A FISH that was thought to have disappeared from Manx waters has been spotted spawning in two rivers in the Island.
Lampreys have been filmed spawning in the River Sulby and the River Dhoo by James Irving, a placement student who is currently working for the fisheries directorate of the Department of Environment, Food and Agriculture.
The first official record of these primitive, eel-like fish in the Island since 1981 was reported in November 2007 but due to the age of the specimens it was not possible to confirm which of the three British species had been found.
Since then brook lamprey have been positively identified in the Rivers Neb and Sulby and specimens likely to be river lamprey have also been found in the latter. Further unidentifiable specimens have been observed in the River Dhoo and Lhen Trench.
However James's discovery of the lamprey spawning is the first time this activity has been filmed before in the Isle of Man.
Juan Turner, MLC and Member for Fisheries, said: "Considering that we were concerned until recently that these fish may have disappeared from Manx watercourses, it is wonderful to discover that they may be thriving in at least some of our rivers. It also demonstrates the value of the river management and monitoring conducted by the Department of Environment, Food and Agriculture."
Spawning takes place in gravel areas similar to those used by brown trout, after which the adults die. After hatching the larvae, known as ammocoetes, spend several years burrowing in sandy silt and feeding on micro-organisms.
Once adult, brook lampreys simply swim up to spawning grounds without feeding. However sea and river lampreys migrate to saltwater to spend time parasitising other fish by latching on to them with their sucker-type mouths.
Sea lampreys have yet to be encountered in Manx watercourses although they have been seen on fish, including basking sharks, off the Island's coast.
Lampreys are very sensitive to pollution and declined in numbers following the industrial revolution, becoming extinct in many British river networks. Although there has been a resurgence of populations in some UK watercourses in recent years, they are still considered vulnerable and all three British species are included in Annex II of the European Habitats Directive.
James is researching the Manx lamprey population as part of his FdSc with Harper Adams University College.
To view footage of the brook lampreys spawning visit www.gov.im/daff/fish/inland/rm/wildlife.xml.
