The population ecology of an exotic mussel, Musculista senhousia, in a Southern California Bay

Musculista senhousia is a small, infaunal mussel native to Asia. Over the last 75 yrs, humans have unintentionally introduced it to various parts of the world, including the Mediterranean, Australasia, and North America. Recently, M. senhousia has become abundant in Mission Bay, San Diego, California. Here, the mussel exhibits many traits typical of opportunistic species. It is small, only attaining a maximum length of about 32 mm, and is capable of rapid growth, reaching up to 25 mm after 1 yr. In San Diego, there was a major peak of recruitment during the late fall of 1990, and low levels of background recruitment throughout much of the year. Although the maximum life span of M. senhousia is approximately 2 yr, mortality is high and most of the population are only annuals. Overall, M. senhousia appears to display similar life-history characteristics both in this invaded system and within its native range.