Nursery Functions of U.S. West Coast Estuaries: The State of Knowledge

By providing increased growth and survival to juveniles of a species, estuaries may provide a “nursery role,” and be disproportionately important to the maintenance of populations relative to other rearing habitats. Yet for many species we do not fully understand what habitats provide a nursery role. As a first step, we summarized the state of knowledge for 15 species in West Coast estuaries. Juveniles of these species were documented in 113 out of 303 estuaries reviewed. Most existing information on the nursery role comes from larger estuaries and commercially important species. However, smaller estuaries provide juvenile habitat for 11 of the 15 species, highlighting the potential nursery value of smaller estuaries. Seagrasses, are the habitat most commonly used by juveniles of most species we reviewed. Subtidal waters, tidal channels, sloughs, and lagoons are also important to juveniles of many focal species. We also synthesized information on 19 threats to estuarine habitats and nursery functions; habitat loss was the most common threat among the 15 species. Our study identified many gaps in knowledge about nursery requirements for these 15 species across this broad geographic range, but provides a foundation for the conservation and restoration of juvenile habitat in West Coast estuaries.