Anadromous Spawning Habitat

Current Issue - Anadromous Spawning Habitat

FHEP has applied impervious thresholds and targets to anadromous spawning habitat in Maryland.

Anadromous fish are fish that migrate from saltwater to freshwater to spawn. Anadromous species in the Bay include striped bass, hickory and American shad, blueback herring, alewife, white perch, and yellow perch. These species all spawn in upstream tidal fresh portions of estuaries and some (shad, herrings, and perch) may use portions of non-tidal streams to spawn. This spawning habitat is vulnerable to land development because it is on the receiving end of the most of the water's drainage, and the spawning and nursery areas are limited in size. Eggs and larvae are sensitive to increases of sediment and pollution, and disruption of their food supply that occur once development exceeds a watershed's limit.

To define the extent of habitat impacted by development in Maryland, we delineated spawning habitat using historical collections of eggs, larvae, and spawning adults. These areas were verified using recent surveys of spawning habitat based on collections of eggs and larvae. Impervious surface thresholds and targets were applied to rate spawning habitat quality. High quality habitat areas (many anadromous species and target levels of development) were defined and mapped. These maps are being used in evaluating properties for land acquisition and being incorporated into Plan Maryland.

Map of Watersheds with Anadromous Spawning Habitat

Above is a map of watersheds with anadromous spawning habitat with the impervious target and threshold applied. Best habitat has many anadromous species present and low (target or below) levels of development. Poor habitat has few species and-or low usage by anadromous species.

These are general recommendations that can be applied, with specific considerations to present condition of spawning habitat and other resource values. For more information contact Jim Uphoff.