Graduation Date
Spring 2022
Document Type
Thesis
Program
Master of Science degree with a major in Biology
Committee Chair Name
Dawn Goley
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Paul E. Bourdeau
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Micaela Szykman Gunther
Third Committee Member Affiliation
Community Member or Outside Professional
Fourth Committee Member Name
Daniel P. Costa
Keywords
Northern elephant seal, Pinniped, Colonization, Dispersal, Juvenile behavior, King Range National Conservation Area
Subject Categories
Biology
Abstract
The King Range colony is the northernmost successful and expanding breeding site for northern elephant seals (Mirounga angustirostris). To evaluate the composition and growth of this colony, I conducted systematic surveys recording counts, age classes, births, and resighting seals with individually identifiable flipper tags. The timing of life-history events (breeding, molting, and resting) of all elephant seal sex and age groups at the King Range was consistent with observations at other colonies. Colony counts during breeding and molting have increased steadily over the 4-year study period (2018-2021), and pup production has increased by 87% since the first year of monitoring. The main driver of colony growth was juvenile elephant seals dispersing from colonies in central California, as revealed by the majority of tag resights being of juveniles from Point Reyes. Juvenile seasonal haul out behavior differed with a higher percentage of ‘new’ juveniles seen in the fall than in the spring and higher variability in seasonal arrival date, tenure, and number of visits in the fall resting haul out than during the spring molt. This difference may be due to the extreme physiological demands on elephant seals during their spring molt, which is absent during the fall. This growing northern elephant seal colony will likely become a seed colony for further northern dispersal as this species continues to be impacted by global climate change. By documenting juvenile dispersal and colony growth, I provide information to managers and the public for use in preparing and managing conflicts that might arise with the predicted expansion and redistribution of this species.
Citation Style
APA
Recommended Citation
Levy, Emma Hatton, "Northern elephant seal (Mirounga angustirostris) colony establishment and growth in the King Range National Conservation Area, California" (2022). Cal Poly Humboldt theses and projects. 569.
https://digitalcommons.humboldt.edu/etd/569