• 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.
    • The implications of Alexandrium tamarense resting cysts in an area of shellfish aquaculture in Ireland

      Silke, J.; McMahon, T. (1998)
      The Irish Marine Institute's Fisheries Research Centre carry out a monitoring programme for the detection of algal toxins in shellfish. This programme is carried out under EU Directive 91/492. During the course of this programme the North Channel area of Cork Harbour has been the only location in Ireland where toxins causing Paralytic Shellfish Poisoning (PSP) have been detected in shellfish above the regulatory limit. For short periods during each of the summers of 1996,1997 and 1998, PSP toxins were found in mussels{Mytilus edulis) from this area above the regulatory limit period necessitating a ban on harvesting. Oysters {Crassostrea gigas) from the same area remained below the regulatory threshold. The dinoflagellate Alexandrium tamarense, a known vector of PSP toxins, was observed in the area during each of the toxic events. The exact origin of the populations of A. tamarense was unknown. A. tamarense is known to produce a cyst stage as part of its life cycle. These cysts can remain viable in the sediments for several years. A survey of the distribution of cysts of A. tamarense in the surface sediments in Cork Harbour was carried out in order to determine if they were potentially seeding the area. They were detected in 6 sites, and successfully germinated to yield vegetative cells. The results of the survey are presented and discussed.