The Effects of El Niño on Pinniped Populations in the Eastern Pacific

Most hypotheses on adaptation stem from comparisons among species. The comparative method offers a way to study questions of ecological mechanisms and evolutionary adaptations, particularly in situations where experimentation is near impossible. Comparisons among species and areas in itself can advance the perspective greatly, but this approach suffers from unknown and uncontrollable variation among species and regions. Adding another dimension of comparison, a large ecological disturbance, to the system is extremely illuminating because it acts independently of preexisting species level and spatial variation and, therefore, simplifies comparisons by eliminating confounding variables. Thus, the chapters in this book are of interest because they not only chronicle the impact of El Nino (EN) on eastern Pacific pinnipeds, but they also provide new perspectives on the ecology, life history, and evolution of these species which could not otherwise have been obtained.