It is well established that fish rely on highly developed chemical signaling systems to find each other and reproduce. This is particularly true for freshwater fishes, likely owing to the naturally high turbidity (darkness from sediment) of most inland waters. Using the goldfish as a model, we have discovered that fish pheromones (the term given to chemical signals between the same species) are derived from hormonal metabolites and function as potent, natural, and specific stimulants of fish behavior and physiology.

The present project (MIN-41-070) focuses on characterizing the molecular basis of pheromone identity and function in the goldfish, and then applying this understanding to the management of closely related species that carry greater economic significance. Two applications are being pursued: stimulating reproduction in cultured fishes, and controlling populations of the many nuisance species found in our lakes. This work is also significant because it explains how hormonal products can exert fundamental influences on fish behavior, an area of concern since it became known that watery human waste is disrupting hormonal balance in wildlife ('endocrine disrupters').

The development of pheromones as a technology to control fish populations is still in the research stage and has yet to be applied. However, state and federal fisheries management agencies will benefit most directly, and as such have expressed strong interest in this project. Both commercial and recreational fishing industries also stand to gain if pheromones can be developed as a tool to assist management agencies in controlling wild fish.

As mentioned above, the sea lamprey has already threatened the operations of several fisheries in the Great Lakes. Similarly, the carp, ruffe, and goby have caused great declines in the quality of many lake fisheries, threatening numerous jobs. Several dozen fishing industry jobs could be created in particular areas like Duluth and large inland lakes infested with carp if they were rid of exotic fish species. Likewise, this technology may increase the efficiency of fish breeding (a perennial problem) in the aquaculture industry.

In the short term, hormonal pheromones appear to have their greatest potential in efforts to manage "nuisance" species, such as the common carp (a close relative of the goldfish), ruffe, round goby, and sea lamprey. These species of 'exotic' (non-native) fish have already greatly altered the ecological balance in many local lakes and rivers and represent a continuous and growing threat. In the case of the sea lamprey, the threat is particularly severe, and this species has already caused the collapse of several fisheries in the Great Lakes by endangering the existence of several fishes. Few options are presently available to control these species other than the use of chemical toxicants, which are extremely expensive, environmentally damaging, and not very effective.

This project examines the specificity and potency of fish pheromones to determine whether and how they can be applied to attract these unwanted nuisance species to traps for removal, male sterilization (and release), or census. The results will provide an alternative means of control which has no negative consequences to the environment.

Exotic fish species are a severe and growing threat to global aquatic ecosystems. This technology could be made available world-wide within the next decade, helping the lifestyles and livelihoods of any community which is dependent on native fish species as a source of food and industry.

Minnesota County
Carlton, Cook, Lake, Pine, St Louis

Publication for Further Information
Sorensen, P.W., and A.P. Scott. 1994. The evolution of hormonal sex pheromones in teleost fish: Poor correlation between the pattern of steroid release by goldfish and olfactory sensitivity suggests that these cues evolved as a result of chemical spy

Web Site for Further Information

Primary Researcher
Peter Sorensen
statini@umn.edu

Participating Individuals
Peter Thomas - University of Texas Paul Collodi - Purdue Alan Brash - Vanderbilt Glen VanDerKraak - Guelph John Caprio - Louisiana State University Thomas Wegner - Applied Economics - Extension Educator-Hennepin County Ext. Office
1 Undergraduate Students
4 Graduate Students

Participating Institutions
Minnesota Sea Grant Great Lakes Fishery Commission National Science Foundation

Department
Fisheries and Wildlife

Government Funding Type
Federal
State

Additional Funding Information
Average annual funding is $100,000.00