Date of Award

Winter 1-31-2021

Document Type

Thesis: Open Access

Degree Name

MS Marine Science

Department

Environmental and Ocean Sciences

Committee Chair

Dr. Drew Talley

Committee Member

Dr. Steven Searcy

Committee Member

Dr. Andrew Thompson

Abstract

As wetlands face continued fragmentation worldwide, an understanding of habitat connectivity and how fishes that rely on these environments is imperative to conduct effective marine management. Site fidelity and habitat connectivity are vital measures of the interdependence of fish populations living in neighboring marshes (or in regions of a single marsh).

Here, we examine the habitat connectivity, site fidelity, and movement of California killifish (Fundulus parvipinnis) within and among three estuaries in Southern California through otolith microelemental analysis. Assessing the site fidelity of estuarine fishes is important to determine the level of connectivity between spatially distinct populations within a bay and between adjacent bays.

Otolith microchemical analysis of F. parvipinnis successfully distinguished capture locations from as close as 2.89 km apart to as far as 184 km apart in San Diego Bay, Mission Bay, and Anaheim Bay. We found no relationship between distance among sites and our ability to distinguish them. Our results suggest populations of F. parvipinnis in Southern California have high site fidelity with low levels of population connectivity on both small and large spatial scales.

Specifically, Pairwise Permutational MANOVA (PERMANOVA) found 43/45 pairwise comparisons were statistically significant. Discriminant function analysis of otolith trace metal concentrations correctly classified, on average, 63.5% of F. parvipinnis to their collection site (DFA range: 20−100%). When comparing intra−bay sites separately, the DFA classification success rate improved to an average of 79.9%. DFA classification success rates were 77.9%, 85%, and 76.7% in Mission Bay, San Diego Bay and Anaheim Bay, respectively. As such, F. parvipinnis do not appear to move between marshes, even those that are only 5 km apart.

This study is the first to analyze the site fidelity of F. parvipinnis within and among these three estuaries, the first to study the otolith microchemistry of F. parvipinnis in Southern California, and one of the few to investigate the power of otolith microchemistry on such a small spatial scale (less than tens of kilometers) in Southern California.

Fundulus parvipinnis are an ecologically important species in Southern California wetlands, thus quantifying their habitat connectivity has implications for interactions with predators and prey, and expands the knowledge base for mitigation and restoration projects of marshes worldwide. Low habitat connectivity on both small and large spatial scales makes F. parvipinnis a potentially sensitive indicator species to elucidate the impacts of wetland fragmentation on species conservation.

Download

Share

COinS