Distinguishing between contaminant and reef effects on meiofauna near offshore hydrocarbon platforms in the Gulf of Mexico

2002 ◽  
Vol 59 (10) ◽  
pp. 1584-1592 ◽  
Author(s):  
Paul A Montagna ◽  
Stephen C Jarvis ◽  
Mahlon C Kennicutt, II
Keyword(s):  
Gulf Of Mexico ◽  
Artificial Reef ◽  
Artificial Reefs ◽  
Offshore Platforms ◽  
Ecological Interactions ◽  
Fouling Community ◽  
Hydrocarbon Production ◽  
Future Studies ◽  
Production Techniques ◽  
Production Effects

Offshore hydrocarbon production effects are localized in the Gulf of Mexico extending only 200 m from platforms. Effects are caused by the contaminant gradient or the fouling community on platform legs. To distinguish between contaminant and reef effects, meiofauna were sampled at production platforms (reef and contaminant effects), artificial reefs (reef, but no contaminant effects), platform removal sites (contaminant, but no reef effects), and controls (no contaminants or reef effects), and replicated in three blocks. The removal sites had higher concentrations of many contaminants than reef or control sites, but lower concentrations than platform sites. Reduced meiobenthic abundances and altered Harpacticoida community structure were primarily a function of reef effects, not contaminant effects. The habitat influence is likely a result of complex ecological interactions near platforms. The reef effect appears to be important in controlling meiofauna near platforms where contaminants are low because of drilling and production techniques used in the Gulf of Mexico. The finding that contaminants alone do not explain faunal patterns around offshore platforms indicates that future studies should include appropriate artificial reef control sites.

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Sex Ratio ◽  
Gulf Of Mexico ◽  
Artificial Reef ◽  
Fork Length ◽  
South Texas ◽  
Spawning Season ◽  
Artificial Reefs ◽  
Batch Fecundity ◽  
Balistes Capriscus ◽  
Gray Triggerfish

<em>Abstract</em>.—Artificial reefs in the northwest Gulf of Mexico act as preferential habitat for Gray Triggerfish <em>Balistes capriscus </em>(Gmelin, 1789) and are heavily targeted by local and international fishing efforts. Three artificial reefs off the south Texas coast were studied to investigate the reproductive characteristics of this ubiquitous reef member whose importance to both commercial and recreational fishing has resulted in a dramatic reduction in Gulf of Mexico-wide estimated biomass for the past 20 years. Characteristics examined included sex ratio, peak spawning season, batch fecundity of females (1 × 10<sup>6</sup> oocytes), fork length (FL, mm) at maturity, and batch fecundity as a function of FL or weight (i.e., Δ1 × 10<sup>6</sup> oocytes = ΔFL). These characteristics were investigated to build a foundational understanding of an understudied region of the Gulf and a relatively new artificial reef habitat. Reef sites managed by the Texas Parks and Wildlife Department Artificial Reef Program were sampled for 1 year, yielding 112 individuals. The sex ratio was 1:1 males to females but varied among sample sites, suggesting that an unidentified factor may have influenced aggregations of males and females. Spawning season was similar in other regions of the Gulf of Mexico (i.e., between June and August with a peak in July). Female batch fecundity was 7.36 × 10<sup>5</sup> ± 2.69 × 10<sup>5</sup> mature oocytes, and the batch fecundity to FL relationship was 14.353 × FL<sup>1.88</sup>, similar to other populations of Gray Triggerfish in the Gulf of Mexico.

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Standard Deviation ◽  
Gulf Of Mexico ◽  
Fisheries Management ◽  
Artificial Reef ◽  
Growth Patterns ◽  
Red Snapper ◽  
Age And Growth ◽  
Artificial Reefs ◽  
Lutjanus Campechanus ◽  
Management Objectives

<em>Abstract</em>.—Identifying morphometrics, age composition, and growth of Red Snapper <em>Lutjanus campechanus </em>(Poey, 1860) in the Gulf of Mexico is crucial for management of this valuable species. Red Snapper are highly associated with artificial reefs situated off the coast of Texas. Artificial reefs, two in federal waters (offshore) and two in state waters (inshore), were sampled quarterly from December 2014 through December 2016. Characteristic differences in age and growth patterns at inshore and offshore sites and across sampled sites were compared. Mean ± standard deviation was calculated for total length (TL), weight, and biological age. Red Snapper collected averaged 464.5 ± 92.6 mm in TL, 1.62 ± 1.03 kg, and 3.8 ± 1.5 years. Significant differences in TL, weight, and age were observed across sites but not between inshore and offshore locations. In comparing 12 previous Red Snapper length-at-age (0–25 years) studies across the Gulf of Mexico, results were similar except for two studies significantly different from one another, but none with respect to our study. Our findings suggest that Red Snapper populations are young and restricted to one or two spawning years before capture on artificial reefs. Continued management of fisheries associated with these reefs are necessary to increase the stock and eventually lead to robust and sustainable fisheries.

Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives

2018 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Gulf Coast ◽  
Artificial Reef ◽  
Reef Fishes ◽  
Fishing Effort ◽  
Artificial Reefs ◽  
Recreational Fishing ◽  
Lutjanus Campechanus ◽  
Associated Species ◽  
Method Of Assessment

<em>Abstract</em>.—Florida boasts an abundance of natural and artificial reefs that support a large and diverse recreational fishery off the Gulf of Mexico coast. Recent efforts to mitigate the effects of the <em>Deepwater Horizon </em>oil spill have increased the number of artificial reefs deployed off Florida’s Gulf Coast. Fisheries-dependent data are needed to assess whether artificial reef programs are meeting intended objectives and to understand changes in recreational angler behavior, which may influence catch per unit effort and biomass of landed fish. The objective of this study was to quantify the use of artificial reefs by recreational anglers targeting reef fishes in the Gulf of Mexico off the west coast of Florida. We utilized an existing survey designed to monitor recreational fishing effort by anglers that target reef fishes from private boats. Over a 20-month period, an estimated total of 776,026 (SD ±27,540) angler trips targeted reef fishes off the Gulf Coast of Florida, of which 46% utilized artificial reefs. Approximately two-thirds of all reef angling trips took place nearshore in state-managed waters, and 70% of trips that utilized artificial reefs occurred in this area. Regionally, the highest proportion of angler trips targeting reef-associated species on artificial reefs took place in the panhandle of Florida, where Red Snapper <em>Lutjanus campechanus </em>are most abundant. Seasonally, state and federal fishing regulations also had an apparent influence on fishing effort and artificial reef use by recreational anglers. The method of assessment we present here could be useful for monitoring future trends in recreational fishing effort with respect to artificial reefs.

scholarly journals Exploring the Spatial Variations of Stressors Impacting Platform Removal in the Northern Gulf of Mexico

2021 ◽  
Vol 9 (11) ◽  
pp. 1223
Author(s):  
Jake R. Nelson ◽  
Lucy Romeo ◽  
Rodrigo Duran
Keyword(s):  
Gulf Of Mexico ◽  
Regional Scale ◽  
Oil Extraction ◽  
Offshore Platforms ◽  
Operating Environment ◽  
Internal Factors ◽  
Actionable Knowledge ◽  
Future Studies ◽  
Offshore Oil ◽  
Shed Light

Although progress has been made to advance our understanding of the risks involved in offshore oil extraction activities, a regional scale understanding of factors contributing to losses in infrastructure integrity are lacking. Recent data integration efforts have resulted in a comprehensive database that allows for an unprecedented study of the external and internal factors that impact the structural and operational integrity of offshore platforms in the Gulf of Mexico. This study constitutes some of the initial explorations into that database by focusing on the relationships among a diverse set of variables and the age at which a platform is removed. We apply Geographically Weighted Regression to account for the heterogeneity of the operating environment, finding robust yet unexpected relationships that shed light on some of the factors that influence platform removal. Our findings pave the way for future studies aimed at building actionable knowledge.

scholarly journals Preliminary Evaluation of the Effectiveness of Using Artificial Reefs to Reduce Breaking Wave Impact on Offshore Structures

2017 ◽  
Author(s):  
Charlotte Loedsen Andersen ◽  
Ida Skov Milthers ◽  
Julie Caroee Kristoffersen ◽  
Christos Thomas Georgakis ◽  
Longbin Tao
Keyword(s):  
Artificial Reef ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Artificial Reefs ◽  
Breaking Wave ◽  
Preliminary Evaluation ◽  
Offshore Platforms ◽  
Wave Impact ◽  
Maximum Displacement ◽  
The People

Waves breaking on offshore platforms can have damaging consequences for the structure and for the safety of the people working on it. Recent unexpected extreme wave events have shown the effects that breaking waves have on offshore platforms. In this paper, the results from a scaled experimental investigation conducted the Newcastle University wind, wave and current tank, are presented. With these tests, the effectiveness of using artificial reefs to avoid or lessen the effects of breaking wave activity is examined. Four different types of artificial reefs are tested and their effects are compared to a reference test with no artificial reef. The comparison is based on the changes of the size and location of the maximum wave amplitude, the maximum displacement of a scaled platform and the artificial reef’s ability to dissipate wave energy. Overall, the results show that placing the rectangular reef in the tank produces the most promising results. However, it is also shown that placing any one of the artificial reefs in the tank will affect a change in the wave motion. Thus, this investigation shows that the use of an artificial reef could be a step in securing a higher level of protection for personnel and operations.

Feasibility of Repurposing Offshore Decommissioned Gas Rigs into Fish Farms

2021 ◽  
Author(s):  
Saptarshi Pal ◽  
Chengi Kuo
Keyword(s):  
North Sea ◽  
Net Present Value ◽  
Cost Benefit Analysis ◽  
Storage System ◽  
Artificial Reef ◽  
Cost Benefit ◽  
Fish Farm ◽  
Fish Feed ◽  
Offshore Platforms ◽  
Fish Farms

Abstract In the past 70 years the world has relied extensively for its energy needs based on hydrocarbons produced significantly offshore. In recent years many installations with fixed platforms and pipelines are reaching the end of their useful life and are required by law to be decommissioned and removed if an approved alternative use cannot be found. This process coincides with focus on decarbonization arising from global warming and climate change. The conventional way of decommissioning is to remove the structure and take it onshore for disposal. Such an activity costs around £28 million for smaller UKCS installations in the Southern North Sea. Possible alternative solutions include their use as a research-leisure complex and artificial reef. Such an approach would have less impact on the environment and it is therefore worthwhile to explore the feasibility of repurposing these decommissioned UKCS platforms. The paper begins by highlighting the background to UKCS offshore decommissioning and farming fish life-cycle. This is followed by a critical review of the three options of total and partial removals and leave-on-site. It is found that repurposing decommissioned platforms for aquaculture farm has not been given sufficient attention and thus offers scope for a project to explore the feasibility of such a solution. Existing offshore fish farming in various countries are examined before using a decision-making matrix to select the most suitable UKCS installation for conversion and this led to using a normally unattended gas platform for the case study. The focus for this paper is on design and operation of an unattended fish farm and its cost benefit analysis. The former covers fish cage selection, capacity calculation, fish handling procedures, fish feed characteristics, feed demand, designing feed logistics and storage system. The processing facilities are layout on two decks and power needs are generated using a hybrid system of diesel and Li-ion battery. The possibility of using renewable sources by connecting to wind energy grids was also considered. For the latter capital and operating expenditure, revenue generated and maintenance costs are estimated before performing net present value prediction of the profitability of the fish farm over 10 years with for example up to 8 cages and three discount rates. The main conclusions derived are: It is technically feasible to convert a decommissioned gas platform to a fish farm and the operation can be economic. However, liability transfer implications in a repurposed offshore decommissioned gas platforms to fish farms were not established to verify the project viability. The conversion of unattended offshore gas platforms in the UKCS to an automated offshore fish farm is a novel solution which has not been implemented in the North Sea before. The work will provide an economic and environmental friendly solution to decommissioning offshore platforms and provide with a possible profitable investment.

scholarly journals REDUCTION OF WAVE OVERTOPPING RATE BY THE USE OF ARTIFICIAL REEFS

1988 ◽  
Vol 1 (21) ◽  
pp. 23
Author(s):  
Toru Sawaragi ◽  
Ichiro Deguchi ◽  
San-Kil Park
Keyword(s):  
Wave Breaking ◽  
Artificial Reef ◽  
Numerical Procedure ◽  
Artificial Reefs ◽  
Irregular Waves ◽  
Analysis Method ◽  
Wave Analysis ◽  
Wave Overtopping ◽  
Unidirectional Flow ◽  
Individual Wave

A wave overtopping rate from a sea dike of various toe depths is formulated based on a weir model in an unidirectional flow. To evaluated the wave overtopping rate from a seadike on an artificial reef by the weir model, a numerical procedure for predicting wave transformations including the effect of forced wave breaking on the reef is constructed. After confirming the applicability of the model through experiments with regular and irregular waves, the effect of artificial reef on wave overtopping is discussed. So-called individual wave analysis method is shown to he applicable to the wave overtopping caused by irregular waves.

scholarly journals A seascape approach for guiding effective habitat enhancement

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Filippo Ferrario ◽  
Thew Suskiewicz ◽  
Ladd Erik Johnson
Keyword(s):  
Artificial Reefs ◽  
Spatially Explicit ◽  
Ecological Interactions ◽  
Eastern Canada ◽  
Algal Cover ◽  
Artificial Structures ◽  
The Past ◽  
Green Sea Urchin ◽  
Ecological Importance ◽  
Habitat Enhancement

Kelp habitats are threatened across the globe, and because of their ecological importance, active conservation and restoration solutions are needed. The use of man-made structures as artificial reefs is one way to enhance kelp habitat by providing suitable substrata, but in the past the ecology of artificial structures has been investigated mainly in contrast to natural coastal habitats, not as elements integrated into the seascape. Indeed, it is now emerging that structuring processes, including ecological interactions (e.g., herbivory), can depend on properties of the surrounding seascape. In Eastern Canada, grazing by the green sea urchin can jeopardize the success of artificial reefs for kelp enhancement. Urchin activity is, however, likely to be influenced by the bottom composition, and thus a seascape approach is needed to integrate urchin behavior and habitat heterogeneity. Adopting a spatially explicit framework, we investigated whether the seascape creates areas of differential grazing risk for kelp by affecting urchin habitat use. Specifically, we transplanted kelp onto modules of artificial substrata distributed on a heterogeneous area that we mapped for bottom type and algal cover. After following kelp survival and urchin distribution over time, we modeled kelp survival as function of urchin metrics and coupled it to urchin use of the habitat models to map grazing risk in the area. Kelp survival was a function of the frequency of the urchins presence. Urchins avoided sandy patches, while bottom composition and algal cover modulated the within-patch urchin use of the habitat, creating heterogeneity in grazing risk. Discrete seascape features (boulders) also increased the grazing risk locally. The heterogeneity of coastal seafloor can thus play a major role in determining the ecological outcomes on artificial structures. Incorporating this information when planning artificial reefs could minimize the detrimental grazing risk, thereby increasing the success of artificial reefs for kelp habitat enhancement.

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