(9:00-9:15)
Movement of weaned northern elephant seal pups during their first at-sea foraging migration
Katie Saenger1★, Kate Riordan1, Molly Murphy1, Heather Harris2, Lauren Campbell2, Elizabeth Eby2, Rhys Evans3, Tim Bean1, Gita Kolluru1, Heather Liwanag11 Department of Biological Sciences, 2 The Marine Mammal Center, 3 Vandenberg Space Force Base, ★Speaker
The northern elephant seal (Mirounga angustirostris, NES) is a well-studied marine mammal known for engaging in long foraging migrations at sea. Adult male NES follow pathways along the coast towards Alaska and adult female NES follow pathways to open ocean. However, there is little information on weaned NES pup foraging behavior. This lack of knowledge is significant because NES have a mortality rate of >50% in the first year. This project aims to better understand the migratory movement and space use of NES during this critical life stage. We deployed satellite tags on weaned NES pups at Vandenberg Space Force Base (VSFB, est. 2016, n=15) and San Nicolas Island (SNI, est. 1949, n=10). Preliminary results show weaned pups migrate shorter distances than adults, utilize areas along the coast, and do not display sexual divergence in their migration pathways. Additionally, some weaned pups engage in multiple foraging trips in their first year, which has not previously been described in the literature. Examining these migratory pathways at this life stage and comparing them between individuals, sexes, rookeries, and years provides insight into dispersal patterns, foraging grounds, and life history, which will inform the conservation and management of this species. |
(9:15-9:30)
[1]: What’s in your water? An assessment of microplastics in the seawater of the Morro Bay Estuary
Ella Leback†★§, Nikki AdamsDepartment of Biological Sciences, †Frost Support, §Santa Rosa Creek Foundation Support, ★Speaker
Microplastics (plastic particles < 5mm) are pervasive throughout global ecosystems, water, sediments, and aquatic and terrestrial organisms. For the past three years, the Adams lab has been measuring microplastics (MPs) in sediments and oysters of the Morro Bay Estuary. We continued our ongoing MP monitoring efforts by examining the concentrations and types of MPs (fiber, angular, or other) in seawater every two weeks at six field sites within the Estuary watershed (including a freshwater stream, Los Osos Creek). We isolated MPs from samples using filtration and digested the organic material using KOH. We stained and identified plastics using fluorescence microscopy. We hypothesized that MP prevalence would vary among sites and seasons, peaking in the back bay, where MPs may originate from terrestrial sources and accumulate due to the back bay's slower flushing time. On average, samples contained 0.01-0.13 (± 0.0007-0.022 SE) MP/mL over 11 months. Initial analysis using a two-way ANOVA of concentration and type of MPs identified slight spatial variation in MP prevalence but no significant variation among sites and collection dates. Nevertheless, the concentration of MPs varies significantly by type and sample date. The concentration of each type varied significantly from one another in the following order: other >fibers> angular (p <0.001, Tukey’s post hoc). There was also a significant interaction between the type of MPs and the sampling date (p<0.05), indicating the types of microplastics in the water column vary over time. Further analysis will explore whether there is a clear seasonal pattern in types of MPs across the Bay. |
(9:30-9:45)
[3]: Analyzing stocking densities and organic line types to quantify settlement success of Nereocystis luetkeana.
Laney Hall1★§, Tatum Schneider1§, Johnny Paneno1, Kevin M. Johnson1§, Gregory Schwartz21 Department of Biological Sciences, 2 BRAE, §Santa Rosa Creek Foundation Support, ★Speaker
Over the last decade, kelp forests in northern California have been negatively impacted by an increased frequency of stressors. Resultantly, an overpopulation of native purple sea urchins are destructively grazing kelp forests creating extensive "urchin barrens", reducing ecosystem biodiversity. Over 96% of bull kelp forests have been lost in northern California impacting the ecological, economic, and cultural viability in the region and creating a wake of ramifications such as federal fisheries disasters. The goal of this study is to investigate the settlement patterns of bull kelp (Nereocystis luetkeana) spores on different types of organic lines (hemp, juut, and cotton), and evaluate the effects of bull kelp spore stocking densities on settlement success. Settlement success was quantified by counting juvenile sporophytes using a dissecting microscope at the end of 6 weeks. Sporophyte growth rates were measured using a compound microscope to take pictures weekly. ImageJ was used to measure both blade length and blade area to calculate growth per week. Seawater chemistry was recorded weekly using a HANNA mobile spectrophotometer, thermometer, refractometer, and pH meter. This protocol will be used for educational purposes, while the data will be shared with aquaculture farms working in both commercial and restoration aquaculture. |
(9:45-10)
[4]: Exploring the Microbial Eukaryote Community in Estuarine Sediments from Morro Bay Using 18S rRNA Sequencing
Sedona Fugitt†★§, Lucy Nelson§, Nick Soares, Alexis PasulkaDepartment of Biological Sciences, †Frost Support, §Santa Rosa Creek Foundation Support, ★Speaker
Morro Bay is a relatively healthy, low inflow estuary that supports diverse communities of microbial eukaryotes, which play key roles in ecosystem functioning. Studying estuarine sediments is important for understanding single celled decomposers, primary consumers, and benthic primary producers which all play important roles in the food web and in nutrient cycling. To investigate these communities, 18S rRNA sequencing was conducted on weekly sediment samples from Morro Bay throughout 2023. Our preliminary analysis focused on key groups including the Bigyra, Cryptophyta, and Ciliophora, given their potential roles in organic matter decomposition, bacterivory, and mixotrophy. Although these groups represented a relatively small proportion of the sequencing reads throughout the entire year (ranging from 0.22-3.69%), their temporal patterns - when interpreted in the context of the water column environmental conditions and microbial community composition patterns - offer insight into the structure and function of estuarine ecosystems. |
(10-10:15)
[5]: Evaluating the influence of a sea otter exclusion ring in the California spiny lobster fishery: Implications for California spiny lobster catch and bycatch
Maria D.S. Lopez Neri1★§, Michael D. Harris2, Heather E.M. Liwanag1, Lisa Needles11 Department of Biological Sciences, 2 CDFW, §Santa Rosa Creek Foundation Support, ★Speaker
Southern sea otters (Enhydra lutris nereis) can become incidentally trapped in shellfish and finfish traps. Based on previous research, modifying the fyke opening (entrance of trap) to include a 5-inch rigid ring can prevent most southern sea otters from entering and becoming entrapped. The California spiny lobster trap fishery overlaps the range of the southern sea otter. Reducing the fyke ring size from the standard 6-to-7-inch diameter flexible opening to a 5-inch diameter, rigid metal ring can reduce or mostly eliminate incidental take of sea otters. However, there is no information on whether this rigid ring would affect the number of spiny lobsters caught, their size, and/or their weight. To investigate this, we used a paired design to fish lobster traps with standard flexible 6-to-7-inch fyke openings (n=15) and traps modified with 5-inch rigid ring fykes (n=15) just before the opening of the commercial spiny lobster fishery season. We analyzed differences between trap types for lobster catch, size and weight using a paired t-test. Results showed traps with the 5-inch exclusion ring caught significantly more lobsters, with no significant change in the size or weight of legal-size (3.25”, 83mm) lobsters. This difference appears to be driven by a higher rate of sheep crab bycatch in the standard traps compared to modified traps. These findings suggest the 5-inch exclusion ring may enhance lobster catch rates while preventing sea otters from entering traps, offering a simple, effective mitigation measure to aid in the recovery and population expansion of the southern sea otter. |
(10:15-10:30)
[6]: Effects of pigmentation on response to environmental stress in Leptosiphon parviflorus (Polemoniaceae)
Magdalene Lo★, Dena GrossenbacherDepartment of Biological Sciences, ★Speaker
Species experiencing environmental heterogeneity may adapt and optimize fitness to specific environments at the local scale. Adaptations within a given population may provide greater fitness in one set of environmental conditions than another, resulting in tradeoffs. One adaptation is the production of anthocyanins, a pigment that produces red, pink, and blue colors in plants and provides protection from abiotic stress, like drought and heavy metals. Leptosiphon parviflorus (variable linanthus, Polemoniaceae) is an annual wildflower in the California Floristic Province that produces plants with pink or white flowers, and these two flower morphs frequently co-occur within populations. Pink morphs have been found to be more fit on serpentine substrates than white morphs, and white morphs more fit on benign substrates than pink morphs. This project seeks to quantify the extent of abiotic selection for pigmentation through greenhouse reciprocal transplants. We anticipate that pink morphs will have patterns of greater fitness under drought and simulated serpentine soil stress than white morphs. These outcomes would suggest that pigmentation is closely tied to local adaptation and that maintenance of this pigmentation polymorphism in this species is due to abiotic factors. |
(10:30-10:45)
[7]: Tick Microflora: Untapped Potential Sources of Antimicrobials
Elizabeth Norris1†★, Matt Bobbitt1, Clara McMahon2, Larisa Vredevoe11 Department of Biological Sciences, 2 Department of Kinesiology and Public Health, †Frost Support, ★Speaker
Antibiotic-resistant pathogens are responsible for a global public health crisis due to a shrinking arsenal of effective antibiotics and a lag in the development of novel antimicrobials as therapeutics. The microflora of insects and other arthropods provide an intriguing source of antibiotic-producing bacteria. Arthropods are known to be colonized by actinomycetes which are known to be good antibiotic producers. Ticks and other blood-feeding arthropods harbor a unique array of endosymbiotic bacteria, including their core microbiome and microbes acquired from the environment. Ixodid ticks have prolonged contact with hosts during feeding, permitting ample opportunities for exposure to host-derived microflora. Many potential microbial colonizers derived from the host may be thwarted by the core tick microbiome via competition and production of antimicrobial compounds that may target a range of host-derived bacteria due to their long co-evolutionary history making them of particular interest to combat certain human and animal pathogens. In this project, we investigated local ixodid tick species as a source of antibiotic-producing bacteria using culture-dependent methods to visualize bacterial interactions. Several species of adult ticks were collected from Poly Canyon at Cal Poly State University, San Luis Obispo. Ticks were surface sterilized and homogenized to cultivate endosymbiotic bacteria on culture media. Selective culture media was also used to encourage the growth of endosymbiotic actinomycetes. Assays were performed to detect production of antimicrobial compounds and identify isolates capable of inhibiting a range of human-associated bacterial species and surrogate species for human pathogens. Eleven tick isolates demonstrated antibiotic-producing potential. Assays were also performed to detect the production of antifungal compounds. Five isolates showed potential antifungal compound production against the tested molds and yeasts. Future steps for the project include further characterization of these isolates’ antimicrobial ability. The most promising isolates will be identified using the BIOLOG gen III microplate. |