PROGRAM INTRODUCTION

For millennia, human dependence on water for consumption, irrigation, and as a source of food has resulted in the establishment of settlements adjacent to aquatic systems. As the human population has expanded the demands for water and food have increased. The increased removal and/or diversion of water combined with decreased water quality due to increased input of the by-products of civilization has resulted in the degradation of aquatic ecosystems around the world. This degradation has resulted in the decline of numerous species with many becoming threatened or endangered. Over the last 50 years there has been considerable effort to mitigate the impacts of

Photo of the Stehekin river in North Cascades National Park.

degraded aquatic systems on fish species by better understanding the ecology, life histories, and interactions between aquatic organisms. However, this has been complicated by several factors including:

• poor definition of species composition in aquatic habitats,
• low resolution taxonomic systems, and
• lack of genetic markers to discriminate gender and life histories of many species.

The development of molecular tools to non-lethally discriminate species, genotypes within species, life history stages, gender, and to align morphologically indiscriminant juveniles with morphologically distinct adults have allowed researchers to begin addressing the issues listed above. In addition, technological advances have made it possible to generate rapid molecular diagnostic systems so that genetic analyses can be incorporated into species monitoring programs by natural resource agencies. Currently, genetic systems have been developed for a limited number of aquatic species and there is a critical need to develop systems for other species to better manage aquatic resources.

Are these immature fish male or females?

To study the genetics of aquatic organisms, scientists at the WFRC have and continue to develop molecular tools to non-lethally discriminate gender, life history stages, closely related species. These systems allow all life stages of animals to be analyzed and to determine the taxonomic status of juvenile animals that lack morphological distinction. A number of different aquatic taxa are being studied including salmonid fishes, sturgeon, lamprey and various invertebrates, microbes, and plants. Brief description of the type of genetic projects pursued by WFRC are described below.

Species-specific molecular genetic markers to differentiate rainbow and cutthroat trout:

Rainbow trout.

Rainbow trout have been planted throughout the west and have negatively impacted native cutthroat by hybridization. Once hybridized, it is difficult to distinguish hybrids and pure species morphologically. To determine study hybridization between rainbow (rbt) and cutthroat (cct) trout

Cutthroat trout.

WFRC scientists have developed 12 rbt-specific and 12 cct-specific molecular markers. These markers are being used to determine the frequency of hybridization in western rivers, study the biology of hybrids, and determine if pure species can be re-established by alternative management strategies.

Gender-specific molecular genetic markers for chinook salmon:

Over the last decade concerns have grown over the effects of chemical pollution on sex ratios of aquatic species. However, there are few diagnostic systems available that discriminate gender of fish species. This project has resulted in the development of two gender-specific markers in chinook salmon. WFRC scientists are applying these markers on the last healthy wild chinook population in the Columbia river. This population is of great concern because a preliminary study indicated that the sex ratios were greatly skewed with more than 80% of the population being female. This could have devastating consequences on this population. In conjunction with gender analysis the fish will be studied for indications of chemically induced sex alteration.

Life history stage-specific makers that discriminate fall and spring chinook salmon in the Columbia river basin:

Management of chinook salmon is complicated by the fact that threatened and endangered populations coexist with other stable populations within a river system. Thus, development of non-lethal diagnostic systems that discriminate life histories at all life stages will aid in the management of chinook salmon populations. The goal of this work was to identify DNA markers that could discriminate between fall-run and spring-run chinook salmon. WFRC scientists successfully isolated a genetic marker that discriminates between fall and spring chinook salmon in the Columbia and Snake River basins. This is currently used to monitor the outmigration of juveniles to better understand the ecology of this species.

Spawning pair of western brook lampreys in captivity at the Columbia River Research Labortory.

Other projects pursued by WFRC scientist involve developing genetic systems to differentiate species of char in Russia and the U.S, species of lamprey and the gender of sturgeon. The goal of this research is to develop and apply genetic systems to understand the biology and ecology of aqautic species so that resource agancies may begin to focus on managing aquatic ecosystems rather than individual species.

I want to learn more about Genetics research at the Western Fisheries Research Center.