Offshore decommissioning activities are expected to increase as oil and gas subsea infrastructure becomes obsolete. Decisions on decommissioning alternatives will benefit from quantifying and ...understanding the marine communities associated with these structures. As a case study, fish assemblages associated with an inshore network of subsea pipelines located on the North West shelf of Western Australia were compared to those in surrounding natural reef and soft sediment habitats using remotely operated vehicles fitted with a stereo-video system (stereo-ROVs). The number of species, the abundance, biomass, feeding guild composition and the economic value of fishes were compared among habitats. The community composition of fish associated with pipelines was distinct from those associated with natural habitats, and was characterised by a greater abundance and/or biomass of fish from higher trophic levels (e.g. piscivores, generalist carnivores and invertivores), including many species considered to be of value to commercial and recreational fishers. Biomass of fish on pipelines was, on average, 20 times greater than soft sediments, and was similar to natural reefs. However, the biomass of species considered important to fisheries recorded on the pipelines was, on average 3.5 times greater than reef and 44.5 times greater than soft sediment habitats. This study demonstrates that fish assemblages on the pipeline infrastructure exhibit high ecological and socioeconomic values.
We compared and contrasted fish assemblage data sampled by baited remote underwater stereo-video systems (stereo-BRUVs) and stereo-video remotely operated vehicles (stereo-ROVs) from subsea ...pipelines, reef and soft sediment habitats. Stereo-BRUVs sampled greater fish diversity across all three habitats, with the stereo-ROV sampling ~46% of the same species on pipeline and reef habitats. Larger differences existed in soft sediment habitats, with stereo-BRUVs recording ~65% more species than the stereo-ROV, the majority of which were generalist carnivores. These differences were likely due to the bait used with stereo-BRUVs attracting fish from a large and unknown area. Fish may have also avoided the moving stereo-ROV, an effect possibly magnified in open soft sediment habitats. As a result of these biases, we recommend stereo-ROVs for assessing fish communities on pipelines due to their ability to capture fish in-situ and within a defined sampling area, but caution is needed over soft sediment habitats for ecological comparisons.
•Stereo-BRUVs and Stereo-ROV sampled different compositions of fish on and off the pipeline.•Stereo-ROV may under-sample fish in open sandy habitats.•Stereo-BRUVs may over-sample fine-scale habitat associations due to bait attraction.•Stereo-ROV samples fish-habitat associations in greater detail.•Stereo-ROV is a more suitable tool for sampling fish on pipeline and fine-scale structures.
As the offshore hydrocarbon industry matures and decommissioning activities are expected to increase, there is a requirement to assess the environmental consequences of different pipeline ...decommissioning options. Previous research on fish and other ecological components associated with pipelines has focused on examining species richness, abundance and biomass surrounding structures. The extent to which subsea pipelines mimic or alter ecosystem function compared with nearby natural habitats is unknown. We analyse differences in fish assemblage biological trait composition and the functional diversity at exposed shallow-water subsea pipelines, nearby natural reef and soft sediment habitats, using mini stereo-video remotely operated vehicles (ROV). Habitats significantly differed in assemblage trait composition. The pipeline and reef habitats shared a more similar functional composition and had the presence of key functional groups required for the development and maintenance of healthy coral reef systems. The reef habitat had the greatest functional diversity, followed by the pipeline habitat and soft sediment habitat respectively.
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•Understanding subsea pipeline ecology is crucial for assessing decommissioning options.•The functional composition of fish was distinct among habitats.•Pipeline habitat had defined functional grouping and species separation.•Reef habitat had greatest functional diversity, followed by pipeline and soft sediment.•Pipelines had key functional groups required for the development of healthy coral reef systems.
We investigated the composition and abundance of fish assemblages associated with seven offshore oil and gas platform jackets in the Gulf of Thailand before (pre-lift and pre-tow), and immediately ...after relocation (post-tow and reefed). Jackets were cut, lifted until partly out of the water, and attached to the rear of a heavy lift vessel. They were towed at speeds of 2.7 – 3.3 knots for between 133.9 and 205.4 km before being placed on the seafloor at an artificial reef site. Sixteen species of fish were observed both before and after jacket towing. We believe these species have sought refuge in the complex structures out of the current and have remained with the jackets. Ten species of fish were observed before towing, but not after. A further seven species of fish were only observed after the jackets were relocated onto the seafloor and were assumed to be early colonisers to the structures. The paper provides empirical evidence of a much-discussed paradigm that fish can swim great distances following moved structures, and further evidence of the ability of fish to rapidly colonise reefed structures.
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•Fish on oil and gas jackets were surveyed before, during and after towing.•16 species of fish remained with the jackets during relocation (followers).•10 species of fish did not follow the jackets (deserters).•7 new species of fish were observed (colonisers) within two days of placement of jackets on the seabed.•“Followers” likely sought refuge in the complex structures out of the current during towing.
Monitoring programs that aim to measure the diversity, abundance and biomass of fishes depend on accurate and reliable biological data to guide the development of robust management plans. It is ...important to implement an appropriate sampling technique that provides a comprehensive assessment, while reducing associated biases in the data collection process. We compared the sampling abilities of four different underwater stereo-video techniques; baited remote underwater stereo-video systems (BRUV), diver operated stereo-video (DOV), and two relatively new methodologies; slow towed stereo-video (STV) and remotely operated vehicle (ROV) fitted with a stereo-video. Comparisons were conducted in a temperate reef system along a single limestone ridge within Geographe Bay, Western Australia. More fish species and individuals were sampled by BRUVs, while transect based methods (DOV, STV, and ROV) were comparable. Combining BRUVs with a transect method resulted in a ~10% increase in observed diversity. BRUVs had a higher statistical power to detect change in comparison to the transect methods. This was due to the higher variability observed in transect methods that may sample greater habitat heterogeneity within a sample unit compared to BRUVs. Although differences did exist, data collected with the ROV was generally comparable to the other transect methods. We believe further research into ROV use is warranted as they provide a safer alternative to diver-based techniques and have the ability to extend into deeper-waters. We recommend that for fish diversity and abundance assessments a sampling strategy that combines BRUVs and a transect method should be adopted.
•BRUVs sampled more fish and species compared to transect methods which were similar.•Using BRUVs with a transect based method increased observed diversity by ~10%.•BRUVs had the greatest statistical power to detect changes in fish assemblages.•Transects sample within habitat heterogeneity and ROV provides a safety advantage.
There is growing interest in understanding the ecological benefits of oil and gas structures. This is the first reported case of the spawning aggregation and mating behaviour of bigeye trevally, ...Caranx sexfasciatus, associated with an oil and gas platform, demonstrating that oil and gas jackets are capable of not only attracting large aggregations of fish, but can provide suitable conditions for reproductive purposes. Fish spawning aggregations (FSAs) are highly vulnerable events that are vitally important for the persistence of many fish species. Urgent protection and conservation of FSA sites is required to secure them from the threat of overfishing. The findings of this study bring into question the management strategies required for oil and gas structures, particularly related to removal during decommissioning, or where structures are left in place and safety exclusion zones no longer apply. These aggregations and behaviours were captured using underwater stereo-video Remotely Operated Vehicle (ROV) methods, allowing for detailed observations.
•Bigeye trevally, Caranx sexfasciatus, were observed spawning at an oil and gas platform jacket in the Gulf of Thailand.•The platform is likely to have site characteristics conducive to spawning for multiple species, similar to a “pinnacle”.•Trevally were observed spawning on the later side of the wider regional spawning period.•Fertilised eggs and larvae may travel to the nearby natural reef (∼150 km away) or mangroves.•Findings of this study contribute to the increasing evidence base that oil and gas platforms provide ecological value.
Background The lack of longitudinal data analyses from birth to adulthood is hampering long-term asthma prevention strategies. Objective We aimed to determine early-life predictors of asthma ...incidence up to age 20 years in a birth cohort study by applying time-to-event analysis. Methods In 1990, the Multicenter Allergy Study included 1314 newborns in 5 German cities. Children were evaluated from birth to age 20 years at 19 time points. Using a Cox regression model, we examined the associations between 36 early-life factors and onset of asthma based on a doctor's diagnosis or asthma medication (primary outcome), typical asthma symptoms, or allergic asthma (including positive IgE measurements). Results Response at 20 years was 71.6%. Two hundred eighteen subjects met the primary outcome criteria within 16,257 person years observed. Asthma incidence was lower in participants who were vaccinated (measles, mumps, and rubella vaccine/tick-borne encephalitis vaccine/BCG vaccine: adjusted hazard ratio HR, 0.66 95% CI, 0.47-0.93). Up to age 20 years, asthma incidence was higher in subjects who had parents with allergic rhinitis (adjusted HR, 2.24 95% CI, 1.67-3.02), started day care early or late (before 18 months: adjusted HR, 1.79 95% CI, 1.03-3.10; after 3 years: adjusted HR, 1.64 95% CI, 0.96-2.79), had mothers who smoked during pregnancy (adjusted HR, 1.79 95% CI, 1.20-2.67), had poor parents (adjusted HR, 1.55 95% CI, 1.09-2.22), and had parents with asthma (adjusted HR, 1.65 95% CI, 1.17-2.31). Not associated with asthma were aspects of diet and breast-feeding, pet ownership, presence of older siblings, and passive smoking. Conclusion Parental asthma and nasal allergy increase asthma incidence in offspring up to adulthood. Avoiding tobacco smoke exposure during pregnancy, receiving vaccinations in early childhood, and starting day care between 1.5 and 3 years of age might prevent or delay the development of asthma.
Background Allergic rhinitis (AR) is one of the most common chronic diseases, usually starting in the first 2 decades of life. Information on predictors, risk, and protective factors is missing ...because of a lack of long-term prospective studies. Objective Our aim was to examine early-life environmental and lifestyle determinants for AR up to age 20 years. Methods In 1990, the Multicenter Allergy Study included 1314 newborns in 5 German cities. Children were evaluated at 19 time points. A Cox regression model examined the associations between 41 independent early-life factors and onset of AR (as the primary outcome), including sensitization against aeroallergens and the secondary outcomes of nonallergic rhinitis and AR plus asthma. Results Two hundred ninety subjects had AR within 13,179 person years observed. The risk of AR was higher with a parental history of AR (adjusted hazard ratio aHR, 2.49; 95% CI, 1.93-3.21), urticaria (aHR, 1.32; 95% CI, 1.00-1.74), or asthma (aHR, 1.29; 95% CI, 0.95-1.75). Early allergic sensitization (aHR, 4.53; 95% CI, 3.25-6.32), eczema within the first 3 years of life (aHR, 1.83; 95% CI, 1.38-2.42), male sex (aHR, 1.28; 95% CI, 1.02-1.61), and birthday in summer or autumn (aHR, 1.26; 95% CI, 1.00-1.58) were independent predictors of AR up to age 20 years. None of the other socioeconomic, environmental, lifestyle, pregnancy, and birth-related factors were associated with AR. Conclusion Only nonmodifiable factors, particularly early allergic sensitization or eczema and parental AR, predicted AR up to age 20 years. No modifiable aspects of early-life environment or lifestyle were identified as targets for primary prevention.
Adaptive thermogenesis is the process of heat generation in response to cold stimulation. It is under the control of the sympathetic nervous system, whose chief effector is the catecholamine ...norepinephrine (NE). NE enhances thermogenesis through β3-adrenergic receptors to activate brown adipose tissue and by 'browning' white adipose tissue. Recent studies have reported that alternative activation of macrophages in response to interleukin (IL)-4 stimulation induces the expression of tyrosine hydroxylase (TH), a key enzyme in the catecholamine synthesis pathway, and that this activation provides an alternative source of locally produced catecholamines during the thermogenic process. Here we report that the deletion of Th in hematopoietic cells of adult mice neither alters energy expenditure upon cold exposure nor reduces browning in inguinal adipose tissue. Bone marrow-derived macrophages did not release NE in response to stimulation with IL-4, and conditioned media from IL-4-stimulated macrophages failed to induce expression of thermogenic genes, such as uncoupling protein 1 (Ucp1), in adipocytes cultured with the conditioned media. Furthermore, chronic treatment with IL-4 failed to increase energy expenditure in wild-type, Ucp1
and interleukin-4 receptor-α double-negative (Il4ra
) mice. In agreement with these findings, adipose-tissue-resident macrophages did not express TH. Thus, we conclude that alternatively activated macrophages do not synthesize relevant amounts of catecholamines, and hence, are not likely to have a direct role in adipocyte metabolism or adaptive thermogenesis.
Repeat carotid endarterectomy (CEA) for recurrent stenosis remains a challenging treatment option associated with high morbidity and mortality. Carotid artery stenting (CAS) is an attractive ...alternative management option for these patients. However, data about the effectiveness and safety of CAS in a large number of unselected patients are less known. We evaluated 3,070 patients who underwent CAS enrolled in a German registry from 1996 to 2006 at 31 sites. We compared clinical and angiographic features and inhospital outcomes of patients with and without previous CEA who underwent CAS. Of 3,070 patients in the registry, 223 (7.3%) underwent CAS for restenosis after previous CEA. Median age was similar in patients with and without previous CEA (70 years, interquartile range 64 to 76 vs 71 years, interquartile range 65 to 76). Ipsilateral neurologic symptoms occurred in approximately 1/2 the patients in both groups. Other co-morbid conditions and angiographic or procedural factors did not differ between the 2 groups. Inhospital events including death (0% vs 0.4%), ipsilateral major stroke (1.4% vs 1.5%), death or major ipsilateral stroke (1.4% vs 1.7%), ipsilateral transient ischemic attack (1.9% vs 2.8%), myocardial infarction (0.4% vs 0.1%), and reintervention (0.7% vs 0.4%) were all low and not significantly different between those with and without previous CEA (p >0.05 for all comparisons). In conclusion, our data for a large number of patients who underwent CAS in a recent contemporary community-based practice attests to the low risk of periprocedural events in patients with recurrent stenosis after previous CEA. This low risk along with the less invasive nature of the procedure should make CAS an attractive and perhaps preferred option for the treatment of these patients.
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