Thesis Defense by Shelby Penn – May 9th

"Comparing mercury accumulation and the macroalgal microbiome between coastal and estuarine populations of sea lettuce (Ulva spp.)"

A Thesis Defense by Shelby Penn

MLML Phycology

Live-Stream | May 9th, 2025 at 10:30 am PDT

ABSTRACT

Mercury is a potent neurotoxin that bioaccumulates and biomagnifies in marine environments. Most research on mercury cycling in the ocean focuses on pelagic food webs, leaving a gap in knowledge regarding macroalgal-based food webs. Seaweed from the genus Ulva is globally distributed in marine and brackish habitats, accumulating metals and toxins with minimal impact on the host. While the mechanisms behind Ulva’s tolerance to marine pollution are unclear, studies suggest that the macroalgal microbiome may play a crucial role. This study investigates how collection location influences mercury uptake and bacterial community composition in Ulva. Estuarine and coastal Ulva were subjected to 1, 50, and 200 ng/L of mercury in 6-day laboratory experiments. Total mercury concentrations were measured using a Direct Mercury Analyzer-80, while the Ulva microbiome's taxonomic composition was estimated from the V3-V4 regions of the 16s rDNA gene. Results indicated that estuarine samples accumulated higher mercury concentrations than coastal samples (PERMANOVA, < 0.001). The microbial community structure differed between coastal and estuarine Ulva samples (PERMANOVA, p = 0.1) at various taxonomic levels. Differential abundance analysis revealed that 81 operational taxonomic units (OTUs) from 8 classes were enriched in coastal Ulva, while 147 OTUs from 12 classes were enriched in estuarine Ulva. This study demonstrates that the Ulva microbiome and mercury uptake are influenced by habitat. Additionally, the microbiome differences due to habitat may affect mercury uptake. Although the microbiome of Ulva in estuarine environments potentially enhances the macroalgal holobiont's resilience to nutrient and toxin loads, host health must also be considered given the toxicity of mercury and the lower accumulation observed in coastal Ulva populations.

BIO

Originally from Virginia, Shelby earned a B.S. from Allegheny College in 2013. During her undergraduate studies, she spent a semester abroad in Bonaire, Dutch Caribbean, where she studied marine ecology and conservation and became certified as a Scientific Diver. While there, she conducted a SCUBA-based research project on the behavior of diseased ocean surgeonfish. She also completed internships at MarineLab in Key Largo, FL, and at the National Aquarium. Her senior thesis focused on the feeding morphologies of two species of darter fish.

Before beginning her graduate studies at Moss Landing Marine Laboratories (MLML), Shelby worked as a marine science instructor, Divemaster, and expedition guide on Catalina Island, in Hawaii, and throughout Southeast Alaska. She joined the Phycology Lab at MLML in 2018, where her master's research focused on the role of the Ulva microbiome in the cycling of mercury in coastal ecosystems. Her initial research interests centered on how mercury and other metals enter coastal food webs, and the role macroalgae play in their bioaccumulation and biomagnification. Through this work, she developed a passion for seaweed-associated microbial communities and will continue her studies as a Ph.D. student, investigating the direct and indirect effects of the marine environment on foundational seaweed holobionts.

While at MLML, Shelby also served as a Monterey Area Research Institutes’ Network for Education (MARINE) Liaison and Society for Women in Marine Science (SWMS) Mentor, participated in Skype a Scientist, contributed to rhodolith research projects on Catalina Island and served as Assistant Dive Safety Officer, supporting a variety of field-based research efforts.

Thesis Defense by Travis Leggett – May 8th

"Advancing Benthic Survey Methods: A Novel Application of Diver-Operated Stereo Video to Survey the Influence of Benthic Habitat Variation on Urchin and Macroalgae Populations in California Rocky Reefs"

A Thesis Defense by Travis Leggett

MLML Invertebrate Ecology

Live-Stream | May 8th, 2025 at 2:00 pm PDT

Abstract
Subtidal surveys are critical for ecosystem monitoring, traditionally involving diver underwater visual census (UVC), though such methods can impose time or logistical restrictions on the study. Imagery-based techniques, such as diver-operated stereo-video (stereo-DOV), offer precise 3-dimensional measurements from 2-dimensional images, facilitating accurate size and distance estimates as well as the ability to survey large areas quickly. This study compared two stereo-DOV angles (45° and 90°) with UVC to estimate benthic macroinvertebrates, macroalgae, and habitat characteristics (relief, substrate, benthic cover) within kelp forests and urchin barrens. We also explored associations between habitat complexity, measured as relief and substrate transitions. Stereo-DOV and UVC surveys yielded similar estimates for species richness, diversity, and purple sea urchin (Strongylocentrotus purpuratus) densities in urchin barrens, and for stipitate algae species. However, algae significantly reduced the effectiveness of both stereo-DOV angles compared to UVC, largely driven by the absence of cryptic species in stereo surveys. The 90° stereo-DOV surveys performed better in kelp forests relative to 45° surveys but still measured lower species richness and diversity compared to UVC surveys. Habitat characterization accuracy was similar between methods, though these similarities occurred mainly for broad substrate categories (e.g., sand, bedrock) and intermediate relief sizes (>10 cm - <1 m). Habitats with relief transitions (>1 per 10m²) showed marginal positive correlations with giant kelp (Macrocystis pyrifera) and negative correlations with purple urchin densities. Substrate transitions positively correlated with stipitate algae density. Our findings suggest stereo-DOV may be suitable for monitoring community-scale changes in urchin barrens with reduced performance in kelp forests. The 90°Stereo-DOVsurvey estimates were more similar to UVC estimates than 45° stereo-DOV surveys, but habitat was a more significant influence on stereo-DOV performance. This study provides insight into using stereo-DOV as a benthic surveying tool in kelp forests and urchin barrens and the potential for habitat transitions to support kelp populations while limiting urchin movement.

Bio

Travis earned a B.S. in Marine Science from CSUMB after transferring from Santa Monica City College. At CSUMB, Travis was introduced to scientific applications for SCUBA diving and began on a career path that would keep him underwater. During his undergraduate degree, he worked with the Partnership for Interdisciplinary Studies of Coastal Oceans at UCSC with Dr. Mark Carr, where he cemented his passion for subtidal research. He went on to work at Hopkins Marine Station of Stanford University as an independent undergraduate researcher, studying the effects of climate stressors on urchins and other benthic grazers. Travis started his Master's at MLML in 2020 with Dr. James Lindholm, studying the influence of habitat contiguity on urchin populations at Monastery Beach in Carmel Bay. Travis received funding from the Center for Coastal and Marine Ecosystems and the Educational Partnership Program for Minority Serving Institutions through NOAA to expand his research to include a methodological comparison of stereo-video and underwater diver visual surveys. While at MLML, Travis served as the Student Body Treasurer and has certified over 100 individual students for various levels of SCUBA training as an instructor at CSUMB. In his free time, Travis enjoys underwater photography, backpacking, travelling, and spending time with his dog Lehua.

Thesis Defense by Noah Kolander – May 5th

"Abalone and seaweed co-culture: growth and shell biomineralization of an iconic California gastropod"

A Thesis Defense by Noah Kolander

MLML Phycology

Live-Stream | May 5th, 2025 at 4:00 pm PDT

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Abstract

Climate change threatens shellfish aquaculture worldwide, with ocean acidification (OA) accelerating shell dissolution and reducing calcification, hindering growth. This study addressed the negative impacts of OA on juvenile red abalone (Haliotis rufescens), a life stage that is particularly susceptible to climate stressors, and the ability of the red seaweed, dulse (Devaleraea mollis), to mitigate these effects. I tested the hypothesis that Integrated Multi-Trophic Aquaculture (IMTA), with abalone and seaweed grown in co-culture, can raise seawater pH through photosynthesis to yield more favorable conditions for abalone growth and shell construction. A 5-month experiment was conducted to determine the benefits of IMTA on abalone growth, shell composition, and morphology under simulated ocean acidification conditions. In each tank, 620 abalone were raised in either High (8.1 ± 0.3), Ambient (7.9 ± 0.2), Medium (7.8 ± 0.3), or Low pH (7.6 ± 0.2). Abalone raised in High and Ambient pH treatments exhibited greater shell length, weight, area, and condition compared to those raised in medium and low pH treatments. Shell analyses indicated that these growth differences translate into differences in physical and chemical properties, with shells from the high and ambient pH treatments containing higher levels of Mg2+ and being more resistant to fracturing. These findings indicate that IMTA could shepherd abalone through the susceptible juvenile stage, increasing resilience of abalone aquaculture even within the context of future climate change.
Bio
I grew up in a little town called Wildomar in Southern California with 3 brothers, my mom and dad. I eventually went off to college at Concordia University where I quickly reignited my passion for marine science after volunteering in our campus marine lab that Sean Bigniami had just finished building the year before I got there. From there on, I was diving, doing research and presenting at conferences, studying pismo clam distributions in Southern California, and eventually conducting an abalone feed trial to determine if preserving their food by freezing or drying it affected abalone growth. I quickly got married after graduation and moved to Miami for my wife to finish her DPT program. While she studied, I worked for the Florida Department of Health and the Department of Agriculture. WHen Steff finished her degree she didn't think twice before asking me where I wanted to go to school next, which at the time was not on my radar, but she convinced me and it was the best choice she'd ever make for me! I then found MLML and applied under Maya deVries and got in. While at MLML, I have worked on too many projects to name, which is partially to blame for my extended stay at MLML, but I wouldn't trade it for anything. I wouldn't trade the friends I've made and the times I;ve had for anything. Thank you all for the support you have given me and for putting up with me.

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Thesis Defense by Celine de Jong – May 6th

"The Influence of Rhodolith Algae on Life History of the Painted Urchin, Lytechinus pictus"

A Thesis Defense by Celine de Jong

MLML Invertebrate Ecology

Live-Stream | May 6th, 2025 at 4:00 pm PDT

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Abstract

Rhodolith beds are globally distributed hotspots of diversity and productivity and serve as nursery habitats for some marine invertebrates. Poorly understood is whether rhodolith beds are nurseries because invertebrate larvae actively select them for settlement or migrate to them at later life stages. We studied the nursery role of rhodolith beds for the painted urchin, Lytechinus pictus at Santa Catalina Island, CA, USA. Subtidal surveys showed that in areas with greater live rhodolith cover, urchin density increased as well as mean urchin size. In caged substrate choice experiments, urchins selected rhodolith substrate relative to carbonate sand, supporting the notion that urchins congregate in rhodolith beds after they have settled. To evaluate whether beds also serve as nurseries by inducing settlement, urchin larvae were assessed following exposure to six cues: live and dead rhodolith, biofilm-inoculated sand, GABA, KCl, and filtered seawater. Live rhodolith induced the strongest settlement response across all treatments, initiating 2.5x greater settlement compared to the inducement control of KCl after 24 hours. Larvae also settled faster in the presence of live rhodolith substrate than other treatments. These results highlight the importance of rhodolith beds for multiple life stages of L. pictus, by inducing settlement of larvae and supporting post-larval individuals. Rhodolith beds receive minimal protections globally, due to limited research on their ecological importance. However, recognizing their role as nursery habitats strengthens the case for the inclusion of rhodolith beds in future management decisions.

 

Bio

Native to the Greater Seattle Area of Washington state, Celine found herself drawn to the sparkling waters of Monterey Bay and earned her BSc. in Marine Biology from the University of California, Santa Cruz in 2018. As an undergraduate, she worked extensively as a scientific research diver and laboratory technician for multiple university-based operations and has contributed data to long-term projects aimed at exploring mechanisms of kelp forest resiliency and ecosystem dynamics - specifically relating to urchin barren patch distribution throughout central California. In addition to her field contributions, she has been actively involved with various community outreach initiatives revolving around marine conservation and science education; notably as a science advisor for the Hydrous and teaching assistant for the Wildlands Studies Big Sur field course, focused on the conservation and preservation of coastal systems.

 

Co-advised by Dr. Amanda Kahn and Dr. Diana Steller, Celine joined MLML in the Fall of 2021 and investigated nursery potential of rhodolith beds for benthic invertebrates, specifically those on Santa Catalina Island, CA. When not wearing her science hat, Celine can be found tending to her garden, trying new recipes, hiking, camping, diving, or looking for washed up treasures on the beach.

 

Thesis Defense By Bennett Bugbee – May 8th

"EFFECTS OF DENSITY ON MORPHOMETRICS AND REPRODUCTIVE PHYSIOLOGY IN THE BULL KELP (NEREOCYSTIS LUETKEANA), AN ANNUAL FOUNDATION SPECIES"

A Thesis Defense by Bennett Bugbee

MLML Phycology

Live-Stream | May 8th, 2025 at 9:00 am PDT

Bennett holding a crowned bull kelp from the Albion soral bank tank at the MLML shore lab.

Abstract

The bull kelp, Nereocystis luetkeana, is the predominant canopy forming kelp along much of the northeastern Pacific. However, it remains largely understudied due to the dynamic nature of its niche coupled with its annual life history. For populations to persist, reproductive sporophytes must release substantial spores to facilitate successful sexual fertilization among male and female gametophytes that will develop into the next cohort of sporophytes. High densities of spores increases the likelihood of completing the alternation of generation life cycle characteristic of kelp genera. Yet those high densities of spores have the potential to result in a high density of sporophytes, competing for light to reach the surface canopy. It is currently unknown how density-dependence will alter the morphological development and reproductive investment of Nereocystis, thereby affecting population persistence. To address this, I investigated how density affects the morphology and reproductive traits of Nereocystis across its life history. Laboratory studies were conducted to test the effects of density on gametogenesis, gametophyte growth, female egg production, and sporophyte production. Additional studies were conducted on juvenile whole sporophytes and crowned sporophytes (i.e., modified to retain a small portion of the pneumatocyst) in land-based tumble culture to assess the effects of density on survivorship, stipe growth, pneumatocyst growth, blade growth, blade development (number), and reproductive investment (soral number, blades bearing sori, and soral size). Low spore density treatments resulted in significantly larger female gametophytes. Intermediate spore densities yielded higher eggs per female, yet there were no significant differences across density treatments. Sporophyte density was significantly greater at higher spore densities. Juvenile sporophytes grown in tumble culture showed no significant difference in survivorship as a function of sporophyte density. High densities delayed sporophyte development compared to sporophytes grown in low density treatments, which were characterized by long stipes and numerous blades. Density-dependent effects on crowned sporophytes were similar to juvenile sporophytes with low densities promoting increased growth and development, while high densities inhibited normal development. At 4 weeks, sporophytes shifted from allocating resources from growth to reproduction. Soral (i.e., reproductive tissue) size and soral number exhibited a significant negative density-dependent relationship. At the individual scale, low density treatments displayed significantly greater reproductive investment. However, scaling reproduction to the population resulted in intermediate densities having the highest cumulative reproductive potential. Given its life history and need for sustained annual reproductive success to fuel population replenishment, these results suggest that Nereocystis may have a higher threshold for negative density-dependent interactions compared to other perennial kelps.

 

Bio

Bennett earned his B.S. in Biology from Pacific Lutheran University in 2018. While at PLU, when not competing on the men’s soccer team, he developed his passion for marine environment and got SCUBA certified. After joining the Phycology lab at MLML, he quickly began spending a lot of time in the water, helping fellow students collect data, developing ideas for his thesis, and working on bull kelp restoration projects in Mendocino and Sonoma counties. Much of his research focused on bull kelp morphometrics and physiology, both in the lab and in the field. Outside of his research, he served as Open House co-chair, brew club organizer, and a Phycological Society of America Student and Early Career Researcher committee member. He can often be found in the tidepools around the Monterey Peninsula or running around with his dog Scuba. After graduation, Bennett will continue at MLML as a technician on the bull kelp restoration efforts in Mendocino, along with working at Monterey Bay Seaweeds.

Thesis Defense by Dylan Sarish – May 1st

"The Influence of Maternal Size/Age Effects On the Physiological Responses of Adult Female Gopher Rockfish (Sebastes carnatus) to Ocean Acidification and Hypoxia"

A Thesis Defense by Dylan Sarish

MLML Ichthyology

Live-Stream | May 1st, 2025 at 4:00 pm PDT

Abstract

Climate change is rapidly reshaping the chemistry of the ocean. Fishes living in California coastal waters experience ocean acidification, elevated pCO2, and hypoxia (OAH) in response to upwelling of deep water, and this process may increase in frequency and intensity with climate change. Nearshore rockfish may be particularly threatened by increasingly frequent OAH conditions due to their long lifespans and late maturation. Maternal effects, whereby larval condition is influenced by non-genetic components of the maternal phenotype (e.g. size, age) or environment, is one process that may allow rockfish to rapidly adapt to climate change. To understand the physiological effects of OAH on pregnant rockfish during gestation, adult female gopher rockfish, Sebastes carnatus, were collected and exposed to four different combined OAH stress treatments, from fertilization to parturition. A second group was exposed to two combined OAH stress treatments. Routine metabolic rate (RMR), maximum metabolic rate (MMR), blood chemistry, including hematocrit (Hct), hemoglobin (tHb), pCO2, HCO3-, ions (Na+, K+, Cl-), and metabolites, were measured to assess physiological responses to OAH stress. Ovarian oxygen levels were measured to examine the potential capacity of females to buffer their developing broods against changing ocean chemistry. Fish exposed to higher OAH stress displayed elevated Hct and tHb, higher blood pCO2 and HCO3-, and decreased MMR, indicating they attempted to compensate for low pH and hypoxia exposure. Only partial compensation was achieved as blood pH was not always maintained near ambient levels. Fish showed signs of buffering their ovaries against hypoxia under OAH exposure. Lastly, pregnancy altered Hct and MMR under OAH exposure and size/age did not have a consistent effect on maternal physiology. By evaluating the responses of maternal physiology to OAH stress, which directly impact larval physiology, we can better understand how climate change affects, fecundity, larval condition, and survival which will influence the management of nearshore fisheries in an ever-changing climate.

Bio

Dylan earned her B.S. in Marine Biology with a minor in Environmental Science from UC San Diego in 2019. While at UCSD, when not practicing as a member of the varsity fencing team, she volunteered for Dr. Andrew Nosal, where she helped with the tagging of sevengill sharks in La Jolla cove, and was in charge of the care and feeding of a tank of juvenile horn sharks in the Scripps Institute of Oceanography’s experimental aquarium. She was also a member of the Coral Ecology Lab under Dr. Stuart Sandin, where she contributed to the 100 Island Challenge. After graduating, Dylan spent some time working for the California Department of Fish and Wildlife, where she contributed to the California Recreational Fisheries Survey (CRFS) as a sampler, assisting with the mission to collect fishery-dependent data on California’s marine recreational fisheries and to accurately estimate catch, effort, and stock.

Dylan joined the Ichthyology lab in Fall of 2022, and examined the effects of ocean acidification and hypoxia on the reproductive success of female gopher rockfish. In her spare time, Dylan enjoys being around animals, baking, and traveling

Thesis Defense by Keenan Guillas – May 1st

"DRIVERS OF RHYTHMIC CONTRACTIONS IN THE TEMPERATE DEMOSPONGES TETHYA CALIFORNIANA AND HYMENIACIDON PERLEVIS"

A Thesis Defense by Keenan C. Guillas

MLML Invertebrate Ecology

Live-Stream | May 1st, 2025 at 2:00 pm PDT

 

Keenan aboard the R/V John H. Martin.

Abstract

Sponges (Phylum Porifera) are suspension feeders whose water filtration is important to benthic ecosystems because of their conversion of large amounts of dissolved carbon and nitrogen into particulate waste available for detritivores. Sponges filter water by drawing it through a complex aquiferous system of canals and pores. Rhythmic contractions of tissue, which temporarily constrict canals and reduce body size, can diminish filtration rates and therefore affect ecosystem services; however, the physiological function of rhythmic contractions is not completely understood. I recorded long-term time-lapses of the demosponges Tethya californiana and Hymeniacidon perlevis to determine the endogenous and environmental factors that influence rhythmic contractions. I found that contractions occurred simultaneously in the osculum, ostia, and whole body in T. californiana. In H. perlevis, contractions originated and spread between many different oscula, with no evidence of cohesive whole-body behaviour. In T. californiana, duration of rhythmic contractions were significantly correlated with body size, oceanographic season, and dissolved oxygen. Both species reduced contraction frequency and increased total time expanded in seawater enriched with Rhodomonas sp. microalgae. This thesis provides support for rhythmic contractions in sponges as products of both endogenous and environmental factors, improving our understanding of the complexity of behaviours in early-diverging aneural metazoans.

 

Bio

Keenan earned his BSc in 2018 from the University of Alberta, where he worked with Dr. Sally Leys investigating the ecology of glass sponge reefs in Hecate Strait, British Columbia. At MLML his research focused on drivers of rhythmic contraction behaviours in the marine demosponges Tethya californiana and Hymeniacidon perlevis. He used time-lapse photography and microscopy to improve our understanding of sponge coordination, behaviour, and resilience. He was also student body vice president and an active member of the MLML community. He is now a research technician in the Marine Structural Biology unit at Okinawa Institute of Science and Technology in Japan. He is also a coffee enthusiast and a fiction writer.

 

Thesis Defense by Marcel Peliks – February 7th

" A COST EFFECTIVE MULTIBEAM SYSTEM YIELDS HIGH TEMPORAL AND SPATIAL RESOLUTION BATHYMETRIC MAPS OF THE MONTEREY CANYON HEAD"

A Thesis Defense by Marcel Peliks

MLML Geological Oceanography

Live-Stream | February 7th, 2025 at 9:30 am PST

Survey in progress aboard the Blue whaler.

Abstract

The coastal environment is a dynamic and complex system constantly in flux. A comprehensive understanding of the nearshore system is crucial for habitat management, modeling impacts of climate change, as well as managing economic resources. Studying nearshore bathymetric environments through mapping has traditionally been challenging due to high surveying costs and adverse environmental conditions. The Monterey Canyon Head offshore of Moss Landing, California exemplifies a complex nearshore feature with significant impacts on the local environment. Previous studies have identified the canyon head as the primary sand sink for two littoral cells: the Santa Cruz and Southern Monterey Bay cells. Nevertheless, the spatial and temporal trends of sediment accretion and erosion in the canyon head remain poorly understood. To address this, a cost- effective multibeam system for high-resolution mapping of complex seafloor topography in shallow water has been assembled, enabling high-frequency repeat mapping of the canyon head. Preliminary testing demonstrates that the system is capable of mapping seafloor features at 1 m resolution at depths up to 60 m, with increasingly finer resolutions achievable at shallower depths. Tests conducted at the canyon head showed repeatable mapping surveys with a root mean square error (RMS) of 10 cm in back-to- back surveys. The greatest differences were observed on steep (>50°) canyon walls and in deeper water (>35 m). A total of seven test surveys were completed between October 2021 and January 2022 resulting in an average survey frequency of twice per month. Comparison maps of these surveys reveal a complex sedimentary cycle characterized by frequent sediment deposition, movement, and failure in the northern tributaries of the canyon head, and minor deposition and bedform migration in the southern tributaries.

 

Bio

Marcel earned a B.S. in Earth Science from the University of California, Santa Cruz, which laid the foundation for his early career as a geologist. Drawn by a passion for instrumentation, geospatial analysis, and geology, he transitioned into the M.S program at MLML - finding his niche in the seafloor mapping field. Since embarking on this path, Marcel has immersed himself in Hydrography and Ocean Exploration, working as a mapping technician aboard NOAA's Okeanos Explorer, contracting private dredging surveys, and most recently working for the Office of Coast Survey to qualify bathymetric data for use in the National Bathymetric Source (NBS). Outside of work, Marcel enjoys spending time in the ocean and mountains, with his closest friends, and by going on extended trips abroad.

 

Thesis Defense by Randi Barton – November 15th

 

"Population genetic analysis informs dispersal capacity in representative marine trematodes"

A Thesis Defense by Randi Barton

MLML Invertebrate Ecology

Live-Stream | November 15th, 2024 at 3:00 pm PST

Abstract

In marine and terrestrial systems, life history drives the distribution of organisms and informs the spatial scale of population connectivity. Nearly all bony reef fishes and invertebrates have a bipartite life cycle with a planktonic larval stage, which increases the organism’s dispersal capacity, and concludes with a relatively non-dispersive adult phase. While many studies have identified the relevant spatial scale for studying population structure in fishes and invertebrates, few have done the same for parasitic taxa, which have even more complex life histories with a higher diversity in the range of dispersal strategies they use. Parasite taxa differ in (1) life cycle complexity, (2) host specificity, and (3) the types of hosts they can infect. All variables are likely to have both independent and synergistic effects on dispersal capacity. This research investigates dispersal capacity using population genetics in two complex life cycle parasites- marine trematodes from Family Microscaphidiidae and Family Paramphistomatidae. We examined the population structure of adult microscaphidiids across the Northern Line Islands and found significant, high genetic structure, suggesting low gene flow. We also examined the population structure of adult and larval paramphistomes across the islands of French Polynesia, and found evidence of cryptic species. Overall, this study supports the idea that parasite life history contributes to their dispersal capacity, and highlights current issues associated with parasite genetic research such as the lack of biodiversity knowledge and the need for more studies on wild populations of parasites in natural systems.

 

Bio

I graduated from CSU, Monterey Bay in 2020 with my B.S. in Biology. During my undergraduate I became interested in population genetics, and began working with Dr. Alison Haupt on a project to better understand marine parasite dispersal using population genetics. This project evolved into my master’s thesis work at MLML, where I am co-advised by Dr. Alison Haupt and Dr. Amanda Kahn. In 2022, I began working at Granite Canyon Marine Pollution Studies Laboratory as a Lab Assistant alongside my studies. Now, I am a Staff Research Associate and oversee lab operations and lead field collections of sediment for a statewide monitoring program. After I graduate from MLML, I hope to incorporate my molecular experience into the toxicology work conducted at Granite Canyon, to enhance our understanding of how pollutants are affecting biological systems in both freshwater and marine ecosystems. Outside of school and work, I love being outside and doing activities such as hiking, backpacking, and tidepooling. I also love a good nap with my two cats.

Thesis Defense by Molly Alvino – May 20th

"Swim Bladder Morphology Influences the Responses of Nearshore Rockfishes to Barotrauma"
A Thesis Defense by Molly Alvino

Fisheries and Conservation Biology Lab

Live-Stream | May 20th, 2024 at 4:00 pm PDT

Abstract

Rockfishes (Sebastes spp.) are ecologically and economically important fishes in the continental shelf and slope regions of the Eastern Pacific Ocean. All species within the Sebastes genus have a buoyancy organ, the swim bladder, which is sensitive to rapid changes in pressure that occur when fish are caught and brought up to the surface. Although all rockfishes have swim bladders, pressure-related injuries (barotrauma) affect rockfish species differently. To determine if swim bladder morphology can explain differences in barotrauma among rockfishes, semi-pelagic (Blue rockfish, S. mystinus and Olive rockfish, S. serranoides) and benthic (Gopher rockfish, S. carnatus and Vermilion rockfish, S. miniatus) species were captured via hook-and-line and manually recompressed using a hyperbaric chamber. Decompressed fish were sacrificed and seven different swim bladder morphological features were quantified and related to external barotrauma injuries observed at the time of capture. Benthic Vermilion rockfish displayed a greater incidence of barotraumatic injuries and had thicker swim bladder membranes with a higher tearing threshold than the semi-pelagic species. Conversely, the swim bladders of Blue rockfish were significantly thinner and more elastic than Vermilion rockfish, and experienced fewer barotraumatic injuries than both benthic species. Despite occupying different habitat zones and responding differently to barotrauma, many swim bladder measurements were similar between Olive and Gopher rockfish. Additionally, the number and severity of barotraumatic injuries significantly decreased as total length increased in Blue rockfish, consistent with a significant increase in tearing threshold and swim bladder membrane thickness with total length. This research furthers the understanding of pressure-related injuries among different rockfish species, while informing fishery managers of the swim bladder morphology directly impacting interspecific discard mortality rates.

 

Bio

Molly grew up in and around the water, and once she was introduced to SCUBA diving in high school, she knew it was what she wanted to do with her life. Following this passion, Molly went on to graduate from Northeastern University in 2020 with a B.S. in Marine Science. Wanting to explore the West Coast, she packed up and moved to California to attend Moss Landing Marine Laboratories within the Fisheries and Conservation Biology Lab. At MLML, Molly has worked on a number of different research projects including the California Collaborative Fisheries Research Program (CCFRP), Shallow Water Mini Landers, Benthic Observation Survey System (BOSS), Surf Zone sampling, and Rockfish Ocean Acidification. When she's not at the lab, you can find Molly doing Crossfit, trying out new food spots, or playing with her cat, Crouton.