Restoration ecology
Monitoring and surveys

Innovative catching method for crayfish

Exotic crayfish can cause a lot of damage: aquatic plants disappear, water quality deteriorates and the ecological balance of areas is disrupted. To combat these issues, exotic crayfish must be removed from ecosystems. Waardenburg Ecology has developed a unique and innovative way to deal with this problem: the Craybar.

The Craybar is designed in such a way that it only catches exotic crayfish. We have tested the Craybar for several years and have never caught any species other than the target crayfish. The Craybar catches both large and very small crayfish. This is important as it is necessary to target an entire population.
Why not just use a standard trap or basket? When traps are full, they no longer catch crayfish, and emptying them can be time consuming and costly. In addition, small crayfish can often escape from standard traps and baskets. These challenges have been solved with the Craybar.

Catching method

We use two methods to trap the exotic crayfish.
1. We attract the crayfish by baiting a very small amount every day with an automatic feeder.
2. We offer them a place to hide. Crayfish like to hide in holes, especially when they are small, have young, are moulting or during the winter.

Crayfish can walk and climb very well, but they can only swim backwards with their tail. Other animals swim forward and can therefore easily swim out of the top of the pyramid-shaped trap. Something crayfish cannot do.

The catching part is connected by a tube to a large storage container that floats on the water's surface. This connection is one-way; once in the tube, the crayfish cannot return. Multiple traps can be used to fish a larger area. The crayfish also remain in good condition in the collection tank, because there is sufficient space and fresh water.
Heron fishing in Craybar

Crayfish on the menu

Our method works together with other wildlife. A unique part of the Craybar is that ultimately animals, rather than people, empty the trap. Crayfish are on the menu of many animals, including herons, storks, grebes, coots, gulls and otter. By designing the collection tank in such a way that crayfish provide an easy meal for these species, the crayfish problem is solved by nature itself. We have therefore called this innovation the Craybar. “Cray” comes from “crayfish”, and “bar” because animals living in the area see the collection tank as the local “snack bar”. By the way, the animals are very tasty and you can find crayfish in local supermarkets. The collection container can therefore also be made suitable for harvesting the caught crayfish for human consumption.