We examined a disease outbreak of the fan mussel, Pinna nobilis (L.), in the Alfacs Bay (South Ebro Delta, Spain) during a period of two years in three zones exposed to a summer salinity gradient resulting from agricultural freshwater discharges and distance to the open sea. Long-term monitoring was also conducted in Fangar Bay (North Ebro Delta), featuring lower salinities and no evidence of disease. Results showed that the salinity gradient of Alfacs Bay (37.4–35.7) was associated to cumulative mortality (100% near the mouth, 43% in middle regions, and 13% in inner regions), thus hindering the spread of pathogens. Young specimens showed to be more tolerant to disease than large adults but become vulnerable over time. In Fangar Bay, lower salinities (30.5–33.5) prevented the disease but individuals were highly vulnerable to Storm Gloria which caused 60% mortality in 3 weeks, and ~100% in 6 weeks.

我们检查了扇贝贻贝（Pinna nobilis）的疾病暴发（L.），在阿尔法奇湾（西班牙南埃布罗三角洲），为期两年，在三个区域中，这些区域暴露于夏季盐度梯度，这是由于农业淡水排放和到远海的距离而造成的。在范加尔湾（北埃布罗三角洲）也进行了长期监测，其盐度较低且没有疾病迹象。结果表明，Alfacs湾的盐度梯度（37.4–35.7）与累积死亡率（口附近100％，中部区域43％，内部区域13％）相关，从而阻碍了病原体的传播。年轻的标本显示出比大人更能抵抗疾病，但随着时间的流逝变得脆弱。在Fangar湾，较低的盐度（30.5–33.5）阻止了该病的发生，但个人极易遭受“风暴Gloria”的袭击，这在3周内造成60％的死亡率，在6周内造成100％的死亡率。