Ficopomatus enigmaticus is a marine annelid invasive to many locations around the world. It was first identified as a non-indigenous species in San Francisco Bay, California in the 1920s, and since then it has been found in other parts of California. Because the full extent of the distribution of F. enigmaticus was unknown, I conducted surveys for the presence or absence of this species along the coast of California. Populations of F. enigmaticus were found at 23 of the 136 sites surveyed along the coast of California. Ficopomatus enigmaticus was found to be widespread in San Francisco Bay, Monterey Bay, and southern California.
Next, I examined the role of larval dispersal in the spread of this species. Many marine invertebrates have a planktonic period of their life history where they may be transported far from the parents. Because larvae are difficult to track in nature, I used a computer model to determine how far larvae might be transported by ocean currents. I found that larvae were predicted to travel relatively short distances from the Long Beach Breakwater (a median of 6 km in the summer and a median of 13 km in the winter). While larvae traveled relatively short distances, larvae were transported to sites where adults were not found (e.g., Alamitos Bay). Thus, the model suggests that there are unoccupied sites that are at risk of invasion by larvae.
Finally, I conducted laboratory experiments to determine the role of settlement in the spread of F. enigmaticus. I found larvae settled and metamorphosed at all salinities tested, thus the metamorphosis of larvae is not limited to intermediate salinities only. Additionally, I found that larvae will settle and metamorphose on a variety of substrates from different habitats, but larvae metamorphosed most readily on adult tube. Because larval dispersal and settlement could not explain why F. enigmaticus are not present at more sites, further work should be conducted to understand the spread of this species. Managers should focus on preventing the spread of this species because F. enigmaticus remains difficult to eradicate once it has arrived.
|Commitee:||Allen, Bengt, Whitcraft, Christine|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 81/8(E), Masters Abstracts International|
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