Graduation Date
Spring 2024
Document Type
Thesis
Program
Master of Science degree with a major in Biology
Committee Chair Name
Dr. Sean Craig
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Dr. Claire Till
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Dr. Matthew Hurst
Third Committee Member Affiliation
HSU Faculty or Staff
Fourth Committee Member Name
Dr. Paul Bourdeau
Keywords
Bryozoan, Invasive species, Larval preference, Antifouling paint, Fouling organism, Copper
Subject Categories
Biology
Abstract
The bryozoan Watersipora subtorquata and its cryptic congener Watersipora ‘new species’ are now globally invasive species. Previous studies have found this species complex to have a high tolerance to copper-based antifouling paints, which represent a large portion of the mitigation effort toward preventing hull fouling by invasive invertebrates. Tolerance alone, however, is unlikely to explain the full extent of Watersipora’s massive and rapid worldwide invasion success. The aim of this research was to move beyond tolerance, and test whether larvae of Watersipora ‘new species’ exhibit a preference for copper-coated settlement surfaces in both laboratory and field settings. For the laboratory portion of my study, I collected maternal colonies from four sites along the northern California coastline, induced larval release, and gave them a settlement surface with four choices: (1) black paint (33% copper), (2) red paint (25% copper), (3) gray primer (0% copper) and (4) unpainted plastic. For the field study, I replicated these settlement surfaces underneath local docks in Humboldt Bay and recorded natural larval settlement every two weeks for roughly four months. The laboratory study found a roughly 4:1 ratio of larvae that preferred to settle on either of the two copper surfaces versus no copper or unpainted plastic. The field study found no obvious preference of larvae for copper surfaces, but the settlement that was observed on field panels may be indicative of larval success rather than larval preference. Taken together, these results suggest that copper may have played a greater role in the spread of this species than previously thought, and that Watersipora “new species” may have evolved a preference for hitchhiking on copper painted ship hulls.
Citation Style
APA
Recommended Citation
Strawhand, Alexander K., "The larval preference of an invasive bryozoan (Watersipora 'new species') for copper-based antifouling paints" (2024). Cal Poly Humboldt theses and projects. 743.
https://digitalcommons.humboldt.edu/etd/743