Estuaries can be harsh habitats for the marine animals that enter them, but they may also provide these species with sub-saline refuges from their parasites. The nemertean egg predator Carcinonemertes errans is known to occur less frequently and in smaller numbers on its host, the Dungeness crab Metacarcinus magister, when the hosts are found within estuaries. We examined the temperature and salinity tolerances of C. errans to determine if this observed distribution represents a true salinity refuge. We monitored the survival of juvenile and larval worms exposed to ecologically relevant salinities (5–30) and temperatures (8–20 °C) over the course of several days under laboratory conditions. Juvenile worms were unaffected by the experimental temperature levels and exhibited robustness to salinity treatments 25 and 30. However, significant mortality was seen at salinity treatments 20 and below. Larvae were less tolerant than juveniles to lowered salinity and were also somewhat more susceptible to the higher temperatures tested. Given that the Dungeness crab can tolerate forays into mesohaline (salinity 5–18) waters for several days at a time, our findings suggest that salinity gradients play an important role in creating a parasite refuge for this species within the estuaries of the Pacific Northwest.
Bibliografisk noteUniversity of Oregon; Max-Planck Odense Center on the Biodemography of Aging; Max Planck Society; University of Southern Denmark 0 25920719
- HAPLOSPORIDIUM-NELSONI MSX CANCER-MAGISTER DANA LOXOTHYLACUS-PANOPAEI CALLINECTES-SAPIDUS OSMOTIC REGULATION IONIC REGULATION CEREBRAL ORGANS LARVAL STAGES SURVIVAL PARASITE