fish gills (leading to disease and death) and reduced feeding efficiency of visual predators. In their comprehensive overview of current and future threats to Malagasy ichthyofauna, Sparks and Stiassny (2003) consider sedimentation and increased turbidity as one of the major negative impacts on native fish populations. The real threat to the estuary, the coral reefs and other marine life at the coast due to increased sediment discharge from rivers such as the Fiherenana in this region of Madagascar, is described elsewhere in EIA Report and will not be dealt with here. 12

16 Construction Vegetation cover may be destroyed without taking anti-erosion measures during clearing of top-soil for construction of infrastructure adjacent to the river. Together with run-off from disturbed riparian areas and new access roads over the banks to gain access for vehicles to the river channel, these actions may increase soil erosion and hence sediment-laden run-off into the river. During excavations in the river bed to construct the causeway, the foundations for the bridge piers or for pipeline/conveyor supports, fine anoxic sediments could be mobilized and washed downstream to the estuary and Toliara coastal lagoon. Mitigation Strict measures to be taken to prevent erosion and sediment-laden runoff water from entering the river. Excavations into the river bed should take place in the dry season and mobilization of fine sediments limited by isolating the working areas. The EMP document should be consulted for detailed mitigation measures in this regard. Significance Statement All project phases WITHOUT MITIGATION WITH MITIGATION Temporal scale Medium term Spatial scale Certainty Severity Significance Severity Significance Regional Probable Severe HIGH - Slight Low - Impact 1.2: Heavy Mineral Concentrate (HMC) contamination Cause and comment Operation Accidental spillages of the HMC slurry (due to pipe leakages, haulage accidents, etc) near or in the river or spillages of the separated heavy minerals (ilmenite, rutile/zircon) during transportation over the Fiherenana River could contaminate the surface water in the lower Fiherenana River. However, the environmental impact of the HMC slurry, made up of minerals occurring naturally in this region, is considered similar to that of any fine sediments from the catchment. In addition, the relatively small volumes of the potential spillage of HMC means that any possible impacts should be low. Mitigation Strict safeguards (Industry best practice) to be implemented to prevent accidental spillages from occurring, Rapid response by suitably trained staff to accidental spills and effective clean-up materials and equipment to be kept readily available to reduce the impacts of any spills. 13

17 Significance Statement Operational phase WITHOUT MITIGATION WITH MITIGATION Temporal scale Spatial scale Certainty Severity Significance Severity Significance Medium term Study Area plus downstream May occur Slight Low- Slight Low- Impact 1.3: Hazardous Material Contamination Cause and comment Construction During the construction of the infrastructure (causeway, bridge, pipeline, conveyor) within the Fiherenana River channel, a range of hazardous materials (hydrocarbons, cement, paints, cleaning/shutter fluids, etc.) associated with the construction activities and machinery used, could pollute the both surface and sub-surface water in the river. Mitigation Strict control of the use of hazardous materials during construction Prevention of hydrocarbon spills from machinery and vehicles working near or in the river All wet cement (before curing complete) to be isolated from both ground and surface water in the river The EMP document should be consulted for detailed mitigation measures and method statements to prevent contamination during the construction phase of the project. Significance Statement Construction phase WITHOUT MITIGATION WITH MITIGATION Temporal scale Spatial scale Certainty Severity Significance Severity Significance Short term Study Area plus downstream Probable Severe Moderate - Slight Low - 14

18 5.2.2 Issue 2: Water Quantity Impact 2.1: Lowering of the water table in the Fiherenana River in the dry season Cause and comment Operation Although highly unlikely, the abstraction of ground water from the alluvial aquifer associated with the Fiherenana River for the MSP (if located near Toliara) could theoretically lower the water table in the adjacent locality in the dry season when there is no surface flow in the river reach near the existing road bridge. This potential impact is only applicable if the slurry transfer station is built. Groundwater abstraction in this locality could impact negatively on both local people reliant on domestic water obtained by excavating shallow pits in this locality, as well as on the Fiherenana estuary by reducing the freshwater inflow. Mitigation Ground water studies should be conducted to determine sustainable groundwater abstraction rates to satisfy the MSP without lowering the water table and the boreholes should be located and utilized so as to minimise any impact on the water table in the Fiherenana River channel in the dry season. Significance Statement Construction phase WITHOUT MITIGATION WITH MITIGATION Temporal scale Spatial scale Certainty Severity Significance Severity Significance Long term Study Area plus downstream May occur Moderate Moderate Low Low Impact 2.2: Lowering of the regional water table in the vicinity of Ranobe Lake Cause and comment Operation Although considered highly unlikely, excessive abstraction of ground water for mining operations in the Ranobe Permit Area adjacent to Lake Ranobe could theoretically impact on the regional water table and thus the Lake water level. This could impact negatively on local people reliant on the lake for fresh water (agricultural and domestic purposes) and for food (fish) and construction materials (reeds & grasses), as well as on the biodiversity supported by Lake Ranobe. However, as most of the water used for mining operations is recycled and any excess will find its way back into the groundwater system, only a minor impact,(if any) on the regional water table is anticipated. Mitigation Previous ground water studies (see main report) have determined sustainable groundwater abstraction rates to satisfy the mine s requirements without over-exploiting the groundwater 15

19 resource at the mine site and surrounds. Therefore all production boreholes developed should be located and operated according to guidelines set out in these groundwater studies so as to prevent any impact on the regional water table that could influence water levels in Lake Ranobe. Significance statement Construction phase WITHOUT MITIGATION WITH MITIGATION Temporal scale Spatial scale Certainty Severity Significance Severity Significance Long term Study Area plus downstream Unlikely Moderate Moderate Low Low Issue 3: Barriers to migration Impact 3.1: Instream structures blocking natural migrations in Fiherenana R. Cause and comment If poorly designed, the construction of any instream structure across the Fiherenana River channel (e.g. causeway, bridge) could interfere with or even totally block the natural upstream migrations of numerous fish and invertebrate species. As marine-breeding species that migrate high upstream as relatively weak-swimming young fish (or larvae) form a very important component of the fish and crustaceans found in the Fiherenana River, both the ecology of the system, as well as the artisanal fisheries could be negatively affected. Mitigation measures All instream structures built across the Fiherenana River channel should be designed to allow the free passage of migratory biota and maintain the continuity between marine/estuarine and freshwater habitats. As a guideline, the natural longitudinal profile of the riverbed both upstream and downstream of the structure should be maintained, in order to allow the natural movement of the mobile bed material and to ensure that water velocities are not increased downstream of or within the structure. Significance Statement Operational phase WITHOUT MITIGATION WITH MITIGATION Temporal scale Spatial scale Certainty Severity Significance Severity Significance Long term Study Area plus upstream reaches May Occur Very Severe High- Slight Moderate - 16

20 6. CONCLUSIONS AND RECOMMENDATIONS This study found that although the Fiherenana River is a seasonal system with no surface flow during the dry winter months in the coastal reaches, it does support valuable migratory fish populations which form an important component of the local subsistence fisheries. This pattern of seasonal desiccation common to rivers in south-western Madagascar, is considered responsible for the relatively low numbers of primary freshwater fish species present in these systems, which are dominated by migratory marine spawning species (Sparks and Stiassny 2003). The main potential impacts of the proposed Toliara Sands Mining Project on aquatic habitats and biota, are related to the proposed location of components of the mine near the Fiherenana River and the new infrastructure (causeway, bridge) required to transport mining products over the river channel to Toliara Port. These potential impacts include increased sedimentation and pollution of the lower Fiherenana River and the blocking of upstream migrations of marine-spawning fish, eels and crustaceans (prawns and crabs). Without any mitigation, these impacts were assessed as potentially being of high significance. However, it was found that the various identified impacts could be easily reduced to low significance if reasonable and appropriate mitigation measures are implemented during both the construction and operational phases of the proposed mining project. 17

21 7. REFERENCES Heemstra, P. & Heemstra, E. (2004). Coastal Fishes of Southern Africa. NISC & SAIAB, Grahamstown, South Africa. 488 pp. IUCN (2012). The Red List of Threatened Species. Version Skelton, P. H. (2001). A complete guide to the Freshwater Fishes of Southern Africa. Struik Publishers, Cape Town, South Africa. 395pp. Sparks, J.S & Stiassny, M.L.J. (2003). Introduction to the Freshwater Fishes, In: The Natural History of Madagascar. Eds: Goodman, S.M. & Benstead, J.P. University of Chicago Press, Chicago. Whitfield, A.K. (1998). Biology and Ecology of Fishes in Southern African Estuaries. Ichthylolgical Monographs of the J.L.B. Smith Institute of Ichthyology, No. 2, 223 pp. 18

22 8. APPENDIX A Details of fish sampling sites and catches made in the Fiherenana River and Lake Ranobe 19

23 SITE F1 Co-ordinates: S; E Site Locality/Name: Fiherenana estuary freshwater interface River System: Fiherenana River: Fiherenana Tributary: main channel Dates: 14/06/2012 Time: 09h00 to 11h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Sandy shallow pools at the head of the estuary Dip-net 6m seine net 10 min in shallow water in riffle in main channel 5 x15m pulls in shallow sandy pools Fish: Mugildae (Mugil sp?.) fry Terapon jabua Crustacea Macrobrachium sp. Varuna litterata (megalopae) B. Description of localities sampled and methods used Site Description Sampling site located at head of the northern arm of the estuary against the northern bank, at the estuarine-freshwater interface. Stream-flow Low river flow at time of sampling, shallow runs and pools upstream of estuary with water < 20cm deep.. Water quality Riverine habitat: Water clear with light-brown stain, conductivity = 300 µs/cm; temperature = C, ph = 8.5. Estuarine habitat: Water clear, conductivity = 11.6 ms/cm, temp. = C, ph = 8.5 No evidence of pollution. Habitats Sampled Sampled both in shallow (< 20cm deep) freshwater pools (and in large, shallow (< 40cm deep) pool at head of estuary. C. Remarks Local knowledge: No information obtained regarding fish catches obtained. A B Site F1: Fiherehana River freshwater-estuarine interface looking downstream (A) and upstream (B). 20

24 SITE F2 Co-ordinates: S; E Altitude: 23m Site Locality/Name: Andio Village floodplain channel on north bank, 7.7 km from Fiherenana River mouth River System: Fiherenana River: Fiherenana Dates: 14/06/2012 Time: 12h00 to 14h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Sandy shallow pools at the head of the estuary Large (30m) seine net used by local fishers 50 m pull in main channel Fish: Oreohromus mossambicus Gambusia sp. (holbrooki?) Crustacea Varuna litterata (adults) B. Description of localities sampled and methods used Site Description Near the village of Andio, a secondary floodplain channel of Fiherenana River connected to main channel during high flows, approximately 30 m wide and < 40cm deep, soft muddy substrate. Stream-flow No flow and low water level in isolated river channel at time of sampling.. Water quality Water muddy brown, no water quality data available Habitats Sampled Local fishers sampled in shallow (< 40cm deep) water in secondary river channel C. Remarks Local knowledge: According to Local fishers, mullet (Mugilidae), eels (Anguillidae) and prawns (Macrobrachium) captured in this locality and consumed by local villagers. A B Site F2: looking downstream (A) and upstream (B) at local fishers using a seine net. 21

25 SITE F3 Co-ordinates: S; E Altitude: 49m Site Locality/Name: Fiherenana River at Ambolikira Village River System: Fiherenana River: Main channel Tributary: Dates: 13/06/2012 Time: 10h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow run in main channel 6m seine net 2 x 10 m pulls in shallow run in main channel Gambusia sp. (holbrooki?) B. Description of localities sampled and methods used Site Description Shallow flow over sand banks, no deep pools or suitable fish cover or habitat present. Stream-flow and Water Quality Low river flow at time of sampling, water with light-brown stain and slightly turbid, conductivity = 390 µs/cm; temperature = C, ph = 8.3. Habitats Sampled Sampled with 6m seine net in shallow water (depth cm, width 3-4 m) running over sand. C. Remarks No suitable habitat of fish due to shallow water and lack of cover. No information from local villages re utilization of fish in the river and no evidence of fishing gear seen in village. A B Ambolikira Village Site F3: looking downstream (A) and south across the shallow river channel (B). 22

26 SITE F4 Co-ordinates: S; E Altitude: 49m Site Locality/Name: Lake Andranofoty Stream, River System: Fiherenana River: Tributary: Andranofoty stream Dates: 13/06/2012 Time: 12h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow pool 6m seine net 3 x 10 m pulls in shallow run in main channel Kuhlia rupestris B. Description of localities sampled and methods used Site Description Shallow channel over sand and pebbles with dense marginal and floating vegetation Stream-flow and Water Quality Low river flow at time of sampling, water clear, conductivity = 420 µs/cm; temperature = C, ph = 7.5. Habitats Sampled Sampled with 6m seine net in shallow water (depth cm, width 5 m) flowing over sand and cobbles C. Remarks Suitable cover and habitat for fish in marginal and floating vegetation, but difficult netting conditions due to dense vegetation. Local villages use traps and seine nets to catch fish including catadromous (i.e. species that breed in the sea) fish such as mullet (Mugilidae) and eels (Anguillidae) as well as gobies. Site F4: Typical river sites sampled for rock flagtail (Kuhlia rupestris) in the Andranofoty stream. 23

27 SITE F5 Co-ordinates: S; E Altitude: 78m Site Locality/Name: Andranoboaboaky Stream, River System: Fiherenana River: Tributary: Andranoboaboaky Dates: 13/06/2012 Time: 14h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow pool with water hyacynth 6m seine net 2 x 10 m pulls in pool Fish: Anguillid eel (juvenile) Eleotris fusca Oreochromis sp.( niloticus?) Gambusia holbrooki Prawns: Macrobrachium sp. B. Description of localities sampled and methods used Site Description Shallow (1m) pool densely covered with water hyacinth (Eichhornia crassipes) in main channel of stream. Stream-flow and Water Quality Low river flow at time of sampling, water clear, no water quality data taken. Habitats Sampled Sampled with 6m seine net in shallow water (depth up to 1.2m, width 12m) among floating hyacinth C. Remarks Suitable cover and habitat for fish floating vegetation, but difficult netting conditions due to dense vegetation.. Local villages use traps and seine nets to catch fish including catadromous mullet (Mugilidae) and eels (Anguillidae) and gobies as well as Macrobrachium prawns all species which breed in the sea. A B Site F5: showing pools densely covered with floating water hyacinth and seine netting activity in vegetation. 24

28 SITE F6 Co-ordinates: S; E Altitude: 247m Site Locality/Name: Manandany Stream, at confluence with Fiherenana River, River System: Fiherenana Tributary: Manandany Dates: 15/06/2012 Time: 12h00 14h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow pools on edge of river, as well as in rocky riffles and stony runs 6m seine net Electrofisher 4 x 10 m pulls in pool Approx. 150m along river reach Fish: Anguilla marmorata (adult) Gobiidae spp.? Awaous aeneofuscus Oreochromis sp.(mossambicus?) Oreochromis niloticus?) Crustacea Macrobrachium prawn. B. Description of localities sampled and methods used Site Description Shallow (<1m) flowing run and pool with boulders and cobbles in main channel of stream. Stream-flow and Water Quality Low river flow at time of sampling, water clear. Conductivity = 570 µs/cm, ph = 8.6, temp = 25 0 C. Habitats Sampled Sampled with 6m seine net in shallow water (depth up to 1.2m, width 12m) on sandy substrate and among cobbles and rocks with electrofisher. C. Remarks Recent fishing activity in the area by locals with seine net probably disturbed fish Local villages use seine nets and traps to catch fish including eels (Anguillidae), but apparently not mullet species. Manandany River Manandany River Sample site Fiherenana River Fiherenana R. Site F6 seen from the left (south) bank of the Fiherenana River at the confluence with the Manandany River. Site F6 viewed from the south with clean Manandany R. flowing into the brown Fiherenana R. 25

29 SITE RL1 Co-ordinates: S; E Altitude: 26m Site Locality/Name: Northern basin of Lake Ranobe River System: Ranobe Lake system Dates: 16/06/2012 Time: 10h00 12h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow water on edge of lake among reeds 6m seine net 4 x 10 m pulls on lake shore Fish: Gambusia holbrooki B. Description of localities sampled and methods used Site Description Shallow (<1m) water among emergent vegetation (sedges) on shore of lake Stream-flow and Water Quality Water clear, but brown stained. Habitats Sampled Sampled with 6m seine net in shallow water (depth up to 1.2m, width 12m) on sandy/muddy substrate among sedges near shore of lake in area cleared of vegetation. C. Remarks Local villages use gill nets and traps set using wooden canoes (mokoros) to catch fish in deeper water, mainly Nile tilapia. Site RL1 on edge of northern basin of Lake Ranobe. 26

30 SITE RL2 Co-ordinates: S; E Altitude: 23m Site Locality/Name: Southern basin of Lake Ranobe River System: Ranobe Lake system Dates: 16/06/2012 Time: 12h00 14h00 A. Summary of catch data: Habitat Gear Fishing Effort Species caught Shallow water on edge of lake among reeds 6m seine net 4 x 10 m pulls on lake shore Fish: Oreochromis niloticus Cyprinus carpio B. Description of localities sampled and methods used Site Description Shallow (<1m) water among emergent vegetation (sedges) on shore of lake Stream-flow and Water Quality Water clear, but brown stained. Conductivity == 790 µs/cm, ph = 7.9, temp = 25 0 C. Habitats Sampled Sampled with 6m seine net in shallow water (depth up to 1.2m, width 12m) on sandy/muddy substrate among sedges near shore of lake. C. Remarks Local villages use seine nets, gill nets and traps to catch fish, mainly Nile tilapia. Sampled with 6m seine net in shallow water (depth up to 1.2m, width 12m) on sandy/muddy substrate among sedges near shore of lake in area cleared of vegetation. C. Remarks Local villages use seine nets, gill nets and traps to catch fish, mainly Nile tilapia and also common carp (Cyprinus carpio) see photograph below. Site RL2 on edge of southern basin of Lake Ranobe. Common carp (Cyprinus carpio) in live cage at Site RL2. 27

31 9. APPENDIX B Photographs of fish and crustacean species captured at the various sites in June

32 Plate B-1. Gambusia holbrooki (Eastern mosquito fish). (Site RL1). Plate B-2. Oreochromis niloticus (Nile tilapia). (Site LR1). Plate B-3. Oreochromis mossambicus (Mozambique tilapia). May be a hybrid with Nile Tilapia. (Site F2). Plate B-4. Kuhlia rupestris (rock flagtail). (Site F4). Plate B-5. Eleotris fusca (dusky sleeper) (Site F5). Plate B-6. Awaous aeneofuscus (freshwater goby). (Site F6). Plate B-7. Anguilla marmorata (Madagascar mottled eel). (Site F6). Plate B-8. Gobiidae (goby). (Site F6). Plate B-9. Mugil sp. (mullet fry). (Site F1). Plate B-10 Terapon jabua (thornfish). (Site F1). 29

33 Plate B-11. Cyprinus carpio (common carp). (Site RL2). Plate B-12. Varuna litterata (swimming crab larvae/ megalopae). (Site F1). Plate B-10. Macrobrachium sp. (freshwater prawn). (Site F6). Plate B-13. Procambarus sp. (marbled freshwater crayfish). 30