Rising temperatures, molting phenology and epizootic shell disease in the American lobster

Phenological mismatch, maladaptive changes in phenology resulting from altered timing of environmental cues, is an increasing concern in many ecological systems, yet its effects on disease are poorly characterized. American lobster (Homarus americanus) is declining at its southern geographic limit. Rising seawater temperatures are associated with seasonal outbreaks of epizootic shell disease (ESD), which peaks in prevalence in the fall. We used a 34-year mark-recapture dataset to investigate relationships between temperature, molting phenology, and ESD in Long Island Sound, where temperatures are increasing at 0.4 °C per decade. Our analyses support the hypothesis that phenological mismatch is linked to the epidemiology of ESD. Warming spring temperatures are correlated with earlier spring molting. Lobsters lose diseased cuticle by molting, and early molting increases the intermolt period in the summer, when disease prevalence is increasing to a fall peak. In juvenile and adult male lob...

物候错配（phenological mismatch）指由环境线索时序改变引发的物候适应不良变化，如今在众多生态系统中日益受到关注，但其对疾病的影响仍未得到充分表征。美洲螯龙虾（Homarus americanus）在其地理分布南界的种群数量持续下降。海水温度升高与流行性壳病（epizootic shell disease，ESD）的季节性暴发密切相关，该病的流行率在秋季达到峰值。本研究依托长岛海峡地区长达34年的标记重捕数据集（mark-recapture dataset），探究了温度、蜕壳物候与ESD之间的关联——该区域海水温度正以每十年0.4摄氏度的速率上升。分析结果支持“物候错配与ESD的流行病学特征存在关联”这一假说：春季水温升高与春季蜕壳提前存在相关性。美洲螯龙虾可通过蜕壳脱落患病的外骨骼，而提前蜕壳会延长夏季的蜕壳间期，此时疾病流行率正逐步上升至秋季峰值。在幼体与成年雄性美洲螯龙虾中……