Maybe the most unlikely heroes for aquaculture, these little guys from Norway play a vital role in ridding farmed salmon of sea-lice. Replacing toxic parasiticides, they are becoming a regular tool in salmon farming. They are found in colder waters such as the North Atlantic, Artic, and North Pacific. The roughly 30 species in 7 genera differ widely in size. Some lumpfish grow up to 24 inches (61 cm), but most are usually much smaller, such as the Pacific Spiny Lumpsucker which grows to under 1 in. (2.5 cm).
Lumpfish have portly little bodies that are nearly spherical. The “sucker” part of their name is derived from their modified pelvic fin which have evolved into adhesive discs. Those discs are used to adhere to the substrate. Just looking at their bodies one can tell that they are not-so-good swimmers. They are a poorly studied group and we know very little about their behavior, however we do know a few things including that they are proving to be effective “cleaner fish” eating sea-lice from salmon in aquaculture net-pens.
In 2015, an estimated 10 million lumpsuckers were used as cleaner fish for salmon farming globally. As we know about fish introductions, there can be unexpected outcomes. Cleaner fish introductions can have impact also, however, to what extent has been largely unknown outside of visual observation.
Researchers set out with HTI acoustic tags to track lumpsuckers in 2D/3D to better understand their behavior and potential impacts in net-pens. Take a look at what we’re learning: