Seasonal infection of invasive Brook Stickleback (Culea inconstans) by the nematode Contracaecum multipapillatum at Turnbull National Wildlife Refuge, Washington

<p>The brook stickleback (Culaea inconstans) was first identified in Washington state in 1999 and has since established high population densities at Turnbull National Wildlife Refuge (TNWR). Fish parasitized by Contracaecum multipapillatum, a nematode known to infect zooplankton, piscivorous birds, and mammals, have previously been found at TNWR in Cheney Washington. This study aims to describe the seasonality of C. multipapillatum infection of brook stickleback, implications of infection on fish intermediate host body condition, and identify potential invertebrates facilitating transmission. Brook stickleback and aquatic invertebrates were collected bimonthly from April-November 2023 in Kepple, Blackhorse, and Middle Pine ponds. Fish body morphometrics were recorded, followed by necropsy to identify nematode presence (prevalence) and the number of nematodes per individual host (intensity). Fish were aged with length frequency histograms identifying two distinct cohorts, adults and young-ofthe- year (YOY). Aquatic invertebrates were identified and seasonal species composition by pond was recorded. Our study found prevalence of C. multipapillatum infection in YOY fish progressively increasing over the season, while adults did not significantly vary. Kepple pond had significantly lower prevalence of infection than both Blackhorse and Middle Pine in all age classes. Intensity of infection did not significantly vary within any date, pond, or age cohort. While copepod densities were visually strongly associated with YOY prevalence of infection, our sample size did not permit us to test for statistical association. We found no significant evidence that infection severely impacts brook stickleback body condition. Yet, our findings indicate copepods as the most likely mode of infection transmission at TNWR.</p>

Name thesis:degree_name

Master of Science (MS) in Biology

Level thesis:degree_level

Thesis: EWU Only

Discipline thesis:degree_discipline

Biology

Year

2024

Author dc:creator

• Flores, Sarah B.

• Animal Experimentation and Research
• Biology
• Terrestrial and Aquatic Ecology

Statement dc:rights

• Access perpetually restricted to EWU users with an active EWU NetID

Repository record dc:identifier

https://dc.ewu.edu/theses/927

OAI identifier oai:identifier

oai:dc.ewu.edu:theses-1930