Covering the behavior and ecology of the northern fur seal, this book is a model long-term study of marine mammals, one that tests theory through both observation of undisturbed behavior and manipulative experiments on individuals. Here Roger Gentry draws on nearly two decades of research on three different islands to show how behavior among these seals changes with population size, sex ratio, and environment, to explain the behavior of the population beginning with individuals, and to generalize the results to other members of the eared seal family. In so doing, he offers one of the most comprehensive studies of its kind on any marine mammal species to date. Gentry shows that the species is driven by very different behavioral traits than have been assumed for it in the past. His book analyzes behavior on scales of hours to lifetimes, investigates the mating system, considers processes that underlie the mating system (site fidelity, behavioral estrus, and the development of territoriality), and addresses specific aspects of maternal strategy (female attendance behavior, pup growth, seasonal influences, and the effects of continental shelf width). Gentry contributes to knowledge about marine mammals by providing a very specific basis for interspecies comparisons, and he suggests a link between population trend and environmental regime shifts. He also guides the debate over seal mating systems from an interpretive to an empirical or experimental basis. Originally published in 1997. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

The National Marine Fisheries Service (l\rNßS) conducted an aerial survey of the beluga whale population in Cook Inlet, Alaska, during 8-14 June 1999. The 41.5 hr surveywas flown in a twin-engine, high-wing aircraft at an altitude of 244 m (800 ft) and speed of 185 km/hr (100 kt) along a trackline 1.4 km from shore, consistent with annual surveys flown each year since 1993. The flights in 1999 included one or more surveys of coastal areas around nearly the entire Inlet and 1,790 km oftransects across the Inlet. Paired, independent observers searched on the coastal (left) side of the plane, where virtually all sightings occur, while a single observer and a computer operatorldatarecorder were on the right side. In addition, each day a different visitor observed from the left side. After finding beluga groups, a series of aerial passes were made to allow at least two pairs of primary observers to make four or more counts of each group. Inter-day counts ranged from 75 to160 belugas near the Susitna River (between the Beluga and Little Susitna Rivers), 13 to 43 in Knik Arm, and 17 to 30 in Chickaloon Bay, but no belugas were found in lower Cook Inlet. The sum of the aerial estimates (using median counts from each site, not corrected for missed whales) ranged from 197 to 221 whales, depending on observer. The index count for 1999 is 217 , which is slightly higher than the index counts for 1998 (193) but lower than all index counts by NMFS observers between 1993-97