Meeting Abstract
Sea star wasting disease (SSWD) has affected > 20 species of sea stars along the Pacific coast since 2013. Small stars like the six-rayed Leptasterias initially appeared resistant as the larger sea stars died off in locations where Leptasterias persisted. Now strong impacts are seen in Leptasterias spp as well. Best characterized in the larger species like Pisaster ochraceus, symptoms of SSWD include white lesions, tissue disintegration, and death. The pathogen or pathology may differ among species. Smaller stars may progress swiftly through SSWD making characterization of incidence and progression hard. Leptasterias spp. show variation in color pattern, particularly in white areas, that are hard to distinguish from early SSWD. To gauge the effects of SSWD, both healthy and symptomatic Leptasterias spp. collected from intertidal sites in California, and Oregon, were monitored daily in the lab for disease progression and photographed under a dissecting microscope. Stars received either a treatment of magnesium chloride (MgCl2) and ice (n=4) or a control group of ice (n=5) to relax them for photography. Treated stars lived from three to forty-six days, exhibiting a slowed disease progression, while control stars lived three to seven days from the sign of initial lesions to death. Variability of symptoms was noted, indicating multiple disease progressions. Etiologies ranged from lesions starting in the axilla and spreading down the rays, holes in the central disk, and lesions starting at the optic cushion and spreading up the rays. Symptoms mirror those seen in P. ochraceous, excluding the holes starting in the central disk, suggesting the same pathogen or pathology may affect the initially resistant small stars.
