The presence of Apicomplexan parasites in king scallops (Pecten maximus) in Scottish waters

•Apicomplexan-like parasite was widespread in Pecten maximus around the Scottish coast.•The parasite does not appear to affect survival of king scallops at a low infection intensity.•There was no significant downgrade of the adductor muscle at low infection intensity.•The partial genome sequence was identical to one previously reported in Icelandic scallop.