Sponsor
Portland State University. Department of Environmental Science and Management
First Advisor
Catherine de Rivera
Date of Award
2024
Document Type
Thesis
Department
Environmental Science and Management
Language
English
Abstract
Marine heatwaves, altered precipitation regimes, and other changing climate conditions are altering the abiotic conditions of Oregon’s estuaries. Furthermore, warmer water temperatures are correlated with the range expansion and population growth of the invasive and broadly tolerant Carcinus maenas, the green crab, in Oregon. Metacarcinus magister, Dungeness crab, one of Oregon’s most valuable fishery species, is also facing these climate stressors, and their young that recruit to estuaries overlap with C. maenas adults. Therefore, we wanted to determine impacts of C. maenas on young-of-the-year (YOTY) M. magister and the roles of salinity, temperature, and predator size in mediating these impacts. We predicted that C. maenas would eat most M. magister under warm water scenarios and in the freshest conditions because C. maenas is expected to be less impacted than M. magister by these stressful conditions. We also predicted that larger C. maenas would consume more YOTY M. magister. A fully crossed, laboratory study examined predation upon Dungeness, with three temperature and two salinity combinations. One adult C. maenas was added into each replicate tank with four Mytilus californianus, as alternative prey, and three juvenile M. magister. We recorded predation across 48 hours. C. maenas ate the majority of Dungeness across all temperature and salinity combinations but ate the most Dungeness in 18.5°C and 32ppt. C. maenas at intermediate carapace width and mass consumed the most YOTY M. magister. Hence, Dungeness face high risk from C. maenas where they overlap in estuaries. We recommend increased trapping efforts of C. maenas during recruitment period by YOTY M. magister to mitigate impacts.
Rights
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Recommended Citation
Gelling, Trever, "Juvenile Dungeness Face High Predation Risk from Green Crabs Across Increased Temperatures at Different Salinities" (2024). Environmental Science and Management Undergraduate Departmental Honors Theses. 1.
https://pdxscholar.library.pdx.edu/esm_theseshonors/1
Comments
Undergraduate Departmental Honors Thesis in Environmental Science and Management