In the population of bottlenose dolphins (Tursiops aduncus) in Shark Bay, Australia, groups of two or three adult males form long-term alliances that sequester, harass, and intimidate adult females, presumably to increase their chances of mating success. Costs that males inflict on females include physical injury, changes in home range and habitat use, reduced foraging, and changes in calf care. Although altered female behavior is evident during association with males, the direct impact males have on female behavior is not entirely clear. That is, male behavior and female responses to such behavior during consortships have not been explicitly documented. A long-term study has collected detailed behavioral data on the Shark Bay population since 1988. Using this dataset, this project will quantify the rate of male aggression directed at females and how female activity budgets and foraging tactics change in response. Preliminary work indicated that rates of received aggression were higher for cycling females than non-cycling females, and higher when females were in the presence of more than one male, potentially confirming that males use aggression to coerce reproductively viable females. Females also spent less time foraging when in the presence of more than one male, hinting at potential costs to the female owing to loss of food. Because females have highly specialized foraging tactics, changes in foraging behavior and home range during prolonged or repeated consortships could impact female condition.

Among the most robust determinants of fitness within the animal kingdom are successful feeding techniques that enable adequate energy acquisition. The need to maintain a steady food supply is especially crucial in mammals who have high metabolic demands in order to maintain a homeostatic internal body temperature. Within the Class Mammalia, the Order Cetacea consists of whales, dolphins, and porpoises, and includes some of the most derived and specialized aquatic carnivores. Of the three Cetacean suborders, Odontoceti retains the ancestral condition of having teeth rather than baleen for filter-feeding as in Mysticeti whales. This allows odontocetes to consume many prey types, ranging from cephalopods to large vertebrates. The aim of this study is to investigate if interspecific differences in bite force and gape size evolved in tandem with the consumption of specific prey types in odontocetes. To achieve this goal, we used skull specimens from the Burke Mammalogy Collection at the University of Washington to take a variety of linear measurements of the cranium and mandible. We used these measurements to estimate gape size and bite force by applying mathematical equations, and then contrasted these values across species that differ in diet. We expect to find that odontocetes evolved cranial adaptations to 1) increase bite force as a means to consume harder prey and 2) increase gape size as a means to consume larger prey. Developing a better understanding of how species maximize energy gain is imperative to determining the factors that drive evolution and species adaptation. This knowledge can also help inform future conservation efforts, improve the general understanding of Odontoceti evolution, and serve as a reference for future studies of mammalian cranial morphology and biomechanics.

Sea otters (Enhydra lutris), members of the mustelid family, are distributed in the near-shore marine environment along the west coast of North America from southern California to Alaska. Sea otters are unique among marine mammals, in that they bring all captured prey to the surface to handle and consume. This behavior allows scientists to directly observe their foraging and estimate energy intake rates based on time spent at the surface processing and consuming prey (handling time), prey type and size, and dive time. The foraging behavior of sea otters is observed using standardized methods throughout the sea otter’s North American range. One assumption made when calculating sea otter energy intake rates is that the same prey type of a given size is equivalent across regions. However, an anomaly in the handling time of kelp crabs (Pugettia spp.) has been discovered, where Washington sea otters (Enydra lutris kenyoni) handle kelp crabs 1.5-2 times faster than sea otters in California (Enhydra lutris nereies). One hypothesis to explain this difference is that Washington kelp crabs have a lower edible biomass than kelp crabs in California, allowing for faster handling times by sea otters. To explore this hypothesis, I collected kelp crabs at two sites on the Washington coast. I measured and compared kelp crab maximum width and edible biomass to test whether kelp crabs in Washington are an equivalent sea otter prey item to kelp crabs in California. Kelp crabs comprise 20% of the overall diet of Washington sea otters, so accurately measuring the edible biomass of kelp crabs enhances the precision of estimating sea otter energy intake rates. Estimating the energy intake rate of sea otters provides additional information on their population health.

Dungeness crabs (Cancer [Metacarcinus] magister) hold commercial and cultural value in Washington State, yet little is known about the effects of climate change on their population--even less is known about their competitor, the graceful crab (C. [M.] gracilis). To investigate the effects of temperature and size on feeding rate, we conducted consumption experiments in aquaria at multiple temperatures and across a variety of sizes (70-100mm carapace width) of Dungeness and graceful crabs. We investigated their weight-specific feeding rates, egestion, and excretion via a basic mass balance bioenergetic equation in which consumption must equal respiration, egestion, excretion, and growth. We measured the egestion and excretion components of consumption by collecting unconsumed food material and fecal material, respectively. This multi-species comparison evaluates size and temperature-dependent feeding patterns that have implications for future spatial distributions and energy requirements of Dungeness and graceful crabs across Puget Sound. Future management of the fishery and ecological impacts under changing conditions are discussed.

Belted Kingfishers (Megaceryle alcyon) are widely distributed across freshwater and marine environments of North America, but the species’ feeding ecology remains poorly studied in marine habitats. In summer 2017, we investigated the behavior and feeding ecology of Belted Kingfishers in the nearshore marine waters of San Juan Island. Our objectives were to assess differences in feeding strategy and success among birds of different ages, to calculate time budgets, and to examine the effects of dynamic environmental factors such as tide and current speed on kingfisher feeding. We conducted focal behavioral observations of adult and juvenile birds at two locations on San Juan Island. Observations on individual feeding success were collected opportunistically during study periods. Overall, adult birds showed a higher success rate and longer average prey length than was observed for juveniles. Feeding success for all age categories was higher at Jackson Beach than at Friday Harbor Labs, suggesting that prey abundance or accessibility may be site specific. Feeding success was fairly consistent over all current speeds but was highest during low tides. Feeding success also showed a diel pattern (highest from 1200 to 1400), differing from prior research in freshwater habitats. Our results are intriguing and demonstrate the need for continued research on how life stage, currents and tidal stage influence marine based Belted Kingfishers and their role in coastal ecosystems and food webs.

Herbivorous fishes feed on stems, leaves, flowers, seeds, fruits, and nuts of diverse aquatic plants, as well as algae. In the Neotropics, many of these fishes have intricately tied ecologies with their prey plant’s life history and facilitate seed dispersal; including the herbivorous cousins of piranhas, pacus. Most pacus experience fluctuation in their diet that reflects the changes in seasonality and plant part availability. A few species of pacus, however, exhibit a specialized feeding strategy known as phytophagy; solely consuming the plant material of Podostemaceae (riverweed). This trend of dietary specialization may be paralleled by a similar shift, away from general herbivory, and towards a specialized phytophage morphology. To investigate the link between diet and morphology within the greater scope of herbivory, we examined four coexisting species including: the seemingly specialized phytophage, Ossubtus xinguense; the generalized phytophages, Tometes kranponhah and Tometes ancylorhynchus; and a facultative phytophage, Myloplus rhomboidalis. We compared the gross morphology of these species with several other serrasalmids using micro-computed tomography scanning to measure functional jaw characteristics, as well as using geometric morphometrics to compare body shapes. Jaw biomechanics indicate that O. xinguense produces the weakest jaw leverage potentially as a result of its sub-terminal mouth. However, we also concluded that the phytophagous species as a group, do not overtly differ from the more generalized herbivorous pacus in terms of jaw mechanics (but remain distinct from the piscivorous piranhas). Body shape analyses also show little divergence among phytophage and herbivore body shapes, suggesting that many herbivores share a similar bauplan adapted for fast flowing waters. With the exception of O. xinguense, phytophagous pacus appear to be equipped with a general herbivory feeding morphology sufficient for a specialized diet. This suggests that phytophagy is not a particularly challenging feeding strategy, but performance may be augmented by additional morphological specialization.

The focus of my research is to clarify the population structure of sockeye salmon, and in particular kokanee salmon, in the Lake Washington and Lake Sammamish watershed. There is a poorly understood population of kokanee, a form of sockeye that does not migrate to the ocean, that often migrates from Lake Washington into the Sammamish river, and does not appear to be a part of the main sockeye population in our lakes. This population is understudied but is particularly intriguing because a native population of kokanee was once abundant in the lake. It is possible that this population is a remnant of these native kokanee and represents the only remaining native salmon genes in the lake. It is also possible that this population is a newly evolved freshwater form of introduced sockeye. Either result would be of great interest in terms of conservation and evolutionary biology. Native genes in Lake Washington would represent an important focus for conservation efforts (as are currently underway in Lake Sammamish), and finding a population that has evolved in Lake Washington within the last century would be an exciting demonstration of the adaptability of salmon. Physical examination of specimen scales, gill rakers and otoliths can reveal evidence of the populations life history and feeding habits. Furthermore, genetic analysis and comparison to known sockeye populations can also provide evidence to suggest the identity of this particular population. Using these morphological and genetic observations I hope to illuminate the mysterious origins of this population and contribute to their conservation and restoration. People living along the rivers in the Lake Washington drainage have benefitted from the kokanee salmon for hundreds of years. The little red fish continues to be a cultural icon and important natural resource in Washington state.