Understanding the factors that contribute to or limit reproductive success is a fundamental objective of the field of ecology, providing insight into the ways ecosystems function and facilitating better management of natural resources. Behaviors that benefit offspring often increase costs to parents, and thus parents must adjust their level of...
Juvenile Chinook salmon (Oncorhynchus tshawytscha) exhibit an array of life history tactics in Oregon's Willamette River Basin, yet we do not know to what extent it is driven by phenotypic plasticity or whether it is predetermined and how conditions in the early rearing environment may affect phenotype expression. We have...
The first objective of this study was to quantify the intensity of space use of 70 juvenile (12-26 months old) Steller sea lions (SSLs) from the western Distinct Population Segment (DPS) in the Kenai Fjord(KF)/Prince William Sound (PWS) region of Alaska as derived from externally attached ARGOS satellite transmitter tags....
Variable ocean conditions can greatly impact lower trophic level prey assemblages in marine ecosystems, with effects propagating up to higher trophic levels. Our goal was to better understand how varying ocean conditions influence diets and niche overlap among a suite of low- to mid trophic level predators. We studied the...
Understanding the movement behavior and foraging strategies of individuals across multiple spatial and temporal scales is essential not only for understanding the biological requirements of individuals but also for linking individual strategies to population level effects. Glacial fjords scattered throughout south-central and southeastern Alaska host some of the largest seasonal...
Effective and sustainable fisheries management not only depends on identifying and defining stocks (fundamental unit of management), but also on having knowledge of factors influencing the abundance, distribution and connectivity of stocks. Population structure of Pacific cod (Gadus macrocephalus) in the southeastern Bering Sea (EBS) remains unresolved although genetic data...
Juvenile walleye pollock (Theragra chalcogramma) are one of the primary prey items for bird and mammal predators in the Bering Sea and support a large commercial fishery. An understanding of the environmental factors that determine the horizontal and vertical distribution of juvenile pollock is needed to estimate the effects that...
Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving
this instability...
Salmon survival and eventual recruitment success have long been thought to be determined within the first summer following ocean migration. Juvenile growth during this period is largely influenced by ocean conditions such as temperature, prey availability, abundance, and quality. Shifts in these conditions due to climatic perturbations are particularly prevalent...
If fisheries managers are to effectively manage commercially exploited fish populations, a basic understanding of the factors that influence fish distribution and abundance is required. In 2005, efforts to identify Essential Fish Habitat (EFH) for the 82 groundfish species managed by the Pacific Fishery Management Council along the West Coast...