Identification of consumed stone flounder, Kareius bicoloratus (Basilewsky), from the stomach contents of sand shrimp, Crangon affinis (De Haan) using mitochondrial DNA analysis

We have developed a method for the identification of consumed stone flounder, Kareius bicoloratus (Basilewsky) larvae and juveniles from the stomach contents of sand shrimp, Crangon affinis (De Haan). We succeeded in isolating stone flounder DNA from the stomach contents of sand shrimp, using a cell lysis buffer containing 8 M urea. DNA for PCR analysis was obtained from stomach contents even when it was isolated 5 hours after the termination of predation. However, the total DNA yield decreased as the time after predation progressed. Stone flounder was distinguished from other prey in the stomach contents of sand shrimp using PCR with universal primers for fish and restriction analysis of mtDNA. Successful amplification of stone flounder mtDNA was possible up until 4 h after the termination of predation, but no amplification was possible 5 h after the termination of predation. In addition, a part of the D-loop region of stone flounder mtDNA was cloned, sequenced, and used to design species-specific PCR primers that allow amplification for stone flounder. PCR products were not obtained from the total DNA of other possible prey of the sand shrimp: 11 fish species; 2 mysid species; one amphipod species; and 2 polychaete species. In this paper, we discuss the advantages and disadvantages of using the PCR method coupled with restriction analysis, and the species-specific PCR method to identify consumed larval and juvenile fish species in the guts of predators. (C) 1997 Elsevier Science B.V.