In the desert Southwest, predation and monsoon thunderstorms are determinants of aquatic invertebrate communities. Recent research has focused on the potential of non-native species, like bullfrogs (Rana catesbeiana), to change communities into which they are introduced. Bullfrogs were introduced into Arizona in the mid-1900s and have established widespread populations that predate on and compete with native fauna. In an effort to control bullfrog populations, state and federal agencies have focused on the eradication of bullfrogs in Southeast Arizona – a biodiversity hotspot with many endemic species. Although the effects of bullfrogs on vertebrate species are documented, how and whether bullfrogs alter aquatic invertebrate communities remains uncertain. We examined how the effects of bullfrogs compare to the seasonal effects of the monsoon in influencing invertebrate communities. The objectives of this study were to 1) examine and quantify the effects of bullfrogs on aquatic invertebrate communities by comparing ponds with and without bullfrogs; 2) determine the effect of monsoonal seasonality by sampling invertebrate communities during the early- and late-monsoon, and 3) observe the interaction of bullfrogs and monsoonal seasonality to explore the relative importance of these two factors in shaping aquatic invertebrate communities. We hypothesized a lower invertebrate abundance and richness in ponds with bullfrogs. We expected to see taxonomic differences in community composition based on body size, dispersal ability, habitat use, feeding group, and defense. We anticipated smaller invertebrates and a higher number of defended invertebrates in ponds with bullfrogs. Finally, we expected that the relative abundance of high dispersing insects would increase in late monsoon samples. Preliminary analyses suggest that invertebrate abundance and richness is negatively related to the number of bullfrogs present at a pond. By studying the effects of bullfrogs on aquatic invertebrate communities, we can begin to understand and quantify the impact of this heavily managed non-native predator.

Imidacloprid (IMI) may be a viable alternative to carbaryl for controlling burrowing shrimp (Neotropea californiensis) that destabilize sediments resulting in poor survival and low yields of the commercially harvested Pacific oyster (Crassostrea gigas). Previous laboratory tests indicate the shrimp are overtly affected (immobile, cannot burrow) when exposed to IMI concentrations in sediment pore water, but are not killed. These results contrast sharply with observed efficacy in the field, i.e. mortality 72-96 hours post application and subsequent reductions in burrow counts. Understanding the factors governing efficacy in the field may improve control. We exposed 10 adult female shrimp that had burrowed within native sandy sediment to IMI (Nuprid® 2F) for 96 hours simulating the theoretical maximum pore water concentration (146 ppb) associated with an application of 0.5 lbs active ingredient [ai] per acre. We compared the response of the shrimp to that of an equal number of negative controls, and five shrimp in a comparable pore water-only exposure, and five in clean seawater. Behavior was monitored daily and water quality was measured at the end of the test. As expected, all shrimp in the water-only IMI exposures were overtly affected, but survived. Eighty percent of the shrimp exposed to IMI within their burrows died, whereas 90 percent of the negative controls survived. Dissolved oxygen (% saturation) varied among treatments (clean seawater: 51-69.6%; seawater + IMI: 42.4-57.4%; clean sediment surface water [alive]: 4.1-20.1%, [dead]: 3.4%; sediment + IMI surface water [alive]: 5.4, 57.9%, [dead]: 4.2-65.4%). Results suggest the shrimp can tolerate very low dissolved oxygen within sediment without IMI, but their sensitivity to IMI increases due to factors associated with their impaired ability to move water within the sediment.

Corals are important marine animals that provide significant habitats for thousands of marine teleost and invertebrate species, natural barriers to protect coastal communities, and sources of income for people in more than 100 countries around the world. Despite their vital importance, however, little is known about their taxonomy. Currently, they are classified based on their calcium-based skeleton morphology and coloration, which often causes problems because of high phenotypic variability within species. Thus, I used DNA sequencing in my research to identify species of the genus Lobophyllia from the Indo-Pacific Ocean. Specifically, I tested whether color morphs from different areas in Indonesia actually represent different species or mere color variations. For that purpose, I conducted PCR amplification of the mitochondrial DNA cytochrome oxidase gene and two nuclear genes in 42 colonies of 14 color morphs of Lobophyllia sp. The PCR products were sequenced in both directions at the High Throughput Sequencing Center of the University of Washington, and phylogenetic trees including known species were used to determine the species identities. I expected that color morphs would be genetically differentiated and therefore might represent different species. Regardless of the outcome, this project has helped to understand the biodiversity in coral reefs better, and is also useful to identify appropriate units for coral management and conservation.

A recent discovery in reproductive endocrinology, the kisspeptin system has been found to play a pivotal role in the regulation of the brain-pituitary-gonadal axis. Kisspeptin signaling in the brain is vital to the onset of puberty, control and regulation of sex steroid production, and regulation of fertility and reproductive function in mammals. However, the importance of the kisspeptin system in other vertebrates, such as fish, is not as clear. The goal of the current study was to clone the kisspeptin genes (kiss1, kiss2, and the receptor kiss1ra) for the first time in the marine teleost Anoplopoma fimbria (sablefish), and explore their potential roles in gonadal development. Previously, expression of the kiss2 gene was demonstrated in the gonads of sablefish. Partial kiss mRNA sequences were obtained by PCR and rapid amplification of cDNA ends (RACE) cloning techniques. Semi-quantitative PCR assays developed for each gene allowed us to measure kiss1, kiss2 and kiss1ra mRNA levels in a variety of adult tissues. We found the highest abundance of these mRNAs in the gonads, brain, and pituitary. In particular, kiss2 mRNA was abundant in the ovary and appeared to be the most highly expressed of the kiss genes. We are currently analyzing the expression of the kiss genes in gonads of fish undergoing sexual differentiation. Preliminary data suggest that there is sexually dimorphic expression of all three genes early in life. The ultimate goal of this project is to determine if gonadal kiss gene expression plays an important role in sexual differentiation and/or gametogenesis in fish.

Commercial fish stock populations can be linked to the health of forage fish populations. The Pacific sand lance, Ammodytes hexapterus, is an essential link between zooplankton and higher trophic levels such as birds, marine mammals, and fishes. Understanding the behavior and habitat of Pacific sand lance is key to ensuring the long-term sustainability of sand lance populations. Sand lance spend most of their time either schooling in the water column or buried beneath the substrate. We performed paired preference trials during daylight hours to compare burrowing tendencies between sediment sizes. Sediments were collected on San Juan Island and sorted using a RoTap sediment analyzer. The grain sizes chosen for the trial were medium sand (0.25 – 0.5 mm), coarse sand (0.5 – 1.0 mm), very coarse sand (1.0 – 2.0 mm), and very fine gravel (2.0 – 4.0 mm). The study was conducted on sub adults (8.5-11.5cm total length) to account for any ontogenetic variability in burrowing behavior. We found that sand lance could burrow into all of the provided substrates, but they prefer coarse sand. Observations have shown that Pacific sand lance spend the majority of the night buried under the sediment. We also conducted nocturnal preference experiments during night time hours (2300 – 0300). At night, A. hexapterus displayed no preference between coarse sand and very coarse sand, but did prefer coarse sand over medium sand. At night, when visual clues are eliminated, the preference for substrate type is relaxed. However, preference is also being evaluated by other sensory systems as there is still a notable distinction in the proportion of buried sand lance between substrates.

Seabird distribution and abundance can be used as indicators of the health of the coastal ecosystem. In the Gulf of Alaska over the last four decades there has been growing evidence of climate change and ocean acidification. The largest oil spill in the United States, the Exxon Valdez, occurred here. We used data from the Coastal Observation and Seabird Survey Team (COASST), a citizen science, beached bird survey program with 14 years of surveys from beaches in the Pacific Northwest, and eight years of data from Alaska. We seek to compare U.S. Fish and Wildlife Service (USFWS) data from historical surveys in the Gulf of Alaska (1970-1989), to the current beached bird data collected through the COASST program (2005-present). Historic data include monthly surveys of sites from the Kenai Peninsula to Yakutat Bay, and one offshore island, Middleton (n>250 surveys). Current COASST data cover this same range, include additional surveys from Kodiak Island, but exclude Middleton (n>1200 surveys). These data will be analyzed to examine the differences in monthly encounter rate (carcasses/km) averaged over this region, cumulative species diversity, and oiling rate (percent of recorded carcasses that are oiled). This comparison will provide insight into possible changes in the encounter rate index in the Gulf of Alaska over the past 40 years.

Each summer, millions of Pacific salmon (Oncorhynchus spp.) leave the ocean to return to the streams and lakes where they were born several years earlier. These fish provide a rich resource of nutrients (e.g. eggs, carcasses) to a wide variety of consumers in their spawning watersheds; from insects to fishes, birds and apex consumers like the coastal brown bear (Ursus arctos). While most fish are consumed by bears in the spawning areas of streams, some proportion of the total population of fish is moved into adjacent riparian zones by the bears for later consumption. Although the importance of this subsidy is well documented, few studies have attempted to measure the population level impact of bear consumption on spawning salmon. We quantified the extent and geographic range of bear consumption and carcass movement in a small stream in Bristol Bay, Alaska by conducting daily surveys on the riparian trails used by bears and counting carcasses found there. Our surveys built upon nearly 50 years of in-stream salmon counts where the daily number of dead and alive fish, as well as the degree of consumption of each fish has been measured. We found that 31% of the total fish population was moved into riparian zones during the 2012 season. The mean distance moved was 3.68 meters and the maximum distance recorded was 30 meters. We found no significant differences in the distance moved between sexes of salmon, or in carcass consumption as a function of distance moved. The large quantity of salmon removed from the stream by bears indicates that salmon abundance estimates obtained through manual stream surveys in 2012 significantly undercounted the returning population of salmon. We suggest that riparian carcass removal be factored into future stream surveys for salmon abundance estimation, and present potential methods for further quantifying this effect.