• 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.
    • Impacts of climate change on harmful algal blooms

      Bresnan, E.; Davidson, K.; Edwards, M.; Fernand, L.; Gowen, R.; Hall, A.; Kennington, K.; McKinney, A.; Milligan, S.; Raine, R.; et al. (Marine Climate Change Impacts Partnership, 2013)
      High biomass Harmful Algal Blooms (HABs) such as Karenia mikimotoi and shellfish toxin producing HAB species continue to be observed in UK and Republic of Ireland waters. Regional differences continue to be seen in the distribution of HABs in UK and RoI waters with impacts mainly observed in the south and west coast of Ireland and regions in the UK with a strong Atlantic influence, e.g. Regions 1, 3, 4, 6 and 7. There is little monitoring aside from the continuous plankton recorder (CPR) in Region 8. The impacts from HABs in Wales, Northern Ireland and the Isle of Man are generally low. Since the last MCCIP report card was issued, blooms of Karenia mikimotoi have caused problems in Ayrshire, Scotland, and also in the north-west coast of Ireland where concerns about the quantity of dead wild fish washing on shore during an event in Ireland in 2012 resulted in two beaches being closed to the public. No clear trend that can be attributed to climate change can be observed in the incidence of shellfish toxin producing HABs since the last report card was issued. During the last two years the incidence of some shellfish toxins has continued to decrease (e.g. paralytic shellfish poisoning toxins in Scotland). High concentrations of yessotoxins (YTX) and azaspiracids (AZAs) have been recorded for the first time in Scotland. Northern Ireland enforced its first shellfish harvesting closure for high concentrations of domoic acid (the toxin responsible for amnesic shellfish poisoning, ASP) in 2012. A recent survey in Scottish waters (Regions 1, 6 and 7) has revealed the presence of domoic acid in the urine and faeces of harbour seals (Phoca vitulina). The impacts of these toxins on the health of marine mammals are unknown and a more detailed study is currently being undertaken. Many of the future impacts of climate change are unknown. Increasing sea surface temperatures as a result of climate change may increase the potential for blooms of species that are not currently found in UK and RoI waters through range expansion or human mediated introduction. There is evidence that no new HAB species have become established during the last two years. An increase in the duration of stratification of the water column may influence the abundance of HABs in UK and RoI waters. This is particularly relevant in shelf areas and Region 8, an area where offshore high biomass K. mikimotoi blooms have been hypothesized to initiate and impact coastal areas along the west of Ireland and Regions 6, 7 and 1. Conversely, an increase in wind speed and duration may reduce the duration of stratification in the water column. This may result in a decrease of some HAB dinoflagellate species and an increase in HAB diatom species. Little is known about the impacts of ocean acidification or changes in offshore circulation on the incidence of HABs. The role of offshore blooms in seeding coastal blooms (e.g. of K. mikimotoi) remains unknown and the lack of monitoring in Region 8 and on the shelf edge compounds this knowledge gap.
    • The oceanography of southwest Ireland: current research activities

      Raine, R.; Whelan, D.; Conway, N.; Joyce, B.; Moloney, M.; Hoey, M.J.; Patching, J.W. (Fisheries Research Centre, 1993)
      The coastal waters of Ireland are rich in physical features affecting both chemistry and biology. Amongst these are the tidal fronts of the Irish Sea (Le Fevre, 1986) and the Irish Shelf Front on the Atlantic coast lying along the 200m iso bath (Huang et al., 1991). Recently, an upwelling system has been described in the vicinity of the Fastnet Rock (Roden, 1986; Raine et al., 1990). Coastal upwelling systems are ecologically very important and are generally extremely productive, as nutrients brought up to the sea surface can stimulate extensive phytoplankton growth. This paper describes further satellite and ship-based investigations which are currently being carried out to examine the mechanisms driving the upwelling system and its effect on local ecology.
    • The use of immunoassay technology in the monitoring of algal biotoxins in farmed shellfish

      Wilson, A.; Keady, E.; Silke, J.; Raine, R. (International Society for the Study of Harmful Algae and Intergovernmental Oceanographic Commission of UNESCO, 2013)
      The use of immunoassay technology as an adjunct method for monitoring biotoxins in shellfish was investigated at aquaculture sites in Killary Harbour, Ireland, during summer 2009. Sub-samples of mussels (Mytilus edulis) were taken from batches collected as part of the Irish National Phytoplankton and Biotoxin Monitoring Programme (NMP). Samples were analysed for Diarrhetic Shellfish Poisoning (DSP) toxins using a commercially available ELISA immunoassay kit. The results were compared with those obtained by chemical (liquid chromatography with mass spectrometry, LC-MS) and biological (mouse bioassay, MBA) methods from the monitoring programme. DSP levels increased in late June 2009 over the European Union maximum permitted level of 0.16 μg g-1 and positive MBA results led to harvest closures. This event was reflected in both the chemical and immunoassay results, where a positive relationship between them was found.