Month: February 2022

Bio

Lauren Cooley is a graduate student in the Vertebrate Ecology Lab at Moss Landing Marine Labs (MLML). She received her BS in Animal Science from Cornell University in 2016 and completed internships at the Alaska SeaLife Center and Florida Fish & Wildlife Conservation Commission. After two years working as a marine mammal and sea turtle stranding technician at the Institute for Marine Mammal Studies in Gulfport, Mississippi, Lauren moved to California to join Dr. Gitte McDonald's lab group in 2018. Her research interests include the ecology, physiology, and conservation of marine mammals and sea turtles with a focus on animal welfare.

For her master's thesis, Lauren investigated the effects of research handling activities on stress levels in juvenile northern elephant seals using hormone, blood parameter, and heart rate data. She also worked as the Data Manager and later Stranding Coordinator for the MLML Marine Mammal & Sea Turtle Stranding Network. In addition to her research work, Lauren is passionate about science communication and served as MLML Social Media Coordinator, Editor of the MLML Drop-In Blog, and Outreach Chair for the Vertebrate Ecology Lab. In February 2022, Lauren moved back east to Cape Cod, Massachusetts to begin a new job as a Stranding Biologist with the International Fund for Animal Welfare (IFAW). She looks forward to a long career in the always exciting marine mammal stranding field and is very thankful for the opportunity to use her fieldwork and research skills in this new conservation-focused role.

Thesis Abstract

Wildlife researchers must balance the need to safely capture and handle their study animals to sample tissues, collect morphological measurements, and attach dataloggers while simultaneously ensuring their results are not confounded by stress artifacts caused by handling. To determine the physiological effects of research activities including chemical immobilization, transport, instrumentation with biologgers, and overnight holding on a model marine mammal species, I collected hormone, blood chemistry, hematology, and heart rate data from 19 juvenile northern elephant seals (Mirounga angustirostris) throughout a translocation experiment. Across my six sampling timepoints, cortisol and aldosterone data revealed a moderate hormonal stress response to handling that was accompanied by minor changes in hematocrit, blood glucose, and blood lactate, but not ketone bodies or erythrocyte sedimentation rate. I also performed the first assessment of heart rate as a stress indicator in this species and found that mean heart rate, interbeat interval range, and apnea-eupnea cycles were influenced by handling. However, by the time seals were recaptured after several days at sea, all hormonal and hematological parameters had returned to baseline levels and 95% of study animals were resighted in the wild up to two years post-translocation. Together these findings suggest that while northern elephant seals exhibit mild physiological stress responses to handling activities in the short term, they recover rapidly and show no long-term deleterious effects, making them a robust species for ecological and physiological research.

Juliana graduated from the University Honors Program at the University of California, Davis in spring 2018 with a B.S. in Biological Sciences. While there, Juliana participated in undergraduate research in the Grosberg Lab, where she assisted with a project on population genetics of symbionts hosted by sea anemones, and conducted an independent research project on symbiont photosystem performance for her undergraduate honors thesis. She also spent a semester studying abroad at the University of Queensland in Australia. After graduation, Juliana took a gap year, which included work in environmental education and volunteer work in museum education, before beginning her M.S. in Marine Science in the Logan Lab at CSUMB and the Ichthyology Lab at MLML in fall 2019. 

For her thesis, Juliana investigated physiological responses to hypoxia in juvenile flatfishes to determine the implications of hypoxic events in their important nursery habitat in Elkhorn Slough. She presented this research at the SACNAS National Diversity in STEM conference, the Western Society of Naturalists Annual Meeting (where she was awarded “Best Graduate Poster”), and the Ocean Sciences Meeting, in addition to presenting this research in the inaugural “Grad Slam” (3-minute thesis) competition at CSUMB, where she won first place. 

Juliana worked as a teaching associate at CSUMB during her first year of graduate school, before beginning a position as a program assistant for the Coastal and Marine Ecosystems Program (CMEP) at CSUMB. In that role, Juliana helps plan, run, and evaluate all of the educational programs within CMEP, including the Research Experience for Undergraduates (REU) program and the annual Sea Lion Bowl. She also works as a naturalist on a whale watching boat in Moss Landing. When not working, Juliana enjoys spending time with her pets, hiking, photography, and art - mostly watercolor painting and digital illustration. Following graduation, Juliana will be starting an Alaska Sea Grant State Fellowship at the Alaska Fisheries Science Center.

Thesis Abstract:

Estuaries serve numerous important ecosystem roles, including providing critical nursery habitat for juvenile fish. However, due to eutrophication and climate change, estuaries experience highly variable dissolved oxygen (DO) levels and hypoxic conditions. Though hypoxia negatively impacts juvenile fish, there are physiological compensatory mechanisms fish utilize to prevent tissue-level hypoxia. This study examines the effects of hypoxia on two ecologically and economically important flatfish species in Elkhorn Slough on California’s central coast: juvenile English sole, Parophrys vetulus, and juvenile speckled sanddabs, Citharichthys stigmaeus. I measured metabolic rate, ventilation rate, and hematocrit, as well as biochemical indicators of hypoxia (HIF-1a and L-lactate) and oxidative stress (superoxide dismutase), following an acute, six-hour exposure to six DO levels ranging from ambient to severely hypoxic: 8.0, 6.0, 4.0, 3.0, 2.0, and 1.5 mg/L O2. I found that both standard metabolic rate (SMR) and maximum metabolic rate (MMR) in English sole decreased as DO level decreased. A more significant change in MMR compared to SMR also led to a significant decrease in aerobic scope (the ability to increase metabolic rate over resting levels) with decreasing DO levels. For both species, ventilation rate increased as DO level decreased, likely as a mechanism to increase oxygen supply. Both species also exhibited a significant increase in anaerobic activity (increased lactate in muscle tissue) at low DO levels (1.5 mg/L O2 for English sole and 2.0 mg/L O2 for speckled sanddabs). English sole also experienced a significant increase in oxidative stress (as measured by SOD in gill tissue) at 1.5 mg/L O2. Overall, all of these factors can lead to or indicate decreased survival and fitness of juvenile flatfish in hypoxic conditions, with decreased survival potentially reducing population size and fishery success. Evaluating thresholds for tolerance of hypoxia may allow us to predict these changes, as well as determine areas of suitable nursery habitat and targets for estuarine restoration. Since many responses to hypoxia were only observed only at very low DO levels (i.e., 2.0 or 1.5 mg/L O2), these flatfish species appear to have a higher tolerance for hypoxic conditions than other teleost fishes and may be able to withstand many of the environmental hypoxia events observed in Elkhorn Slough, as long as DO levels do not drop below lethal thresholds. Species-specific differences were also found. For two metrics measured, ventilation rate and L-lactate, speckled sanddabs exhibit a nonlinear response, with highest values at mid DO levels, in contrast to a more linear response for English sole, with highest values at low DO levels, suggesting responses to hypoxia may be employed at different DO thresholds for the two species. Additionally, an oxidative stress response was only present in English sole, and not in speckled sanddabs, potentially indicating that speckled sanddabs are better able to withstand hypoxic conditions compared to English sole. If English sole are less tolerant of hypoxic conditions, suitable nursery habitat for this species could be reduced more significantly than for speckled sanddabs, potentially altering the relative distribution and abundance of the two species. 

Gammon graduated from the University of Miami (UMiami) in the Spring of 2019 with a BS in Marine Science and Biology. His research career started with Dr. Diego Lirman's Benthic Ecology and Coral Restoration Lab at UMiami and the citizen science based, coral restoration program Rescue a Reef. His primary research project with the lab was investigating the most effective outplanting methods for microfragmented massive corals. He presented his findings at the Reef Futures 2018 conference in the Florida Keys and published the results in the PeerJ scientific journal. Gammon joined the Ichthyology Lab in the Fall of 2019.

During his time at MLML, Gammon helped lead the efforts for the surf zone marine protected area (MPA) monitoring program which is a project studying the effects of MPAs on California's sandy beaches. The project is a collaborative effort through the University of California – Santa Barbara and Humboldt State University in addition to MLML to sample beaches throughout the state. The project started in 2019 and has continued during the summer every year since. Gammon used this project as inspiration for his thesis by expanding on it to focus on the seasonal changes within the surf here in central California. Through his thesis, he also recorded a rare species of guitarfish that has never been observed north of southern California. With his fellow lab mate, Rachel Aitchison, they published this range extension in the Journal of the Ocean Science Foundation.

When not doing research, you might find Gammon in one of the exhibits at the Monterey Bay Aquarium as a volunteer SCUBA diver helping to keep the inside of the tanks clean. Gammon also works part-time for the California Department of Fish and Wildlife (CDFW) in the geographic information systems (GIS) lab of the Marine Region Department, helping with the California Recreational Fishermen Survey project run by the CDFW. After graduating, Gammon is looking forward to starting a career combining data and policy to help conserve the ocean's resources.

Thesis Abstract:

The surf zone is an important and highly dynamic ecosystem situated at the land-sea interface; however, it is relatively understudied in California. Beaches are one of the most, intensely used coastal resources by humans (e.g., recreation, fishing, development), and can be altered by human impacts, potentially affecting the species that reside there. In addition, oceanographic conditions such as upwelling, temperature, and storm-generated waves have a predictable seasonality that may drive shifts in species assemblages throughout the year. This study investigated the factors influencing spatial and temporal changes in surf zone communities at four beaches in central California from July 2020 to June 2021, testing seasonal trends, the effects of marine protected areas (MPA), and associations with environmental conditions. Each site was sampled eleven times, roughly once a month, for the sampling window using replicated (n = 6 per sampling day) horizontal baited remote underwater video stations (BRUVS). The MaxN statistic (i.e., the maximum number of individuals of the same species observed in a single frame of the video), was calculated for fish and invertebrates on each sampling day, while the relative abundance of drift algae was extracted from still frames using percent cover estimation techniques. Environmental data were obtained from in situ observations on the day of sampling (e.g., water temperature, salinity, wind speed, wave height and period) or weather station sources (e.g., wind and wave direction). Fish and invertebrate abundance and community composition were analyzed separately due to differences in relative abundance and behavior. The results indicated that fish assemblages exhibit seasonality. Species like the barred, calico, and walleye surfperch and leopard shark were far more common in the winter and spring and the speckled sanddab was more common in the summer. Other species like the silver surf perch, thornback ray, dwarf perch, and black-and-yellow rockfish were common throughout the year. There were no impacts on seasonality on invertebrate assemblages, but the system was dominated by the purple dwarf olive snail, Pacific sand crab, slender crab, and red rock crab species. Marine protection inside MPAs had a significant impact on the community structure of fish species, with species such as the reef perch, black perch, kelp rockfish, black-and-yellow rockfish, striped surfperch, rainbow surfperch, señorita, cabezon, and pile perch being observed more commonly within MPAs and other species such as the thornback ray, grass rockfish, barred surfperch, and walleye surfperch being more common at reference sites. There were no effects of MPA status on the invertebrate species diversity or community assemblage. Significant environmental variables for both fish and invertebrate species included wave height and visibility with the former being the dominant driver of surf zone assemblage. Fish species like the barred, calico, and walleye surfperch and leopard shark and invertebrate species like the Dungeness crab, purple dwarf olive snail, and Pacific sand crab were more common during larger wave events while most other species were more abundant on calmer days. Future studies should continue monitoring the surf zone to gather additional years of sampling and sample additional MPA sites to determine if there are greater impacts of MPAs on surf zone species. This study is one of the first to study the temporal trends of central California surf zone. The seasonal trends identified and association of species with MPAs provide key insight into the species that inhabit the surf zone and can be used to help inform management decisions on fishing regulations for these species.