The last month has seen two of our Riverfly Partnership monitors coming to us with a strange finding – lamprey larvae (or ‘ammocoetes’ as they are also known). One of the most primitive vertebrates alive today, lampreys are fascinating parasitic fish that are jawless and attach themselves to other fish to feed on blood and scales (although at the larvae stage they are filter feeding and not parasitic). They are similar in shape to eels and have a series of uncovered round gill openings (known as gill pores) on the sides of the head.
Lamprey ammocoete found on the River Wylye during a Riverly training session for the Wiltshire Wildlife Trust.
Recent reports have stated that lampreys are returning to rivers where they had not been previously seen for 200 years. A combination of poor water quality, a reduction in available habitat and man-made barriers to migration are all thought to have been responsible for this decline.
You can read more on the decline of the lamprey here: https://www.theguardian.com/environment/2015/sep/04/older-than-the-dinosaurs-lamprey-fish-return-to-uk-rivers-after-200-years
All of our findings have been sent to the UK Lamprey Watch, a project which has been set up to help to conserve and protect the UK’s lamprey species.
If you find a lamprey in your river, please help by recording your find at the following link!: https://envscot-csportal.org.uk/lampreywatch/
