Predicting the age at maturity of Asian carp using air temperature

Asian carp (bighead carp, Hypophthalmichthys nobilis; grass carp, Ctenopharyngodon idella and silver carp, H. molitrix) are a group of invasive species that are predicted to cause ecological effects if they invade the Great Lakes basin. Although Asian carp age at maturity is known to be an important factor in the risk of establishing a population, there is relatively little maturity data for North America. We found that air temperature can be used to predict the age at maturity of Asian carp. Nonlinear regressions using mean annual air temperature and annual degree days to predict age at maturity explain 60% and 62% of the variation respectively. These models predict that maturation is possible in locations that were previously excluded from Asian carp spawning range based on data from the Amur River. As expected, we find faster maturation in more southern areas of North America, although there are relatively large errors predicting age at maturity in the Mississippi River population. We conclude that due to the effect of faster maturation on population growth rates, southern Great Lakes locations (e.g. Lake Erie) may be at greater risk of faster population establishment.