River Lampreys spawning on Lower River Slaney

The following is a video of River Lampreys Lampetra fluviatilis and adult Minnows Phoxinus phoxinus (in their spawning colours) interacting on the Lower River Slaney at Scarawalsh during early May 2016.

The nest-building lampreys disturb the sediments throwing up food items for the Minnows. But the Minnows will also eat the ova shed by the lampreys. A lamprey can be seen grabbing a minnow at 1:45 and the lampreys will be stressed and annoyed by this interference. We have also seen Minnows interact like this with Sea Lampreys Petromyzon marinus. This video was filmed in 4k (GoPro Hero 4) during early May 2016.

The River Lamprey is intermediate in size between the larger Sea Lamprey and the smaller Brook Lamprey Lampetra planeri – the two other lamprey species that occur in Ireland. River lamprey adults have an average adult length of approximately 30 cm but some individuals grow to 40 cm. They are a migratory species, which grows to maturity in estuaries and then moves into fresh water to spawn. The larvae spend several years in silt beds before metamorphosing and migrating downstream to estuaries. Due to their extended juvenile phase in depositing habitats they are particularly vulnerable to dredging works.

For further information on River Lampreys see the following links:-

Also, make sure to contact us if you have any queries and we would love to hear about any observations of lamprey spawning activity.

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