>Geoffrey Read wrote:
>> However, other NZ marine > fauna have apparently reached West Coast USA
>across the Pacific (a nudibranch > was it recently?), and, as Jim
>indicates, the shallow water is the area where > intrusions are most
>likely. For what it's worth A. verrilli in NZ is a > near-shore species.
I'm not well-versed in the marine-introductions literature and probably
should keep my own counsel but, as a matter of curiosity, I wonder why one
would expect introduced species to occupy, as a rule, more or less
identical habitats. Certainly, species may have inate properties that make
it difficult or impossible to expand their original habitat parameters.
This seems like a rather strict adaptationist view. There are
well-documented examples in marine ecological literature indicating the
potential significance of a single predator, for instance, in controlling
the vertical range of a species. Likewise, my impression is that there are
plenty of terrestrial examples of introduced species expanding well beyond
what would be expected to form "natural" boundaries in a new habitat.
The nudibranch may not be so odd.
Season's greetings from the nemerteans to one of their favorite food groups...
Jon L. Norenburg
Department of Invertebrate Zoology-MRC 163
National Museum of Natural History
Washington, DC 20560
E-mail: norenbur at onyx.si.edu
Voice: 202-633-9278 / Fax: 202-357-3043