Introducing the Incredible HALK (Hierarchical Age Length Key)

Check out our new paper in Fisheries introducing a hierarchical method for age assignment for fisheries data.

The Incredible HALK (Hierarchical Age Length Key), led by Paul Frater, offers a new method to leverage length and age data in data-poor or sporadically sampled systems. It assigns ages using wider and wider selections of available data based on nested hierarchies assigned by the user. For example, the first tier might be within-sampling event, then within-lake, then within-year across-lakes, then within county, and so on. This allows users to assign ages to measured, but unaged, fish with reasonable accuracy, opening the door to much more in-depth assessment of growth, mortality, maturity, and other important metrics in stock assessment. Check out the HALK RShiny application to try it on your own data.
Image: Figure 2 from Frater et al. 2023.