A new bivalve host record for the exotic parasite Perkinsus marinus in the Gulf of California

Perkinsus marinus belongs to the Chromista Kingdom and is recognized as an opportunistic parasite of mollusks native to the west coast of the Atlantic Ocean. The native range of this species is the Atlantic Ocean, however, it was introduced to the Gulf of California (GC) by a transfaunation of oysters. This microorganism has invaded new niches in the GC and continues to colonize different species of bivalve mollusks. For the first time, P. marinus was detected in the mussel Mytella strigata from the southeast coast of the GC in 2020 by staining and molecular techniques. The moderate number of cells of this myzozoan in the mussel coincides with the reports for other species of ostreids, venerids, and mytilids in the area, which suggests that it is expanding its geographical range and host species. The invasive potential of the parasite in new environmental niches and species of mollusks with commercial importance elevate the need for a risk assessment.