Imagine someone sailing down a river in a small motorboat on a warm day. She is enjoying the warm sunshine and cool breeze when suddenly a 20-pound silver carp hits her in the head. The presence of Asian carp in U.S. waterways make this risk very real on rivers and canal systems, particularly in Illinois and Missouri .
The several types of Asian carp include the silver, black, grass, and big head carp. These have been farmed and eaten in China for over 1,000 years; it is among the top aquaculture foods worldwide. In the United States, however, Asian carp is considered to be an invasive species. It disrupts the structure and composition of native fish communities to the point of threatening native aquatic species.
Biologists are working to understand the biology and ecology of Asian carp. The aim is to develop methods of controlling the species without damaging native fish. Understanding the population dynamics of the carp will help biologists develop and implement measures that reduce its population, allowing scientists to model the statistics of carp populations.
Populations are dynamic entities, consisting of all of the species living within a specific area. They fluctuate based on a number of factors: seasonal and yearly changes in the environment, natural disasters such as forest fires and volcanic eruptions, and competition for resources between and within species.
Demography, the statistical study of population dynamics, uses mathematical tools to investigate how populations respond to changes in their biotic and abiotic environments. Researchers originally designed demographic tools, such as life tables, to study human populations. To determine insurance rates, life insurance companies developed methods to analyze life expectancies of individuals in a population. The term "demographics" is often used in discussions of human populations, but demographic approaches can be applied to all living populations.