Author: Mary F. Willson

Publisher: Forgotten Books

Published: 2019-01-02

Total Pages: 64

ISBN-13: 9780260638083

Excerpt from Variation in Salmonid Life Histories, Patterns and Perspectives Salmonid fishes differ in degree of anadromy, age of maturation, frequency of reproduction, body size and fecundity, sexual dimorphism, breeding season, morphology, and to a lesser degree, parental care. The advantages of large body size in reproductive competition probably favored the evolution of ocean foraging, and the advantages of safe breeding sites probably favored freshwater spawning. Both long-distance migrations and reproductive competition may have favored the evolution of semelparity. Reproductive competition has favored the evolution of secondary sexual characters, alternative mating tactics, and probably nest-defense behavior. Salmonids provide good examples of character divergence in response to ecological release and of parallel evolution. The great phenotypic plasticity of these fishes may facilitate speciation. Patterns of variation and the processes that generate them are valuable tools for foresighted management practices, predicting the outcomes of anthopogenic changes, managing to maintain biodiversity or particular populations of wildlife consumers, and maintaining the viability of fish populations. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.