Fisheries - Enviro Dynamics Namibia

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F I S H E R I E S , M A M M A L S A N D S E A B I R D S S P E C I A L I S T S T U D Y Figure 35. Total catch per station for west coast sole from hake-survey data (1997 – 2010). n=48 Figure 37. Distribution of orange roughy from hakesurvey data (1995 – 2010). n=4 Final Report <strong>Namibia</strong>n Marine Phosphate (Pty) Ltd. Figure 36. Total catch per station for west coast sole from monksurvey data (1997 – 2010). n=42 Figure 38. Distribution of orange roughy from monksurvey data (2007 – 2010). n=29 Page 62
F I S H E R I E S , M A M M A L S A N D S E A B I R D S S P E C I A L I S T S T U D Y Based on the survey data we conclude the following with respect to the impact of the mining on the abundance and distribution of the main commercial fish species : Hake : (Figure 27) - Hake (M. capensis) are found throughout the mining lease area. One station in the MLA and just south of SP-1 has a high frequency of occurrence of hake. Otherwise we assume the abundance of hake in the MLA and surrounding areas is fairly uniform with higher levels of hake abundance in deeper water. Mining at the specific sites is therefore expected to impact on hake but due to their mobility hake will most likely avoid the mined area. This will result in displacement of hake biomass into adjacent areas, mortality is unlikely. From an ecosystem perspective this will have implications only in a localised context (we assume hake will avoid the mined area). Disturbance of the substrate will not result in loss of food for hake since hake generally do not feed on substrate organisms and predate mostly on other fish species and squid. Horse mackerel : (Figure 28) - In the MLA horse mackerel abundance is low although high incidence of this species is expected north and westwards of the MLA. Horse mackerel are highly mobile and as with hake, are expected to be displaced outside of the mined locations. Mortality is not expected and the impact on the ecosystem is expected to be low. Monk : (Figures 29 and 30) - Monk are found throughout the MLA and the adjacent areas. Distribution appears fairly uniform. Monk are aggressive ambush predators and are found mostly on flat muddy substrate. They are also not highly mobile fish and have mostly patchy localised distribution patterns. These characteristics are expected to make monk vulnerable to mortality from the physical nature of the dredging process. This will have a localised impact on the trophic ecology but due to the relatively small area of the mining sites (up to 3 km 2 mined annually and 60 km 2 in the 20 year life of mine), this impact is expected to be moderate. The removal of the preferred substrate type for monkfish will have a long-term (at least 15 years) impact on the availability of monk in and around the mining sites (starting with SP-1). Note it is not possible without long-term monitoring to determine the rate of substrate recovery (appendix 1c) or the potential for monk to repopulate the mined areas. Pelagic species : (Figure 31) - Abundance of small pelagic species is assumed to be low (based on the distribution of catch and effort only) in the MLA. Availability of this species group increases into Zone 1 and northwards into Zones 2 and 3. Due to data limitations we are unable to estimate relative abundance beyond 23°S. One survey station indicates that small pelagic species are found in the MLA. We assume therefore that small pelagic species are highly likely to be found throughout the MLA but that the impact of mining and the resulting plumes cannot be stated with sufficient confidence. Snoek : (Figure 32) - This species is found in and around the MLA. They are highly mobile and are only found seasonally and in aggregations with high abundance at these times. Snoek, when occurring in the area of the MLA and mining operation, are expected to avoid the area – i.e. will be displaced. This is not expected to have a significant impact on the ecology in the MLA and adjacent zones. Bearded goby : (Figures 33 and 34) - Two surveys suggest that gobies are distributed throughout the MLA and will occur inside the mining sites (SP1-3). Gobies have been identified as having a key trophic role in the ecosystem. As gobies are a mobile species they will be displaced. Mortality Final Report <strong>Namibia</strong>n Marine Phosphate (Pty) Ltd. Page 63
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Final Report Namibian Marine Phosph
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Final Report Namibian Marine Phosph
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Tables and Figures F I S H E R I E
Page 13 and 14: 1 INTRODUCTION F I S H E R I E S ,
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Page 37 and 38: 4.2 TURTLES F I S H E R I E S , M A
Page 45 and 46: 5 LEGISLATION F I S H E R I E S , M
Page 47 and 48: Extent Duration Intensity/ Magnitud
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Page 81 and 82: 10 CONCLUSIONS F I S H E R I E S ,
Page 85 and 86: 12 REFERENCES F I S H E R I E S , M
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Fisheries - Enviro Dynamics Namibia

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