Genetic Analysis of Wild and Captive Black Carp in the Mississippi River Basin
Black carp have likely been present in the Mississippi River since the 1990s, but their current distribution and spread is not well understood. Genetics is helping to shed light on this species, including its diversity, the relatedness of wild and captive fish, and its introduction history.
The Science Issue and Relevance: The black carp (Mylopharyngodon piceus) is a large (>1 m long) mollusk-eating riverine fish from eastern Asia imported into the United States for aquaculture purposes. Catches by commercial fishers indicate wild black carp have been present in the lower and middle portions of Mississippi River Basin since the 1990s. However, existing field data are insufficient for determining if their current distribution is the result of multiple introductions or widespread dispersal and propagation of a few fish from a single introduction. This study uses genetic analysis to investigate the diversity and relatedness of wild and captive (aquaculture) black carp present in the Mississippi River Basin and shed light on its introduction history.
Methodology for Addressing the Issue: Genetic analyses focused on seven microsatellite (nDNA) and three mitochondrial (mtDNA) markers (i.e., control region, Cytochrome b, and 16S). Black carp samples (specimens and muscle tissues) represented original material obtained over the course of ten years (2002-2011) and consisted of 51 captive-reared specimens from various aquaculture sources and 14 wild-caught individuals from the northern and southern extremes of the species’ recorded range in the Mississippi basin. Because some captive-reared and wild-caught individuals were known triploids, microsatellites were scored as pseudodominant loci.
Future Steps: Multilocus genotypes will be developed for the 65 black carp specimens. These loci will be used to identify genetic relationships between the wild and captive black carp. Additionally the population structure of the wild population will be used to track the invasion pathway and determine breeding groups vs. genetically divergent groups separated by gene flow barriers throughout the non-native range.
Black carp have likely been present in the Mississippi River since the 1990s, but their current distribution and spread is not well understood. Genetics is helping to shed light on this species, including its diversity, the relatedness of wild and captive fish, and its introduction history.
The Science Issue and Relevance: The black carp (Mylopharyngodon piceus) is a large (>1 m long) mollusk-eating riverine fish from eastern Asia imported into the United States for aquaculture purposes. Catches by commercial fishers indicate wild black carp have been present in the lower and middle portions of Mississippi River Basin since the 1990s. However, existing field data are insufficient for determining if their current distribution is the result of multiple introductions or widespread dispersal and propagation of a few fish from a single introduction. This study uses genetic analysis to investigate the diversity and relatedness of wild and captive (aquaculture) black carp present in the Mississippi River Basin and shed light on its introduction history.
Methodology for Addressing the Issue: Genetic analyses focused on seven microsatellite (nDNA) and three mitochondrial (mtDNA) markers (i.e., control region, Cytochrome b, and 16S). Black carp samples (specimens and muscle tissues) represented original material obtained over the course of ten years (2002-2011) and consisted of 51 captive-reared specimens from various aquaculture sources and 14 wild-caught individuals from the northern and southern extremes of the species’ recorded range in the Mississippi basin. Because some captive-reared and wild-caught individuals were known triploids, microsatellites were scored as pseudodominant loci.
Future Steps: Multilocus genotypes will be developed for the 65 black carp specimens. These loci will be used to identify genetic relationships between the wild and captive black carp. Additionally the population structure of the wild population will be used to track the invasion pathway and determine breeding groups vs. genetically divergent groups separated by gene flow barriers throughout the non-native range.