In Germany and neighboring countries, a large number of projects are being carried out to study the migratory behavior of fish.

Fish are tagged in a variety of ways. The techniques used for this purpose are presented here.

Have you caught or found a fish that is marked in this way or similarly?

Would you like more information or to report your find? Simply click on one of the images below.

© Stefan Ludwig

Using the example of the European sturgeon (Acipenser sturio), individual types of markings that are applied to a wide variety of fish species are shown here.

Marking techniques

The various techniques used to study fish migration are shown here.

For a more detailed explanation, simply click on one of the images with your mouse and the technique will be described and illustrated in more detail.

Why are fish tagged?

Tagging allows the migration behavior of fish to be studied.

Valuable information about the routes and numbers of fish can be obtained. This is also known as monitoring.

How are fish tagged?

Fish are tagged with colored dots, tags, fin clips, and transmitters, among other things. Transmitters can be attached externally or implanted inside the body.

An overview of common tagging methods can be found on the right-hand side. Click on the respective photo for further information.

What should I do if I catch or find a tagged fish?

Be sure to report it! Click here for the reporting form.

Scientists rely on your help. Every report is very valuable!

© Stefan Ludwig