As an angler, we sometimes catch fish with a mark and, of course, we wonder what this means.

In 2018, DTU Aqua will conduct 3 different studies of the salmon in the river Storå.

DTU Aqua examines the survival of the early springers that are caught and released by anglers in April in the river Storå. Earlier experiments with markings of the early salmon have failed, so DTU will try a new method that is much more "realistic" this year, which results in minimal additional strain on salmon in connection with the markings.

A team of 10 anglers, chosen by DTU Aqua in collaboration with Holstebro and Omegns Fiskeriforening, will from 8th to 13th of April 2018 catch and mark up to 25 salmon in Storåen.

The salmon are faught and landed in the normal way, and quickly people from DTU Aqua "clipp" a radio transmitter onto the dorsal finn before being releasing. So no anesthesia or extra handling. Each radio transmitter weighs 2-3 grams and has a legible number between 1 and 25, so you can read it if you later catch a marked fish and release it again.

The marking is done before the start of the season in order to create the best prerequisites for a good and true outcome of the survey and not to disturbe the premiere fishing.

Until the midsummer, DTU Aqua will locate the marked fish from a boat or canoe about once a week, so we hope for your patience with the little disturbance the sailing will make.

If you catch a salmon with a radio transmitter, it must be released and the number of the transmitter (1-25) must be forwarded as soon as possible to DTU Aqua together with information about the catch and state of the fish. This is done by calling Niels Jepsen: +4529285028 or sending an email to nj@aqua.dtu.dk.

During the season there will also be supplementary markings of  caught salmon. This is done by equipping some (6-8) of Storåen's most scilled anglers with a "gun" and spaghetti labels, which  easily can be applied to the salmon before releasing.

Hopefully, they may mark a good number of salmon over the season, which DTU Aqua can capture during the stock survey, to be done in Storåen this fall. It also provides researchers with an opportunity to assess the survival of released fish. A biology specialist from Aalborg University (Poul Kusk) will be responsible for this part of the study and he will also help with the other activities.

Both of the above markings will be included in the stock analysis that will be carried out with electric fishing in September and October.

You can still find salmon without the adipose fin from previous markings .

Our goal for the Storå system is that we get a self-producing stock of wild salmon and in order for us to keep an eye on how it succeeds, it is necessary to distinguish between wild salmon born in the waterstream and salmon in a breeding pooland then released to the river.

Therefore, in the period 2009 to 2017, when the releases stopped, we marked all breeded salmon by cutting the adipose fin before releasing to the river.

In this way, it clearlu shows whether the salmon is wild or if it is released as a breeded parr in the river.

Therefore, it's important that you as an angler keep an eye on the fat fin, whether you release the salmon or if you are allowed to take it home to the dining table. And your observation must, of course, be stated in your catch report.

Here is an example of what you are looking for.

Above a wild salmon with adipose fin and on the right a fish without fat fin.

Thank you for your help with a proper registration!

The historic corner!

In Danish water systems, various marking tests have often been conducted, which should tell something about the behavioral patterns of the fish. Where do they come from? Where do they go? And are they ever coming back? And if yes, then when?

All these questions can help researchers find answers by releasing labeled fish to our water systems.

In the river Storå, the following study has been carried out (Unfortunately, only in Danish):

• Smoltudvandring fra Storå 2007 samt smoltdødelighed under udvandringen gennem Felsted Kog og Nissum Fjord

The marking of fish could be different and you could encounter the following types that could also occur in combination with each other:

• Fins could be cut
• CWT (coded wire ta
• Acoustic and radio markings
  
• Carlin labels

In respect of the surveys above, it was important that your catch report contained information about all the marks you found, both on released and on fish that you brought home to the dining table.

In the river Storå you could meet fish with the following markings:

Right and left are found by holding the tail of the fish towards you and the head away from you, and then you look over the back of the fish.

The list has been prepared according to the information available at this time and may therefore be incomplete with regard to fish released to other water systems. If you have information about markings in other water systems, we would like to hear from you.

 
                 

Radiotransmitter with antenna              Here you see the antenna           Floyd T-bar with a number

Acoustic transmitter                             Carlin label                      Coded wire tag