Data from: 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 lobsters, September ESD prevalence was correlated with early
molting, while October ESD prevalence was correlated with summer seawater
temperature. This suggests that temperature-induced molting phenology
affects the timing of the onset of ESD, but, later in the summer, this
signal is swamped by the stronger signal of summer temperatures, which we
hypothesize are associated with an increased rate of new infections.
October ESD prevalence was ~80% in years with hot summers, and ~30% in
years with cooler summers. Yearly survival of diseased lobsters is
<50% that of healthy lobsters. Thus, population impacts of ESD are
expected to increase with increasing seawater temperatures.