Short winters threaten temperate fish populations

Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973–2010) field patterns for Lake Erie yellow perch, Perca flavescens , which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations. Reductions in winter duration under climate change may have negative consequences for ectotherms adapted to seasonal temperature regimes. Here Farmer et al . show how short winters have, in part, caused failed lake fishery recruitment by altering spawning phenology and lowering the quality of eggs and larvae.