May 18, 2018 Mary Gates Hall MARINE ECOLOGY AND FOOD WEBS 1D Session Moderator: Bonnie Becker, Academic Affairs (Tacoma) MGH 228 12:30 PM to 2:15 PM * Note: Titles in order of presentation. Effects of Male Coercion in Bottlenose Dolphins Predicting Diet through Quantification of Biomechanical (Tursiops aduncus) on Female Foraging Behavior Differences in Cranial Morphology in Odontoceti Elizabeth Marina (Liz) Allyn, Senior, Aquatic & Fishery Grace X. Sun, Senior, Biology (General) Sciences Austin Fletcher Sears, Senior, Biology (Physiology) UW Honors Program Mentor: Sharlene Santana, Biology Mentor: Janet Mann, Biology, Georgetown University Mentor: Aaron Wirsing, Environmental and Forest Sciences Among the most robust determinants of fitness within the an- Mentor: Megan Wallen imal kingdom are successful feeding techniques that enable adequate energy acquisition. The need to maintain a steady In the population of bottlenose dolphins (Tursiops aduncus) food supply is especially crucial in mammals who have high in Shark Bay, Australia, groups of two or three adult males metabolic demands in order to maintain a homeostatic inter- form long-term alliances that sequester, harass, and intimi- nal body temperature. Within the Class Mammalia, the Order date adult females, presumably to increase their chances of Cetacea consists of whales, dolphins, and porpoises, and in- mating success. Costs that males inflict on females include cludes some of the most derived and specialized aquatic car- physical injury, changes in home range and habitat use, re- nivores. Of the three Cetacean suborders, Odontoceti retains duced foraging, and changes in calf care. Although altered the ancestral condition of having teeth rather than baleen for female behavior is evident during association with males, the filter-feeding as in Mysticeti whales. This allows odontocetes direct impact males have on female behavior is not entirely to consume many prey types, ranging from cephalopods to clear. That is, male behavior and female responses to such large vertebrates. The aim of this study is to investigate if in- behavior during consortships have not been explicitly doc- terspecific differences in bite force and gape size evolved in umented. A long-term study has collected detailed behav- tandem with the consumption of specific prey types in odon- ioral data on the Shark Bay population since 1988. Using tocetes. To achieve this goal, we used skull specimens from this dataset, this project will quantify the rate of male aggres- the Burke Mammalogy Collection at the University of Wash- sion directed at females and how female activity budgets and ington to take a variety of linear measurements of the cranium foraging tactics change in response. Preliminary work indi- and mandible. We used these measurements to estimate gape cated that rates of received aggression were higher for cycling size and bite force by applying mathematical equations, and females than non-cycling females, and higher when females then contrasted these values across species that differ in diet. were in the presence of more than one male, potentially con- We expect to find that odontocetes evolved cranial adapta- firming that males use aggression to coerce reproductively vi- tions to 1) increase bite force as a means to consume harder able females. Females also spent less time foraging when prey and 2) increase gape size as a means to consume larger in the presence of more than one male, hinting at potential prey. Developing a better understanding of how species max- costs to the female owing to loss of food. Because females imize energy gain is imperative to determining the factors that have highly specialized foraging tactics, changes in foraging drive evolution and species adaptation. This knowledge can behavior and home range during prolonged or repeated con- also help inform future conservation efforts, improve the gen- sortships could impact female condition. eral understanding of Odontoceti evolution, and serve as a reference for future studies of mammalian cranial morphol- ogy and biomechanics. Undergraduate Research Program 1 www.uw.edu/undergradresearch Fast Kelp Crab Consumption: Implications for geness and graceful crabs. We investigated their weight- Washington Sea Otters specific feeding rates, egestion, and excretion via a basic mass Carter Justis Johnson, Senior, Biology (General), Aquatic & balance bioenergetic equation in which consumption must Fishery Sciences equal respiration, egestion, excretion, and growth. We mea- Mentor: Jessica Hale, School of Aquatic and Fishery sured the egestion and excretion components of consumption Sciences by collecting unconsumed food material and fecal material, Mentor: Kristin Laidre, Polar Science Center/APL and respectively. This multi-species comparison evaluates size School of Aquatic and Fishery Sciences and temperature-dependent feeding patterns that have impli- Sea otters (Enhydra lutris), members of the mustelid family, cations for future spatial distributions and energy require- are distributed in the near-shore marine environment along ments of Dungeness and graceful crabs across Puget Sound. the west coast of North America from southern California to Future management of the fishery and ecological impacts un- Alaska. Sea otters are unique among marine mammals, in der changing conditions are discussed. that they bring all captured prey to the surface to handle and consume. This behavior allows scientists to directly observe Marine Feeding Ecology and Energetics of Belted their foraging and estimate energy intake rates based on time Kingfishers (Megaceryle alcyon) on San Juan Island spent at the surface processing and consuming prey (handling Laurel Anne Yruretagoyena, Senior, Biology (Ecology, time), prey type and size, and dive time. The foraging be- Evolution & Conservation) havior of sea otters is observed using standardized methods Hannah Mckown Booth, Senior, Environmental Science & throughout the sea otter’s North American range. One as- Resource Management (Wildlife Conservation) sumption made when calculating sea otter energy intake rates Mary Gates Scholar, UW Honors Program is that the same prey type of a given size is equivalent across Mentor: William Breck Tyler, Friday Harbor Labs regions. However, an anomaly in the handling time of kelp Mentor: David Slager, Biology crabs (Pugettia spp.) has been discovered, where Washing- Megaceryle alcyon ton sea otters (Enydra lutris kenyoni) handle kelp crabs 1.5- Belted Kingfishers ( ) are widely dis- 2 times faster than sea otters in California (Enhydra lutris tributed across freshwater and marine environments of North nereies). One hypothesis to explain this difference is that America, but the species’ feeding ecology remains poorly Washington kelp crabs have a lower edible biomass than kelp studied in marine habitats. In summer 2017, we investigated crabs in California, allowing for faster handling times by sea the behavior and feeding ecology of Belted Kingfishers in the otters. To explore this hypothesis, I collected kelp crabs at nearshore marine waters of San Juan Island. Our objectives two sites on the Washington coast. I measured and compared were to assess differences in feeding strategy and success kelp crab maximum width and edible biomass to test whether among birds of different ages, to calculate time budgets, and kelp crabs in Washington are an equivalent sea otter prey item to examine the effects of dynamic environmental factors such to kelp crabs in California. Kelp crabs comprise 20% of the as tide and current speed on kingfisher feeding. We conducted overall diet of Washington sea otters, so accurately measur- focal behavioral observations of adult and juvenile birds at ing the edible biomass of kelp crabs enhances the precision two locations on San Juan Island. Observations on individual of estimating sea otter energy intake rates. Estimating the en- feeding success were collected opportunistically during study ergy intake rate of sea otters provides additional information periods. Overall, adult birds showed a higher success rate and on their population health. 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 abun- Consumption across Temperature and Size in Dungeness dance or accessibility may be site specific. Feeding success and Graceful Crabs: Bioenergetic Implications for was fairly consistent over all current speeds but was highest Ecology and Fisheries Management during low tides. Feeding success also showed a diel pattern Grace Rachele Workman, Senior, Aquatic & Fishery (highest from 1200 to 1400), differing from prior research in Sciences freshwater habitats. Our results are intriguing and demon- Mentor: P. Sean McDonald, Program on the Environment strate the need for continued research on how life stage, cur- Dungeness crabs (Cancer [Metacarcinus] magister) hold rents and tidal stage influence marine based Belted Kingfish- commercial and cultural value in Washington State, yet lit- ers and their role in coastal ecosystems and food webs. tle 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 con- sumption experiments in aquaria at multiple temperatures and across a variety of sizes (70-100mm carapace width) of Dun- 2 Are All Herbivores Created Equal? Linking Diet