'TOP' Fishery Surveys

Managed fisheries

Instream development features

Background

The ESB (Electricity Supply Board) control the angling rights of the Shannon system, except those waters which are sub let on long term leasehold by the ESB to the Central Fisheries Board.The Central Fisheries Board in turn have entrusted this leasehold on The Shannon Region Fisheries Board who are responsible for the management and development of these waters. Each year routine development work is undertaken to ensure that our managed fisheries and the fish habitat is preserved and maintained in optimum condition.

The Board carry out routine predator control. The programme involves the culling of coarse fish such as pike and perch from the Rivers and Lakes developed and managed for game fishing. Pike are regarded as scavengers in trout fisheries and when over populated are an undesirable species in such waters. It is necessary to control their numbers by employing removal methods. In lakes pike are culled in the spring time of the year before they spawn on the shallows. Gill nets with appropriate mesh size are used for this purpose. In rivers culling is carried out using electo fishing methods.

Habitat Improvement

Salmonids which refer to salmon and trout species require a clean, well oxygenated natural stream habitat with adequate riffle, glide and pool sequences. Due to land use (drainage) and other factors nature cannot always provide the most ideal habitat. In stream development work is very often necessary to provide this. Salmonids lay their eggs in small streams. These streams are very often too wide and too shallow to support an adequate salmonid population and consequently a fishery is unable to sustain itself particularly with present day angling pressures. The Board seeks to improve or restore the habitat by introducing in stream features. These include

Spawning Facilities

To create beds where spawning can take place using suitable gravel thus allowing adult fish to lay their eggs. There must be sufficient clean water and a constant flow for successful incubation and hatching of eggs.

Adequate Depth

A fish of 15cm requires a channel depth of 15 - 30 cm, which is quite often missing from our Midland streams and rivers

Cover

Juvenile salmonids being shy by nature need places to conceal themselves and be protected against predators such as cormorants, herons and otters. Introduction of instream objects is the answer here. To the contrary, where there is too much overhead cover it can shade out a stream bed making it an unproductive environment for fish and other aquatic life. Reducing the canopy of over hanging trees will allow sufficient light to penetrate the stream bed and as a result will make a stretch more productive.

Holding pools

Young trout and salmon like to move from the main flow to maintain a restful position. In such positions they can quickly intercept passing food items such as aquatic insects, by darting out into the main flow. Rocks, logs, weirs and other objects are constructed and placed to break up a uniform flow and allow for proper holding pools, riffles and glides. With strategic placement of such objects bank erosion can be greatly reduced.

During instream development work the Board introduces all these instream features to improve habitat which in turn helps to maintain a fishery which should ideally be naturally self replenishing. Selection of suitable construction materials ensures that major maintenance work is kept to a minimum. To further support and accelerate the self replenishing process of the restored habitat, salmonid fry are planted out. This is particularly beneficial in nursery streams which have been unproductive for a long period. A lot of this type of work has been undertaken over recent years under E.R.D.F. ( European Regional Development Fund ) Assistance programmes.

Coarse Fisheries

Major development of coarse angling venues include the erection of fishing structures such as fishing stands and cat walks, car parking facilities and better access in a number of popular locations on the Shannon, e.g. Annacotty in Limerick and Lough na Blaithi in Leitrim. Under 'TOP' projects, EU Structural Funds as facilitated through TAM (Tourist Angling Measure) has made this possible. To view a progress report on 'TOP' Projects click here or at the top of the page.

As part of the Boards ongoing upgrading of its technology to assist in Fishery Management the Board has purchased a new more powerful Electro Fishing Equipment which will greatly assist in its Lake Predator Control and Stock Assessment Programmes.

While Electro Fishing Equipment has been used very successfully down through the years to assess fish populations on rivers and to remove predator fish from them this is the first time that the Fishery Service has been able to use such equipment on lakes. The apparatus can be used to remove safely fish from lakes and allow them to be transferred unharmed to other waters. Recent trials on the midland lakes have proven very successful and following a period of training and assessment, the Shannon Board will put the new equipment into service very soon.