Date of Award


Document Type

Thesis and Dissertation

Degree Name

Master of Science (MS)


Department of Mathematics

First Advisor

Olcay Akman


Pacific mole crabs (Emerita analoga) are one of the most important and abundant

invertebrates in sandy beach environments. Consequently, they are a common food source

for seabirds and sea otters. Since the mole crab serves as the primary intermediate host for

acanthocephalan parasites, they have been linked to a number of mortality events. It is

currently estimated that 13-16% of deaths in the threatened California sea otter population

have been caused by infection. In addition, unusually high loads of acanthocephalan

parasites have been linked to episodic deaths of thousands of surf scoters. Studies suggest

that acanthocephalan development and transmission may be strongly effected by weather

patterns. In this research paper, we introduce a system of differential equations for parasite

transmission between surf scoter, sand crab, and sea otter populations.

Temperature-dependent parameters within the model allow us to examine the role of

climate oscillation in El Niño(EN) and La Niña(LN) years on abundances of infected

hosts. We applied t-test to crab prevalence data, and we performed sensitivity analysis, and

Floquet theory on our model to conclude that EN events increase the prevalence of

infected crabs.


Imported from ProQuest Seck_ilstu_0092N_11059.pdf


Page Count


Included in

Mathematics Commons