Fouling of hulls is a major problem for world shipping – for private leisure craft as well as large cargo ships – with barnacles being a major culprit. It reduces the performance of vessels and increases their fuel requirements. Medetomidine has proved effective in preventing fouling of ship bottoms and now researchers attempting to develop new, environmentally friendly methods to limit marine fouling have identified the gene that causes barnacles to react to the substance, opening up the possibility of an antifouling paint that is gentle to both barnacles and the environment.

Medetomidine is a veterinary medicine that has been shown to prevent barnacle larvae from attaching to ship’s hulls. In cooperation with colleagues at the universities of Turku and Helsinki, Professor Anders Blomberg at the Department of Cell and Molecular Biology at the University of Gothenburg has succeeded in identifying and describing the gene that controls how barnacles sense and react to medetomidine.

When the barnacle cyprid larva encounters a surface containing medetomidine the molecule enters the octopamine receptor in the larva. This makes the larva legs start kicking and it cannot settle to the painted surface. This is a reversible effect that disappears when the larva swims away from the surface so it regains its function and can settle somewhere else.

The results, which are published in the scientific journal Molecular Pharmacology, explain how it is possible to develop an environmentally friendly and effective antifouling paint which instead of killing barnacles acts as a “deterrent”.

“Understanding how the substance works when it binds to the receptor also makes it possible to develop selective agents that only affect barnacles and not other marine organisms,” says Professor Blomberg.