Fish Gene Tools

Why it matters: Stock assessments estimate trends and variability in fisheries abundance and productivity, which are used to predict sustainable levels of future harvest. Managers use the results to develop management actions to optimize yield and ensure long-term sustainability of stocks. Stock assessment models rely heavily on age composition data that are used to estimate growth, recruitment, and mortality that determine stock status. However, producing age composition data currently requires invasive techniques, such as the lethal collection of otoliths. Additionally, it takes 2.5 years on average from the time of otolith collection to obtain age estimates. Therefore, this project aims to transform the speed, efficiency, and cost by which these data are collected, processed, and incorporated into time series analysis and management of Gulf fisheries by using epigenetic ageing techniques. Epigenetic ageing is a process by which the age of an individual is determined by measuring chemical modifications of DNA at specific locations in the genome. Rather than requiring the collection of otoliths from within the head of a fish, epigenetic ageing requires only a small sample of non-lethally collected tissue, such as a fin clip.

What the team is doing: The project team will co-produce a Gulf-wide system of mass fin clip collection and archiving, with the NOAA Southeast Fisheries Science Center, Gulf States Marine Fisheries Commission, Gulf Council, state agencies, and fishers. They will develop species-specific genomic tools that can be used to age 16 species of managed fish. Finally, the team will quantify the impact of epigenetic age data on key population parameter estimates, stock status estimates, and management advice for three Gulf fisheries species: red snapper, gag grouper, and gray triggerfish.

Expected outcome: The project will allow for an increase in the amount and types of age data that can be included in stock assessment models, thus better characterizing stock dynamics and decreasing uncertainty in management advice. The techniques developed will allow fish for which otoliths cannot be collected, such as live discards, to be aged, broadening the types of sampling included in age composition estimates. This will result in increased confidence and precision in estimates of the overfishing limit, which will translate into more effective management advice and increased economic efficiency of Gulf fisheries.