Development of Measurement Methods for Testing of Hydrokinetic Devices to Evaluate the Environmental Effect on Local Substrate

Modifications and upgrades to the hydraulic flume facility in the Environmental Fluid Mechanics and Hydraulics Laboratory (EFM&H) at Bucknell University are described. These changes enable small-scale testing of model marine hydrokinetic(MHK) devices. The design of the experimental platform provides a controlled environment for testing of model MHK devices to determine their effect on localsubstrate. Specifically, the effects being studied are scour and erosion around a cylindrical support structure and deposition of sediment downstream from the device.

Marine fish assemblages associated with fish aggregating devices (FADs): effects of fish removal, FAD size, fouling communities, and prior recruits

Fishes are widely known to aggregate around floating objects, including flotsam and fish aggregating devices (FADs).The numbers and diversity of juvenile fishes that associated with floating objects in the nearshore waters of the eastern tropical Pacific were recording by using FADs as an experimental tool. The effects of fish removal, FAD size, and the presence or absence of a fouling community at the FAD over a period of days, and the presence of prior recruits over a period of hours were evaluated by using a series of experiments. The removal of FAD-associated fish assemblages had a significant effect on the number of the dominant species (Abudefduf troschelii) in the following day’s assemblage compared to FADs where the previous day’s assemblage was undisturbed; there was no experimental effect on combined species totals. Fishes do, however, discriminate among floating objects, forming larger, more species-rich assemblages around large FADs compared to small ones. Fishes also formed larger assemblages around FADs possessing a fouling biota versus FADs without a fouling biota, although this effect was also closely tied to temporal factors. FADs enriched with fish accumulated additional recruits more quickly than FADs that were not enriched with fish and therefore the presence of prior recruits had a strong, positive effect on subsequent recruitment. These results suggest that fish recruitment to floating objects is deliberate rather than haphazard or accidental and they sup-port the hypothesis that flotsam plays a role in the interrelationship between environment and some juvenile fishes. These results are relevant to the use of FADs for fisheries, but emphasize that further research is necessary for applied interests.

Practical aspects of frequency-domain identification of dynamic models of marine structures from hydrodynamic data

The motion response of marine structures in waves can be studied using finite-dimensional linear-time-invariant approximating models. These models, obtained using system identification with data computed by hydrodynamic codes, find application in offshore training simulators, hardware-in-the-loop simulators for positioning control testing, and also in initial designs of wave-energy conversion devices. Different proposals have appeared in the literature to address the identification problem in both time and frequency domains, and recent work has highlighted the superiority of the frequency-domain methods. This paper summarises practical frequency-domain estimation algorithms that use constraints on model structure and parameters to refine the search of approximating parametric models. Practical issues associated with the identification are discussed, including the influence of radiation model accuracy in force-to-motion models, which are usually the ultimate modelling objective. The illustration examples in the paper are obtained using a freely available MATLAB toolbox developed by the authors, which implements the estimation algorithms described.

Method for comparing the capture efficiency of benthic sampling devices

Traditional comparisons between the capture efficiency of sampling devices have generally looked at the absolute differences between devices. We recommend that the signal-to-noise ratio be used when comparing the capture efficiency of benthic sampling devices. Using the signal-to-noise ratio rather than the absolute difference has the advantages that the variance is taken into account when determining how important the difference is, the hypothesis and minimum detectable difference can be made identical for all taxa, it is independent of the units used for measurement, and the sample-size calculation is independent of the variance. This new technique is illustrated by comparing the capture efficiency of a 0.05 m(2) van Veen grab and an airlift suction device, using samples taken from Heron and One Tree lagoons, Australia.

A spatial assessment of the risk to a mobile marine mammal from bycatch

Several species of marine mammals are at risk of extinction from being captured as bycatch in commercial fisheries. Various approaches have been developed and implemented to address this bycatch problem, including devices and gear changes, time and area closures and fisheries moratoria. Most of these solutions are difficult to implement effectively, especially for artisanal fisheries in developing countries and remote regions. Re-zoning of the Great Barrier Reef World Heritage Area (GBRWHA) in 2004 closed 33% of the region to extractive activities, including commercial fishing. However, the impact of re-zoning and the associated industry restructuring on a threatened marine mammal, the dugong (Dugong dugon), is difficult to quantify. Accurate information on dugong bycatch in commercial nets is unavailable because of the large geographic extent of the GBRWHA, the remoteness of the region adjacent to the Cape York Peninsula where most dugongs occur and the artisanal nature of the fishery. In the face of this uncertainty, a spatial risk-assessment approach was used to evaluate the re-zoning and associated industry restructuring for their ability to reduce the risk of dugong bycatch from commercial fisheries netting. The new zoning arrangements appreciably reduced the risk of dugong bycatch by reducing the total area where commercial netting is permitted. Netting is currently not permitted in 67% of dugong habitats of high conservation value, a 56% improvement over the former arrangements. Re-zoning and industry restructuring also contributed to a 22% decline in the spatial extent of conducted netting. Spatial risk assessment approaches that evaluate the risk of mobile marine mammals from bycatch are applicable to other situations where there is limited information on the location and intensity of bycatch, including remote regions and developing countries where resources are limited.

Informational report: Bycatch reduction devices used in the Pink Shrimp trawl fishery

The California Fish and Game Commission (Commission) has the authority to require one or any combination of Bycatch Reduction Device (BRD) types in the trawl fishery within California waters for Pacific ocean shrimp (Pandalus jordani), most commonly referred to as pink shrimp. The purpose of this report is to provide the Commission with the best available information about the BRDs used in the pink shrimp trawl fishery. The mandatory requirement for BRDs occurred in California in 2002, and in Oregon and Washington in 2003, resulting from an effort to minimize bycatch of overfished and quota managed groundfish species. Three types of BRDs currently satisfy the requirement for this device in the California fishery: 1) the Nordmøre grate (rigid-grate excluder); 2) soft-panel excluder; and 3) fisheye excluder; however, the design, specifications, and efficacy differ by BRD type. Although no data has been collected on BRDs directly from the California pink shrimp fishery, extensive research on the efficacy and differences among BRD types has been conducted by the Oregon Department of Fish and Wildlife (ODFW) since the mid-1990s. Rigid-grate excluders are widely considered to be the most effective of the three BRD types at reducing groundfish bycatch. Over 90 percent of the Oregon pink shrimp fleet use rigid-grate excluders. The majority of the current California pink shrimp fleet also uses rigid-grate excluders, according to a telephone survey conducted by the California Department of Fish and Game (Department) in 2007-2008 of pink shrimp fishermen who have been active in the California fishery in recent years. Hinged rigid-grate excluders have been developed in recent years to reduce the bending of the BRD on vessels that employ net reels to stow and deploy their trawl nets, and they have been used successfully on both single- and double-rig vessels in Oregon. Soft-panel excluders have been demonstrated to be effective at reducing groundfish bycatch, although excessive shrimp loss and other problems have also been associated with this design. Fisheye excluders have been used in the California fishery in the past, but they were disapproved in Oregon and Washington in 2003 because they were found to be less effective at reducing groundfish bycatch than other designs. The reputation of the United States west coast pink shrimp fishery as one of the cleanest shrimp fisheries in the world is largely attributed to the effectiveness of BRDs at reducing groundfish bycatch. Nevertheless, BRD research and development is still a relatively new field and additional modifications and methods may further reduce bycatch rates in the pink shrimp fishery.(PDF contains 12 pages.)

Biological Platforms for Environmental Sensor technologies and their uses as indicators of the marine environment, Seward, Alaska, September 19-21, 2007: workshop proceedings

The Alliance for Coastal Technologies (ACT) Workshop entitled, "Biological Platforms as Sensor Technologies and their Use as Indicators for the Marine Environment" was held in Seward, Alaska, September 19 - 21,2007. The workshop was co-hosted by the University of Alaska Fairbanks (UAF) and the Alaska SeaLife Center (ASLC). The workshop was attended by 25 participants representing a wide range of research scientists, managers, and manufacturers who develop and deploy sensory equipment using aquatic vertebrates as the mode of transport. Eight recommendations were made by participants at the conclusion of the workshop and are presented here without prioritization: 1. Encourage research toward development of energy scavenging devices of suitable sizes for use in remote sensing packages attached to marine animals. 2. Encourage funding sources for development of new sensor technologies and animal-borne tags. 3. Develop animal-borne environmental sensor platforms that offer more combined systems and improved data recovery methodologies, and expand the geographic scope of complementary fixed sensor arrays. 4. Engage the oceanographic community by: a. Offering a mini workshop at an AGU ocean sciences conference for people interested in developing an ocean carbon program that utilizes animal-borne sensor technology. b. Outreach to chemical oceanographers. 5. Min v2d6.sheepserver.net e and merge technologies from other disciplines that may be applied to marine sensors (e.g. biomedical field). 6. Encourage the NOAA Permitting Office to: a. Make a more predictable, reliable, and consistent permitting system for using animal platforms. b. Establish an evaluation process. c. Adhere to established standards. 7. Promote the expanded use of calibrated hydrophones as part of existing animal platforms. 8. Encourage the Integrated Ocean Observing System (IOOS) to promote animal tracking as effective samplers of the marine environment, and use of animals as ocean sensor technology platforms. [PDF contains 20 pages]

Interactions Between Platform Terminal Transmitters and Turtle Excluder Devices

Satellite telemetry is a common tool for examining sea turtle movements, and many research programs have successfully tracked adults. Relatively short satellite track durations recorded for juvenile Kemp’s ridley sea turtles, Lepidochelys kempii, in the northwestern Gulf of Mexico raised questions regarding premature transmission loss. We examined interactions between juvenile sea turtles outfitted with platform terminal transmitters (PTT’s) and turtle excluder devices (TED’s) and the potential for transmission loss due to this interaction. A pilot study was conducted with eight 34-month-old, captive-reared loggerhead sea turtles, Caretta caretta; a larger trial the following year used twenty 34-month-olds. Half of the turtles in each trial were outfitted with dummy PTT’s (8×4×2 cm), and all turtles were sent through a trawl equipped with a bottom-opening Super-Shooter TED. No apparent damage was sustained by any PTT, but four of five PTT-outfitted loggerheads encountering the TED carapace-first exhibited increased escape times when the PTT wedged between the TED deflector bars (10.2 cm apart). Overall, 15 loggerheads (54%) impacted the TED carapace-first. Attachment of PTT’s to smaller sea turtles may slow or, in worst cases, inhibit escape from TED’s. Likewise, loose or poorly secured PTT’s could impede escape or be shed during such an interaction. Researchers tracking small turtles in or near regions with trawling activity should consider PTT size and shape and the combined PTT/adhesive profile to minimize potentially detrimental interactions with TED’s.

Characteristics of the wave energy resource at the Atlantic marine energy test site

The wave energy industry is progressing towards an advanced stage of development, with consideration being given to the selection of suitable sites for the first commercial installations. An informed, and accurate, characterisation of the wave energy resource is an essential aspect of this process. Ireland is exposed to an energetic wave climate, however many features of this resource are not well understood. This thesis assesses and characterises the wave energy resource that has been measured and modelled at the Atlantic Marine Energy Test Site, a facility for conducting sea trials of floating wave energy converters that is being developed near Belmullet, on the west coast of Ireland. This characterisation process is undertaken through the analysis of metocean datasets that have previously been unavailable for exposed Irish sites. A number of commonly made assumptions in the calculation of wave power are contested, and the uncertainties resulting from their application are demonstrated. The relationship between commonly used wave period parameters is studied, and its importance in the calculation of wave power quantified, while it is also shown that a disconnect exists between the sea states which occur most frequently at the site and those that contribute most to the incident wave energy. Additionally, observations of the extreme wave conditions that have occurred at the site and estimates of future storms that devices will need to withstand are presented. The implications of these results for the design and operation of wave energy converters are discussed. The foremost contribution of this thesis is the development of an enhanced understanding of the fundamental nature of the wave energy resource at the Atlantic Marine Energy Test Site. The results presented here also have a wider relevance, and can be considered typical of other, similarly exposed, locations on Ireland’s west coast.

The Impact of Offshore Wind Farms on Marine Ecosystems: A Review Taking an Ecosystem Services Perspective

The rapid increase in renewable energy generation from wind has increased concerns about the impacts that wind arrays have on the marine environment and what these impacts mean for society. One method for identifying the impacts of offshore wind farms (OWFs) on human welfare is through the assessment and valuation of ecosystem services. Using an ecosystem services approach, this paper reviews the impacts of OWFs on the ecosystem services delivered by marine environments. During the construction phase, supporting services such as reduced energy capture and nutrient cycling are changed due to the introduction of hard substrate and the reduction in soft sediment habitat at turbine bases. This may lead to changes in all other ecosystem services, both negative and positive. Quantifying these changes, however, is a challenge partly due to data limitations and a lack of clear understanding of the impacts of OWFs on the marine ecosystems. Scientific effort needs to quantitatively explore the impacts of OWFs on ecosystem functionality and the gathering of data that enables the assessment of changes to ecosystem services. Data needed to better quantify and value the impacts of OWFs on ecosystem services are suggested. The development of methods which integrate socioeconomic valuation of ecosystem services into the evaluation of renewable energy devices compliments efforts in assessing the environmental impacts and should enable a holistic assessment of the impact of renewable energy production and greenhouse gas mitigation technologies on the U. K. carbon footprint.

Frequent locations of oceanic fronts as an indicator of pelagic diversity: application to marine protected areas and renewables

Frequent locations of thermal fronts in UK shelf seas were identified using an archive of 30,000 satellite images acquired between 1999 and 2008, and applied as a proxy for pelagic diversity in the designation of Marine Protected Areas (MPAs). Networks of MPAs are required for conservation of critical marine habitats within Europe, and there are similar initiatives worldwide. Many pelagic biodiversity hotspots are related to fronts, for example cetaceans and basking sharks around the Isle of Man, Hebrides and Cornwall, and hence remote sensing can address this policy need in regions with insufficient species distribution data. This is the first study of UK Continental Shelf front locations to use a 10-year archive of full-resolution (1.1 km) AVHRR data, revealing new aspects of their spatial and seasonal variability. Frontal locations determined at sea or predicted by ocean models agreed closely with the new frequent front maps, which also identified many additional frontal zones. These front maps were among the most widely used datasets in the recommendation of UK MPAs, and would be applicable to other geographic regions and to other policy drivers such as facilitating the deployment of offshore renewable energy devices with minimal environmental impact.

Studies on Soft Bycatch Reduction Devices for Selective Trawling

Trawling, though an efficient method of fishing, is known to be one of the most non-selective methods of fish capture. The bulk of the wild caught penaeid shrimps landed in India are caught by trawling.In addition to shrimps, the trawler fleet also catches considerable amount of non-shrimp resources. The term bycatch means that portion of the catch other than target species caught while fishing, which are either retained or discarded. Bycatch discards is a serious problem leading to the depletion of the resources and negative impacts on biodiversity. In order to minimize this problem, trawling has to be made more selective by incorporating Bycatch Reduction Devices (BRDs). There are several advantages in using BRDs in shrimp trawling. BRDs reduce the negative impacts of shrimp trawling on marine community. Fishers could benefit economically from higher catch value due to improved catch quality, shorter sorting time, lower fuel costs, and longer tow duration. Adoption of BRDs by fishers would forestall criticism by conservation groups against trawling.

An assessment of the economic impact of climate change on the coastal and marine sector in the British Virgin Islands

Owing to their high vulnerability and low adaptive capacity, Caribbean islands have legitimate concerns about their future, based on observational records, experience with current patterns and consequences of climate variability, and climate model projections. Although emitting less than 1% of global greenhouse gases, islands from the region have already perceived a need to reallocate scarce resources away from economic development and poverty reduction, and towards the implementation of strategies to adapt to the growing threats posed by global warming (Nurse and Moore, 2005). The objectives of this Report are to conduct economic analyses of the projected impacts of climate change to 2050, within the context of the IPCC A2 and B2 scenarios, on the coastal and marine resources of the British Virgin Islands (BVI). The Report presents a valuation of coastal and marine services; quantitative and qualitative estimates of climate change impacts on the coastal zone; and recommendations of possible adaptation strategies and costs and benefits of adaptation. A multi-pronged approach is employed in valuing the marine and coastal sector. Direct use and indirect use values are estimated. The amount of economic activity an ecosystem service generates in the local economy underpins estimation of direct use values. Tourism and fisheries are valued using the framework developed by the World Resources Institute. Biodiversity is valued in terms of the ecological functions it provides, such as climate regulation, shoreline protection, water supply erosion control and sediment retention, and biological control, among others. Estimates of future losses to the coastal zone from climate change are determined by considering: (1) the effect of sea level rise on coastal lands; and (2) the effect of a rise in sea surface temperature (SST) on coastal waters. Discount rates of 1%, 2% and 4% are employed to analyse all loss estimates in present value terms. The overall value for the coastal and marine sector is USD $1,606 million (mn). This is almost 2% larger than BVI’s 2008 GDP. Tourism and recreation comprise almost two-thirds of the value of the sector. By 2100, the effects of climate change on coastal lands are projected to be $3,988.6 mn, and $2,832.9 mn under the A2 and B2 scenarios respectively. In present value terms, if A2 occurs, losses range from $108.1-$1,596.8 mn and if B2 occurs, losses range from $74.1-$1,094.1 mn, depending on the discount rate used. Estimated costs of a rise in SST in 2050 indicate that they vary between $1,178.0 and $1,884.8 mn. Assuming a discount rate of 4%, losses range from $226.6 mn for the B2 scenario to $363.0 mn for the A2 scenario. If a discount rate of 1% is assumed, estimated losses are much greater, ranging from $775.6-$1,241.0 mn. Factoring in projected climate change impacts, the net value of the coastal and marine sector suggests that the costs of climate change significantly reduce the value of the sector, particularly under the A2 and B2 climate change scenarios for discount rates of 1% and 2%. In contrast, the sector has a large, positive, though declining trajectory, for all years when a 4% discount rate is employed. Since the BVI emits minimal greenhouse gases, but will be greatly affected by climate change, the report focuses on adaptation as opposed to mitigation strategies. The options shortlisted are: (1) enhancing monitoring of all coastal waters to provide early warning alerts of bleaching and other marine events; (2) introducing artificial reefs or fish-aggregating devices; (3) introducing alternative tourist attractions; (4) providing retraining for displaced tourism workers; and (5) revising policies related to financing national tourism offices to accommodate the new climatic realities. All adaptation options considered are quite justifiable in national terms; each had benefit-cost ratios greater than 1.

Modelling and Simulation of Moored Devices for Ocean Currents Energy Harnessing

The main objective of this paper is the presentation of modelling solutions off loating devices that can be used for harnessing energy from ocean currents. It has been structured into three main parts. First, the growing current interest in marine renewable energy in general, and in extracting energy from currents in particular, is presented, showing the large number of solutions that are emerging and some of the most significant types. GESMEY generator is presented in second section. It is based on a new concept that has been patented by the Universidad Politécnica de Madrid and which is currently being developed through a collaborative agreement with the SOERMAR Foundation. The main feature of this generator is that on operation is fully submerged, and no other facilities are required to move to floating state for maintenance, which greatly increases its performance. Third part of the article is devoted to present the modelling and simulation challenges that arise in the development of devices for harnessing the energy of marine currents, along with some solutions which have been adopted within the frame of the GESMEY Project, making particular emphasis on the dynamics of the generator and its control