The basic principle of all molecular genetic methods is to employ inherited, discrete and stable markers to identify genotypes that characterize individuals, populations or species. Such genetic data can provide information ori the levels and distribution of genetic variability in relation to mating patterns, life history, population size, migration and environment. Although molecular tools have long been employed to address various questions in fisheries biology and management, their contributions to the field are sometimes unclear, and often controversial. Much of the initial impetus for the deployment of molecular markers arose from the desire to assess fish stock structure based on various interpretations of the stock concept. Although such studies have met with varying success, they continue to provide an impetus for the development of increasingly sensitive population discriminators, yielding information that can be valuable for both sustainable exploitation and the conservation of fish populations. In the last major synthesis of the subject, Ryman and Utter (1987) summarized progress and applications, though this was prior to the wide-scale adoption of DNA methodology. New sources of genetic markers and protocols are now available, in particular those that exploit the widely distributed and highly variable repeat sequences of DNA, and the amplification technique of the polymerase chain reaction.

Fisheries genetics researchers will find invaluable the thirty-eight peer-reviewed contributions in this book, presented at the 20th Lowell Wakefield Fisheries Symposium "Genetics of Subpolar Fish and Invertebrates," held in May 2002 in Juneau, Alaska. Looming over concerns of lost fisheries stocks and persistent erosion of genetic variability are predictions of global warming, which may further tax genetic resources. One consequence is an increased reliance on genetic applications to many aspects of fisheries management, aquaculture, and conservation. The contributions in this book are important to modern fisheries science and genetics, and illustrate the evolution of the field over the past decade. The improved technology provides tools to address increasingly complicated problems in traditional applications and ecological and behavioral studies. The union between molecular and quantitative genetics, where many of the major questions about population structure and evolution remain unanswered, will also benefit from the new technologies.

The aim of this book is to systematize and discuss population genetic studies of freshwater fish in a region that harbors the greatest diversity of species among all inland water ecosystems. This volume explores the genetic evaluation for a number of orders, families and species of Neotropical fishes, and provides an overview on genetic resources and diversity and their relationships with fish domestication, breeding, and food production.

Sequenced biological macromolecules have revitalized systematic studies of evolutionary history. Molecular Systematics of Fishes is the first authoritative overview of the theory and application of these sequencing data to fishes. This volume explores the phylogeny of fishes at multiple taxonomic levels, uses methods of analysis of molecular data that apply both within and between fish populations, and employs molecule-based phylogenies to address broader questions of evolution. Targeted readers include ichthyologists, marine scientists, and all students, faculty, and researchers interested in fish evolution and ecology and vertebrate systematics. Focuses on the phylogeny and evolutionary biology of fishes Contains phylogenies of fishes at multiple taxonomic levels Applies molecule-based phylogenies to broader questions of evolution Includes methods for critique of analysis of molecular data