 |
 |
|||
At latest count there are 5 indigenous species of Littorina winkles1 inhabiting the wave-splash areas of west-coast shores. The largest is Littorina sitkana and the smallest is L. subrotundata, with 3 intermediate-sized species Littorina scutulata2, L. plena, and L. keenae. Two other Littorina species L. saxatilis3 and L. littorea4 are known from introductions from the Atlantic coast into the San Francisco Bay region but, at least for the former species, has limited distribution. NOTE1 “winkle” is a common shortened version of “periwinkle”. References to “perwyncles” and “pennywinkles” in English writings date from the early 16th C. Our west-coast species are too tiny to eat, but one or two of the Atlantic-coast species are quite large and tasty. Winkle-pickers in Britain and other Atlantic-coast countries, including North America, have been practising their trade for centuries. Some 19 species of Littorina are recorded from north Pacific and Atlantic oceans NOTE2 the featured snail in the ODYSSEY is a member of this species NOTE3 in 1993 researchers discovered a population of an Atlantic-coast species Littorina saxatilis in San Francisco Bay, California that seemed to be well established. The probable method of introduction is thought to have been as incidental travellers with the masses of east-coast brown seaweeds Ascophyllum and Fucus used as packing for shipments of baitworms and/or lobsters from Maine. The researchers note the discovery of 2 other littorinid species L. littorea and L. obtusata imported with baitworms into the San Francisco Bay area but add that, unlike L. saxatilis, neither appears to have established a permanent colony. NOTE4 recently, several populations of L. littorea, the large periwinkle so favoured by "winkle-picking" connoisseurs in Europe and the Atlantic coast of North America, have been discovered by researchers from the University of British Columbia on local beaches. As the species is commonly sold in Periwinkle Littorina littorea 1X Ochre star Pisaster ochraceus eating |
||||
 |
||||
|
||||
|
||||
Phylum Mollusca (lit. “soft” or “shellfish” L.)
|
||||
|
introductions. However, as this species lives somewhat lower in the intertidal zone than the 4 indigenous species and thus may be susceptible to predation by ochre sea stars Pisaster ochraceus (see photograph on Right), there may exist a natural control for them not present on east-coast shores. Of the 2 main locations mentioned by the author, though, one has ochre stars in abundance and yet the non-indigenous species survives. The discovery is interesting and justifies further research. 
