An Assessment and Classification of Mating Scars on Female Great White Sharks in the Northeastern Pacific

Alyssa Walter1, Kaitlyn Yee2, Scot D. Anderson4, Samantha Andrzejaczek3 , Barbara A. Block3, Taylor K. Chapple3,5, Alexandra DiGiacomo3, Paul E. Kanive4,  Dr. Salvador Jorgensen1

 

1 Department of Marine Science, California State University Monterey Bay

2 Environmental Studies Department, California State University San Jose

3 Hopkins Marine Station, Stanford University, Pacific Grove, CA, United States

4 California White Shark Project , Inverness, CA, United States

5 Coastal Oregon Marine Experiment Station, Oregon State University, Newport, OR, United States

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White sharks (Carcharodon carcharias) are one of the most studied shark species, yet their elusive mating behavior has long perplexed researchers. Valuable insights into white shark mating habits can be gained from courtship-induced mating scars, which have yet to be properly classified in published literature. This project aims to quantify and define white shark mating  scars, and infer where mating events may be occuring.

 

Scar classifications were determined by an extensive literature review, shark encounter video data, and expert consultation. Video data has been collected by a consortium of researchers in central California since 2006 from Point Reyes, Ano Nuevo Island, the greater Farallon Islands, and Monterey Bay. Video clips were analyzed by multiple students to score scar types, color, and body locations. To overcome uncertainty in scar classification, we used Python and sql to create a database and to tally votes and confidence measures from multiple students resulting in consensus scar scores. This form of ‘crowdsourcing’ increases accuracy of classifications by non-expert researchers.

 

Very low numbers of fresh ‘mating grabs’ were recorded in coastal central California. This suggests mating does not occur regularly at these aggregation sites. White shark encounters were most frequent during peak juvenile elephant seal presence, suggesting that intensive foraging periods may preclude mating activities. A better understanding of the reproductive cycle of white sharks can contribute to the development of effective conservation and management strategies.

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Exploring Fish Associations with Deep Sea Coral with NOAA National Marine Sanctuaries

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Alyssa Walter1,2, Elizabeth Duncan1, Jennifer Selgrath1

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1-Channel Islands National Marine Sanctuary

2-California State University Monterey Bay

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This study explores fish associations with Deep Sea Coral and Sponges (DSCS) in NOAA National Marine Sanctuaries, focusing on the Nautilus 123 research cruise. Conducted at depths of 50 to 4000 meters, the research employs ROV video collections and transect analysis to document DSC species and annotate fish associations. Notably, commercially fished species like Thornyheads and Dover sole show connections with DSC species. The findings stress the need for long-term monitoring and protective measures, emphasizing the importance of maintaining Essential Fish Habitat (EFH), safeguarding fish stocks, and mitigating potential sea floor disturbances from activities like wind energy and oil/gas exploration. This research contributes vital insights for informed conservation efforts in deep-sea ecosystems.

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Dispersal and Life History of the Class Trematoda

 

Walter Alyssa1, Curiel Gabriel1,  Barton Randi1, Lee Hannah1, Haupt Alison1,, Sandin Stewart2, Zgliczynski Brian2,  Wood Chelsea3 . 

 

1 Department of Marine Science, California State University Monterey Bay

2 Center for Marine Biodiversity and Conservation, Scripps Institute of Oceanography

3 School of Aquatic Fishery Science, University of Washington

Over the last decade, a number of studies have set out to understand the role of parasites in ecological communities. Here we build off of large-scale efforts to better understand the role of marine parasites in their ecosystems. Specifically, this project aims to explore how closely related parasites are to each other using genetic sequencing tools. To accomplish this goal, we examined the genetic diversity of one species of adult trematode (trematoda) and a seperate species of trematode in their larval form (metacercariae) from host species of coral reef fishes. Trematodes included in this study were obtained from coral reef fish samples collected at a subset of islands and atolls across the Line Islands, Republic of Kiribati and French Polynesia. We extracted DNA using Qiagen kits and then amplified and Sanger sequenced the mitochondrial locus. All data collected were run through sequencing software MEGA to compare how similar the genetic sequence of each individual parasite is to one another. The results provide insights into the  genetic dispersal of trematodes across the Line Islands and French Polynesia. Additionally, we examine ocean currents, weather patterns, and distance between sites to form hypotheses about how patterns in gene dispersal affect community assemblages.

 

Exploring the Effects of Stress on the Health of Red Abalone: Factors Leading to Shell Loss and Mortality

 

Alyssa Walter, Kayla Roy, Luke Gardner

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California State University Monterey Bay

Moss Landing Marine Laboratories

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While raising red abalone (Haliotis rufescens) for use in another study with white abalone (Haliotis sorenseni), we found the muscles attaching to their shells becoming weak, causing shell loss and mortality. An experiment exploring this shell loss with white abalone led us to believe shell loss was caused by compounding stressors of infection and density, so we decided to explore other possibilities with reds. To understand this phenomenon, we set up an experiment utilizing the stressors of increased density (how crowded each tank is) and exposure to unshelled specimens to explore their impact on shell loss. The hypothesis is that abalone put under stress (higher density tanks and tanks occupied with shell less specimens) will have higher rates of shell loss, and stunted growth rates. There are 12 tanks in the study: 6 controls (for the presence and absence of shell less abalone), 3 low density (5 shelled abalone), and 3 high density (25 abalone). The 6 non-control tanks also began with 10 unshelled abalone. The research process includes counting all abalone 2 times a week (checking for shell loss and mortalities), monitoring feeding rates, and monthly data collection days. So far there has been no shell loss in the reds, and many mortalities of unshelled individuals. We have seen slightly decreased growth and feeding rates from high density infected tanks. This preliminary data seems to partially agree with my hypothesis, and we will continue the study as long as the unshelled abalone survive.

(Project through the UROC Researchers Program, California State University Monterey Bay, and Moss Landing Marine Labs. Mentor: Kayla Roy)

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