Underwater camera explores microcosms in Lake Zug

The Aquascope is anchored to its buoy in Lake Zug (Photo: Canton of Zug).
The Aquascope is anchored to its buoy in Lake Zug (Photo: Canton of Zug).
The Aquascope underwater camera has been installed in Lake Zug. It is the second permanent measuring station for plankton in Swiss water bodies. The underwater camera delivers high-resolution images and is able to analyse them automatically. This will provide important insights into the water quality and aquatic biodiversity of Lake Zug in the future.

Plankton is an indicator of the health status of water bodies. Plankton are animal and plant organisms such as tiny crustaceans and small algae that float in the water and do not move or only move very slightly in the water. They are an important source of food for the larger animal species in the water. If the population or composition of the plankton changes, this can have a major impact on the lake ecosystem and thus also on the fish stocks. In Lake Zug, the catch figures for whitefish in particular fluctuate greatly - the bread-and-butter fish of professional fishermen. The concentration of blue-green algae, such as the Burgundy blood algae (planktothrix rubescens), also changes over the course of the year. This affects the water quality and can have an impact on the utilisation of the lake.

Technology offers further possibilities

The Aquascope in Lake Zug is the second permanent measuring station for plankton data in Swiss water bodies after Lake Greifen. In order to obtain high-quality data, the Office for Forests and Wildlife evaluated various locations in Lake Zug for the installation of the Aquascope. These had both advantages and disadvantages. An installation in the harbour would be more accessible. However, the image quality is poorer due to boat traffic and a higher proportion of dirt particles in the water. Eawag’s experience has shown that the best results can be expected when the Aquascope is installed in the open water zone and the device is surrounded by open water within a radius of 15-20 metres. The Aquascope is now located about 30 metres from the Walchwil hatchery and floats in the lake with the help of a special buoy designed and built by Chavanne Boatyard in Malters. The location is equipped in such a way that further technical devices could be installed to collect other data. A measuring chain for collecting data on the oxygen content and water temperature of Lake Zug has already been planned. A sonar device for fish monitoring could also be installed.
Kanton Zug, Jeannine Lütolf