Factors Affecting Distribution of Crab Species Within the Titlow Beach Marine Preserve: Carapace Size of Porcelain Crab (Petrolisthes eriomerus) Along a Six Meter Vertical Transect; Rehabilitation Capacity of Shoreline Organisms to Anthropologic Alterations

Authors

Lauren C. Jackson, University of Washington TacomaFollow

Author Biography

Lauren Jackson is a senior at the University of Washington, Tacoma in Environmental Science, Geosciences with a minor in ArcGIS/ESRI graduating in June 2026. She has previously worked as a Pierce County Library Early Learning Specialist, served one term as an AmeriCorps Environmental Project Coordinator for the Pierce College District in Washington State and is a member of the Northwest Geological Society. She recently spent time studying oceanic sediment core analysis, taken from the JOIDES Resolution scientific discovery vessel, at the Gulf Coast Repository in College Sation, Texas. Lauren hopes to build her career in the seismic and/or volcanic hazard studies of the Pacific Northwest.

Document Type

Undergraduate Research Paper

Abstract

Tacoma, Washington’s Titlow Beach, used as a bustling social resort in the early 1900s, a swimming hole until the mid-1900s, and a research-based beach-front-rehabilitation reserve in modern times, is considered an area in which anthropogenic alterations have caused significant impacts to marine life. In a benchmark study of Porcelain crabs (Petrolisthes eriomerus), specimens were observed at low tide to determine if there was a significant difference in carapace size versus distance from shore, as it was hypothesized that larger sized specimens would be located near the shoreline for thermal stress, predation avoidance, and egg release for mature females. Crabs were collected along the beachfront, at mean low tide, on April 30, 2025. Data that were collected for this study did not garner the results expected, that the average carapace size would increase as one descended toward the waterline. Very few direct comparison studies were found on the carapace distribution of crab populations within the Puget Sound region, making this study an important benchmark for current and future resource management purposes. The results put forth in this paper show there was no significant difference in average carapace size of Porcelain crabs from 0 meters to 3 meters along a 6-meter measured transect tape. A larger sample size, possibly of more than one species of true crab for comparison, would be ideal and would help to determine if the results from this study were accurately representative of size distribution of crabs amongst the intertidal zones of Puget Sound beaches.

University

University of Washington Tacoma

Course

TBIOL 340: Ecology and Its Applications

Instructor

Dr. Eliza Heery

Recommended Citation

Jackson, Lauren C. (2025) "Factors Affecting Distribution of Crab Species Within the Titlow Beach Marine Preserve: Carapace Size of Porcelain Crab (Petrolisthes eriomerus) Along a Six Meter Vertical Transect; Rehabilitation Capacity of Shoreline Organisms to Anthropologic Alterations," Access*: Interdisciplinary Journal of Student Research and Scholarship: Vol. 9: Iss. 2, Article 4.
Available at: https://digitalcommons.tacoma.uw.edu/access/vol9/iss2/4