Brief review of fish pheromones and discussion of their possible uses in the control of non-indigenous teleost fishes

Most species of fish rely on pheromones (chemical signals released by conspecifics) to mediate social behaviours. Three categories of pheromones can be discerned based on their function: anti-predator cues, social cues, and reproductive cues. Each of these categories comprises pheromones that can induce primer effects (developmental and/or endocrinological changes) and/or releaser effects (strong behavioural changes). A handful of fish pheromones have been chemically identified and all are remarkably potent. Almost all are metabolic products whose production is seemingly unspecialised, insofar as they are not synthesised by specialised structures. Importantly, their potency and specificity makes them ideal candidates for use in control of both threatened (native) and unwanted (non-indigenous) fish species. As has been so for insect control and now sea lamprey control in the North American Great Lakes, these cues could be used in many ways as part of integrated control programmes for invasive teleost fishes. Ideally, these programmes would be designed to simultaneously exploit multiple weaknesses in species' life histories while being fully cognisant of stock-recruitment relationships. Generally the approach would be to use a variety of pheromones to supplement and increase the efficiencies of other control strategies including the application of poisons or fish with genetic modification, trapping for removal or sterilisation, and barriers to prevent spread. Integrated pest control using pheromones appears especially practical for the common carp (Cyprinus carpio) which appears to use many of the same cues as the goldfish (Carassius auratus) and for which half a dozen pheromones have already been identified.