Pheromones and Fear of Invasives

Every trout angler knows the dangers of invasive species, how they can disrupt native communities, destroy habitats, displace treasured species, transmit new diseases and otherwise create ecological mayhem.  Australians, especially, can attest both to the ravages of the invasives themselves, and to the perils of inappropriate control measures hastily implemented in the hope of preventing further damage by exotic species running amok.
Biological and chemical control methods themselves have often created greater problems than the invasive species they were meant to control. The cane toad in Australia and Mirex application to control fire ants in the southeastern U.S. provide textbook examples of how not to respond when invasive species are first found in your neighborhood.

Fortunately, pest control research has turned a corner in its search for a silver bullet whenever the spectre of new invasive species arises. Broad spectrum and ecologically persistent organic pollutants such as DDT and Mirex are gradually being displaced as control agents as new methods of control are being discovered. The new approaches are not mere tinkering in the chemistry lab, but are characterized by targeting the specific life history features of individual invasive species, so that control methods will affect them without poisoning everything else in the immediate vicinity.  A good example of this approach in fisheries is the selective toxicant TFM used in Great Lakes sea lamprey control.

While this toxicant, discovered in 1958, remains a powerful tool in the sea lamprey control arsenal, the search for additional control methods remains a priority for Great Lakes fishery managers. One such method has emerged after nearly 20 years of meticulous research. This is the discovery, by Prof. Peter Sorensen at the University of Minnesota, of a biologically active compound secreted by larval sea lampreys (ammocoetes) living out their pre-parasitic life stage in tributaries of the Great Lakes. These pheromones have proven attractive to adult lampreys seeking potential spawning sites in Great Lakes streams. Recent field trials suggest that adult lampreys can be lured into streams that provide optimal trapping sites so that they can be destroyed before they have a chance to produce another generation of lampreys.

The power of pheromone attractants as biological control agents may also be effective in controlling other invasive species. Such trials are currently underway in Australia as a mechanism for controlling the common carp. If successful there, it may be possible that this method can be used in North American waters, finally offering an opportunity to control a species that has plagued fishery managers here for over a century.