Thesis Defense by Brijonnay Madrigal – December 13th

Determining ecotype presence and the call repertoire of killer whales (Orcinus orca) from passive acoustic monitoring near Point Hope, Alaska in the Southeastern Chukchi Sea

A Thesis Defense by Brijonnay Madrigal

The Vertebrate Ecology Lab

Friday, December 13th, 2019 at 4pm

MLML Seminar Room

Brijonnay Madrigal is a master's student working under the co-advisement of Alison Stimpert and Birgitte McDonald in the Vertebrate Ecology Lab. She graduated from the University of Hawai’i at Mānoa in 2016 with a B.S. in Marine Biology and a B.A. in Communication. Prior to her time at Moss Landing, as an undergraduate and Ernest F. Hollings scholar, she completed a research internship at the NOAA Southeast Fisheries Science Center, where she determined sperm whale abundance from passive acoustic monitoring. She later worked as a research assistant for a project conducted in collaboration with both the U.S. Navy and the Hawai’i Institute of Marine Biology Marine Mammal Research Program, to assess dolphin presence through whistle detection at a sonar detonation sites off O'ahu, Hawai'i. Throughout her time at MLML, in addition to her thesis work, she conducted a passive acoustic study to determine acoustic behavior and repertoire composition of Risso's dolphin in the Monterey Bay. She enjoys education and outreach and has worked at the Monterey Bay National Marine Sanctuary as a volunteer coordinator and educator for more than three years. Driven by her passion for marine mammal acoustics she developed a K-12 program called "Listen up!" to educate kids about marine mammals and sounds in the ocean.

Thesis Abstract:
As apex predators, killer whales (Orcinus orca), can have large impacts on ecosystems through top-down predation. In the North Pacific, three genetically distinct ecotypes exist that differ in diet, range, morphology, and vocal behavior. Killer whales are known to occur in the Chukchi Sea but, few data exist regarding ecotypes present. Since killer whale ecotypes differ in vocal behavior, they can be distinguished based on call type, call rate, and bandwidth. An Autonomous Underwater Recorder for Acoustic Listening (AURAL) device was deployed 75 km off Point Hope, Alaska in the southeastern Chukchi Sea to identify which killer whale ecotypes were present in this region. A total of 1315 killer whale calls were detected on 38 days during the summers of 2013 to 2015. Calls were manually grouped into six categories based on the general call contours: multi-part, downsweep, upsweep, modulated, single modulation and tonal. The majority of detections were tonal calls (n = 607, 46%), and multi-part calls (n = 351, 27%) that contained high frequency and low frequency components. Comparison of the current call dataset with published literature showed similarities in peak frequency with other transient populations. These results indicate occasional presence of transient killer whales in the southeastern Chukchi Sea. This study provides the first comprehensive, catalogue of transient killer whale vocalizations in this region.

Brijonnay Madrigal Presents: Determining ecotype presence and the call repertoire of killer whales (Orcinus orca) from passive acoustic monitoring near Point Hope, Alaska in the Southeastern Chukchi Sea

Thesis Defense by Sharon Hsu – December 13th

Using stable isotopes to determine foraging areas of leatherback turtles: limitations of the isotope tracking technique in the western Atlantic Ocean

A Thesis Defense by Sharon Hsu

The Vertebrate Ecology Lab

Friday, December 13th, 2019 at 12pm

MLML Seminar Room

Sharon's love for the ocean started at a young age. She grew up playing in the tidepools and she has never lived far from the water. Sharon received her B.S. in Ecology, Behavior, and Evolution from UC San Diego, and then spent a number of years working abroad, first as a Peace Corps volunteer in the Republic of Vanuatu and later as a project coordinator for a sea turtle conservation group in Costa Rica and volunteer coordinator for various conservation projects. Her research interests include reproductive energetics of sea turtles and the use of stable isotopes to understand migration and foraging patterns. Sharon is currently working on establishing a collaborative project with biologists from Costa Rica.

Thesis Abstract:

Reproductive output has long been linked to habitat quality and resource availability. Individuals foraging in high-quality habitats with high resource availability will have better body conditions and higher survival rates, as well as greater reproductive output. Post-nesting, Western Caribbean leatherback turtles are known to migrate to at least two foraging regions: the western North Atlantic and Gulf of Mexico. This study had three objectives: [1] conduct a comprehensive review of existing stable isotope data and create a map of isotope values, or “isoscapes” to use as a reference for the western North Atlantic and Gulf of Mexico; [2] use stable isotope analysis (SIA) to examine bulk skin stable carbon and stable nitrogen as indicators of foraging region for nesting turtles in Parismina, Costa Rica; and [3] assess the differences of foraging region on female body size and reproductive output. Synthesized isoscapes showed substantial variation between taxa and sampling regions. Specifically for leatherbacks, stable carbon values were higher in the Gulf of Mexico than the western North Atlantic, but no other consistent trends were distinguishable. It was not possible to infer foraging region for skin samples collected in Parismina based on stable isotope values, nor was there a relationship between stable carbon values and reproductive output. This study highlighted the need for more stable isotope data and longer-term reproductive data collection. Although I was unable to validate it as a primary technique to study leatherback movements between nesting and foraging grounds, SIA still holds important conservation value for leatherbacks in conjunction with satellite tracking.

Sharon Hsu Presents: Using stable isotopes to determine foraging areas of leatherback turtles: limitations of the isotope tracking technique in the western Atlantic Ocean

Our stranding network searches for answers in recent spike of deceased marine mammals

Lauren Cooley and Sharon Hsu are both students in the Vertebrate Ecology Lab. They are also volunteers with our Stranding Network, a network of people who collect data on deceased marine mammals. Students who volunteer with the stranding network have been very busy this year with a high rate of strandings in the area. Read more about what life is like as a stranding volunteer in this article by Monterey County Now.

Thesis Defense by Katie Harrington-July 11th

Seasonal time-energy allocation of an island-restricted Falconid, the Striated Caracara, using a low-cost, open-source inertial movement GPS logger

A Thesis Defense by Katie Harrington

Vertebrate Ecology Lab

Thursday, July 11th, 2019 at 12 pm

MLML Seminar Room

Katie began research on striated caracaras in 2015 and has since took over leadership of a long-term research site begun by Hawk Mountain Sanctuary in 2010. Along with overseeing and implementing the expansion of a banding program and educational outreach to farmers and schoolchildren in the islands, Katie’s research has focused on striated caracaras’ seasonal movements, feeding ecology, and energy use. Katie is currently collaborating with researchers in mainland South America to study the population genetics of striated caracaras within and beyond the Falklands, and to support and encourage research into their little-known populations in Chilean and Argentine Tierra del Fuego.


Thesis Abstract:

According to life history theory, animals should have adaptive strategies to cope with seasonal fluctuations in resource availability. However, the introduction of human settlements to natural landscapes can affect the spatial and temporal patterning of resources and disrupt the naturally occurring resource variation to which an animal is adapted. Human subsidies impact animal populations by affecting their density, population growth rate, and abundance. Research has shown that island species dependent on human subsidies are more prone to population declines and local extirpations. While population level effects are known, little research has been aimed at individual level behavior and energy allocation effects. Here, I investigate the time-energy allocation and activity budgets of striated caracaras (Phalcoboenus australis), a scavenging and predatory Falconid in the Falkland Islands, a highly seasonal and human-subsidized environment. I developed the Tapered Wings Logger, a low-cost, lightweight inertial movement GPS logger, and made the logger design available for researchers and applicable across many systems. I deployed the loggers on caracaras to examine seasonal differences in time-energy allocation and activity budgets. The acceleration data were used to calculate overall dynamic body acceleration (ODBA, gravitational g), a proxy for energy expenditure, and to estimate behavioral state using hidden Markov models. I combined the GPS data with ecological knowledge of the species and study sites to help validate model results. Additionally, I investigated space use with daily distances traveled and home range kernel density estimates. My results suggest that on a daily scale, caracaras overwintering at a farm settlement worked 20% harder than in summer (24-hr ODBA: winter 2848.07 ± 577.26 g; summer 2380.85 ± 435.65 g [x̄ ± SD]). During daytime, hourly ODBA rates were nearly two times higher in winter compared to summer (winter 239.50 ± 51.61 g; summer 127.92 ± 26.01 g). Caracaras exhibited more intense activity in winter, spending twice as long in the high activity state compared to summer (winter 99.0 ± 45.2 min, summer 44.1 ± 26.1 min). In addition, during winter, caracaras traveled greater cumulative daily distances (winter 23.75 ± 7.50 km, summer 10.94 ± 3.29 km) and daily ranges were 13 times larger (95% KDE: winter 8.34 ± 11.04 km2, summer 0.64 ± 0.49 km2). This study emphasizes that even with human subsidies to cope with seasonal food availability, caracaras work harder in winter than in summer to obtain enough energy to meet daily requirements. Many island-restricted species will likely face increased variation in resource availability in response to environmental change and human population expansion. I suggest conservation managers consider these results for how to target their efforts to maximize the benefit during a critical life stage of a near threatened species.

Thesis Defense by Heather Barrett-May 24th

The energetic cost of human disturbance on the southern sea otter (Enhydra lutris nereis)

A Thesis Defense by Heather Barrett

Vertebrate Ecology Lab

Friday, May 24th, 2019 at 4 pm

MLML Seminar Room

Heather Barrett is a master’s student under Dr. Gitte McDonald in the Vertebrate Ecology Lab. She graduated from the University of California Santa Cruz in 2009 with a B.S. in Ecology and Evolution and studied abroad in England, France, and Belize. Prior to her research at Moss Landing Marine Labs, Heather interned with the Monterey Bay Aquarium’s Sea Otter Research Program, worked abroad in education, managed data entry and fieldwork with California Department of Fish and Wildlife’s long-term biodiversity assessment in Northern California, and assisted with whale shark research in Mexico. Heather currently is a team member with Sea Otter Savvy and hopes to continue her work with research, science communication, and outreach.

Thesis Abstract:

With increased human populations and tourism in coastal areas, there is increased potential for disturbance of marine wildlife.  Impacts of disturbance are not well understood for many coastal species, such as the southern sea otter (Enhydra lutris nereis). Due to high metabolic rates, sea otters are at particular risk of increased energetic costs due to human disturbance. To investigate effects of disturbance, behavioral scans were conducted over three years to record sea otter activity in response to potential disturbance stimuli at three locations in California: Monterey, Moss Landing, Morro Bay. We developed a hidden Markov model to examine how activity varies as a function of location, time of day, group size, pup to adult ratio, habitat (kelp vs. open water), and occurrence of and proximity to potential disturbance stimuli. We combined our results with published estimates of activity-specific metabolic rates, translating changes in activity state into corresponding energetic costs. Our results indicate that the effects of disturbance stimuli on sea otter behavior are location specific, and vary non-linearly with distance from disturbance stimuli. Our model quantifies the distance-disturbance relationship, and calculates the distance at which the likelihood of disturbance is low: averaged across locations, there is <10% potential disturbance when stimuli are >54 meters away. We also estimate energetic costs(kJ) associated with various disturbance scenarios: for example, daily energy expenditure is expected to increase by 212.53kJ ± 15.75, 154.64kJ ± 13.84 and 62.54kJ ± 5, for Monterey, Moss Landing and Morro Bay, respectively, with six small-craft approaches of 20m for a 27.7kg male otter in kelp with 10 otters and a pup ratio of 0.25. Our analyses represent a novel approach for estimating behavioral responses and energetic costs of disturbance, thereby furthering our understanding of how human activities impact sea otters and providing a sound scientific basis for management.

Listen Up! Our grad students are doing some awesome outreach

Listen Up!

Brijonnay Madrigal is a student in the Vertebrate Ecology Lab who studies bioacoustics of Risso's Dolphins in the Monterey Bay.  To share her love and knowledge of the incredible sounds of marine mammals, Brijonnay has developed an outreach program in the Monterey Bay area. "Listen Up!" is an interactive program that teaches K-12 students about marine mammals, acoustics, sounds in the ocean, and conservation. The program has already reaches 10 elementary schools, 1 middle school, and 10 high schools in the area.


Alison Stimpert gives insight on government shutdown

January 11, 2019

MLML's Dr. Alison Stimpert talks about how the government shut down is affecting scientists in this NPR article.


Alison Stimpert, a marine biologist with California State University, writes, "Even though I am continuing to work, many of my collaborators (USGS, NOAA) are furloughed and projects we are working on together cannot move forward." She says that means "project planning meetings are being delayed, as well as permit applications for upcoming work."
Stimpert studies bioacoustics — "acoustic behavior and effects of noise on marine species," she explains — in waters off of California, Hawaii, Massachusetts, Alaska and Antarctica. She says that in some cases, the shutdown means she may have to reorganize some travel or wait to start a phase of research until collaborators can work. In other areas, it might have more serious implications: "We might miss an opportunity to deploy an instrument, which makes us miss collecting an entire season of data." And Stimpert says that if she or her collaborators have future federal funding delays, it could mean that "I can't purchase an instrument that I need, but might (and I am not alone in this) mean my other funding runs out and I can no longer fund my position, making me lose my benefits."

MLML’s Dr. Alison Stimpert co-authored recently published study on blue whale behavior

Dr. Alison Stimpert

Research Faculty member Dr. Alison Stimpert serves a co-author for a large collaborative study on blue whales that has revealed preferences in the direction (right vs left handedness) that the whales will roll during lunge feeding.  The study was published in Current Biology on November 20th, 2017 and featured in UCSC News, as well as The Guardian.  You can download the paper for free for 50 days here.