Understanding population dynamics of fishes is essential to the development of fisheries management strategies and age composition is a critical data component furthermore for restoration…

The U.S. Fish and Wildlife Service (USFWS), Region 2, awarded the Texas Parks and Wildlife Department (TPWD) a Formula Grant of $153,840 under the State Wildlife Grants (SWG) Program (CFDA 15.634) effective November 1, 2025, with completion targeted for August 31, 2027. This award funds the development of an epigenetic clock for southern flounder (Paralichthys lethostigma), a species of greatest conservation need in Texas. The project addresses critical limitations in traditional fish aging methodologies by establishing DNA methylation-based age prediction models that utilize small, non-lethal tissue samples (fin clips) rather than the labor-intensive and destructive otolith analysis technique. This innovation will enable more efficient, economical, and timely collection of precise age data to support both wild stock management and hatchery operations across Texas bays and estuaries.

TPWD partnered with Texas A&M University-Corpus Christi (TAMU-CC) as the sub-awardee to develop the epigenetic aging methodology. By establishing this non-invasive alternative to traditional aging techniques, the project will enhance TPWD's capacity to generate accurate age composition data essential for fisheries management and restoration aquaculture operations, while simultaneously expanding the types of samples and populations that can be assessed for demographic analysis.

Understanding population dynamics of fishes is essential to the development of fisheries management strategies and age composition is a critical data component furthermore for restoration aquaculture understanding broodstock age is important for optimizing spawning success otolith analysis the traditional aging technique is labor intensive and can only be performed on dead fish thus limiting the amount of age data that can be collected and the types of samples that can be included levels of DNA methylation in specific parts of the genome are strongly correlated with age and can be used to develop age prediction models epigenetic clocks because levels of methylation can be measured using small tissue samples and genetic techniques IT offers a relatively noninvasive nonlethal alternative to otolith based aging furthermore by using well established techniques methylation based aging would allow data to be collected in a timely and economically efficient manner drastically improving the ability to generate precise accurate age estimates the focus of this project will be to build an epigenetic clock for the southern flounder paralichthys lethostigma a species of greatest conservation need in texas southern flounder are found across texas bays and estuaries and are a major component of estuarine trophic structures in addition they are currently raised in state aquaculture facilities to stock local bays and estuaries the aging tools developed in this study will provide a means for assessing age of southern flounder using a single nonlethal tissue sample FIN clip providing data to support management of wild stocks and hatchery operations