Critically low water levels on salmonid nursery streams

According to Met Éireann, Ireland has now experienced the longest dry weather spell since 1995. A situation of “Absolute drought” was announced at the end of last week following 15 consecutive days where rainfall was less than 0.1 mm at Met Éireann rainfall measuring stations. These drought conditions are having a devastating effect on watercourses and aquatic life throughout Ireland, with smaller salmonid nursery streams now severely affected.

The photographs below were taken by ECOFACT staff during a survey of streams in the upper River Blackwater (Munster) catchment. Some of these streams, which are fed by surface run-off, are now on the verge of drying up. If these streams are not topped up soon as a result of much needed rainfall, there will be very significant impacts on aquatic life.

This slideshow requires JavaScript.

It is hard to predict the long-term implications of drought on fish populations. Numbers of fish fluctuate  naturally with varying environmental conditions. Fish populations are robust and have survived severe  droughts in the past; however this will depend on stocking levels and environmental conditions. Many fish stocks in smaller streams are already under significant pressure as a result of agricultural pollution and drainage works so cumulative effects are important here. Effects of the 1995 and 1996 droughts were felt for many years after, and were blamed for a severe decline in trout numbers in some lakes for example (i.e. Lough Derg*). (*Or was this caused by massive restocking of unfed salmon fry from Parteen salmon hatchery by the ESB?).

In the UK, thousands of fish have been rescued from streams as water levels have dropped to exceptionally low levels. UK Meteorologists say the last six months have been the driest since 1953. Inland Fisheries Ireland are seeking the help of anglers and the general public to report any sightings of distressed fish due to high water temperatures or low water levels. More information on their Fish in Distress alert can be found here.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s