Genetic Investigations of Grass Shrimp (Palaemonetes Spp.) Populations along the Gulf of Mexico Coast

Abstract

Salt marshes serve as essential habitat for many organisms. Grass shrimp of the genus Palaemonetes encompass approximately 25 to 70 percent of nekton within salt marsh edge habitat, serving as prey items for commercially and recreationally important fish species and playing an integral role in the breakdown of detrital materials. Morphological identification of species within the genus Palaemonetes is challenging; therefore, development of reliable genetic methods of species identification would be useful. Unambiguous identification of individual species is crucial in population studies to eliminate the inclusion of cryptic species. The objective of this study was to develop a reliable genetic assay for identification of Palaemonetes spp. High Resolution Melting Analysis (HRMA) of amplified products was used to genotype mtDNA haplotypes. Amplicons melted for the three species between 75°C - 77°C and each species displayed distinct melting profiles. P. vulgaris melted at the lowest temperature, followed by P. intermedius, with P. pugio melting at the highest temperature. The assay designed in this study will be used in future saltmarsh ecology studies involving Palaemonetes spp., eliminating time-consuming and error-prone morphological identification. It will also reduce the potential inclusion of conspecifics that would affect the measures of differentiation and variability in genetic population studies.