02124nas a2200241 4500008004100000245022800041210006900269260001000338300001000348490000700358520132800365653001301693653001201706653001301718653001401731653001201745653001501757653001101772653001301783100002701796700002501823856003401848 1999 eng d00aMetazoan parasites and pearls in coexisting mussel species: Mytilus californianus, Mytilus galloprovincialis, and Septifer bifurcatus, from an exposed rocky shore in Baja California, Northwestern Mexico0 aMetazoan parasites and pearls in coexisting mussel species iMyti cJAN 4 a10-160 v423 aMetazoan parasites, Modiolicola gracilis Wilson (Copepoda), Pseudomyicola spinosus Rafaelle & Monticelli (Copepoda), Urastoma cyprinae Graff (Platyhelminthes), unidentified encysted trematode cercaria, and pearls were found in coexisting mussel species: Mytilus californianus Conrad, Mytilus galloprovincialis Lamarck, and Septifer bifurcatus (Conrad) from the upper intertidal zone of an exposed rocky shore in Baja California, northwestern Mexico. Incidence of parasites and pearls was greater in M. californianus, the largest species of mussels examined, than in the other mytilids. The lowest incidence of parasites and pearls was in S. bifurcatus, the smallest species of mussels examined. The highest parasite prevalence coincided with the autumn and winter months when M. californianus and M. galloprovincialis had a lower condition index and were reproductively active. All parasites produced histological alterations in their hosts; a hemocytic reaction and compression of tissues were commonly observed. In spite of M. californianus being the most parasitized species, it is the dominant component in the upper intertidal zone. These results suggest that factors specific to the infesting metazoan parasites in M. galloprovincialis and S. bifurcatus reduce their competitiveness capacity against M. californianus.10abivalvia10aecology10amollusca10amytilidae10amytilus10aparasitism10apearls10aseptifer1 aCáceres-Martínez, J.1 aVásquez-Yeomans, R. u://00007810980000202081nas a2200229 4500008004100000245020700041210006900248300001000317490000700327520132800334653001301662653001201675653001301687653001401700653001201714653001501726653001101741653001301752100002701765700002501792856003401817 1999 eng d00aMetazoan parasites and pearls in coexisting mussel species: Mytilus californianus, Mytilus galloprovincialis, and Septifer bifurcatus, from an exposed rocky shore in Baja California, Northwestern Mexico0 aMetazoan parasites and pearls in coexisting mussel species Mytil a10-160 v423 aMetazoan parasites, Modiolicola gracilis Wilson (Copepoda), Pseudomyicola spinosus Rafaelle & Monticelli (Copepoda), Urastoma cyprinae Graff (Platyhelminthes), unidentified encysted trematode cercaria, and pearls were found in coexisting mussel species: Mytilus californianus Conrad, Mytilus galloprovincialis Lamarck, and Septifer bifurcatus (Conrad) from the upper intertidal zone of an exposed rocky shore in Baja California, northwestern Mexico. Incidence of parasites and pearls was greater in M. californianus, the largest species of mussels examined, than in the other mytilids. The lowest incidence of parasites and pearls was in S. bifurcatus, the smallest species of mussels examined. The highest parasite prevalence coincided with the autumn and winter months when M. californianus and M. galloprovincialis had a lower condition index and were reproductively active. All parasites produced histological alterations in their hosts; a hemocytic reaction and compression of tissues were commonly observed. In spite of M. californianus being the most parasitized species, it is the dominant component in the upper intertidal zone. These results suggest that factors specific to the infesting metazoan parasites in M. galloprovincialis and S. bifurcatus reduce their competitiveness capacity against M. californianus.10abivalvia10aecology10amollusca10amytilidae10amytilus10aparasitism10apearls10aseptifer1 aCáceres-Martínez, J.1 aVásquez-Yeomans, R. u://000078109800002