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(a) Map of the North Sea showing the locations of offshore oil/gas platforms (the filled black circles) (Source: OSPAR, 2012). The circle and cross symbol indicates the location of the Miller platform and the red square defines the area of ICES statistical rectangle 46F1. (b) Map of ICES 46F1 showing the locations of offshore platforms, pipelines, subsea structures and associated 500 m safety zones. Blue diamond symbols represent locations of trawl surveys conducted in the IBTS operations between Q1 2011 and Q3 2012 (Codes as in Table 1).
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This study reports temporal variations in the environmental conditions and the structure of fish assemblages observed in the vicinity of an offshore oil platform and the surrounding seafloor in the North Sea. Multi-seasonal sampling was conducted at a typical large steel jacketed facility, using mid-water fish traps at three different depths (i.e.,...
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... most of the available literature on the ecology of fish populations surrounding oil/gas platforms comes from either in the Gulf of Mexico or off the coast of California in the USA. The Gulf of Mexico, for example, accommodates the largest concen- tration of offshore platforms (~4500) anywhere in the world ( Parente et al., 2006) and hosts an extensive recreational fishery that relies on these offshore structures (Stanley and Wilson, 1991). For this reason, fishery-dependent data on the occurrence and seasonal abundance of selected fish species around oil/gas plat- forms have been readily available in this region (Stanley and Wilson, 1991) as well as off the coast of California ( Love and Westphal, 1990). However, any fishery or survey vessels are currently not permitted to operate closer than 0.5 km to each oil/ gas platform in the North Sea due to stringent safety regulations (500 m safety zones). For similar reasons, fishing directly from any operational platforms is normally banned. However, the Miller platform ( Fig. 1) ceased production in 2007 and has since been used as a search and rescue helicopter base, which resulted in providing a unique opportunity to undertake a direct study on the relation- ships between fish populations and the physical presence of offshore platform in the North ...
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... study was carried out at BP's Miller platform situated in the central northern part of the North Sea (58 43 0 19.70 00 N, 01 24 0 07.40 00 E) which lies within ICES statistical rectangle 46F1 ( Fig. 1a and b). The platform was installed in 1991 in a water depth of approximately 103 m on an unconsolidated sandy seafloor. The platform has a large steel jacket structure (eight-legged) weighing approximately 18,600 t with a size of 71 Â 55 m at the base, tapering to 71 Â 30 m at the top. It provides a complex open lattice structure and a large surface area throughout the entire water column. The platform ceased production in September 2007 and currently hosts a Search and Rescue helicopter base for provision of offshore rescue and recovery operations for the central North Sea area. The platform is therefore maintained with minimum on- board personnel, and although illuminated during the night, the levels of noise and discharge of food waste were much reduced compared to those of operational platforms, representing one of the typical obsolete platform structures found in the ...
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... subset of fish data was extracted for ICES statistical rectangle 46F1 (nearby control sites, Fig. 1 and Table 1) and for the whole North Sea region, using a large-scale bottom trawl survey data derived from the IBTS database (http://www.ices.dk/Pages/default. aspx). The IBTS has been providing independent indices of fish distribution and relative abundance in the North Sea, using a bottom-trawl net (GOV trawl -mesh size at the opening: 200 mm; mesh size at the codend: 20 mm; details for the specification of the GOV-trawl can be found in ICES, 2010) which has been fully standardised amongst the participating nations since 1983. The survey grid is based on an ICES statistical rectangle of approxi- mately 30  30 nautical miles (0.5 latitude  1 longitude), each of which is normally sampled by the ships of two different nations per survey (two hauls per rectangle). The whole survey area comprises a total of around 160 ICES statistical rectangles across the North Sea, and the survey normally takes place twice a year for the first quarter (Q1: winter) and the third quarter (Q3: summer). At each station, the trawl net is towed for approximately 30 min and the catch is sorted and enumerated to determine the relative abun- dances and length distributions for all fish species caught. The catch per species is standardised to catch per unit effort described as the number of individuals caught per 1 h tow (CPUE IBTS ). Details on the sampling methods and protocols are available in the IBTS survey manual (ICES, 2010). In addition, a subset of data for spatio- temporal variations in both surface and bottom temperatures for the whole North Sea region were extracted using ICES oceano- graphic database ...
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... variations in water temperatures recorded at the Miller platform (Fig. 6) were generally consistent with the North Sea regional trends (Fig. 11). In both surface and bottom waters, temperatures were generally higher in Y2 than in Y1 in the respective Q1 and Q3 seasons throughout the North Sea, although temperature values in Y2Q3 in bottom waters observed around the east coast of Scotland became locally colder than those observed in Y1Q3. This region coincided with the area where marked increase in fish catches of poor cod was recorded (Fig. 10r and t)
(Fig. 11f and h). In terms of the vertical distribution of temperature, the water column was stratified during Q3 summer seasons, with markedly higher temperatures observed in the southern North Sea and a thermocline located in the region of around 50 m water depth (Fig. 11b, d, f and h). After the summer months, the strong strati- fication of the water mass disappeared, and there was little varia- tion in water temperatures throughout the water column in the winter months in Q1 (Fig. 11a, c, e and ...
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... variations in water temperatures recorded at the Miller platform (Fig. 6) were generally consistent with the North Sea regional trends (Fig. 11). In both surface and bottom waters, temperatures were generally higher in Y2 than in Y1 in the respective Q1 and Q3 seasons throughout the North Sea, although temperature values in Y2Q3 in bottom waters observed around the east coast of Scotland became locally colder than those observed in Y1Q3. This region coincided with the area where marked increase in fish catches of poor cod was recorded (Fig. 10r and t)
(Fig. 11f and h). In terms of the vertical distribution of temperature, the water column was stratified during Q3 summer seasons, with markedly higher temperatures observed in the southern North Sea and a thermocline located in the region of around 50 m water depth (Fig. 11b, d, f and h). After the summer months, the strong strati- fication of the water mass disappeared, and there was little varia- tion in water temperatures throughout the water column in the winter months in Q1 (Fig. 11a, c, e and ...
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... variations in water temperatures recorded at the Miller platform (Fig. 6) were generally consistent with the North Sea regional trends (Fig. 11). In both surface and bottom waters, temperatures were generally higher in Y2 than in Y1 in the respective Q1 and Q3 seasons throughout the North Sea, although temperature values in Y2Q3 in bottom waters observed around the east coast of Scotland became locally colder than those observed in Y1Q3. This region coincided with the area where marked increase in fish catches of poor cod was recorded (Fig. 10r and t)
(Fig. 11f and h). In terms of the vertical distribution of temperature, the water column was stratified during Q3 summer seasons, with markedly higher temperatures observed in the southern North Sea and a thermocline located in the region of around 50 m water depth (Fig. 11b, d, f and h). After the summer months, the strong strati- fication of the water mass disappeared, and there was little varia- tion in water temperatures throughout the water column in the winter months in Q1 (Fig. 11a, c, e and ...
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... variations in water temperatures recorded at the Miller platform (Fig. 6) were generally consistent with the North Sea regional trends (Fig. 11). In both surface and bottom waters, temperatures were generally higher in Y2 than in Y1 in the respective Q1 and Q3 seasons throughout the North Sea, although temperature values in Y2Q3 in bottom waters observed around the east coast of Scotland became locally colder than those observed in Y1Q3. This region coincided with the area where marked increase in fish catches of poor cod was recorded (Fig. 10r and t)
(Fig. 11f and h). In terms of the vertical distribution of temperature, the water column was stratified during Q3 summer seasons, with markedly higher temperatures observed in the southern North Sea and a thermocline located in the region of around 50 m water depth (Fig. 11b, d, f and h). After the summer months, the strong strati- fication of the water mass disappeared, and there was little varia- tion in water temperatures throughout the water column in the winter months in Q1 (Fig. 11a, c, e and ...
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... variations in water temperatures recorded at the Miller platform (Fig. 6) were generally consistent with the North Sea regional trends (Fig. 11). In both surface and bottom waters, temperatures were generally higher in Y2 than in Y1 in the respective Q1 and Q3 seasons throughout the North Sea, although temperature values in Y2Q3 in bottom waters observed around the east coast of Scotland became locally colder than those observed in Y1Q3. This region coincided with the area where marked increase in fish catches of poor cod was recorded (Fig. 10r and t)
(Fig. 11f and h). In terms of the vertical distribution of temperature, the water column was stratified during Q3 summer seasons, with markedly higher temperatures observed in the southern North Sea and a thermocline located in the region of around 50 m water depth (Fig. 11b, d, f and h). After the summer months, the strong strati- fication of the water mass disappeared, and there was little varia- tion in water temperatures throughout the water column in the winter months in Q1 (Fig. 11a, c, e and ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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... on the IBTS trawl survey database, spatio-temporal changes in the distribution and abundance of the major fish spe- cies observed at the Miller platform were examined for the whole North Sea region (Fig. 10). The spatial patterns varied markedly between species, although the degree of temporal variations exhibited within each species generally remained low but rather species specific. For example, distribution of saithe was generally constrained in the northern North Sea along the edge of the Nor- wegian Deep, yet this northern-oriented trend appears more pro- nounced in Q1 as the densities of saithe became mostly zero (absent) around the northern central North Sea where the Miller platform was also located (Fig. 10a and c) when compared with Q3 ( Fig. 10b and d). Haddock showed almost identical patterns of occurrence in the northerly area of the North Sea across seasons with some noticeable declining trends in their abundances observed from Y1Q1 to Y2Q3 (Fig. 10e, f, g and h). At the Miller platform, haddock were caught mostly in the summer and autumn months (Fig. 8b), but such strong seasonality, however, was not evident in their temporal pattern in the surrounding areas in the northern North Sea. Cod showed a wider geographical range distributed throughout the North Sea with higher occurrence and catch rate mainly observed along a broad zone stretching from northeast archipelago of Scotland to northern Denmark (Fig. 10i, j, k and l) but with some large areas of absence or very low abundance recorded in the shallow waters around east of Scotland and southern North Sea in Q3 seasons. Tusk was repeatedly caught at the Miller platform in this study, but this species was rarely caught in the large-scale bottom trawl surveys and only limited number of survey catch was thus recorded in each season (Fig. 10m, n, o and p). Poor cod appeared distributed only western part of the North Sea mainly concentrated along northeast archipelago of Scotland down through to the east coast of southern England (Fig. 10q, r, s and t), and the highest and lowest abundances were observed in Y2Q3 and Y1Q3, ...
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The species selectivity of demersal fishing gear in mixed whitefish fisheries needs to be improved for vessels with limited cod (Gadus morhua) quota which are encountering increasing abundances of cod in some areas of the North Sea, particularly around Shetland. Based on the known behavioural characteristics of cod within a demersal trawl, a new es...
Citations
... There is evidence that oil and gas platforms in the North Sea act as artificial reefs supporting a diversity of taxa and large numbers of a range of species [22][23][24][25][26][27], and potentially affecting the local ecology of those species [28]. In addition, the legally enforced 500 m safety zones surrounding North Sea oil and gas platforms allow them to act as de facto marine protected areas (MPAs), offering protection from certain anthropogenic pressures such as fishing and shipping. ...
... Several gadoid species are found in midwater as well as near the seabed, but oil platforms provide hard substrate throughout the vertical extent of the water column, and may thus alter the vertical distributions of nearby fish, although evidence for this may be limited. For example, saithe have a semi-demersal distribution [71], frequently foraging in midwater, and have been recorded throughout the water column at a North Sea oil platform [27]. In the same study, however, cod were only found in the deepest depth-stratum sampled, suggesting the oil platform may not cause predominantly demersal fish to move higher into the water column. ...
Thousands of offshore oil and gas platforms have been installed throughout the world’s oceans and more structures are being installed as part of the transition to renewable energy. These structures increase the availability of ecological niches by providing hard substrate in midwater and complex 3D habitat on the seafloor. This can lead to ‘hotspots’ of biodiversity, or increased densities of flora and fauna, which potentially spill over into the local area. However, the distances over which these higher densities extend (the ‘range of influence’) can be highly variable. Fish aggregate at such structures, but the range of influence and any implications for wider fish populations, are unclear. We investigated the relationship between fish and platform areal densities using high resolution fisheries acoustic data. Data were collected in the waters surrounding the vessel exclusions zones around 16 oil and gas platforms in the North Sea, and throughout the wider area. We estimated densities of schooling fish using echo-integration, and densities of non-schooling fish using echo-counting. At 10 platforms, non-schooling fish densities were elevated near the platform relative to background levels in the equivalent wider area. The range of influence, defined here as the range to which fish densities were elevated above background, varied from 0.8 to 23 km. In areas of high platform density, fish schools were encountered more often, and non-schooling fish densities were higher, when controlling for other sources of environmental variation. This is the first time such long-range effects have been identified; previously, ranges of influence have been reported in the order of just 10s-100s of metres. These findings suggest that the environmental impact of these structures may extend further than previously thought, which may be relevant in the context of upcoming management decisions around the decommissioning of these structures.
... Offshore O&G infrastructure and associated activities have both negative and positive effects on marine ecosystems (Burdon et al., 2018). Infrastructure may act as artificial reefs, enabling the development of complex heterogenous communities including diverse biota Todd et al., 2020), and increasing the diversity and biomass of demersal, and pelagic fish species (Claisse et al., 2014;Fujii, 2015;Meyer-Gutbrod et al., 2020). They may also act as settlement habitat or stepping-stones for invasive species (Da Silva et al., 2014;Sammarco et al., 2014Sammarco et al., , 2010Schulze et al., 2020), introduce artificial lights and noise that alter species behaviour (Barker and Cowan, 2018;Rich and Longcore, 2006;Todd et al., 2020), and introduce contaminants and nutrients (Henry et al., 2018;Koppel et al., 2023;MacIntosh et al., 2021). ...
... Species have also shown seasonal increases in their abundance in areas with high densities of artificial structures in the North Sea, such as platforms, wrecks, and turbines [90]. Data from baited fish traps at the decommissioned Miller platform found significant numbers of Saithe (Pollachius virens) and suggest a series of turnovers of individual fish using platforms, perhaps regulated at seasonal scales [91]. ...
Offshore oil and gas platforms (OGP) have been installed worldwide and initially with limited consideration given to the nature of their positive or negative long-term interactions with the natural marine habitats. However, as OGP reach the end of their useful life, with many being decommissioned and removed, it is timely to review the growing evidence of the association of marine biota with OGP to provide a summary and synthesis for policy makers and to give insight to decisions in increasingly crowded marine spatial plans. In the last decade, there has been rapid increase in studies concerning the ecological role of OGP. This research reveals strong contextual difference between platforms in different geographical regions, but all OGP add to local biodiversity particularly where hard substrata are introduced to areas dominated by depositional (mud and sand) habitats. This includes the attraction and increased productivity of fish, sessile invertebrates, and algae while also affecting change in the benthic habitats beneath platforms. There also evidence of the OGP changing local hydrodynamics conditions with effects on phytoplankton and local scour. In terms of the biota associated with OGP, water depth is a major driver of community type across systems. This study emphasises that while knowledge of OGP communities and species has improved, there are still significant knowledge gaps that may prevent the most environmentally beneficial decisions being made around decommissioning. There are few studies following the effect of decommissioning (topping, toppling, or removal) on the ecology of the systems as they change with time (longitudinal research) for the decommissioning event. There is also a need for more studies comparing the biodiversity and functionality of OGP system to artificial and natural reefs and habitats to better understand the ecological cost-benefit of decommissioning scenarios. Finally, commercial data is often unavailable and even when available, surveys are often conducted using varied methodology that prevents comparative analysis. By imposing/agreeing standards and sharing data around the ecological cost-benefit of decommissioning strategies, improve policy guidance concerning OGP planning, and management might emerge.
... The associated proliferation of oil and gas platforms may have some benefits, by providing a complex hard structure in a region dominated by soft sediments. This may support the settlement of sessile invertebrates and algal biofilms, which could fuel a more complex food web (Brandt et al., 2014;De Mesel et al., 2015;Fujii, 2015;Ronconi et al., 2015). The presence of platforms establishes exclusion zones that may benefit fish communities in a heavily trawled sea (Sheahan et al., 2001). ...
... Another type of anthropogenic influence in the marine environment globally, is the presence and operation of offshore oil and gas (O&G) infrastructure. These structures are placed strategically on continental shelfs (Claisse et al., 2014;Fujii, 2015) where crude oil and natural gas pockets are identified (van Elden et al., 2019) and typically comprise pipelines, wells, platforms or floating facilities with substantial additional subsea infrastructure (e.g. umbilicals, flowlines, etc) deployed to support these activities. ...
Regional patterns of fish diversity, abundance, distribution, and assemblage composition are driven by a combination of biotic and abiotic conditions in the marine environment, but these conditions can be altered through anthropogenic activities, such as those associated with oil and gas extraction. The present study utilises data on fish relative abundance and diversity obtained from 1546 baited remote underwater video deployments conducted between 2004 – 2019 in depths of 9 – 170 m across 2000 km of coastline in north-west Australia on natural habitats and subsea pipelines to understand the influence of oil and gas infrastructure on fish assemblages. A total of 450 fish taxa from 56 families was observed, with populations dominated by generalist and invertebrate carnivore taxa. At the regional scale, subsea pipelines had lower diversity (lower taxonomic richness) than natural environments, but possessed a higher abundance of piscivorous and herbivorous fish taxa. Clear patterns in fish assemblage composition were observed in multivariate analyses, reflecting the proximity of oceanic shoals and banks, depth, and to a lesser extent, oil and gas infrastructure. Shallow-water and close to shoals assemblages were characterised by a diversity of site-attached (e.g., wrasses, tuskfish), reef-associated taxa (e.g., emperors). Mesophotic fish assemblages were characterised by commercially important (e.g., goldband snapper), wide-ranging (e.g., sharks) and sand-affiliated (e.g., toadfish, threadfin bream) taxa. Proximity to pipelines and platforms ranked low as predictors in the multivariate analyses suggesting a negligible regional influence of these structures on fish communities in comparison to depth and shoal habitats. Local-scale influences of subsea infrastructure, however, may be important for some fish species (infrastructure vs. immediate surrounds). Our study highlights the influence of abiotic factors on regional-scale patterns in fish assemblage structure across north-west Australia.
... However, these associations may not necessarily be permanent, as the habitat requirements of fish may change as they grow and mature. Some species may only utilise O&G structures during specific ontogenetic stages (Fujii, 2015;Munnelly et al., 2021). For example, red snapper (Lutjanus campechanus) utilise O&G platforms when young but migrate to less vertically complex structures as they mature (Gallaway et al., 2009). ...
Subsea pipelines and wells installed to support the oil and gas industry represent some of the most extensive and numerous anthropogenic structures throughout global marine ecosystems. There remains a paucity of information on the habitat value of these structures for fishery target species and, as a result, little understanding of how decommissioning should be conducted to minimise impacts to populations of these economically and socially important species. We assess the diversity and abundance of species that are targets of recreational and commercial fisheries on 33 subsea wells and 17 pipelines across the tropical northwest and temperate southeast marine regions of Australia. We examine relationships between fish identity and abundance and a range of environmental (e.g., depth, location), infrastructure-specific (e.g., pipeline position, diameter, age, length of pipeline, height of well, position on well), and biological (% cover of epibiota) variables using video filmed by remotely operated vehicles during their routine offshore inspection and maintenance campaigns. A total of 100 fishery target species were observed across subsea well and pipeline infrastructure, 56 species uniquely observed on pipelines and nine unique to wells. The families Lutjanidae (snapper), Serranidae (rock cods, groupers, perch), and Carangidae (trevallies) were most common and abundant on both wells and pipelines. In the northwest, lutjanids were most abundant around the base of wells, in shallow depths, on shorter wells, and where pipelines spanned the seafloor. A greater number of fishery target species and abundance of ocean perch (Helicolenus spp.) were also associated with pipelines that spanned the seafloor in temperate southeast Australia. The combined biomass of three species of snapper on wells in the northwest was 1,270 kg, with production levels for these species on each well estimated to be 105.2 g m² year⁻¹. The present study serves as an important reference point for informing decommissioning decisions for pipeline and well infrastructure and demonstrates the utility of industry-held data for science. We suggest that key predictor variables identified here be incorporated into comprehensive before-after-control-impact scientific studies for specific fields/assets to enable the prediction of potential impacts of decommissioning scenarios on marine communities present and quantification of such impacts after the decommissioning activity has occurred.
... Structures can also have negative effects, such as disturbing seabed habitats and causing increased levels of pollution (Cordes et al., 2016). These effects may vary over time, relating to environmental conditions and stage of ecological succession (Fujii, 2015;Gates et al., 2019;Todd et al., 2019). Consequently, artificial structures have a potential role in restoring degraded marine ecosystems such as coral reefs (Rinkevich, 2014), mollusc reefs (Walles et al., 2016), algal forests (Gianni et al., 2013) and historically trawled or degraded habitats (Bond et al., 2018a), and have been proposed for restoration of disturbed deep-sea habitats (Cuvelier et al., 2018). ...
Large structures are introduced into deep-water marine environments by several industrial activities, including hydrocarbon exploitation. Anthropogenic structures can alter ecosystem structure and functioning in many marine ecosystems but the responses on continental margins are poorly known. Here, we investigate the short-term response of benthic megafauna to the installation of a 56 km-long 30 cm diameter pipeline on the Angolan Margin (Block 31) from 700 to 1800 m water depth using remotely operated vehicle imagery. Clear depth-related patterns exist in the density, diversity and community structure of megafauna observed in 2013 prior to pipeline installation. These patterns are altered in a subsequent survey in 2014, three-months after pipeline installation. Significant increases in density, particularly in mid-slope regions are observed. Diversity is generally, but not consistently, enhanced, particularly in the shallower areas in 2014. Clear changes are noted in community structure between years. These changes are primarily caused by increases in the abundance of echinoderms, particularly the echinoid Phormosoma sp. indet. There was no evidence of colonisation of the pipeline in three months by visible fauna. The few large anemones observed attached to the pipe may be able to move as adults. The pipeline appeared to trap organic material and anthropogenic litter, and may enhance available food resources locally as well as providing hard substratum. These results indicate complex and ecosystem-dependent responses to structure installation and caution against simplistic approaches to environmental management.
... Finally, the sul1 and intI1 genes were poorly quantified in the MNS (2/8 and 1/8 samples from this area, respectively). This area, unlike the others, is quite far from the coasts and thus from their influence, but has a concentration of offshore platforms for gas and oil exploitation (Fujii, 2015). However, we have quantified the sul1 and intI1 genes in seawater samples collected far from the coast, in areas that could be described as subject to little anthropogenic impact. ...
The marine environment is a potential natural reservoir of antimicrobial resistance genes (ARGs), subject to anthropogenic effluents (wastewater, industrial, and domestic), and known as a final receiving system. The aim of this study was to investigate the abundance and geographical distribution of the three blaTEM, sul1, and intI1 genes, proposed as indicators of contamination to assess the state of antimicrobial resistance in environmental settings, added to the tetA gene and the microbial population (tuf gene) in the English Channel and North Sea areas. Bacterial DNA was extracted from 36 seawater samples. The abundance of these genes was determined by quantitative PCR (qPCR) and was analyzed in association with environmental variables and geographical locations to determine potential correlations. The blaTEM and tetA genes were quantified in 0% and 2.8% of samples, respectively. The sul1 and intI1 genes were detected in 42% and 31% of samples, respectively, with an apparent co-occurrence in 19% of the samples confirmed by a correlation analysis. The absolute abundance of these genes was correlated with the microbial population, with results similar to the relative abundance. We showed that the sul1 and intI1 genes were positively correlated with dissolved oxygen and turbidity, while the microbial population was correlated with pH, temperature and salinity in addition to dissolved oxygen and turbidity. The three tetA, sul1, and intI1 genes were quantified in the same sample with high abundances, and this sample was collected in the West Netherlands coast (WN) area. For the first time, we have shown the impact of anthropogenic inputs (rivers, man-made offshore structures, and maritime activities) and environmental variables on the occurrence of three indicators of environmental contamination by antimicrobial resistance in the North Sea and English Channel seawaters.
... Offshore oil and gas platforms in the Gulf of Thailand have created a complex, 3-dimensional habitat that supports a diverse fish community in what is otherwise a featureless, open ocean environment. Similar results have been described in Southern California (Love et al., 2005;Claisse et al., 2014;Pondella et al., 2015a), the GoM (Hastings et al., 1976;Scarborough-Bull, 1989;Scarborough-Bull and Kendall, 1994;Stanley and Wilson, 1997), the North Sea (Jørgensen et al., 2002;Fujii, 2015;Todd et al., 2018Todd et al., , 2020 and Western Australia (McLean et al., 2019). Coral reef or coral reef-associated species accounted for 90% of the fish that were counted on the seven platforms, including damselfish, wrasse, surgeonfish, parrotfish and other families more commonly observed on shallow coral reefs. ...
Decommissioning of offshore oil and gas structures is either occurring, or imminent in most regions of the world. Most jurisdictions require that offshore structures be removed for onshore disposal. However, there is growing interest in understanding the ecological and socio-economic benefits of leaving structures in the water. Descriptions of how fish utilize the vertical structure created by wellhead platform jackets (platforms) will provide insights into possible outcomes of decommissioning alternatives, such as full removal, leave in situ, or translocation to a designated reefing site. We surveyed fish assemblages associated with seven platforms and five reference sites located ∼150 km offshore in the central Gulf of Thailand. The platforms spanned the entire water column (∼75 m) and were a mix of three and four legged structures. We used a Remotely Operated Vehicle (ROV) fitted with an underwater stereo video system to quantify the abundance, size, biomass, and economic value of fish associated with the platforms. We recorded 43 species of fish on the platforms and five reference sites with most fishes on platforms categorized as coral-reef or coral-reef-associated species. We observed a strong vertical zonation in the fish assemblage on the platforms. The Regal demoiselle (Neopomacentrus cyanomos) was numerically dominant (75% of all fish observed). We measured 3,933 kg of fish on the platforms with Caranx sexfasciatus accounting for 76.12% of that. We conservatively estimate each platform had a scaled mean biomass of ∼2,927 kg and the fished species had scaled mean economic value of 175,500 Thai Baht per platform. We estimated that the biomass of fish associated with the seven platforms was at least four times higher per unit area than some of the world’s most productive coral reefs.
... The predictable food source close to the platforms may therefore play an important role in supporting the annual energetic strategy of porpoises in the area (Fujii & Jamieson, 2016), and porpoise activity around platforms is likely related to increased foraging opportunities on certain prey species that use O&G structures and the surrounding fishery-free zone as artificial reefs for shelter and/or to find food. (Fujii, 2015). Some seasonal and inter-annual variation in densities of these fish were found, but the changes were relatively minor and are unlikely to fully explain the shifts observed in porpoise presence near F I G U R E 8 Ambient noise measured as 5-min average third-octave-level in bands centred at the six frequencies indicated in Figure 7. Box plots are shown for day (orange) and night (grey) for five distances from DanF. ...
Harbour porpoises frequently alter their behaviour in response to underwater sound from shipping, seismic surveys, drilling and marine renewables. Less well understood is the response of porpoises to sounds emitted from oil and gas (O&G) platforms during routine operations.
The responses are not easily predicted as platforms can act simultaneously and to varying degree as a source of disturbance through noise and attraction through an artificial reef effect with increased prey abundance and diversity.
To investigate the presence and feeding behaviour of harbour porpoises around platforms, autonomous acoustic loggers were placed for up to 2 years, at 21 stations 0–25.6 km from the largest platform in the Danish North Sea.
Harbour porpoises were detected at all distances year round in two distinct seasonal activity patterns. During July–January, porpoises were attracted to the platform as indicated by high foraging activity within 800 m of the platform. Echolocation activity levels were up to twofold higher than those observed at 3.2–9.6 km from the platform.
Similar high echolocation activity was observed 200 m from neighbouring offshore installations located within 15 km, regardless of their size, during May–July.
This study shows that porpoises may be attracted to offshore O&G platforms despite confirmed elevated underwater noise and are likely exploiting higher prey abundance in the vicinity of such structures. This is possibly due to increased prey availability created by the combined effect of the artificial reef formed by the underwater structure and the local protected area around all platforms where fishery is banned.
Hard substrate and untouched seabed are rare and valuable habitats to many organisms in heavily trawled waters like the North Sea, and the ecological importance of these structures should be considered in the development of decommissioning strategies.
