Estuary and Ocean Science Center, Biology Department, San Francisco State University, San Francisco, California, United States of America.
Santa Rosa Junior College, Santa Rosa, California, United States of America.
PLoS One. 2019 Nov 21;14(11):e0225248. doi: 10.1371/journal.pone.0225248. eCollection 2019.
Sea star wasting disease (SSWD) describes a suite of disease signs believed to have led to catastrophic die-offs in many asteroid species, beginning in 2013. While most studies have focused on large, easily visible sea stars with widely-dispersing larvae, less information is available on the effect of this disease outbreak on smaller sea star species, such as the six-armed sea star Leptasterias spp. Unlike many larger sea stars, Leptasterias brood non-feeding young instead of broadcast-spawning planktonic larvae. Limited dispersal and thus limited gene flow may make these sea stars more vulnerable to local selective pressures, such as disease outbreaks. Here, we examined Leptasterias populations at sites along the California coast and documented abundance changes coincident with recent Pacific coast SSWD in 2014. Detection of Leptasterias in central California declined, and Leptasterias were not detected at multiple sites clustered around the San Francisco Bay outflow in the most recent surveys. Additionally, we categorized disease signs in Leptasterias in the field and laboratory, which mirrored those seen in larger sea stars in both settings. Finally, we found that magnesium chloride (MgCl2) slowed the progression of physical deterioration related to SSWD when applied to sea stars in the laboratory, suggesting that MgCl2 may prolong the survival of diseased individuals.
海星消瘦病（SSWD）描述了一系列疾病迹象，据信这些迹象导致了 2013 年以来许多海星物种的灾难性灭绝。虽然大多数研究都集中在体型较大、易于观察且幼虫分布广泛的海星上，但关于这种疾病爆发对体型较小的海星物种（如六腕海星 Leptasterias spp.）的影响的信息较少。与许多大型海星不同，Leptasterias 孵化的是不摄食的幼体，而不是播散的浮游幼虫。有限的扩散和因此有限的基因流可能使这些海星更容易受到局部选择压力的影响，例如疾病爆发。在这里，我们检查了加利福尼亚沿海各地的 Leptasterias 种群，并记录了与 2014 年最近太平洋沿岸 SSWD 同时发生的丰度变化。在加利福尼亚中部检测到的 Leptasterias 数量减少，在最近的调查中，在旧金山湾出口周围聚集的多个地点未检测到 Leptasterias。此外，我们对野外和实验室中的 Leptasterias 进行了疾病迹象分类，这与在这两种环境中观察到的大型海星的疾病迹象相吻合。最后，我们发现氯化镁（MgCl2）在实验室中应用于海星时，可减缓与 SSWD 相关的身体恶化的进展，这表明 MgCl2 可能延长患病个体的存活时间。
