Fisheries intern signing off

5th Mar 2021
by Victoria Semple

My time at GFT has come to an end, it has been a fantastic six months and I have had so many great experiences.

In my last post, I talked about learning about running an Atlantic Salmon hatchery, since then I have had the opportunity to get out to the upper Water of Tarf and help planting out ova (eggs) into artificial redds in the river. It was really interesting to have to think like a salmon and select suitable areas of river to dig the redd. We were looking for areas of riffle with enough flow to properly oxygenate the eggs and suitable gravels and pebbles to build the redd. The process is quite simple, first we moved some gravel to create a depression in the riverbed, much like what a salmon would do, next we placed a delivery tube in the depression and returned the gravel back around it. It was important to make sure that the gravels were packed tightly enough so that the eggs would not be washed out by the flow, but also not too compact to mean there wouldn’t be enough water flowing through to provide oxygen to the eggs. Next, we carefully poured the eggs down the tube and into the redd, checking to make sure we had no escapees and then poured some water on top to push them out of the tube at the bottom. Then we filled the tube with smaller gravel, these would make sure the redd was complete and there was a layer covering the eggs when the tube was removed. Next was the moment of truth, very carefully we removed the tube, ensuring the eggs would remain in the redd. We created four successful redds full of eggs that day, with very few escapees. It was great to experience the complete process, from checking over and weighing the broodstock in the hatchery to placing the eggs back in the river to hopefully hatch very soon. I’ll be interested to hear about the success of the stocking program when GFT complete their electrofishing surveys later in the year.

Aside from the stocking project, I have also been getting involved in river improvement works this year. I joined the team completing instream habitat works on Loch Strand Burn (a tributary of the Tarf) to assist with adding features such as tree kickers and boulders into the burn. These features aim to create flow and substrate variation. Loch Strand Burn is a modified waterway that was dredged in the past for drainage. As a result of this, the channel is very straight and a lot of the substrates required for spawning are absent, as a result, salmon presence in the area is extremely low. By adding features such as tree kickers and boulder, we can alter the flow within the channel. Tree kickers are made of logs that are slightly set into the riverbank and attached to the riverbed, they, along with the boulders, will deflect the flow of the water in different ways. These features create variation in both flow and substrate, forming habitat suitable for different life stages. We hope that this will allow salmon and more trout to spawn in the area increasing the population.

In addition to conducting instream improvements on Loch Strand Burn, we have also been planting broadleaf trees around the burn to provide dappled shade to keep the water cool. This is in order to future-proof the burn against climate change. We have also been planting trees in a similar capacity around the River Luce. I have been able to get stuck into to tree planting, working with the team to plant a total of 600 trees on Loch Strand Burn and a further 1,800 by the Luce. It has been hard work, but great to get out and dig deep!

My time at GFT has provided me with so many great experiences that have given me the skills I need to be successful in the field of fisheries management and conservation. I intend to take the skills and knowledge I have developed at GFT forward as I progress in my career and I have no doubt that this experience will be invaluable to my future in the field.