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Current Research
For the last number of years the CFB has been engaged in assessing the potential numbers of lamprey in certain key channels. Most of this work has focussed on counting sea lamprey redds (spawning nests). Counting these redds allows an estimation of numbers of returning lamprey into a system. The size of redd constructed by each of the three lamprey species (brook, river and sea) varies significantly (Kelly and King, 2001). Brook lamprey redds are approximately fifteen centimetres in diameter and tend to be found in small channels. River lamprey, due to their larger size, are capable of constructing larger redds in areas of coarser gravel. Since sea lamprey are the largest, they also have the largest redds (c. 1m across). Therefore, simple walking or boat surveys allow a count of redds to be made in each channel. This can be used to infer the numbers of lamprey in that channel.
In the early stages of the Kilkenny FRS, it was apparent that existing methods for sampling ammocoete lamprey were inadequate. This led to a new quantitative method being developed for the base-line survey and key habitat identification.
This method has been tested over a wide range of habitats and has been found to be statistically robust and repeatable. The results from this analysis are currently being prepared for publication.
A method has been developed for the removal of resident lamprey in areas of channels where unavoidable human encroachment threatens the population. This involves the use of a bank-based excavator and has been found to be effective in salvaging ammocoetes for transfer into less threatened habitat.
As an adjunct to the quantitative methodology a more flexible qualitative method is currently being developed and tested.
Fyke-netting surveys are undertaken on an on-going basis to track both the numbers and season of migrating adult lamprey in the River Nore and other target channels
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