Non-indigenous marine species of Humboldt Bay, California

A number of both intentionally and inadvertently introduced species have been in Humboldt Bay for a long time, in some cases going back to the first settlement of the region by Europeans in the mid 1800's. During this survey, we collected and identified 95 species that are possibly non-indigenous marine species (NIS) in Humboldt Bay. There were representatives from most major groups of organisms, ranging from vascular plants to fish. We compared the occurrence of introduced species in Humboldt Bay to their occurrence mentioned in previous studies done along the Pacific coast of North America. The data on co-occurrence suggest that San Francisco Bay could be an important source area for introductions to Humboldt Bay, a finding consistent with ship and small boat traffic moving between these two locations. The number of species that appear to be found only in Humboldt Bay (27) suggests that there may be factors in the nature of shipping or other human influences that are unique to the bay.