The sea lamprey is critically endangered and at risk of extinction in Sweden. The Improve Aquatic LIFE project has a particular focus on the species. In the fish counter in River Ätran, two sea lampreys recently passed by and were caught by the underwater camera.
The situation of the sea lamprey (Petromyzon marinus) is very serious. The species has been severely affected by hydropower development and migration barriers, which make it difficult for fish to reach their spawning grounds. In addition, there is a shortage of large fish along the west coast, which means that the sea lamprey lacks the necessary host fish during their parasitic stage at sea.
Sea lamprey is currently considered Sweden’s most endangered fish. Within Improve Aquatic LIFE, sea lamprey is one of the priority species. By removing migration barriers, creating fishways and restoring and improving habitats in important areas, the hope is that the species will remain and eventually increase in Swedish waters.
Underwater cameras allow us to find out what fish species are present and approximately how many there are.
Underwater camera can give us answers
One way to keep track of migrating fish species is to use fish counters. An underwater camera document passing fish and animals and in many cases can even make a species identification.
Recently, two sea lampreys passed the fish counter at Herting in River Ätran. Stefan Kläppe, CEO of TiVA who developed the camera shared a video sequence where the rare fish were seen swimming by. Kläppe himself commented:
– Every sighting feels significant. Hopefully conservation efforts will pay off for this unique and ancient fish.
Also the related river lamprey on film
Water ecologist Mathias Ibbe at the county administrative board in Östergötland shared a similar movie, when another species of lamprey – river lamprey (Lampetra fluviatilis) – passed the fish counter in Pjältån.
– With underwater cameras, we can find out which fish species are present and approximately how many there are. We can also see the impact of different environmental measures, such as improving the ability of fish to pass through migration barriers. For example, in the Improve Aquatic LIFE project, we follow how river lamprey and sea trout migrate up the Pjältån river. Many people are surprised at how much life there is in a small stream, and want to help improve the environment. I often start my working day with a cup of coffee and look at what has swam past the camera during the night.
Fish counters must be managed in an exemplary manner
Elisabeth Thysell, fisheries consultant at Halland County Administrative Board, emphasizes the importance of properly maintaining installed fish counters, so that grids do not become clogged or turbulence prevents weak-swimming species.
– It is important that there is a budget to clear an installed fish counter. A fish counter is good for monitoring and information, but there can also be problems with letting all the fish pass through a narrow opening in a watercourse. We need to keep this in mind every time we install fish counters.