Research Projects: Marine Mammal Research Consortium

About the Consortium > Research Projects

The following studies are currently being funded. More are being added as we update the list. You can learn more about these studies by clicking on the links. Details of completed research can be obtained from the lists of publications, which contain the findings of more than 100 papers published to date.

PROJECT 1: INTERACTION OF DIET AND IMMUNE CHALLENGES
PRINCIPAL INVESTIGATORS: David Rosen, Stuart Turvey, Martin Haulena
Summary:Changes in the type and availability of prey to Steller sea lions may be affecting the animal’s ability to stave off disease and other physiological challenges. This study investigates the potential interaction between immune function and diet (fatty acid prey composition and level of nutrition) in captive Steller sea lions through in vivo and in vitro cellular responses. This study will aid species management and recovery by investigating a potential mechanism for the decline and lack of recovery of Steller sea lions in the wild.

PROJECT 2: BIOENERGETICS & NUTRITIONAL PHYSIOLOGY OF CAPTIVE OTARIIDS
PRINCIPAL INVESTIGATORS: Dr. David Rosen
Summary: Funds are requested to maintain and conduct basic research on the Consortium’s collection of trained Otariids (Steller sea lions and northern fur seals). The captive research program investigates a range of hypotheses to explain population declines and to formulate scientifically sound strategies for species recovery. It conducts research on physiology, nutrition and bioenergetics. It also serves to develop and validate techniques and technologies that can be applied to the study of animals in the wild. Basic research on morphological growth, metabolism, and feeding efficiency are part of an unprecedented data set and are used as the backbone to concurrent research projects. The captive animals have proven an invaluable resource to Consortium research and external scientists.

PROJECT 3: VIDEO-BASED ATTENDANCE PATTERNS OF STELLER SEA LIONS (Eumetopias jubatus) AT THE PRIMARY NURSERY HAUL-OUT IN OREGON
PRINCIPAL INVESTIGATOR: Markus Horning
Summary: Lack of sufficient prey resources can have a direct effect on pinniped attendance patterns resulting in increased foraging durations, less time ashore, and ultimately, reduced pup survival. One method of inferring the availability and quality of food resources is by examining maternal attendance patterns. We propose to use video cameras to record Steller sea lion attendance patterns at Sea Lion Caves, the primary Steller sea lion nursery area in Oregon, and compare to similar studies in Alaska. This study is timely, as the northern California Current System has recently exhibited dramatic annual fluctuations affecting prey resources for top predators.

PROJECT 4: NORTHERN FUR SEAL BODY SIZE
PRINCIPAL INVESTIGATOR: Andrew W. Trites
Summary: Growth increments of fur seal teeth collected in 2007 will be measured to reconstruct relative feeding conditions experienced by young fur seal in the North Pacific over the past 3 years. Body lengths of fur seals harvested on St. Paul Island in 2007 will also be measured to compare with historical measurements taken since 1911. These two sets of morphometric measurements provide insights into the conditions currently experienced by fur seals and should provide new insights into the factors that caused the decline of fur seals and are preventing their recovery.

PROJECT 5: NORTHERN FUR SEAL FORAGING HABITAT
PRINCIPAL INVESTIGATOR: Andrew W. Trites
Summary: We will continue a study initiated in 2005 to track lactating females to describe the attendance patterns and fine scale foraging behavior of fur seals on St. Paul Island, Alaska. We will identify summer habitat from tracked individuals, and will construct a second model to identify habitat in the Bering Sea and North Pacific Ocean using a knowledge-based approach previously developed for Steller sea lions.

PROJECT 6: THE EFFECTS OF MIXED DIETS
PRINCIPAL INVESTIGATORS: D.J. Tollit, D.A.S. Rosen, A. W. Trites
Summary: This is a continuation of a long-term mixed diet manipulation project with captive Steller sea lions that uses multi-faceted, novel techniques to provide important bioenergetic and diet information required for recovery and ecosystem-based management. The project investigates how different patterns of prey intake affect sea lion health, physiology and our ability to accurately describe diet. In this second year we will process all archived tissue samples, as well as new complementary samples (collected after project refinements) and integrate all datasets for ensuing dissemination. An additional long term captive blubber fatty acid signature study will be undertaken with three harbor seals to determine new low-lipid calibrations for QFASA.

PROJECT 7: STELLER SEA LION FORAGING IN OPEN WATER
PRINCIPAL INVESTIGATORS: Andreas Fahlman, David Rosen, Andrew Trites
Summary: Physiological processes (e.g., metabolism, circulation) of trained sea lions will be studied under more realistic field conditions (e.g. water depth and temperature) than can be established in swimming pools. The potential metabolic trade offs between thermoregulation, fasting (body condition) and diving will be determined for Steller sea lions. Results will provide insight into the limitations that thermoregulation places on dive duration or foraging trip efficiency, and how changes in prey field (number of fish) affect sea lion energy balance and foraging behavior.

PROJECT 8: HORMONE ANALYSIS TO ASSESS NUTRITIONAL STRESS IN STELLER SEA LIONS AND NORTHERN FUR SEALS
PRINCIPAL INVESTIGATORS: Andrew W. Trites and Samuel K. Wasser
Summary:Approximately 3000 fecal samples will be collected and analyzed from northern fur seals and Steller sea lions to assess physiological stress via cortisol, and isolate nutritional stress therein via triiodothyronine (T3) and corticosterone. Study results will provide a current assessment of the general physiological health of the populations analyzed, thus identifying at-risk populations, and assisting in the development of conservation measures.

PROJECT 9: MODELING NORTH PACIFIC PINNIPEDS
PRINCIPAL INVESTIGATORS: Brian C. Battaile, David A.S. Rosen, Andrew W. Trites
Summary: A major focus of North Pacific conservation and recovery efforts has been to understand the demography and physiology of seals and sea lions, and how changes in the environment interact with the two. We propose to update and expand the Steller sea lion bioenergetic model and perform a Population Viability Analysis (PVA) for northern fur seals. The bioenergetics component will restructure and update the current model with the latest physiological data from the Consortium’s captive Steller sea lion research program. We will also incorporate the effect of environmental changes on the physiology of individuals and its ultimate impact on life history parameters. The PVA on the northern fur seals will provide a better understanding of the demographic processes that may be driving its declining population trajectory. Our PVA will address the probability of extinction and/or listing of this species under the U.S. Endangered Species Act, and determine critical life stages for conservation. These two models will provide an invaluable management tool to explore the physiological and demographic links between physical and biological environmental changes in the North Pacific pinniped population trends.

PROJECT 10: STABLE ISOTOPES OF JUVENILE NORTHERN FUR SEALS
PRINCIPAL INVESTIGATOR: Andrew W. Trites and Amy C. Hirons
Summary: The decline of Pribilof Islands northern fur seals may be related to conditions experienced outside of the Bering Sea. A pilot study will be undertaken using stable isotope signatures of canine teeth from 3 year old males collected in 2005 and 2006 to determine whether seals that experienced stunted or enhanced growth fed at the same latitude and upon species occupying the same trophic levels during similar developmental periods. If a population bottleneck is occurring with juvenile male fur seals of differential size, this study will assist in identifying where and when the bottleneck begins.

Continuing Research

Bioenergetic Studies with Captive Steller Sea Lions
Bioenergetic studies help quantify the energetic costs of various components of the sea lion's energy budget, their interaction, and their changes with age.

Physiological Stress
Steller sea lion scats are being examined to learn how stress is affected by diet.

Dietary Analysis and Brand Resights of Steller Sea Lions
Researchers survey British Columbia for branded sea lions, and collect scats from rookeries and haulouts in British Columbia and Southeast Alaska for dietary and hormone analysis.

Northern Fur Seals: Developing a Comprehensive Research Plan
Researchers are developing a comprehensive research plan for northern fur seals.

Assessing Changes in the Productivity of the North Pacific from Body Size & Annual Growth Increments in the Teeth of Northern Fur Seals
Body lengths and teeth of northern fur seals are measured and compared with historical collections and measurements.

Working Together to Better Understand Steller Sea Lion Habitat and Commercial Fisheries
A new management tool will help to identify critical habitat and the overlap between fisheries and Steller sea lions.

Fine Scale Foraging Behavior of Steller Sea Lions and
Northern Fur Seals
Fine scale foraging data will help to identify critical habitat and assess the extent of spatial overlap with commercial fisheries.

Development of the Steller Sea Lion Open Water Project: testing the effectiveness and energetic costs of telemetry instruments
The proposed studies will collectively yield critical information on the accuracy and precision of specific tags, and their suitability for deployment on wild animals, and the energetic costs and potential behavioral reactions of wearing research instruments. In a population context, these data will allow assessments of the limitations of using tag telemetry in the wild, and will allow researchers to refine their analyses of diving and swimming data to account for the influence of the tag.

Physiological Studies of Captive Northern Fur Seals
A captive Northern fur seal research program will be established to expand the scope of scientific investigations into changes that have occurred in the North Pacific ecosystem.

Prey Requirements of the Northern Fur Seal
Using data from pelagic surveys, captive studies and literature reviews, a bioenergetic model will be developed to estimate the prey requirements of northern fur seals.