• Effects of cooking and heat treatment on concentration and tissue distribution of okadaic acid and dinophysistoxin-2 in mussels (Mytilus edulis)

      McCarron, P; Kilcoyne, J; Hess, P (Elsevier, 2008)
      Using high performance liquid chromatography with mass spectrometry the influence of conventional steaming and other heat treatments on the level of azaspiracids, okadaic acid and dinophysistoxin-2 in mussels (Mytilus edulis) was investigated. A prior study looking at the influence of steaming on the concentration and distribution of azaspiracids showed significant increases in concentration as a result. Described is a follow-up study using two separate mussel samples, where the contribution of water loss during steaming to increases of toxin levels was examined. In addition to water loss it was demonstrated that heating of fresh azaspiracid contaminated mussels resulted in significant increases in the quantity of the desmethyl analogue (azaspiracid-3) measured. A systematic heat treatment experiment confirmed these findings and showed that azaspiracid-3 was the most thermally instable of the three regulated azaspiracid analogues. In parallel, the same studies were carried out for okadaic acid and dinophysistoxin-2 also naturally present in the samples used. Concentration increases correlated with water loss during steaming. More so than for azaspiracids, increased distribution of okadaic acid and dinophysistoxin-2 from the digestive glands to the remainder tissues was observed as a result of the processes examined. This suggests that analysis of whole flesh tissues, as opposed to dissected digestive glands, is more appropriate for regulatory purposes, particularly if cooked samples are being analysed. The findings of the studies reported here have importance in terms of the methodology applied in regulatory phycotoxin monitoring programmes. Therefore, options for sample pre-treatment are discussed.
    • The effects of growth phase and light intensity on toxin production by Dinophysis acuminata from the northeastern United States

      Tong, M; Kulis, D M; Fux, E; Smith, J L; Hess, P; Zhou, Q; Anderson, D M (Elsevier, 2011)
      For many years, the study of toxic Dinophysis species was primarily restricted to field populations until it was recently demonstrated that some of these organisms can be mixotrophically cultured in the laboratory with the ciliate prey, Myrionecta rubra, which had previously been fed with cryptophytes of the genus Teleaulax and Geminigera. Here we investigated the influence of growth phase and light intensity on the production of diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins (PTXs) in cultures of Dinophysis acuminata from the northeastern United States. The cell toxin content of okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), and the okadaic acid diol ester (OA-D8) varied significantly with growth phase under all light treatments, at 6 °C. Each toxin quota remained low during middle and late exponential phases, but significantly increased by mid-plateau phase. DTX1 and OA-D8 were variable through plateau phase, while OA and PTX2 significantly decreased as the culture aged. Although maximum toxin content was not achieved until middle plateau phase, the rate of toxin production was generally greatest during exponential growth. The low and relatively constant cellular toxin levels observed during exponential and early-plateau phase indicate a balance between toxin production and growth, whereas in the middle-plateau phase, toxin production continues even though the cells are no longer capable of dividing, leading to higher toxin quotas. Light was required for Dinophysis growth and the production of all toxins, however, there was no significant difference in growth rates or toxin quotas between the higher light treatments ranging from 65 to 300 μmol photons/sq.m/s. These results demonstrate that DSP production in D. acuminate is constitutive, and that specific toxins are differentially produced or accumulated during the cells’ growth phase, possibly in response to changes to their environment.
    • Effects of temperature and salinity on the survival and development of larval and juvenile Palaemon serratus (Decapoda: Palaemonidae) from Irish waters

      Kelly, Eoghan; Tully, Oliver; Browne, Ronan (Cambridge University Press, 2012)
      The combined effects of temperature and salinity on the survival and development of larval and juvenile Palaemon serratus from the west coast of Ireland were investigated. Survival over time was measured at thirty combinations of temperature and salinity ranging from 10–19°C and 9–34‰ in a fully factorial design. Salinity had a stronger influence than temperature on survival at all larval stages except stage V. For juveniles the main effect changed from temperature between 100 and 200 degree days to salinity between 200 and 600 degree days and temperature between 600 and 800 degree days. Estimates of time taken to 50% mortality showed that juveniles tolerated lower salinities for longer periods and exhibited optimal salinity values which were 3% lower than larvae, at temperatures between 10 and 15°C. Larval stage durations were found to be influenced by temperature but not salinity. Comparison with published data suggests that populations of P. serratus have adapted to local conditions of temperature and salinity. The results presented here have practical implications for fisheries assessment and management, as the incorporation of environmental effects into stock–recruitment models can improve their predictive capacity.
    • 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.
    • Environmental factors associated with invasion: modeling occurrence data from a coordinated sampling programme for Pacific oysters

      Kochmann, J.; O’Beirn, F.X.; Yearsley, J.; Crowe, T.P. (Springer Netherlands, 2013)
      Documenting establishment and spread of invasive species requires extensive co-ordinated sampling programmes. Identifying the factors promoting or inhibiting local establishment of an invasive species can improve capacity to predict further spread and underpin strategies to limit spread. Here, a structured sampling programme was used to assess the current distribution of feral populations of Pacific oysters, Crassostrea gigas, in Ireland. Sixty-nine sites were sampled using a standardised protocol combining semi-quantitative and quantitative approaches. Sites were chosen to represent variation in proximity to aquaculture and a range of environmental variables. Oyster populations were found at 18 locations, with densities ranging from single individuals to nine individuals per m2. The broad size range of oysters found is indicative of more than one recruitment event. Logistic regression indicated that feral oysters were positively associated with the presence of hard substrata or biogenic reef, long residence times of embayments and large intertidal areas. There was also a tendency for oysters to occur disproportionately in bays with aquaculture, but >500 m from it. Small-scale analysis within sites showed that oysters were almost exclusively attached to hard substrata and mussel shell. The approach taken here provides a rigorous repeatable methodology for future monitoring and a detailed basis for the prediction of further spread.
    • Estimating biomass, fishing mortality, and “total allowable discards” for surveyed non-target fish

      Shephard, S.; Reid, D.G.; Gerritsen, H.D.; Farnsworth, K.D. (Oxford University Press, 2014)
      Demersal fisheries targeting a few high-value species often catch and discard other “non-target” species. It is difficult to quantify the impact of this incidental mortality when population biomass of a non-target species is unknown. We calculate biomass for 14 demersal fish species in ICES Area VIIg (Celtic Sea) by applying species- and length-based catchability corrections to catch records from the Irish Groundfish Survey (IGFS). We then combine these biomass estimates with records of commercial discards (and landings for marketable non-target species) to calculate annual harvesting rates (HR) for each study species. Uncertainty is incorporated into estimates of both biomass and HR. Our survey-based HR estimates for cod and whiting compared well with HR-converted fishing mortality (F) estimates from analytical assessments for these two stocks. Of the non-target species tested, red gurnard (Chelidonichthys cuculus) recorded some annual HRs greater than those for cod or whiting; challenging “Pope's postulate” that F on non-target stocks in an assemblage will not exceed that on target stocks. We relate HR for each species to two corresponding maximum sustainable yield (MSY) reference levels; six non-target species (including three ray species) show annual HRs ≥ HRMSY. This result suggests that it may not be possible to conserve vulnerable non-target species when F is coupled to that of target species. Based on biomass, HR, and HRMSY, we estimate “total allowable catch” for each non-target species.
    • An evaluation of the impact of early infestation with the salmon louse Lepeophtheirus salmonis on the subsequent survival of outwardly migrating Atlantic salmon, Salmo salar L., smolts

      Jackson, D.; Cotter, D.; Ó Maoiléidigh, N.; O'Donohoe, P.; White, J.; Kane, F.; Kelly, S.; McDermott, T.; McEvoy, S.; Drumm, A.; Cullen, A.; Rogan, G. (Elsevier, 2011)
      The potential impact of sea lice infestation on outwardly migrating Atlantic salmon smolts has been investigated by treating populations of ranched salmon, prior to release, with a prophylactic sea lice treatment conferring protection from sea lice infestation, for up to 9 weeks. Established populations of ranched Atlantic salmon with well described rates of return were chosen to investigate the potential contribution of early infestation with the salmon louse, Lepeophtheirus salmonis to mortality in Atlantic salmon. Against a backdrop of a declining trend in survival rates of Atlantic salmon many studies are attempting to elucidate potential causes for this decline. Results from this study over a period of 9 years point to infestation with the salmon louse (L. salmonis) as being a minor component of marine mortality in the stocks studied.
    • 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.
    • Examining changes in Irish fishing practices in response to the cod long-term plan

      Davie, Sarah; Lordan, Colm (Oxford University Press, 2011)
      In 2009, there were marked changes in Irish demersal fishing effort owing to the implementation of a new cod long-term plan (CLTP). This replaced previous top-down cod recovery plans, first implemented in 2002, that set days-at-sea limits for fishing vessels. The new plan specifies a harvest control rule, annual effort ceilings for EU Member States, and rules for adapting fishing effort. It encourages cod avoidance, but leaves Member States to allocate effort between individual vessels. During 2009, effort was allocated through a series of pilot schemes in Ireland. These can be considered as an evolution towards co-management. Industry and state authorities worked closely together to develop strategies for effort management and cod avoidance. The impact of recent effort-management measures on the Irish fleet, fishery, and métiers affected by the CLTP is evaluated. Vessel movements within and between métiers are described and discussed, and unintended impacts resulting from the implementation of management schemes are highlighted. In future, possible fishers' responses to policy initiatives should be considered prior to implementation to minimize potentially adverse consequences.
    • Field and mesocosm trials on passive sampling for the study of adsorption and desorption behaviour of lipophilic toxins with a focus on OA and DTX1

      Fux, E; Marcaillou, C; Mondeguer, F; Bire, R; Hess, P (Elsevier, 2008)
      It has been demonstrated that polymeric resins can be used as receiving phase in passive samplers designed for the detection of lipophilic marine toxins at sea and was referred to as solid phase adsorption toxin tracking (SPATT). The present study describes the uptake and desorption behaviour of the lipophilic marine toxins okadaic acid (OA) and dinophysistoxin-1 (DTX1) from Prorocentrum lima cultures by five styrene—divinylbenzene based polymeric resins Sepabeads® SP850, Sepabeads® SP825L, Amberlite® XAD4, Dowex® Optipore® L-493 and Diaion® HP-20. All resins accumulated OA and DTX1 from the P. lima culture with differences in adsorption rate and equilibrium rate. Following statistical evaluation, HP-20, SP850 and SP825L demonstrated similar adsorption rates. However, possibly due to its larger pore size, the HP-20 did not seem to reach equilibrium within 72h exposure as opposed to the SP850 and SP825L. This was confirmed when the resins were immersed at sea for 1 week on the West Coast of Ireland. Furthermore, this work also presents a simple and efficient extraction method suitable to SPATT samplers exposed to artificial or natural culture media.
    • 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.
    • First estimates of age, growth, and maturity of boarfish (Capros aper): a species newly exploited in the Northeast Atlantic

      White, Emma; Minto, Cóilín; Nolan, Conor P.; King, Erna; Mullins, Eugene; Clarke, Maurice (Oxford University Press, 2011)
      Boarfish in the Northeast Atlantic have recently been exploited commercially for fishmeal. It is a sexually dimorphic species with an estimated maximum age of 26 years, late age at maturity (A50 = 5.25 years), relatively fast rate of growth (K = 0.186 year−1), and a small asymptotic length (L∞ = 128.9 mm).
    • Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farm salmon

      McGinnity, Philip; Prodohl, Paulo; Ferguson, Andy; Hynes, Rosaleen; Ó Maoiléidigh, Niall; Baker, Natalie; Cotter, Deirdre; O'Hea, Brendan; Cooke, Declan; Rogan, Ger; Taggart, John; Cross, Tom (The Royal Society, 2003)
      The high level of escapes from Atlantic salmon farms, up to two million fishes per year in the North Atlantic, has raised concern about the potential impact on wild populations. We report on a twogeneration experiment examining the estimated lifetime successes, relative to wild natives, of farm, F1 and F2 hybrids and BC1 backcrosses to wild and farm salmon. Offspring of farm and ‘hybrids’ (i.e. all F1, F2 and BC1 groups) showed reduced survival compared with wild salmon but grew faster as juveniles and displaced wild parr, which as a group were significantly smaller. Where suitable habitat for these emigrant parr is absent, this competition would result in reduced wild smolt production. In the experimental conditions, where emigrants survived downstream, the relative estimated lifetime success ranged from 2% (farm) to 89% (BC1 wild) of that of wild salmon, indicating additive genetic variation for survival. Wild salmon primarily returned to fresh water after one sea winter (1SW) but farm and ‘hybrids’ produced proportionately more 2SW salmon. However, lower overall survival means that this would result in reduced recruitment despite increased 2SW fecundity. We thus demonstrate that interaction of farm with wild salmon results in lowered fitness, with repeated escapes causing cumulative fitness depression and potentially an extinction vortex in vulnerable populations.
    • 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.
    • Identification and Characterization of Cyprinid Herpesvirus-3 (CyHV-3) Encoded MicroRNAs

      Donohoe, O. H.; Henshilwood, K.; Way, K.; Hakimjavadi, R.; Stone, D. M.; Walls, D. (PLoS ONE, 2015)
      MicroRNAs (miRNAs) are a class of small non-coding RNAs involved in post-transcriptional gene regulation. Some viruses encode their own miRNAs and these are increasingly being recognized as important modulators of viral and host gene expression. Cyprinid herpesvirus 3 (CyHV-3) is a highly pathogenic agent that causes acute mass mortalities in carp (Cyprinus carpio carpio) and koi (Cyprinus carpio koi) worldwide. Here, bioinformatic analyses of the CyHV-3 genome suggested the presence of non-conserved precursor miRNA (pre-miRNA) genes. Deep sequencing of small RNA fractions prepared from in vitro CyHV-3 infections led to the identification of potential miRNAs and miRNA–offset RNAs (moRNAs) derived from some bioinformatically predicted pre-miRNAs. DNA microarray hybridization analysis, Northern blotting and stem-loop RT-qPCR were then used to definitively confirm that CyHV-3 expresses two pre-miRNAs during infection in vitro. The evidence also suggested the presence of an additional four high-probability and two putative viral pre-miRNAs. MiRNAs from the two confirmed pre-miRNAs were also detected in gill tissue from CyHV-3-infected carp. We also present evidence that one confirmed miRNA can regulate the expression of a putative CyHV-3-encoded dUTPase. Candidate homologues of some CyHV-3 pre-miRNAs were identified in CyHV-1 and CyHV-2. This is the first report of miRNA and moRNA genes encoded by members of the Alloherpesviridae family, a group distantly related to the Herpesviridae family. The discovery of these novel CyHV-3 genes may help further our understanding of the biology of this economically important virus and their encoded miRNAs may have potential as biomarkers for the diagnosis of latent CyHV-3.
    • 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.
    • Impact of early infestation with the salmon louse Lepeophtheirus salmonis on the subsequent survival of outwardly migrating Atlantic salmon smolts from a number of rivers on Ireland's south and west coasts

      Jackson, D.; Cotter, D.; Ó Maoiléidigh, N.; O'Donohoe, P.; White, J.; Kane, F.; Kelly, S.; McDermott, T.; McEvoy, S.; Drumm, A.; Cullen, A. (Elsevier, 2011)
      The potential impact of sea lice infestation on outwardly migrating Atlantic salmon smolts has been investigated by treating populations of ranched salmon, prior to release, with a prophylactic sea lice treatment conferring protection from sea lice infestation, for up to 9 weeks. Established populations of ranched Atlantic salmon with well described rates of return were chosen to investigate the potential contribution of early infestation with the salmon louse, Lepeophtheirus salmonis to mortality in Atlantic salmon. Results of five releases from four locations are presented and compared with a time series of releases from Lough Furnace in Newport, County Mayo. The results of this study would suggest that infestation of outwardly migrating salmon smolts with the salmon louse (L. salmonis) was a minor component of the overall marine mortality in the stocks studied.
    • Impact of Lepeophtheirus salmonis infestations on migrating Atlantic salmon, Salmo salar L., smolts at eight locations in Ireland with an analysis of lice-induced marine mortality

      Jackson, D; Cotter, D; Newell, J; McEvoy, S; O'Donohoe, P; Kane, F; McDermott, T; Kelly, S; Drumm, A (John Wiley and Sons, 2013)
      Sea lice infestation as a source of marine mortality of outwardly migrating Atlantic salmon smolts has been investigated by treating groups of ranched salmon, prior to release, with a prophylactic sea lice treatment conferring protection from sea lice infestation. A number of studies have been carried out in Ireland using both established ranched populations and groups of hatchery reared fish imprinted for 5–8 weeks in the sites of experimental releases. In this study, data on 352 142 migrating salmon from twenty-eight releases, at eight locations along Ireland's South and West coasts covering a 9-year period (2001 to 2009) are reviewed. Both published and new data are presented including a previously unpublished time series. The results of a meta-analysis of the combined data suggest that while sea lice-induced mortality on outwardly migrating smolts can be significant, it is a minor and irregular component of marine mortality in the stocks studied and is unlikely to be a significant factor influencing conservation status of salmon stocks.
    • Impact of naturally spawning captive-bred Atlantic salmon on wild populations: depressed recruitment and increased risk of climate-mediated extinction

      McGinnity, P; Jennings, E; deEyto, E; Allott, N; Samuelsson, P; Rogan, G; Whelan, K; Cross, T (Royal Society Publishing, 2009)
      The assessment report of the 4th International Panel on Climate Change confirms that global warming is strongly affecting biological systems and that 20–30% of species risk extinction from projected future increases in temperature. It is essential that any measures taken to conserve individual species and their constituent populations against climate-mediated declines are appropriate. The release of captive bred animals to augment wild populations is a widespread management strategy for many species but has proven controversial. Using a regression model based on a 37-year study of wild and sea ranched Atlantic salmon (Salmo salar) spawning together in the wild, we show that the escape of captive bred animals into the wild can substantially depress recruitment and more specifically disrupt the capacity of natural populations to adapt to higher winter water temperatures associated with climate variability. We speculate the mechanisms underlying this seasonal response and suggest that an explanation based on bio-energetic processes with physiological responses synchronized by photoperiod is plausible. Furthermore, we predict, by running the model forward using projected future climate scenarios, that these cultured fish substantially increase the risk of extinction for the studied population within 20 generations. In contrast, we show that positive outcomes to climate change are possible if captive bred animals are prevented from breeding in the wild. Rather than imposing an additional genetic load on wild populations by releasing maladapted captive bred animals, we propose that conservation efforts should focus on optimizing conditions for adaptation to occur by reducing exploitation and protecting critical habitats. Our findings are likely to hold true for most poikilothermic species where captive breeding programmes are used in population management.
    • 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.