• Report on the incidence and implications of phytoplankton blooms on the East Coast and particularly Wexford Harbour, Summer 1984

      Doyle, J.; Dunne, T. (1984)
      The Fisheries Research Centre had a number of reports of discoloured water between Brittas Bay Co. Wicklow and Wexford Harbour and south to Kilmore Quay. Samples of water received from Dr. David Jeffrey, Department of Botany TCD, collected from Penny-come-quick beach, co. Wicklow on June 17th and examined by Tom Dunne in the Laboratory contained dense colonies of Phaeocystis pouchetii - a microscopic algae. Subsequent samples collected by Miss Ann Kiley, Wexford County Council, traced the extent of the bloom as far south as Neamstown near Kilmore Quay. A sample taken at Cullenstown west of Kilmore Quay was clear. Also associated with this bloom were large numbers of needlelike diatoms (Nitzschia spp. More seriously, blooms of another microscopic alga (Prorocentrum minimum) began to develop in early July during the later phase of the Phaeocystis bloom.
    • Observations on a bloom of Flagellate "X" in the West of Ireland

      Dunne, T. (ICES, 1984)
      In July 1983 major mortalities of farmed trout and salmon were associated with a bloom of an unidentified organism hitherto unrecorded in Ireland. Three further blooms occurred in 1984, two of which were associated with mortalities. The morphology of this organism (Flagellate "X") as observed in 1983 is described.
    • Dinoflagellate cysts in Irish coastal sediments - a preliminary report

      O'Mahony, J.H.; Silke, J. (1993)
      Since the mid 1970's the production of bivalve shellfish in Ireland has increased annually to a present level of some 17,000 tonnes. Several problems limit the continued expansion of the industry, most notably the problem of natural biotoxins. These toxins are accumulated in the product by the ingestion of toxic phytoplankton. This causes no obvious ill effects to the shellfish themselves but upon consumption may be transferred to human or other vertebrate consumers causing illness and sometimes death. In Ireland the most common of the toxins are those associated with Diarrhetic Shellfish Poisoning (DSP) which causes diarrhoea. Other more serious toxins which to date have not been confirmed in Ireland are those associated with Paralytic Shellfish Poisoning (PSP) which causes paralysis or even death and Amnesic Shellfish Poisoning (ASP) which causes short term memory loss. Of the phytoplankton species which can result in toxicity, under both bloom and non bloom conditions, the dinoflagellates play an important role. Many of these dinoflagellates have been shown to include a dormant benthic cyst stage in their life cycle. Therefore a better understanding of the dynamics of toxic events may be obtained by studying the distribution and abundance of benthic cysts. There is growing international concern about the transport of harmful aquatic organisms, including cysts, into new areas via the discharge of ships ballast water. Also, as a result of EC directive 91/67/EEC permitting the free movement of shellfish between EU member states there is now increasing concern in Ireland that harmful cysts may be introduced with shipments of imported shellfish. Little research has been carried out on the distribution of dinoflagellate cysts in Irish marine sediments. In this paper preliminary results of a study designed to map the distribution and undertake taxonomic studies on dinoflagellate and other cysts in Ireland are presented and discussed. Also presented are the results of the examination of cysts associated with imported shellfish.
    • Observed sequential occurrence of phytoplankton and zooplankton in the Dunkellin Estuary, Galway Bay, Ireland

      Byrne, P.; O'Mahony, J.H.T. (ICES, 1993)
      The Dunkellin is a small tidally-dominated estuary to the south-east of Galway Bay in western Ireland. The plankton of the estuary was studied for 18 months between December 1984 and July 1986. This paper presents results on the variation in the sequential occurrenCe of phytoplankton and zooplankton between the inner and outer estuary. Phytoplankton and microzooplankton occurred in high numbers in the spring to autumn months. Highest abundances of phytoplankton and microzooplankton (non-tintinnid ciliates and tintinnid ciliates) were recorded 10 the Inner estuary, whereas mesozooplankton were predominant in the outer reaches.
    • Toxic phytoplankton in Irish waters

      Silke, J.; McMahon, T.; Nolan, A. (1995)
      The subject of harmful and toxic marine algae has recently gained a growing public and scientific interest both in Ireland and abroad because of the occurrence of these toxins in shellfish.
    • Assessment of the risk of introducing harmful marine organisms by shipping to Bantry Bay

      Minchin, D. (1997)
      The main shipping activity in Bantry Bay is centred at Leahill, a site where there is aggregate extraction with direct transmission to bulk carriers at a dedicated pier. The size of vessels ranges from 250 to7,800mtNRT but with the majority of vessels being of 700 to l,800mtNRT. Ballast water from these vessels is required to be deposited at sea before entering the Bay should these vessels becoming from outside of Ireland. If this is done the risk of introducing dinoflagellate species present in those ports in Atlantic France and Spain will be reduced. Vessels from Irish ports are not required to discharge ballast before entering the Bay. The main risk to Bantry Bay, albeit small - because the amount of ballast discharged is small, is from inoculations of the toxic dinoflagellate Alexandrium tamarense from ships that have ballasted in Cork Harbouror Belfast Lough. It would be prudent for vessels ballasting in these sea inlets not to do so in the region and during the time of the toxic algal bloom events. Although vegetative stages of A. tamarense have been identified from the plankton of Bantry Bay and Alexandrium sp. cysts have been found in fine sediments it is not known whether further inoculations of A. tamarense either in its vegetative or cyst state could result in a PSP event within the Bay. The development of a management plan for ships' ballasting in Cork Harbour and Belfast Lough based on cyst distributions and the distribution of algal bloom events could greatly reduce the risk of a transfer. In the meantime discoloured water in Cork Harbour and Belfast Lough should not be ballasted. The Cork Harbour Commissioners will be advised when algal bloom events take place so that basic precautions.
    • Harmful phytoplankton events caused by variability in the Irish Coastal Current along the west of Ireland

      O'Boyle, S.; Nolan, G.; Raine, R. (UNESCO IOC, 2001)
      Frequent sampling in summer along the western and northwestern coasts of Ireland showed the rapid onshore development of blooms of potentially harmful phytoplankton species. In both 1998 and 1999, concentrations of Gyrodinium cf. aureolum rose by four orders of magnitude to over one million cells per litre in Donegal Bay(northwestern Ireland) in less than 10days. The rapid development of these populations was linked to advection resulting from unfavourable wind-forcing of the Irish Coastal Current (ICG) which runs northwards along the western Irish coast. Current measurements showed that after a particular sequence of changes in wind direction phytoplankton populations could be rapidly advected from areas of slack circulation on the shelf via the ICC into aquaculturally sensitive coastal zones such as Donegal Bay. The model presented is similar to one already demonstrated for the occurrence of toxic events in the bays of southwestern Ireland. Other historical harmful events along the west and northwest coasts relating to substantial losses in both finfish and shellfish culture could also be explained using the model. These include the G. aureolum bloom of 1992, the Prorocentrum balticum bloom in 1997.
    • Review of phytoplankton monitoring 2005

      Moran, S.; Silke, J.; Salas, R.; Chamberlain, T.; Lyons, J.; Flannery, J.; Thornton, V.; Clarke, D.; Devilly, L. (Marine Institute, 2006)
      A national phytoplankton monitoring programme, has been in operation in Ireland since 1986, and fulfils requirements of the EU Council Directive 91/492/EEC. This programme provides an important part of the baseline data in the overall integrated shellfish monitoring programme. The analysis of samples received on a regular basis from a site can provide very important information in assembling a population profile for the area. This helps in crucial decisions, for example in Management Cell Decisions - conducted by representatives from the industry, MI, FSAI and DCMNR - when borderline toxin results are present. Phytoplankton monitoring is also hugely important in the Water Framework Directive, which all EU countries must follow, in developing an index of water quality in Ireland and Europe. The Irish Monitoring programme also gives valuable public health information to County Councils, Environmental Health Officer’s and the public during times of bloom events. This paper provides an overview of phytoplankton sampling, analysis and reporting in 2005. The occurrence of potentially toxic and harmful phytoplankton found in Irish coastal and shelf waters in 2005 is also reviewed and the quality scheme in operation is described.
    • Nucleic acid tests for toxic phytoplankton in Irish waters-phytotest: Marine Strategic RTDI project AT/04/02/02 - research update

      Maher, M.; Kavanagh, S.; Brennan, C.; Moran, M.; Salas, R.; Lyons, J.; Silke, J. (Marine Institute, 2007)
      The Phytotest project is a 3 year collaborative project funded through the Marine Strategic Programme in Advanced Technologies as part of the National Development plan 2000-2006. The project partners include the National Diagnostics Centre at NUI Galway and MI. The overall objective of the project is the development of nucleic acid tests (molecular methods) for the identification of key toxic phytoplankton species in Irish waters. In the final year of the programme the aim is to transfer the molecular methods developed in the project into MI to support their monitoring service. Currently, the monitoring for phytoplankton species in Irish waters is performed by light microscopy which can easily identify some plankton species based on distinctive morphological traits. Other species in particular, Pseudonitzschia spp. and Alexandrium spp. cannot be identified to species level by light microscopy. Identification of these species requires more sophisticated microscopic techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These techniques cannot easily be integrated into a routine testing environment. Molecular methods utilise unique information contained within an organism’s genome in order to identify it. This genetic information can be exploited in a range of molecular test platforms enabling microorganisms to be identified to species level. Additionally, there has been a major drive towards the development of highly automated platforms to support molecular tests for high-throughput testing in routine laboratory settings.
    • Review of phytoplankton monitoring 2006

      Moran, S.; Silke, J.; Salas, R.; Chamberlain, T.; Lyons, J.; Shannon, S. (Marine Institute, 2007)
      This paper provides an overview of phytoplankton sampling, analysis and reporting in 2006. The occurrence of potentially toxic and harmful phytoplankton found in Irish coastal and shelf waters in 2006 is compared with the previous year. The succession of phytoplankton blooms in Bantry is described and environmental data that may explain the onset of toxic species is described.
    • Development & implementation of the Phytotest project

      Kavanagh, S.; Brennan, C.; Lyons, C.; Chamberlain, T.; Salas, R.; Moran, S.; Silke, J.; Maher, M. (Marine Institute, 2008)
      Phytotest is a 3-year research and development project funded through the Marine Institute Strategic Research Programme in Advanced Technologies as part of the National Development plan 2000-2006. The project is a collaboration between the National Diagnostics Centre at NUI Galway and the MI and involves the development of real-time PCR assays for Dinophysis and Pseudo-nitzschia species that are important in Irish waters. In the current final phase of the project, the real-time PCR assays are being transferred to the MI to support the phytoplankton monitoring service.
    • Review of phytoplankton monitoring programme and research activities

      Salas, R.; Chamberlain, T.; Lyons, J.; Hynes, P.; Silke, J. (Marine Institute, 2008)
      This paper provides a review of the activities of the Phytoplankton Unit in the Marine Institute as part of the National Monitoring Programme for 2007 and compares the findings with those recorded during 2005 and 2006., It also presents an overview of the research activities carried out by the phytoplankton team during the year with a focus on culturing phytoplankton and the introduction of real time PCR techniques for phytoplankton identification.
    • Molecular methods for monitoring harmful algal bloom species

      Keady, E.; Maher, M. (Marine Institute, 2009)
      Shellfish production can be adversely affected by the presence of harmful microalgae (HABs). Toxins produced by Dinophysis, Alexandrium and Pseudo-nitzschia species can accumulate in shellfish and have the potential to cause serious human illness. In order to satisfy EU legislative requirements pertaining to the production and export of shellfish (EC Hygiene Regulations 2004, No. 853/2004 and No. 854/2004, which replaced the EU Shellfish Hygiene Directive 91/492/EEC in January 2006), monitoring the presence of harmful algal species and biotoxins in coastal waters is performed by EU member states. Routine microscopic monitoring methods are unable to identify certain toxic species, in particular, Alexandrium and Pseudo-nitzschia spp. Electron microscopy is required for species identification and this technique cannot be integrated into a routine monitoring programme. Molecular techniques utilise unique sequence signatures within microorganism genomes for species specific identification. Molecular methods applied for the identification and quantification of HAB species include Fluorescent in-situ hybridisation (FISH) and in-vitro amplification based methods, in particular, real-time PCR.
    • Review of the phytoplankton monitoring programme and research activities in 2008

      Salas, R.; Lyons, J.; Hynes, P.; Chamberlain, T.; Silke, J. (Marine Institute, 2009)
      The National Monitoring programme for phytoplankton is a well established programme and this was shown through the improvement and refinement of Phytoplankton shellfish and finfish sites around the country. One important development in the last 2 years has been to increase the number of sentinel sites. A sentinel site is a designated sampling site where a total community Phytoplankton cell count and identification is carried out. The number of sentinel sites has increased from 11 in 2005 to 24 in 2008. This means a better coverage of all the bays around the country. The number of phytoplankton samples analysed in 2008 has seen an increase from the previous year.
    • The role of Azadinium spinosum (Dinophyceae) in the production of azaspiracid shellfish poisoning in mussels

      Salas, Rafael; Tillmann, Urban; John, Uwe; Kilcoyne, Jane; Burson, Amanda; Cantwell, Caoimhe; Hess, Philipp; Jauffrais, Thierry; Silke, Joe (Elsevier, 2011)
      Azaspiracids (AZAs) are a group of lipophilic polyether compounds first detected in Ireland which have been implicated in shellfish poisoning incidents around Europe. These toxins regularly effect shellfish mariculture operations including protracted closures of shellfish harvesting areas for human consumption. The armoured dinoflagellate Azadinium spinosum Elbrächter et Tillmann gen. et sp. nov. (Dinophyceae) has been described as the de novo azaspiracid toxin producer; nonetheless the link between this organism and AZA toxin accumulation in shellfish has not yet been established. In August 2009, shellfish samples of blue mussel (Mytilus edulis) from the Southwest of Ireland were analysed using liquid chromatography–tandem-mass spectrometry (LC–MS/MS) and were found to be above the regulatory limit (0.16 μg g−1 AZA-equiv.) for AZAs. Water samples from this area were collected and one algal isolate was identified as A. spinosum and was shown to produce azaspiracid toxins. This is the first strain of A. spinosum isolated from Irish waters. The Irish A. spinosum is identical with the other two available A. spinosum strains from Scotland (3D9) and from Denmark (UTHE2) in its sequence of the D1–D2 regions of the LSU rDNA. A 24 h feeding trial of blue mussels (M. edulis) using an algal suspension of the Irish A. spinosum culture at different cell densities demonstrated that A. spinosum is filtered, consumed and digested directly by mussels. Also, LC–MS/MS analysis had shown that AZAs were accumulating in the shellfish hepatopancreas. The toxins AZA1 and -2 were detected in the shellfish together with the AZA analogues AZA3, AZA6, AZA17 and -19 suggesting that AZA1 and -2 are metabolised in the shellfish within the first 24 h after ingestion of the algae. The levels of AZA17 detected in the shellfish hepatopancreas (HP) were equivalent to the levels of AZA1 but in the remainder tissues the levels of AZA17 were four to five times higher than that of AZA1, only small quantities of AZA3 and -19 were present with negligible amounts of AZA6 detected after the 24 h period. This could have implications in the future monitoring of these toxins given that at present according to EU legislation only AZA1–AZA3 is regulated for. This is the first report of blue mussels’ (M. edulis) feeding on the azaspiracid producing algae A. spinosum from Irish waters.
    • AZA – the producing organisms – biology and trophic transfer

      Tillmann, U.; Salas, R.; Jauffrais, T.; Hess, P.; Silke, J. (CRC Press, 2014)
      Compared to the knowledge on toxin structure, detection methods, and toxicology, convincing clarification of the aetiology of AZP was seriously lacking behind for quite a long time. Based upon the seasonal and episodic accumulation of AZA toxins in suspension-feeding bivalve molluscs – a situation similar to several other marine biotoxins - a planktonic source has been suspected from the outset. Furthermore, due to their polyether structural features, AZA has been suspected to be a dinoflagellate metabolite. Thus, it was no surprise that is was a dinoflagellate species which was first claimed to be the source of AZA. The link between AZA and P. crassipes, however, remained controversial because production of AZA by P. crassipes could not be verified in spite of numerous attempts based upon field surveys and laboratory investigations of cultured and isolated cells. Moreover, in contrast to other proven producers of phycotoxins, which are all primarily phototrophic, P. crassipes is a heterotrophic dinoflagellate, known to prey upon other dinoflagellates as food. The likelihood, therefore, that another dinoflagellate may produce AZA, which then accumulates in P. crassipes through normal feeding processes, could not be neglected.