Highest crab abundances occurred near the turbidity maximum where relative salt marsh area was greatest. Salt marsh surface area and turbidity were the strongest determinants of crab abundance (positive association in both cases). Out-of-sample predictions of juvenile blue crab counts from a model considering fully nonseparable spatiotemporal dependence outperformed predictions from simpler models. Using 21 years of spatio-temporally indexed survey data (i.e., water chemistry, turbidity, blue crab, and predator abundance) and GIS information on potential nursery habitats (i.e., seagrass, salt marsh, and unvegetated shallow bottom), we constructed five Bayesian hierarchical models with varying spatial and temporal dependence structures to infer variation in nursery habitat value for young juveniles (20–40 mm carapace width) of the blue crab Callinectes sapidus within three tributaries (James, York and Rappahannock Rivers) in lower Chesapeake Bay. While small-scale studies remain important tools to assess nursery value of structured habitats and environmental factors, targeted applications that unify survey data over large spatial and temporal scales are vital to generalize inference of nursery function, identify highly productive regions, and inform management strategies.
![female blue crab female blue crab](https://insider.si.edu/wp-content/uploads/2014/07/SERCbluecrab2.jpg)
![female blue crab female blue crab](https://delmarvafisheries.org/wp-content/uploads/2020/06/female-blue-crab-1200x900-1-300x225.jpg)
Nursery grounds provide conditions favorable for growth and survival of juvenile fish and crustaceans through abundant food resources and refugia, and enhance secondary production of populations.