Filmed here Brook Lamprey (Lampetra planeri) breeding and egg laying. Showing their behaviour in creating a scrape to lay their eggs in and fertilise them. In shallow water at the edge of the river among the sand and gravel deposited on a bend. They pick up stones that are in the way and drop them nearby. Then thrash their bodies to create a trough in which eggs can be laid and fertilised.
A place they have used for a number of years. The profile changes from year to year. Sometimes dramatically. In 2017 they were further out and in deeper water than previously. Winter storms and water flow had changed the river bed. Without a UV filter it was impossible to film them, even standing over them, perhaps next spring.