Abundance patterns of juvenile blue crabs (Callinectes sapidus) in nursery habitats of two Texas bays

In Christmas Bay, Texas, monthly densities of juvenile blue crabs, smaller than 40 mm carapace width, were highest is seagrass (2.8 to 50.6 m exp -2), intermediate in salt marsh (1.3 to 22.1 m exp -2) and lowest on bare sand (0.6 to 5.6 m exp -2). In West Bay, Texas, where seagrasses were absent, crab densities were intermediate in salt marsh (2.2 to 13.0 m exp -2) to low on bare mud (0.1 to 1.7 m exp -2). The lowest seasonal abundances occurred in the early spring after mean sizes occurred in the late summer and fall corresponding to seasonal recruitment. Crabs were larger in mean size in salt marsh than in seagrass or nonvegetated habitats. Although seagrasses are often the preferred nursery of Callinectes sapidus, seagrasses occur infrequently in NW Gulf and salt marshes are used as an additional nursery. Features that increase utilization of salt marshes in the NW Gulf compared to other regions are reticulated marsh geomorphology, low tidal amplitude and long periods of tidal inundation.