Stock management
How we monitor and manage the fish in Ireland's inland fisheries and within its sea angling boundary.
Stock management is the term given to the programme of managing the live fish in Ireland's inland fisheries and sea angling boundary.
The programme comprises three operation categories:
Fish salvage
Fish salvage is an operation we carry out to remove all fish species from waters that are at risk. Waters may be designated at risk when:
- Streams dry out in drought conditions
- Channels and water are diverted during construction work
Certain river systems flow directly over pervious rock (carboniferous limestone) which allows water to seep through the rock joints. This is an issue in the summer during long periods of drought when water levels are low; many streams can dry out concurrently. Staff work vigorously through the season to salvage fish from the drying-out streams and place them in the nearest safe source of water.
We may also salvage fish from channels prior to construction work to reduce potential harm to fish health. Fish are normally released as close as possible to the source point, so they can return easily when construction stages are completed and the risk is reduced.
Below, is an example of a pervious rock river in Cong that dries out during drought periods. The images show the river in normal conditions and then in drought conditions.
Species control
Gill netting
Since the earliest days of fisheries management in Ireland, it has been the practice of the competent authority (Inland Fisheries Trust, Central and Regional Fisheries Boards and now Inland Fisheries Ireland) to selectively manage the species composition of fish in some of our waterbodies.
Data collected and experience gained over decades has led to today’s species control practices. In these waterbodies, species that were long thought to have been artificially introduced are having an impact on the health and abundance of native salmonid stocks. For this reason, a certain number of fish may be removed from these waterbodies annually.
For example, the removal of pike is currently thought to be an effective way of helping to maintain healthy stocks of salmonid fish in some of our lakes. It is done by gill netting in selected areas on the lakes where pike are known to spawn.
Electrofishing
Electrofishing gear is also used to stun and remove pike from the river mouths and shallow nursery habitats on some of the lakes. These operations are timed to intercept pike as they move into certain areas on the lake to feed on the migrating parr and smolts of salmonids on a seasonal basis. Once removed, the pike are either disposed of or brought to other waters where stocks of these fish are thought to be low.
This re-stocking is only practiced on waters where pike are deemed unlikely to unduly impact on the other fish species present.
