Environmental Statement - Maersk Oil

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3 ‐ 20 Balloch Field Development Environmental Statement Section 3 Baseline Environment Activities that result in the disruption of the seabed, such as the deposition of discharged drill cuttings, can affect the benthic fauna (Clark, 1996). It follows that the deposition of rock, subsea structures and pipes also have an effect. An ICES (International Council for the Exploration of the Sea) report on the structure and dynamics of the North Sea benthos (Rees, 2007) concludes that the ecological effects of anthropogenic influences arising from oil and gas installations and aggregate extraction were not identifiable on a large ICES Block scale and that there was no evidence of a footprint associated with clusters of installations, but rather that any variations identified were associated predominantly with natural forces. In addition, it concludes that the benthos are sufficiently resilient to accommodate the consequences of contemporary anthropogenic influences over large scales without significant degradation. Epifauna The seabed photos taken in the Balloch environmental surveys showed that the epifauna was sparsely distributed (Fugro, 2005 and 2010). The most prominent of the sessile epifauna was the seapen Virgularia mirabilis, which was present in photographs throughout the survey area (Fugro, 2010). A shoal of juvenile fish (Gadidae spp.) was observed at stations 7 and 8 in the Fugro 2010 survey. There was a lack of any hard substrate except epilithic (rock‐living) species. Other recorded epifauna included sea stars (Astropecten irregularis) and Norwegian lobsters (Nephrops norvegicus). Example photographs of the most prominent epifaunal and infaunal taxa are provided in Figure 3‐10. Figure 3‐10 Example epifauna that were captured during the Fugro 2010 survey. Plate 1: Seastar, Astropecten irregularis Plate 2: Sea pen, Virgularia mirabilis Plate 3: A shoal of juvenile gadoids Plate 4: A Norwegian lobster, Nephrops norvegicus, and carridean shrimps
Balloch Field Development Environmental Statement Section 3 Baseline Environment Macrofauna The results of the macrofaunal survey (Fugro, 2010) suggest the community within the proposed Balloch development area is highly diverse with 152 discrete macrofaunal taxa (>0.5 mm) being represented in the samples collected within the survey area. These comprised of 70 annelid, 39 crustacean, 36 molluscan and 3 echinoderm, along with 4 others belonging to other phyla. Annelids were dominant in the samples, representing 65.4 % of the fauna. The most abundant taxon recorded during the Fugro (2010) survey was the amphinomid polychaete Paramphinome jeffreysii, an almost ubiquitous member of CNS communities that frequently dominates the fauna in unimpacted areas. P. jeffreysii is a north Atlantic species generally found burrowing in mud and fine sands from the shallow sub tidal to depths of over 100 m. The second most numerically dominant species was a bivalve, the filter feeding Adontorhina similis, which is typically found in the North Sea (including around oilfields) in mixed sediments at water depths of between 85 m and 161 m. Levinsenia gracilis was the third most numerically dominant species. L. gracilis, from the Paraonidae family, is a deposit and filter feeding polychaete worm found in fine sediments including coarse silt and muddy sand from the lower shore to the deep sublittoral. The fourth and fifth most numerically dominant species (Galathowenia oculata agg. and Spiophanes kroyeri respectively) were found at similar levels across the survey area. These are both deposit feeding polychaetes. Both species are tube forming and G. oculata agg. is known to form dense worm colonies. Multivariate statistical analysis of the macrofaunal station data (0.3 m 2 ) identified two statistically significant clusters and a single outlying station. The outlying station was significantly different as a different taxa was observed to be dominating the fauna at this location. The same station was also identified as an outlier in the granulometric multivariate analysis due to the presence of higher proportions of very fine silt and clay, indicating that the sediment was a possible discriminating factor. The two clusters identified from the macrofaunal data were also very similar to the granulometry clusters, with just two stations switching from one cluster to the other. BIOENV calculations (which measure how close two sets of multivariate data are) supported the theory that sediment type plays a significant role in determining the macrofauna, with significant correlations found between the overall macrofaunal community composition and individual phi units. The physico‐chemical data showed little variation across the survey area and as a result there was only one statistically significant correlation between faunal community and the physico‐chemical parameters (mean particle size in µm). Collectively, the data suggested that the survey area is a relatively uncontaminated fine‐grained habitat and has a community structure typical for such a habitat in the CNS. Comparisons with the communities listed within The Marine Habitat Classification for Britain and Ireland, Version 04.05 (Connor et al., 2004) suggested that the closest biotope was ‘Levinsenia gracilis and Heteromastus filiformis in offshore circalittoral mud and sandy mud’ (SS.SMu.OMu.LevHet), an offshore mud and sandy mud biotope with a faunal community characterised by the polychaetes Levinsenia gracilis and Heteromastus filiformis. Other important taxa include Paramphinome jeffreysii, Nephtys hystricis and Spiophanes kroyeri among others (Orbinia norvegica, Thyasira equalis). This biotope has been previously identified in the CNS and NNS. 3.6.3. FISH At present more than 330 fish species are thought to inhabit the shelf seas of the UKCS (Pinnegar et al., 2010) Pelagic species (e.g. herring (Clupea clupea), mackerel (Scomber scombrus), blue whiting (Micromesistius poutassou) and sprat (Sprattus sprattus) are found in mid‐water and typically make extensive seasonal movements or migrations. Demersal species (e.g. cod (Gadus morhua), haddock (Melanogrammus aeglefinus), sandeels (Ammodytes tobianus), sole (Solea solea) and whiting (Merlangius merlangus) live on or near the seabed and similar to pelagic species, many are known to passively move (e.g. drifting eggs and larvae) and/or actively migrate (e.g. juveniles and adults) between areas during their lifecycle. 3 ‐ 21
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B ‐ 2 Halocarbon release during e
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B ‐ 4 Lube and hydraulic oil spil
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Discharges to Sea Discharge from pi
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Production Phase Environmental Aspe
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B ‐ 10 Drainage water Discharge o
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Physical presence Oil and gas infra
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Major accidental events Other envir
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Environmental Statement - Maersk Oil

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