A Sea Lamprey attached to a Grey Mullet
Wonderful observation, Bob! Is it sucking blood?
University of Edinburgh and Biodiversity Observatory (OU)
A good photo of both fish.
I think the lamprey is a half-grown sea lamprey, they can get almost a metre long and as thick as a medium rope. They do not suck blood but rasp away at the flesh.
I think the grey mullet is a Thin-lipped Grey Mullet Liza ramada, on the basis of the relatively short and dark pectoral fin. There should be a dark spot at the base of the pectoral, which I think I can see but cannot be sure.
Not sure if they stop at sucking blood or carry on into the fish's flesh. Such complicated sucking apparatus (I was going to say mouthparts but they are famous for not having any jaws as such) would be wasted if they were just going to extract blood. Unless all those "teeth" are just to make sure the lamprey doesn't fall off until it is ready to.
Lat/Lng: 50.6, -2.5
OS grid ref: SY6779