Impacts of temperature on Asian Carp life history and population growth
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Date
2021-12-21
Authors
Brook, Madison
Journal Title
Journal ISSN
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Publisher
University of Waterloo
Abstract
Asian carp (bighead carp, Hypophthalmichthys nobilis; black carp, Mylopharyngodon piceus; grass carp, Ctenopharyngodon idella; and silver carp, H. molitrix) are a group of invasive species predicted to cause ecological and economic effects in the Great Lakes region should they invade and establish populations. They are known for their ability to consume large amounts of food, fast growth rates, and large fecundities, making them invasive species of great concern. The age at sexual maturity of the population has been identified as being an important variable in determining the likelihood of any species of Asian carp establishing a population, as faster maturation typically corresponds to faster population growth. However, there is relatively little available information about the ages at maturity of Asian carp populations in North America.
Common air temperature metrics can be used to predict the age at maturity of bighead, silver and grass carp ages at maturity across North America. Using age at maturity and temperature data from around the world, we found that annual average temperature and annual average degree days could explain 60% and 62% of the variation in ages at maturity, respectively. Both metrics predicted faster maturation in more southern locations, though annual average degree days predicted higher ages at maturity than annual average temperature did.
Using the significant relationship between air temperature and age at maturity, we constructed a temperature-dependent age-size integral projection population model for grass carp. This model predicted faster population growth in more southern locations. An elasticity analysis of the model demonstrated that adult survival rates are very important in determining grass carp population growth rates, indicating that management actions like fishing will have proportionally large effects on populations. In addition, temperature dependent growth parameters demonstrated that temperature dependent growth may dramatically change our predictions of population growth rates across different temperatures, and should be further researched. Consideration of temperature when determining population growth rates can be used to guide management priorities by indicating the areas that are most at risk of fast population growth rates, allowing additional allocation of resources in those priority locations. Our results indicate that more southern areas in the Great Lakes, like Lake Erie, are most at risk of fast population growth. Overall, we demonstrate that the inclusion of environmental conditions, like temperature, in population models can reveal important insights about population growth rates that may otherwise be overlooked.
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Keywords
Asian carp, temperature, age at maturity, invasive species, population growth rate, population model, North America