Karenia mikimotoi (Miyake and Kominami ex Oda)

Kakkonen, Jenni E., Worsfold, Tim M., Ashelby, Christopher W., Taylor, Andrea & Beaton, Katy, 2019, The value of regular monitoring and diverse sampling techniques to assess aquatic non-native species: a case study from Orkney, Management of Biological Invasions 10 (1), pp. 46-79 : 53-55

(16) Karenia mikimotoi (Miyake and Kominami ex Oda)

Gert Hansen and Ø. Moestrup, 2000

Status in U.K. – cryptogenic.

During the surveys considered here, Karenia mikimotoi has been recorded from Scapa Flow on a single occasion, from a phytoplankton sample in 2015. However, it has frequently been identified in Scottish waters and was responsible for significant blooms recorded in 1999, 2003 and 2006 in Orkney and surrounding waters ( Davidson et al. 2009). It was described from Japan and has a near cosmopolitan distribution. Based on this, Streftaris et al. (2005) regarded it as non-native in Europe and Minchin (2007a) likewise regarded it as non-native in Ireland. Hégaret et al. (2008) consider that relocation of bivalve molluscs for aquaculture represents a potential vector for its spread and van den Bergh et al. (2002) likewise suggest

that transplantation of Japanese oysters to France from 1966 onwards may have aided its invasion. Transport in ballast water represents another potential vector. However, contrary to these opinions, Gómez (2008) simply regarded K. mikimotoi as cosmopolitan and likely transported by water currents. Given this conflict we herein regard it as cryptogenic pending further investigation.