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Robert W. Elner - One of the best experts on this subject based on the ideXlab platform.
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trace elements in pacific Dunlin calidris alpina pacifica patterns of accumulation and concentrations in kidneys and feathers
Ecotoxicology, 2015Co-Authors: Toby C St Clair, Ronald C. Ydenberg, Robert W. Elner, Patricia A Baird, L I BendellAbstract:Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report concentrations of cadmium, copper, and zinc in kidneys as well as copper, lead, mercury, selenium and zinc in feathers. Relationships between element concentrations and Dunlin age, sex, bill length, habitat preference, trophic level, and sample group were investigated with regression analyses. Stable isotope ratios of carbon and nitrogen in Dunlin muscle tissue were used to determine habitat preference and trophic level, respectively. Cadmium concentrations in kidneys were significantly related to habitat preference: [Cd] in estuarine foragers >[Cd] in terrestrial foragers. Cadmium accumulation was age-dependent as concentrations increased significantly within 10 months of hatch dates but not afterward. Concentrations of cadmium and zinc in kidneys as well as lead and mercury in feathers were below those known to cause deleterious effects in birds. In contrast, selenium concentrations in feathers (range: 2.1–14.0 µg/g) were often at levels associated with toxicity risks (>5 µg/g). Toxicity thresholds are not available for copper in kidneys or copper and zinc in feathers; however, measured concentrations of these elements were within documented ranges for sandpipers. Future studies should assess potential impacts of selenium on embryonic development in Dunlin and other sandpipers. Risk assessments would yield more conclusive results for all elements if impacts under ecologically relevant stresses (e.g. development in the wild, migration, predation) were better understood.
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Sediment in Stomach Contents of Western Sandpipers and Dunlin Provide Evidence of Biofilm Feeding
Waterbirds, 2010Co-Authors: Kimberley J. Mathot, Dieta R. Lund, Robert W. ElnerAbstract:Abstract. Western Sandpipers and Dunlin are capable of grazing biofilm. As there has been no assessment of this dietary constituent in stomach contents, the stomachs of 89 Western Sandpipers and 56 Dunlin collected during breeding migration through the Fraser River delta, British Columbia, Canada, were examined. Invertebrates, traditionally regarded as the principal prey, comprised a minor fraction of mean stomach volumes (Dunlin: 40%; Western Sandpipers: >75%). Although the mean volume of sediment was significantly greater in Western Sandpipers than Dunlin, there was no effect of sex for either species. Stomach sediment volume appears a convenient index of biofilm intake and sediment loads indicative of biofilm grazing h...
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Evidence of a new feeding mode in western sandpiper (Calidris mauri) and Dunlin (Calidris alpina) based on bill and tongue morphology and ultrastructure
Marine Biology, 2005Co-Authors: Robert W. Elner, Peter G. Beninger, Daniel L. Jackson, Tracy M. PotterAbstract:Sandpipers of the genus Calidris tend to have similar body shapes and use narrow, tubular bills to feed on invertebrates in aquatic habitats over an extensive migratory range. Highly plastic foraging behaviours have been displayed but the associations between diet and feeding mechanics are less well understood. Here, scanning electron microscopy was used to relate the ultrastructure of the bills and tongues of two sympatric congeners, western sandpiper ( C. mauri ) and Dunlin ( C. alpina ), to function and elucidate the sensory and mechanical basis to feeding. The morphology of the relatively larger, more robust bill of the Dunlin suggests specialization for probing although both species are known to feed on epifaunal and infaunal prey. In general, external and internal bill features appear similar for the congeners and the microstructure of taste bud and salivary gland complexes in their mouth cavities correspond to descriptions for other birds. However, the tongues of the two species are remarkable for their distinctive micro-structural details as well as copious mucus and extraneous material. In particular, each species has unique tongue papillae, and the keratinized lateral spines along the edges and at the tips of the western sandpiper tongue are markedly longer and denser than for those of the Dunlin. Based on the unique features of the tongues and associated observations, inter-species differences in foraging performance can be inferred. Further, evidence suggests that the western sandpiper, and, to a lesser extent, the Dunlin, deposit feed on surficial biofilm materials, as opposed to incidentally imbibing such materials while targeting epifaunal prey. Commensurate with the evidence, a novel functional and mechanistic case for unfiltered biofilm grazing in birds is proposed.
David B. Lank - One of the best experts on this subject based on the ideXlab platform.
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Low Frequencies of Supernormal Clutches in the Southern Dunlin and the Temminck's Stint
Ardea, 2019Co-Authors: Veli-matti Pakanen, David B. Lank, Donald Blomqvist, Lars-Åke Flodin, Mikael Larsson, Torgrim Breiehagen, Olavi Hildén, Terje Lislevand, Kimmo Nuotio, Peter OlssonAbstract:Supernormal clutches are found across bird species. Such clutches often result from more than one female laying eggs in the same nest and can reflect different behaviours from parasitism to laying mistakes. Enlarged clutches are readily visible among waders due to a maximum maternal clutch size of four eggs, yet surprisingly little is known about this phenomenon. Since supernormal clutches are rare, large sample sizes are required to reliably quantify their natural frequencies. We used a large dataset to estimate the frequency of supernormal clutches in the polygamous Temminck's Stint Calidris temminckii and the monogamous Southern Dunlin C. alpina schinzii, and examine the timing of supernormal clutches in relation to the general distribution of nest initiation dates. While supernormal clutches were very rare, they were over four times more common in the Temminck's Stint (0.50%, n = 1594) than in the Southern Dunlin (0.11%, n = 2766). Dunlin show among the lowest frequency of supernormal clutches reported for waders. In the Temminck's Stint, supernormal clutches were found in the middle of the season, while in the Southern Dunlin such clutches occurred in late season replacement nests. The higher rate and timing of enlarged clutches in Temminck's Stints probably relates to the lspecies' breeding system, which can include simultaneous courtship of multiple partners, but more work is needed to assess the relative influence of different factors. We argue that intraspecific nest parasitism is unlikely to be a primary reproductive tactic in small sandpipers.
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The redistribution of non-breeding Dunlins in response to the post-DDT recovery of falcons.
Oecologia, 2017Co-Authors: Ronald C. Ydenberg, Jennifer Barrett, David B. Lank, Michiel FaberAbstract:Large-scale changes in predator populations are occurring worldwide due to (re-)introductions, over-exploitation, or recovery after decimation by pesticides and persecution. These widespread changes may affect the distribution of their prey. We studied the continental-scale distributions of non-breeding Calidris alpina pacifica and C. a. hudsonia (Pacific and Atlantic Dunlins, respectively), as numbers of their major predators—peregrines (Falco peregrinus) and merlins (F. columbarius; together ‘falcons’)—increased after DDT was banned in 1973. For the period 1975–2010 we compiled the number of Dunlins and falcons in each of 244 Christmas Bird Count circles, which cover most of the Dunlins' non-breeding ranges. Over the study period, falcons increased by 6.5- (Pacific) and 3.1- (Atlantic) fold, spread to more count circles, and the number of Dunlins per falcon fell. The annual total count of the two Dunlin sub-species fluctuated strongly and independently. We measured annual aggregation as the expected proportion of a subspecies total found on the same count circle as a randomly selected Dunlin. The average aggregation of Pacific Dunlins (0.117) was about double that of Atlantic Dunlins (0.059), with annual variation largely attributable to changes in a few large count circles. The slope of the aggregative response to year-on-year changes in Dunlin numbers was identical on the two coasts. The response to the ongoing falcon increase was positive and significant on the Pacific and slightly negative on the Atlantic. We interpret these results using a version of the ideal free distribution that includes predation danger.
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Large and irregular population fluctuations in migratory Pacific (Calidris alpina pacifica) and Atlantic (C. a. hudsonica) Dunlins are driven by density-dependence and climatic factors
Population Ecology, 2015Co-Authors: Cailin Xu, David B. Lank, Jennifer Barrett, Ronald C. YdenbergAbstract:Understanding the forces driving population dynamics is critical for species conservation and population management. For migratory birds, factors that regulate population abundance could come from effects experienced on breeding areas, wintering grounds, or during migration. We compiled survey data for Pacific and Atlantic subspecies of Dunlins ( Calidris alpina pacifica and C. a. hudsonica ) from range-wide Christmas bird counts (1975–2010), and investigated the influences on this population index of density-dependence, falcon numbers, a set of seasonal environmental conditions during breeding, migration and non-breeding periods, and large-scale meteorological measures. For both sub-species, numbers fluctuated irregularly, varying threefold over the survey period, with no long-term upward or downward trend. Based on Royama’s general model framework, the change in numbers between successive years for both sub-species was negatively affected by the total count in the previous year (i.e., negative density-dependence) and by the eastward component of storm movement during fall migration, with slower motion associated with higher population growth. The remaining environmental factors differed between the sub-species (snowmelt date on the Pacific, temperature on the Atlantic) or acted in opposite directions (soil moisture). The directional effects of each of these factors are consistent with the biology of Dunlin, and together they explain 67.4 (72.9 %) of the variation in the rate of change of Pacific (Atlantic) Dunlin annual counts. Falcon numbers were not predictive, despite a tenfold increase in abundance, suggesting compensatory mortality. This study highlights directions for future studies, and provides a model for the analysis of other migratory species.
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Winter body mass and over-ocean flocking as components of danger management by Pacific Dunlins
BMC Ecology, 2010Co-Authors: Ronald C. Ydenberg, Dick Dekker, Gary Kaiser, Philippa Cf Shepherd, Lesley Evans Ogden, Karen Rickards, David B. LankAbstract:Background We compared records of the body mass and roosting behavior of Pacific Dunlins ( Calidris alpina pacifica ) wintering on the Fraser River estuary in southwest British Columbia between the 1970s and the 1990s. 'Over-ocean flocking' is a relatively safe but energetically-expensive alternative to roosting during the high tide period. Fat stores offer protection against starvation, but are a liability in escape performance, and increase flight costs. Peregrine falcons ( Falco peregrinus ) were scarce on the Fraser River estuary in the 1970s, but their numbers have since recovered, and they prey heavily on Dunlins. The increase has altered the balance between predation and starvation risks for Dunlins, and thus how Dunlins regulate roosting behavior and body mass to manage the danger. We therefore predicted an increase in the frequency of over-ocean flocking as well as a decrease in the amount of fat carried by Dunlins over these decades. Results Historical observations indicate that over-ocean flocking of Dunlins was rare prior to the mid-1990s and became common thereafter. Residual body masses of Dunlins were higher in the 1970s, with the greatest difference between the decades coinciding with peak peregrine abundance in October, and shrinking over the course of winter as falcon seasonal abundance declines. Whole-body fat content of Dunlins was lower in the 1990s, and accounted for most of the change in body mass. Conclusions Pacific Dunlins appear to manage danger in a complex manner that involves adjustments both in fat reserves and roosting behavior. We discuss reasons why over-ocean flocking has apparently become more common on the Fraser estuary than at other Dunlin wintering sites.
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MARINE AND AGRICULTURAL HABITAT PREFERENCES OF Dunlin WINTERING IN BRITISH COLUMBIA
Journal of Wildlife Management, 2004Co-Authors: Philippa Cf Shepherd, David B. LankAbstract:Abstract We examined winter habitat preferences of individual Dunlin (Calidris alpina) in the Fraser River delta, British Columbia, Canada, adjacent to agricultural land near an area of dense and increasing human settlement. We used radiotelemetry and compositional analysis to quantify and describe Dunlin habitat selection at 2 scales (regional and local) throughout the 24-hr day and daily tidal cycles. We tested for differences between sex and age classes, and among birds captured at different sites. Patterns of habitat preference differed between sexes and among Dunlin from different sites in the delta, but we detected no difference between age classes. We ranked habitat types in order of Dunlin preference and tested for significant differences among habitat ranks. Dunlin showed a significant preference for tidally influenced marine habitats at both scales and throughout the study area. However, most individuals (>80%) also used terrestrial habitats, usually during high tide and primarily at night. The ...
Ronald C. Ydenberg - One of the best experts on this subject based on the ideXlab platform.
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The redistribution of non-breeding Dunlins in response to the post-DDT recovery of falcons.
Oecologia, 2017Co-Authors: Ronald C. Ydenberg, Jennifer Barrett, David B. Lank, Michiel FaberAbstract:Large-scale changes in predator populations are occurring worldwide due to (re-)introductions, over-exploitation, or recovery after decimation by pesticides and persecution. These widespread changes may affect the distribution of their prey. We studied the continental-scale distributions of non-breeding Calidris alpina pacifica and C. a. hudsonia (Pacific and Atlantic Dunlins, respectively), as numbers of their major predators—peregrines (Falco peregrinus) and merlins (F. columbarius; together ‘falcons’)—increased after DDT was banned in 1973. For the period 1975–2010 we compiled the number of Dunlins and falcons in each of 244 Christmas Bird Count circles, which cover most of the Dunlins' non-breeding ranges. Over the study period, falcons increased by 6.5- (Pacific) and 3.1- (Atlantic) fold, spread to more count circles, and the number of Dunlins per falcon fell. The annual total count of the two Dunlin sub-species fluctuated strongly and independently. We measured annual aggregation as the expected proportion of a subspecies total found on the same count circle as a randomly selected Dunlin. The average aggregation of Pacific Dunlins (0.117) was about double that of Atlantic Dunlins (0.059), with annual variation largely attributable to changes in a few large count circles. The slope of the aggregative response to year-on-year changes in Dunlin numbers was identical on the two coasts. The response to the ongoing falcon increase was positive and significant on the Pacific and slightly negative on the Atlantic. We interpret these results using a version of the ideal free distribution that includes predation danger.
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Large and irregular population fluctuations in migratory Pacific (Calidris alpina pacifica) and Atlantic (C. a. hudsonica) Dunlins are driven by density-dependence and climatic factors
Population Ecology, 2015Co-Authors: Cailin Xu, David B. Lank, Jennifer Barrett, Ronald C. YdenbergAbstract:Understanding the forces driving population dynamics is critical for species conservation and population management. For migratory birds, factors that regulate population abundance could come from effects experienced on breeding areas, wintering grounds, or during migration. We compiled survey data for Pacific and Atlantic subspecies of Dunlins ( Calidris alpina pacifica and C. a. hudsonica ) from range-wide Christmas bird counts (1975–2010), and investigated the influences on this population index of density-dependence, falcon numbers, a set of seasonal environmental conditions during breeding, migration and non-breeding periods, and large-scale meteorological measures. For both sub-species, numbers fluctuated irregularly, varying threefold over the survey period, with no long-term upward or downward trend. Based on Royama’s general model framework, the change in numbers between successive years for both sub-species was negatively affected by the total count in the previous year (i.e., negative density-dependence) and by the eastward component of storm movement during fall migration, with slower motion associated with higher population growth. The remaining environmental factors differed between the sub-species (snowmelt date on the Pacific, temperature on the Atlantic) or acted in opposite directions (soil moisture). The directional effects of each of these factors are consistent with the biology of Dunlin, and together they explain 67.4 (72.9 %) of the variation in the rate of change of Pacific (Atlantic) Dunlin annual counts. Falcon numbers were not predictive, despite a tenfold increase in abundance, suggesting compensatory mortality. This study highlights directions for future studies, and provides a model for the analysis of other migratory species.
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trace elements in pacific Dunlin calidris alpina pacifica patterns of accumulation and concentrations in kidneys and feathers
Ecotoxicology, 2015Co-Authors: Toby C St Clair, Ronald C. Ydenberg, Robert W. Elner, Patricia A Baird, L I BendellAbstract:Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report concentrations of cadmium, copper, and zinc in kidneys as well as copper, lead, mercury, selenium and zinc in feathers. Relationships between element concentrations and Dunlin age, sex, bill length, habitat preference, trophic level, and sample group were investigated with regression analyses. Stable isotope ratios of carbon and nitrogen in Dunlin muscle tissue were used to determine habitat preference and trophic level, respectively. Cadmium concentrations in kidneys were significantly related to habitat preference: [Cd] in estuarine foragers >[Cd] in terrestrial foragers. Cadmium accumulation was age-dependent as concentrations increased significantly within 10 months of hatch dates but not afterward. Concentrations of cadmium and zinc in kidneys as well as lead and mercury in feathers were below those known to cause deleterious effects in birds. In contrast, selenium concentrations in feathers (range: 2.1–14.0 µg/g) were often at levels associated with toxicity risks (>5 µg/g). Toxicity thresholds are not available for copper in kidneys or copper and zinc in feathers; however, measured concentrations of these elements were within documented ranges for sandpipers. Future studies should assess potential impacts of selenium on embryonic development in Dunlin and other sandpipers. Risk assessments would yield more conclusive results for all elements if impacts under ecologically relevant stresses (e.g. development in the wild, migration, predation) were better understood.
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Winter body mass and over-ocean flocking as components of danger management by Pacific Dunlins
BMC Ecology, 2010Co-Authors: Ronald C. Ydenberg, Dick Dekker, Gary Kaiser, Philippa Cf Shepherd, Lesley Evans Ogden, Karen Rickards, David B. LankAbstract:Background We compared records of the body mass and roosting behavior of Pacific Dunlins ( Calidris alpina pacifica ) wintering on the Fraser River estuary in southwest British Columbia between the 1970s and the 1990s. 'Over-ocean flocking' is a relatively safe but energetically-expensive alternative to roosting during the high tide period. Fat stores offer protection against starvation, but are a liability in escape performance, and increase flight costs. Peregrine falcons ( Falco peregrinus ) were scarce on the Fraser River estuary in the 1970s, but their numbers have since recovered, and they prey heavily on Dunlins. The increase has altered the balance between predation and starvation risks for Dunlins, and thus how Dunlins regulate roosting behavior and body mass to manage the danger. We therefore predicted an increase in the frequency of over-ocean flocking as well as a decrease in the amount of fat carried by Dunlins over these decades. Results Historical observations indicate that over-ocean flocking of Dunlins was rare prior to the mid-1990s and became common thereafter. Residual body masses of Dunlins were higher in the 1970s, with the greatest difference between the decades coinciding with peak peregrine abundance in October, and shrinking over the course of winter as falcon seasonal abundance declines. Whole-body fat content of Dunlins was lower in the 1990s, and accounted for most of the change in body mass. Conclusions Pacific Dunlins appear to manage danger in a complex manner that involves adjustments both in fat reserves and roosting behavior. We discuss reasons why over-ocean flocking has apparently become more common on the Fraser estuary than at other Dunlin wintering sites.
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Raptor predation on wintering Dunlins in relation to the tidal cycle
The Condor, 2004Co-Authors: Dick Dekker, Ronald C. YdenbergAbstract:Abstract At Boundary Bay, British Columbia, Canada, Peregrine Falcons (Falco peregrinus) captured 94 Dunlins (Calidris alpina) in 652 hunts. The two main hunting methods were open attacks on flying Dunlins (62%) and stealth attacks on roosting or foraging Dunlins (35%). Peregrines hunted throughout the day, yet the kill rate per observation hour dropped 1–2 hr before high tide and peaked 1–2 hr after high tide. The drop in kill rate coincided with the departure of the mass of Dunlins for over-ocean flights lasting 2–4 hr. The peak in kill rate occurred just after the tide began to ebb and the Dunlins returned to forage in the shore zone. The hypothesis that closeness to shoreline vegetation is dangerous for Dunlins is supported by three converging lines of evidence: (1) the high success rate (44%) of peregrine hunts over the shore zone compared to the rate (11%) over tide flats and ocean; (2) the high kill rate per observation hour at high tide; and (3) the positive correlation of kill rate with the heigh...
Marcel G J Tilanus - One of the best experts on this subject based on the ideXlab platform.
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Mitochondrial control-region sequences in two shorebird species, the turnstone and the Dunlin, and their utility in population genetic studies.
Molecular biology and evolution, 1994Co-Authors: Paul W Wenink, Allan J Baker, Marcel G J TilanusAbstract:We determined the mitochondrial control-region sequences of five turnstones (Arenaria interpres) and three Dunlins (Calidris alpina). Comparisons revealed that the central part (part II) is conserved relative to much more variable parts at the beginning (part I) and the end (part III). This pattern of sequence conservation is also found in the control regions of other vertebrates. The average sequence divergence between turnstone and Dunlin was 21.8% for part I, 7.5% for part II, and 29.5% for part III. Within-species sequence divergence over the entire control region was much lower, at 0.9% for turnstones and 2.0% for Dunlins. In both shorebird species, part III contains a repetitive sequence composed only of A and C nucleotides, which has not been found in the control regions of other birds. A survey of the part I sequences of 25 turnstones and 25 Dunlins sampled around the world revealed that these species have very different population genetic structures. Dunlins are not only much more differentiated in their sequences but also have a strongly subdivided population genetic structure. Pleistocene vicariant events combined with strong natal philopatry and high mutation rates of the sequences are likely responsible for this population genetic subdivision. Conversely, part I sequences of turnstones are weakly differentiated and are geographically unstructured. We argue that this is not the result of global gene flow but that, instead turnstones have recently expanded from a refugial population that was bottlenecked.
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hypervariable control region sequences reveal global population structuring in a long distance migrant shorebird the Dunlin calidris alpina
Proceedings of the National Academy of Sciences of the United States of America, 1993Co-Authors: Paul W Wenink, Allan J Baker, Marcel G J TilanusAbstract:Abstract Hypervariable segments of the control region of mtDNA as well as part of the cytochrome b gene of Dunlins were amplified with PCR and sequenced directly. The 910 base pairs (bp) obtained for each of 73 individuals complete another of the few sequencing studies that examine the global range of a vertebrate species. A total of 35 types of mtDNA were detected, 33 of which were defined by the hypervariable-control-region segments. Thirty of the latter were specific to populations of different geographic origin in the circumpolar breeding range of the species. The remaining three types indicate dispersal between populations in southern Norway and Siberia, but female-mediated flow of mtDNA apparently is too low to overcome the effects of high mutation rates of the control-region sequences, as well as population subdivision associated with historical range disjunctions. A genealogical tree relating the types grouped them into five populations: Alaska, West Coast of North America, Gulf of Mexico, western Europe, and the Taymyr Peninsula. The Dunlin is thus highly structured geographically, with measures of mutational divergence approaching 1.0 for fixation of alternative types in different populations. High diversity of types within populations as well as moderate long-term effective population sizes argue against severe population bottlenecks in promoting this differentiation. Instead, population fragmentation in Pleistocene refuges is the most plausible mechanism of mtDNA differentiation but at a much earlier time scale than suggested previously with morphometric data.
Jon Gluyas - One of the best experts on this subject based on the ideXlab platform.
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The Dunlin, Dunlin SW, Osprey and Merlin fields, Blocks 211/23 and 211/24, UK North Sea
Geological Society London Memoirs, 2020Co-Authors: R. Ball, Jon GluyasAbstract:Abstract Located 160 km NE of the Shetland Islands in the East Shetland Basin, the Dunlin Cluster comprises four produced fields, Dunlin, Dunlin SW, Osprey and Merlin, in addition to some near-field satellite discoveries, Skye and Block 6. Dunlin was discovered in July 1973 and production began in August 1978. The field was developed using a concrete gravity-base platform, Dunlin Alpha, which also served as the production facility for the rest of the Dunlin Cluster. Osprey was discovered in 1974 but not tied-in until January 1991. Dunlin SW was discovered in 1973 but not brought onto production until 1996. Merlin was discovered in February 1997 and tied-in later that same year. Fairfield Energy acquired the Dunlin Cluster in 2008, and a programme of investment and facilities improvements, primarily in fuel gas infrastructure and power generation, sought to boost water-injection rates and bolster production, thereby extending the life of the asset. Ultimately, the Dunlin Cluster ceased production on 15 June 2015 after having maximized economic hydrocarbon recovery. The total Dunlin Cluster production exceeded 500 MMbbl of oil (Dunlin and Dunlin SW, 395 MMbbl oil; Osprey, 92 MMbbl oil; and Merlin, 27 MMbbl oil).
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the Dunlin Dunlin sw osprey and merlin fields blocks 211 23 and 211 24 uk north sea
Geological Society London Memoirs, 2020Co-Authors: R. Ball, Jon GluyasAbstract:Abstract Located 160 km NE of the Shetland Islands in the East Shetland Basin, the Dunlin Cluster comprises four produced fields, Dunlin, Dunlin SW, Osprey and Merlin, in addition to some near-field satellite discoveries, Skye and Block 6. Dunlin was discovered in July 1973 and production began in August 1978. The field was developed using a concrete gravity-base platform, Dunlin Alpha, which also served as the production facility for the rest of the Dunlin Cluster. Osprey was discovered in 1974 but not tied-in until January 1991. Dunlin SW was discovered in 1973 but not brought onto production until 1996. Merlin was discovered in February 1997 and tied-in later that same year. Fairfield Energy acquired the Dunlin Cluster in 2008, and a programme of investment and facilities improvements, primarily in fuel gas infrastructure and power generation, sought to boost water-injection rates and bolster production, thereby extending the life of the asset. Ultimately, the Dunlin Cluster ceased production on 15 June 2015 after having maximized economic hydrocarbon recovery. The total Dunlin Cluster production exceeded 500 MMbbl of oil (Dunlin and Dunlin SW, 395 MMbbl oil; Osprey, 92 MMbbl oil; and Merlin, 27 MMbbl oil).
