A Comparison of Aspects of the Biology of Paranemertes peregrina (Nemertea) from Bodega Harbor, California, and Washington Statel

In Bodega Harbor, California, the nemertean Paranemertes peregrina spawns in June or July. Adults in the study area were small in comparison to worms found on two Washington mud flats. Population density of active worms averaged 7.38 worms/m 2 , with much variation due to time of day of low tides. Approximately 28 percent of the active population ate during the low tide periods that were sampled. Prey included spionids, nephtyids, polychaetes with capillary setae, and syllids (in decreasing importance). The number of prey families in the diet of California nemerteans was higher than in the two Washington mud flat populations and preferred nereid prey was less abundant in California and comprised less of the total diet of nemerteans there. Spionids were the major prey of California nemerteans in spring and summer; nereids were the major prey in fall and winter. In food preference tests, nemerteans showed negative responses to phoronids and lumbrinerids and positive responses to Nephtys caecoides. In comparison to three Washington populations, the population in Bodega Harbor was most similar to a rocky intertidal population and much different from two mud flat populations. I Manuscript accepted 27 March 1979. 2 California State College, Stanislaus, Department of Biological Sciences, Turlock, California 95380. THE PREDATORY NEMERTEAN Paranemertes peregrina occurs in various habitats along the Pacific coast of North America from Ensenada, Mexico, through the Aleutian and Commander Islands (Coe 1940), and in Japan (Yamaoka 1940). Life history and feeding biology of this nemertean were studied in both rocky and mud flat intertidal habitats in Washington State (Roe 1971, 1976). The present observations concern aspects of life history and feeding biology of P. peregrina in a more southern habitat at Bodega Harbor, California; and comparisons are made of Washington and California populations of P. peregrina. MATERIALS AND METHODS Nemerteans were observed in and collected from the mud flat in the Bodega Marine Laboratory preserve in Bodega Harbor, California. Most worms were counted and collected along the edges of a low area that contained water even during low tide. The area was comprised of sandy mud and became quite hard and dry during low tides except in low places where water remained. Ulva and Entermorpha spp. were present most of the year in low places, but the major portion of the mud flat was bare most of the year. The mud flat was superficially similar to both mud flat areas studied in Washington in sediment and in animals and plants living on and in it. Densities of active Paranemertes peregrina were determined by counting numbers per square meter in each square meter along a 25-m transect laid along the edge of the low area described above. For estimates of size and sex of the worms through time and study of food of the worms, 50 worms from the area were collected during each sampling period. Each of the 50 worms was isolated in a small jar containing clean seawater al1d was kept near 15°C for at least 48 hr. Then length and width of each worm was mea-