Electrofishing

Population Surveys on the River Avon and Tributaries – August 2011

FDSFB were able to provide their biologist, Dr Joanne Girvan, for three days in early August 2011 to electro-fish various tributaries and selected areas in the main Avon, in an attempt to update historic records of the fish population in the Avon catchment.

Electro fishing uses a portable generator to pass a low voltage electric current into the water using a metal hoop. The hoop is swept back and forth across the river, and upstream for ten to twenty minutes, stunning any fish or eels present. Normally the time scale allows a 25 to 30 yard stretch of water to be sampled. Any stunned fish are netted and placed in containment tanks. Fish are then recorded by species, by numbers present, and by their length. Scale samples are also taken.

The three Clubs had electro-fished areas of the Avon in the past, and the intent was to resurvey these areas and to also investigate fish populations in the primary Avon tributaries to provide base information for use in any future pollution incidents.

On the first day, three sites were chosen and fished on the Logie Water, which runs from Armadale to Westfield. The first site, approximately 100m above the WWTW at Westfield, only produced two 8” fish, but both salmon parr. No other fish were found. The area sampled was approximately 8x25m. The second site was on the Coulston Burn about 200m above the weir at the old paper works site at Westfield. This burn runs from Bathgate and has suffered from low levels of dissolved oxygen for years. The area sampled was approximately 1x30m and surprisingly only produced five stone loaches. No other fish were found, stressing the polluted nature of the burn. A final site on the Logie north of the B8028 between Armadale and Westfield, produced five adult trout of around 8”. Again no other trout of any year class were found. However the Logie was determined to be healthy and to be suitable for future stocking.

Two days later, after some rain, electrofishing commenced on the Mains Burn at Homebase in Linlithgow. This Burn had been stocked about 4 years ago by LAC with fed fry. The 1x25m area sampled produced 21 trout between 1.5” and 9” in length and several sticklebacks. This represented several year classes and showed that the burn is healthy.

The last site sampled was within the main village at Whitecross about 4 years ago by LAC with fed fry. The 1x25m area sampled produced 21 trout between 1.5” and 9” in length and several sticklebacks. This represented several year classes and showed that the burn is healthy.and gathered quite a crowd of interested villagers of all ages. The burn was around 6” deep and a 1mx20m area produced around 28 trout and four eels. Again several year classes were present.

It had been hoped to find salmon parr in both the Mains and Manuel Burns but none were found. However we now have updated information on both these important spawning burns and base line information on the Logie.

Population Surveys on the River Avon and Tributaries – May 2012

Once again FDSFB provided the services of their biologist, Dr Joanne Girvan, for four days in 2012, three days in May and a day in September. The intent was to determine the presence or otherwise of salmon parr in various in various sections of the Avon and its tributaries and to monitor the success of “Trout in the Classroom” programmes at two local Primary Schools.

On the first day, four sites were chosen and fished. One upstream of the Bathgate WWTW on the Coulston Burn and three on the Logie Water. These sites included one downstream of the bridge on the B8028, that was fished in 2011, a site several hundred metres downstream of the Armadale WWTW and a site just below the bridge on Mill Road, Armadale near the Garden Centre. In general the water was running slightly cloudy in all four sites. Results from the Coulston were as disappointing as 2011. The water smelled slightly of animal sewage and only a handful of Stoneloach and minnows were found in a 25m stretch of the Burn. This confirms that the Burn remains unattractive to trout despite the upgrade work to the WWTW. The site at the B8028 (see 2011 above), and that below the Armadale WWTW again yielded no trout but numbers of stone loach, stickleback and minnows. Fortunately the last site found two year classes of trout, proving breeding as well as large numbers of minnows, sticklebacks and some stone loach. The cloudy water may have affected the fishing and further surveys will be carried out next season.

Day two concentrated on the upper Avon and the Culloch Burn at Slamannan. The stretch at Balmitchell Bridge which had effectively suffered a total kill in July 2011 due to pollution yielded 6 trout, and significant numbers of minnows. There were no trout from the 2011 year class. A site at the Slamannan WWTW yielded a mere 3 trout. (See also below). Fortunately sampling the Culloch Burn above the bowling green area provided 17 trout, mainly from 2010 and 2012 year class. Again there were no trout from 2011.

Day three saw the team back at the base line site at Aldi in Linlithgow. This time electrofishing found a total of 23 trout of three different year classes, but again none from 2011. A 100mm roach was also found obviously from the canal.

We also carried out an educational project by electrofishing the Manuel Burn at Whitecross Primary School. This had been the release site for the trout hatched by the School children under the Trout in the Classroom Programme. Under the watchful eyes of around 30 children, we collected a total of 53 trout up to 6” in length. Although the majority were 2012 year class, there were fish from 2011, 2010 and 2009 in the sample. Even without the 2012 fish, the burn is obviously very healthy.

In September we were able to revisit sites on the upper Avon for further electrofishing. The results were surprising given the experience in May. The site at Slamannan WWTW, two sites on the Culloch Burn near the fire station and a site upstream of the Culloch were sampled. We collected a total of 36 trout of several year classes, and 36 trout parr, all from 2012 year class. These had managed to evade us in May, and we were delighted with what equated to one parr per metre of river.

Our Burns have a very healthy population of juvenile trout, although it is unlikely if trout in the Mains, the Manuel, the Logie or the Culloch Burns would actually drop down into the main Avon. More importantly, we proved that salmon are spawning further upstream that we previously knew, and that our salmon population has managed to survive the 2011 fish kill.