Lumpfish with data storage tag. Photo: Kim Aarestrup.

The researchers stuck on lumpfish

Friday 20 Apr 18


Kim Aarestrup
DTU Aqua
+4535 88 31 42


Ben Whittaker
Swansea University

Researchers have, for the first time, tagged lumpfish with electronic tags in Denmark. The project aims to shed light on the fish’s unknown behaviour in the ocean.

The lumpfish (also known as a lumpsucker, stone-biter or sea-hen) is a special species. Not only does it look like a ball covered in spikes and slime with a suction cup for a belly, but most of the species’ lifecycle remains a mystery. The fish come to the coast to spawn, where they have long been recognized as a good sign for the arrival of spring and fished for their delicious eggs equivalent to caviar. 

Researchers from DTU-Aqua and Swansea University are now trying to unravel their mysterious destination. They hope to do so with so-called data storage tags (DST); electronic tags that record depth and temperature of water the lumpfish are moving through.

This data will be the first of its kind for Danish lumpfish. Using the results, researchers can investigate lumpfish behaviour at sea, as well as where the fish have been travelling in the period they were away from the coasts. In the long-term, the results may be used in connection to the management of the species to ensure a bright future for these special fish.

If you find a tag 

The researchers have captured and tagged 31 lumpfish in Aalbæk Bay, Northern Denmark.

Researchers will only get the data back from the fish once the tag is returned to them.This can be done in one of two ways: Either the fish may be captured in fisheries-related activity, after which the tag should be removed and be sent directly to the researchers (address can be found on the tags), or the tags may be found floating at sea or stranded on beaches, in which case the tag should also be sent to the researchers. A reward is associated with tags being returned.

Facts about lumpfish

The mature lumpfish males are typically 25-35 cm and are characterized by a colourful body patterns. On the contrary, the larger females (typically 35-50 cm) are mostly dull in colour.

The females are highly sought after for their roe. Their savoury caviar is the reason behind a great deal of fishing for them at the start of the year. The females lay up to 200,000 eggs in a nest selected by the males; the males subsequently defend the eggs until hatching.

After spawning, the fish disappear from the area and nobody really knows where they go.