Now showing items 41-60 of 123

    • Spatial and seasonal variation of peatland-fed riverine macroinvertebrate and benthic diatom assemblages and implications for assessment: a case study from Ireland

      O’Driscoll, C.; de Eyto, E.; Rodgers, M.; O’Connor, M.; Asam, Z-u-Z; Kelly, M.; Xiao, L. (Springer, 2014)
      Blanket peat catchments are important biodiversity refugia. Key pressures on peatland catchment water bodies include artificial drainage, forestry, over-grazing, wind farm development and climate change, and assessment of these pressures requires sensitive monitoring programmes. This study, undertaken in two neighbouring blanket peat catchments, examined the variability in macroinvertebrate and diatom assemblages and related indices in response to spatial and seasonal variability. Multivariate analysis revealed significant trends in the taxa distribution of both groups and the indices downstream and away from the constraining influence of the peat. However, the ecological quality ratios and status assessments for the associated water bodies were consistent irrespective of spatial variability in assemblages and raw indices. Significant seasonal trends emerged only in the macroinvertebrate assemblages and indices. This study contributes to the understanding of sources of uncertainty in ecological assessment and thus provides valuable information for the calibration of assessment protocols for sensitive peatland catchments.
    • Whole-tree harvesting and grass seeding as potential mitigation methods for phosphorus export in peatland catchments

      O'Driscoll, Connie; O'Connor, Mark; Asam, Zaki-ul-Zaman; DeEyto, Elvira; Poole, Russell; Rodgers, Michael; Zhan, Xinmin; Nieminen, Mika; Xiao, Liwen (Elsevier, 2014)
      Forest clearfelling is potentially a major environmental problem with respect to the degradation of water quality in receiving water courses due to phosphorus (P) release from soil and clearfelling residue stocks. Recent studies have highlighted the need to investigate the performance and benefits of potential mitigation methods such as whole tree harvesting (WTH) and grass seeding. In this study, fifteen plots (0.014 ha each) were constructed in a standing coniferous forest and P concentrations in plot runoff were monitored for one year prior to clearfelling. Following clearfelling three replicates of five forest harvesting management practices/treatments were applied to the plots: brash with grass seeding (Treatment 1), brash (Treatment 2), brash mat/ tree extraction route (Treatment 3), WTH (Treatment 4) and WTH with grass seeding (Treatment 5). These treatments were designed to comparatively assess the benefits of WTH and grass seeding practices on mitigating P released from forested peatlands following clearfelling and to determine the sources and sinks of P following clearfelling operations. Annual average total reactive phosphorus (TRP) concentrations in the plot runoff were < 20 µg L-1 in all treatments before clearfelling, and increased to 79 µg L-1, 160 µg L-1, 335 µg L-1, 50 µg L-1 and 38 µg L-1 in Treatments 1, 2, 3, 4 and 5, respectively, after clearfelling. These results highlight that WTH and grass seeding can be used efficiently as methods to improve water quality, aiding in the protection of the biota residing in the aquatic systems draining peatland catchments.
    • A multi-proxy palaeolimnological study to reconstruct the evolution of a coastal brackish lake (Lough Furnace, Ireland) during the late Holocene

      Cassina, Filippo; Dalton, Catherine; Dillane, Mary; De Eyto, Elvira; Poole, Russell; Sparber, Karin (Elsevier, 2013)
      This study examines the evolution of Lough Furnace, a coastal brackish lake in the west of Ireland, using high-resolution sensors in the water column and palaeolimnological examination of the sediment archive. Palaeoenvironmental reconstructions suggest that meromixis formed as a result of sea level rise prior to ca. 4000 cal. yr BP. Increased seawater inflow has progressively led to permanent water stratification, which caused the onset of anoxia, making the monimolimnion a harsh environment for biological life. Diatom floristic interpretations suggest a progressive upcore increase in salinity, which is paralleled by a reduction in cladocera remains. Diagenetic processes have not altered the sediment organic matter signature. Organic matter mainly derives from freshwater DOC and appears to be linked to the presence of peat bogs in the catchment as confirmed by the C/N ratio. Upcore variations in the C/N ratio with a ca. 800-year periodicity have been interpreted as the result of alternating dry and wet climatic phases during the late Holocene, which appear synchronous with the NAO and long-term solar cycles. The current hydrology is largely controlled by freshwater inflow, which determines permanent meromictic conditions. Overturns are rare, requiring a specific combination of factors such as exceptionally dry and warm summers followed by cool autumns. According to the climate projections for the next century in Ireland, permanent meromictic conditions will probably continue.
    • Natural selection acts on Atlantic salmon major histocompatibility (MH) variability in the wild

      de Eyto, E.; McGinnity, P.; Consuegra, S.; Coughlan, J.; Tufto, J.; Farrell, K.; Megens, H.J.; Jordan, W.; Cross, T.; Stet, R.J.M. (Royal Society Publishing, 2007)
      Pathogen-driven balancing selection is thought to maintain polymorphism in major histocompatibility (MH) genes. However, there have been few empirical demonstrations of selection acting on MH loci in natural populations. To determine whether natural selection on MH genes has fitness consequences for wild Atlantic salmon in natural conditions, we compared observed genotype frequencies of Atlantic salmon (Salmo salar) surviving in a river six months after their introduction as eggs with frequencies expected from parental crosses. We found significant differences between expected and observed genotype frequencies at the MH class II alpha locus, but not at a MH class I-linked microsatellite or at seven non-MH-linked microsatellite loci. We therefore conclude that selection at the MH class II alpha locus was a result of disease-mediated natural selection, rather than any demographic event. We also show that survival was associated with additive allelic effects at the MH class II alpha locus. Our results have implications for both the conservation of wild salmon stocks and the management of disease in hatchery fish. We conclude that natural or hatchery populations have the best chance of dealing with episodic and variable disease challenges if MH genetic variation is preserved both within and among populations.
    • Comparative effects of the marine algal toxins azaspiracid-1, -2, and -3 on Jurkat T lymphocyte cells

      Twiner, M.; El-Ladki, R.; Kilcoyne, J.; Doucette, G.J. (ACS Publications, 2012)
      Azaspiracids (AZA) are polyether marine toxins of dinoflagellate origin that accumulate in shellfish and represent an emerging human health risk. Although monitored and regulated in many European and Asian countries, there are no monitoring programs or regulatory requirements in the United States for this toxin group. This did not prove to be a problem until June 2009 when AZAs were identified in US seafood for the first time resulting in human intoxications and further expanding their global distribution. Efforts are now underway in several laboratories to better define the effects and mechanism(s) of action for the AZAs. Our investigations have employed Jurkat T lymphocyte cells as an in vitro model to characterize the toxicological effects of AZA1, AZA2, and AZA3. Cytotoxicity experiments employing a metabolically based dye (i.e., MTS) indicated that AZA1, AZA2, and AZA3 each elicited a lethal response that was both concentration- and time-dependent, with EC50 values in the sub- to low nanomolar range. On the basis of EC50 comparisons, the order of potency was as follows: AZA2 > AZA3 > AZA1, with toxic equivalence factors (TEFs) relative to AZA1 of 8.3-fold and 4.5-fold greater for AZA2 and AZA3, respectively. Image analysis of exposed cells using Nomarski differential interference contrast (DIC) imaging and fluorescent imaging of cellular actin indicated that the morphological effects of AZA1 on this cell type are unique relative to the effects of AZA2 and AZA3. Collectively, our data support the growing body of evidence suggesting that natural analogues of AZA are highly potent and that they may have multiple molecular targets.
    • How much of the seabed is impacted by mobile fishing gear? Absolute estimates from Vessel Monitoring Systems (VMS) point data

      Gerritsen, H.D.; Minto, C.; Lordan, C. (Oxford University Press, 2013)
      Demersal trawling impacts extensively on the seabed and the extent and frequency of this impact can be assessed using Vessel Monitoring Systems (VMS) data (positional data of fishing vessels). Existing approaches interpolate fishing tracks from consecutive VMS locations (track interpolation) and/or aggregate VMS point data in a spatial grid (point summation). Track interpolation can be quite inaccurate at the current 2-hour time interval between VMS records, leading to biased estimates. Point summation approaches currently only produce relative estimates of impact and are highly sensitive to the grid size chosen We propose an approach that provides absolute estimates of trawling impact from point data and is not sensitive to an arbitrary choice of grid cell size. The method involves applying a nested grid and estimating the swept area (area covered by fishing gear) for each VMS point. We show that the ratio of the swept area to the surface area of a cell can be related to the proportion of the seabed that was impacted by the gear a given number of times. We validate the accuracy of this swept-area ratio approach using known vessel tracks and apply the method to international VMS data in the Celtic Sea.
    • Assessing the risk of vulnerable species exposure to deepwater trawl fisheries: the case of orange roughy Hoplostethus atlanticus to the west of Ireland and Britain

      Dransfeld, L.; Gerritsen, H.D.; Hareide, N.R.; Lorance, P. (Cambridge University Press, 2013)
      With slow growth rates, late maturity and a high maximum age of 100 years or more, orange roughy can be classified as a vulnerable deepwater fish species that can only sustain low rates of exploitation. Historical patterns of exploitation associated with this species suggest that it is currently not possible to manage its fisheries in the Northeast Atlantic sustainably, and the total allowable catch for orange roughy has been gradually reduced to zero for European fisheries since 2010. Orange roughy to the west of Ireland and Britain occurs on distinct bathymetric features (seamounts, hills and canyons) as well as on flat ground along the continental slope. Productivity-susceptibility analysis (PSA) was performed to evaluate the biological vulnerability of orange roughy in relation to other deepwater species and the risk that recent and current fisheries pose to its populations in the study area. Time-dependant PSA, based on the spatial overlap between orange roughy distribution and recent and current deepwater fisheries demonstrated a strong reduction in risk over time when fisheries stopped directed targeting practices and continued with mixed deepwater trawl fisheries. Some spatial overlap between the species and current fisheries remains, and while the method can show relative risk reduction, it cannot provide information on whether the risk is low enough to allow the recovery of depleted populations.
    • Chemical aspects of ocean acidification monitoring in the ICES marine area.

      Hydes, D.J.; McGovern, E.; Walsham, P. (International Council for the Exploration of the Sea, 2013)
      It is estimated that oceans absorb approximately a quarter of the total anthropogenic releases of carbon dioxide to the atmosphere each year. This is leading to acidification of the oceans, which has already been observed through direct measurements. These changes in the ocean carbon system are a cause for concern for the future health of marine ecosystems. A coordinated ocean acidification (OA) monitoring programme is needed that integrates physical, biogeochemical, and biological measurements to concurrently observe the variability and trends in ocean carbon chemistry and evaluate species and ecosystems response to these changes. This report arises from an OSPAR request to ICES for advice on this matter. It considers the approach and tools available to achieve coordinated monitoring of changes in the carbon system in the ICES marine area, i.e. the Northeast Atlantic and Baltic Sea.
    • Winter measurements of biogeochemical parameters in the Rockall Trough (2009–2012)

      McGrath, T.; Kivimäe, C.; McGovern, E.; Cave, R.R.; Joyce, E. (Copernicus publications, 2013)
      This paper describes the sampling and analysis of biogeochemical parameters collected in the Rockall Trough in January/February of 2009, 2010, 2011 and 2012. Sampling was carried out across two transects, one southern and one northern transect each year. Samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) were taken alongside salinity, dissolved oxygen and dissolved inorganic nutrients (total-oxidised nitrogen, nitrite, phosphate and silicate) to describe the chemical signatures of the various water masses in the region. These were taken at regular intervals through the water column. The 2009 and 2010 data are available on the CDIAC database.
    • An operational biogeochemical model of the North-East Atlantic: model description and skill assessment

      Dabrowski, T.; Lyons, K.; Berry, A.; Cusack, C.; Nolan, G. (Elsevier, 2013)
      This paper presents a high resolution operational biogeochemical model of the North-East Atlantic that encompasses part of the continental shelf and adjacent deep sea and includes all of Ireland's territorial waters. The setup of the model is described, followed by its skill assessment in reproducing chlorophyll and nitrate spatio-temporal variability. Part of the model skill assessment concerns the evaluation of its usefulness in a decision-making process and is based on the application of a binary discrimination analysis. The model is one-way nested within a 1/12° Mercator Ocean PSY2V4R2 operational model that provides physical forcing at the lateral open boundaries. Nitrate fields are also proscribed at the open boundaries; the World Ocean Atlas 2009 monthly climatologies are used in the upper 500 m and at greater depths a formula that relates nitrate concentration to temperature and latitude is applied in the model. The model represents the intra-annual variability of surface chlorophyll and nitrate concentrations at monthly time scales across key oceanographic regions reasonably well; deficiencies are identified in some regions along with possible causes. The model can reproduce important characteristic bio-physicochemical features e.g. the frontal dynamics and upwelling off southwest Ireland and the properties of different water masses in the Rockall Trough. The model is deemed suitable for operational purposes, with a high probability to make correct positive and negative decisions. Operational since 2011, the output is publicly available via a dedicated THREDDS server.
    • Numerical modelling of spatio-temporal variability of growth of Mytilus edulis (L.) and influence of its cultivation on ecosystem functioning

      Dabrowski, T.; Lyons, K.; Curé, M.; Berry, A.; Nolan, G. (Elsevier, 2013)
      One of the key needs of the aquaculture industry is the implementation of effective management methods to ensure the sustainability, economic viability and minimization of negative impacts on both human and ecosystem well-being. The authors developed a Fortran 90 implementation of the dynamic energy budget (DEB) model for Mytilus edulis. The model has been further developed to include physiological interactions with the ecosystem and coupled to a biogeochemical nutrient–phytoplankton–zooplankton–detritus (NPZD) model. Phytoplankton and detritus uptakes, oxygen utilisation, CO2 production, NH4 excretion, egestion of faeces, and assimilation of food are modelled. A novel approach was derived that accounts for the allocation of C and N in mussel flesh and shell organic fraction. The DEB–NPZD model has been subsequently coupled to a high resolution three dimensional numerical coastal ocean model of the south–west coast of Ireland, where approximately 80% of national rope mussel is produced annually. Simulations have been carried out for the time period July 2010–June 2011, for which the field data on mussel biometrics and ambient seawater properties were collated. The model accurately reproduced the spatio-temporal variability in blue mussel growth. It is also shown that the ecosystem dynamics is affected by the presence of aquaculture farms. The modelling system presented allows for the assessment of the impacts of aquaculture activities on water quality, quantification of the production and ecological carrying capacities and improvement of our understanding of the ecosystem functioning with particular emphasis on interactions between various trophic levels.
    • Evaluation of the impacts of aquaculture and freshwater habitat on the status of Atlantic salmon stocks in Ireland

      Jackson, D.; McDermott, T.; Kane, F.; O’Donohoe, P.; Kelly, S. (Scientific Research Publishing, 2013)
      Atlantic salmon (Salmo salar) returns to rivers in Ireland have fallen in the last decade resulting in the dramatic closure or curtailment of tradi- tional fisheries. Concerns that stocks were slow to recover prompted further investigation of all factors believed to impact on salmon. In exam- ining geographic and temporal trends in Atlantic salmon stock abundance at a River Basin Dis- trict level, the effect of salmon aquaculture sites and freshwater habitat quality as potential driv- ers of stock abundance are evaluated. This study found no correlation between the pres- ence of aquaculture and the performance of ad- jacent wild salmon stocks. Freshwater habitat quality was found to have a highly significant correlation with stock status, suggesting that it may be a key driver, implicated in the survival of individual stocks.
    • Identifying functional stakeholder clusters to maximise communication for the Ecosystem Approach to Fisheries Management

      Duggan, Deirdre E.; Farnsworth, Keith D.; Kraak, Sarah B. M. (Elsevier, 2013)
      Interaction with ecological models can improve stakeholder participation in fisheries management. Problems exist in efficiently communicating outputs to stakeholders and an objective method of structuring stakeholder differences is lacking. This paper aims to inform the design of a multi-user communication interface for fisheries management by identifying functional stakeholder groups. Intuitive categorisation of stakeholders, derived from survey responses, is contrasted with an evidence-based method derived from analysis of stakeholder literature. Intuitive categorisation relies on interpretation and professional judgement when categorising stakeholders among conventional stakeholder groups. Evidence-Based categorisation quantitatively characterises each stakeholder with a vector of four management objective interest strength values (Yield, Employment, Profit and Ecosystem Preservation). Survey respondents agreed little in forming intuitive groups and the groups were poorly defined and heterogeneous in interests. In contrast the Evidence-Based clusters were well defined and largely homogeneous, so more useful for identifying functional relations with model outputs. The categorisations lead to two different clusterings of stakeholders and suggest unhelpful stereotyping of stakeholders may occur with the Intuitive categorisation method. Stakeholder clusters based on literature-evidence show a high degree of common interests among clusters and is encouraging for those seeking to maximise dialogue and consensus forming.
    • Report of the Study Group on Nephrops Surveys (SGNEPS)

      Doyle, J.; Lordan, C. (International Council for the Exploration of the Sea (ICES), 2013)
      The Study Group on Nephrops Surveys (SGNEPS) met in Ancona, Italy from 6–8 March 2012. The group consisted of 12 scientists from Ireland, Scotland, England, Northern Ireland, Spain, Denmark, Portugal and Italy under the chairmanship of Colm Lordan, Ireland. SGNEPS has an important role as the international coordina-tion group for Nephrops UWTV surveys in the North Atlantic and Mediterranean. Heretofore SGNEPS has focused on planning, protocols, quality control, design and survey development issues. At the 2012 meeting group compiled a table summarizing the station densities and precision levels of most annual Nephrops UWTV surveys. Large variations in survey station densities occur across the grounds currently sur-veyed. Station density, accuracy and precision trade-offs were investigated and dis-cussed in detail for the two main survey design types (random stratifies and grids). The main outcome of these deliberation was that a minimum precision level of <20% CV (also known as Relative Standard Error) should be attained for these types of surveys. There may be operational reasons why individual surveys should aim for higher precision than that (e.g. to ensure good coverage and accurate burrow surfac-es). In some areas station densities could be reduce to allow for improved coverage to previously unsurveyed Nephrops grounds. Progress towards integrated stock assess-ments for Nephrops which make use of all sources of fisheries dependent and inde-pendent information was reported to the group. There was consensus that the current ICES framework for assessing and providing catch options based on the UWTV sur-veys remains the most appropriate methodology for the moment. There has been significant progress since WKNEPH (ICES, 2007) in addressing many of the per-ceived uncertainties in the methodology. The remaining assumptions on burrow occupancy, burrow size, growth, discard survival can only be addressed through dedicated research projects of which there have been few. Several video enhancement and technological developments were presented to the group and these look very promising in terms of improving certainty of burrow identification and facilitating validation counts. The group also discussed the various Nephrops trawl surveys and biological sampling requirements under the DCF and concluded that the role of the group should be expanded to cover these in future.
    • First Detection of Paralytic Shellfish Poisoning (PSP) Toxins in Icelandic Mussels (Mytilus edulis): Links to Causative Phytoplankton Species.

      Burrell, Stephen; Gunnarsson, Thor; Gunnarsson, Karl; Clarke, Dave; Turner, Andrew D. (Elsevier, 2013)
      Paralytic shellfish poisoning (PSP) toxins were detected in blue mussels (Mytilus edulis) from two harvesting areas, Eyjafjordur on the north coast and Breidafjordur on the west coast of Iceland in 2009. During a bloom of Alexandrium spp. at both locations in June of that year, blue mussels were found to be contaminated with paralytic shellfish toxins (PSTs), leading to extensive closures of these harvesting sites. Phytoplankton data taken during this time showed the presence of large numbers of A. tamarense, with smaller numbers of A. ostenfeldii also being detected. Mussel samples were analysed by mouse bioassay (MBA) and liquid chromatography with fluorescence detection (LC-FLD). Toxicity over 10 times the European Union (EU) regulatory limit was observed in samples from Eyjafjordur while levels over 4 times this limit were detected in samples from Breidafjordur. The toxin profile determined by LC-FLD was found to be composed primarily of the carbamate toxins gonyautoxin-2,3 (GTX-2,3). Saxitoxin (STX) was also detected in all samples analysed and was the second most abundant toxin present. Gonyautoxin-1,4 (GTX-1,4) was detected at lower concentrations in half the samples analysed from both locations. Comparison is made between predicted toxin profiles from these algal species and the toxin profiles determined through LC-FLD analysis. These results represent the first identification and PST profile determination in shellfish harvested from Icelandic waters.
    • Size-selective fishing drives species composition in the Celtic Sea

      Shephard, Samuel; Fung, Tak; Houle, Jennifer E.; Farnsworth, Keith D.; Reid, David G.; Rossberg, Axel G. (Oxford Journals, 2012)
      Fishing alters community size structure by selectively removing larger individual fish and by changing the relative abundance of different-sized species. To assess the relative importance of individual- and species-level effects, two indices of fish community structure were compared, the relative abundance of large fish individuals (large fish indicator, LFI) and the relative abundance of large fish species (large species indicator, LSI). The two indices were strongly correlated for empirical data from the Celtic Sea and for data from simulated model communities, suggesting that much of the variability in the LFI is caused by shifts in the relative abundance of species (LSI). This correlation is explained by the observation that most of the biomass of a given species is spread over few length classes, a range spanning the factor 2 of individual length, such that most species contributed predominantly to either the small or the large component of the LFI. The results suggest that the effects of size-selective fishing in the Celtic Sea are mediated mainly through changes in community composition.
    • Recent data suggest no further recovery in North Sea Large Fish Indicator

      Fung, Tak; Farnsworth, Keith D.; Reid, David G.; Rossberg, Axel G. (Oxford Journals, 2012)
      We detail the calculations of North Sea Large Fish Indicator values for 2009–2011, demonstrating an apparent stall in recovery. Therefore, recovery to the Marine Strategy Framework Directive's good environmental status of 0.3 by the 2020 deadline now looks less certain and may take longer than was expected using data from 2006 to 2008.
    • Effects of weather-related episodic events in lakes: an analysis based on high-frequency data

      Jennings, Eleanor; Jones, Stuart; Arvola, Lauri; Staehr, Peter A.; Gaiser, Evelyn; Jones, Ian D.; Weathers, Kathleen C.; Weyhenmeyer, Gesa A.; Chiu, Chih-Yu; de Eyto, Elvira (Wiley-Blackwell, 2012)
      Summary 1. Weather-related episodic events are typically unpredictable, and their duration is often short. Abiotic and biological responses are often missed in routine monitoring. These responses are, however, now of particular relevance given projected changes in extreme weather conditions. 2. We present data from high-frequency monitoring stations from lakes in Europe, North America and Asia that illustrate two classes of abiotic effects of weather events: (i) generally short-lived effects of storms on lake thermal structure and (ii) the more prolonged effects of high rainfall events on dissolved organic matter levels and water clarity. We further relate these abiotic effects to changes in dissolved oxygen or in chlorophyll a levels. 3. Three differing causes for weather-related decreases in surface dissolved oxygen levels were observed: (i) entrainment of anoxic water from depth, (ii) reduction in primary productivity and (iii) increased mineralisation of organic carbon delivered from the catchment. 4. The duration of in-lake effects tended to be longer for events driven by weather conditions with a longer return period, that is, conditions that were relatively more severe and less frequent at a site. While the susceptibility of lakes to change was related in part to the severity of the meteorological drivers, the impacts also depended on site-specific factors in some cases. 5. The availability of high-frequency data at these sites provided insight into the capacity of the lakes to absorb current and future pressures. Several of the changes we observed, including increases in carbon availability, decreases in photosynthetically active radiation and increased disturbance, have the capacity to shift lakes towards an increased degree of heterotrophy. The magnitude and direction of any such change will, however, also depend on the magnitude and direction of climate change for a given location and on lake and catchment characteristics.
    • Improved Isolation Procedure for Azaspiracids from Shellfish, Structural Elucidation of Azaspiracid-6 and Stability studies

      Kilcoyne, Jane; Keogh, Adela; Clancy, Ger; Le Blanc, Pat; Burton, Ian; Quilliam, Michael A.; Hess, Philipp; Miles, Christopher O. (ACS Publications, 2012)
      Azaspiracids are a group of lipophilic polyether toxins produced by the small dinoflagellate Azadinium spinosum. They may accumulate in shellfish and can result in illnesses when consumed by humans. Research into analytical methods, chemistry, metabolism, and toxicology of azaspiracids has been severely constrained by the scarcity of high-purity azaspiracids. Consequently, since their discovery in 1995, considerable efforts have been made to develop methods for the isolation of azaspiracids in sufficient amounts and purities for toxicological studies, in addition to the preparation of standard reference materials. A seven-step procedure was improved for the isolation of azaspiracids-1–3 (1, 2, and 3) increasing recoveries 2-fold as compared to previous methods and leading to isolation of sufficiently purified azaspiracid-6 (6) for structural determination by NMR spectroscopy. The procedure, which involved a series of partitioning and column chromatography steps, was performed on 500 g of Mytilus edulis hepatopancreas tissue containing 14 mg of 1. Overall yields of 1 (52%), 2 (43%), 3 (43%), and 6 (38%) were good, and purities were confirmed by NMR spectroscopy. The structure of 6 was determined by one- and two-dimensional NMR spectroscopy and mass spectrometry. The stability of 6 relative to 1 was also assessed in three solvents in a short-term study that demonstrated the greatest stability in aqueous acetonitrile.
    • A predictive model for estimating river habitat area using GIS-derived catchment and river variables

      McGinnity, P; de Eyto, E; Gilbey, J; Gargan, P; Roche, W; Stafford, T; McGarrigle, M; Ó Maoiléidigh, N; Mills, P (Blackwell Publishing Ltd., 2012)
      The implementation of many fisheries management-related activities in fresh water depends on habitat area inventories over extensive geographical scales. While river lengths are readily available, representative widths, necessary for area calculations, are difficult to obtain. As field surveys to collect this information are resource intensive, a predictive model was developed to enable the calculation of river wetted width using GIS-derived values for catchment and river descriptors. A model containing upstream catchment area and the Shreve river drainage network index accounted for 88% of the variation in field measured river wetted width. Comparisons in Irish and Scottish rivers between modelled and measured widths were highly correlated and suggest that the model may be transferable to neighbouring geographic areas. As an example, the model is applied to provide an estimate of the usable fluvial habitat available to Atlantic salmon in Ireland.