Upper Newport Bay

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Upper Newport Bay is one of the major estuarine areas still remaining along the Southern California coast. It supports a variety of plant communities and is an important breeding and feeding area for a number of animals. The Bay is composed of mudflats and marsh islands which are exposed to tidal action. At the northeastern end there is marsh with both salt and freshwater characteristics. The dominant community is the saltmarsh association with pickleweed, Salicornia sp., saltgrass, Distichlis spicata, cord grass, Spartina foliosa, eel grass, Zostera marina, and saltwort, Batis maritima. A wide variety of red, green and brown algae is found here.

On the bluffs, coastal sage scrub is the main association, though it shows numerous variations including several species of Opuntia, among them one of the last stands of Opuntia prolifera in Orange County. Two rare plants are found in the area, Dudleya stolonifera and Cordylanthus maritimus.

A wide variety of animals is present, the most conspicuous being the birds, with over 155 species recorded. This is a favorite stop and wintering area for a number of migrant waterfowl and shorebirds. The endangered light-footed clapper rail, Rallus longirostris levipes, breeds here.

At least 61 species of fish have been reported in the Bay, making it one of the most valuable spawning grounds on the south coast. Numerous invertebrates are found here; noteworthy are the very abundant sea pansy, Renilla kollikeri, and the amphipod, Corophium sp.

Surrounding much of the Upper Bay are bluffs and steep slopes which show outcrops of Miocene and Pliocene marine deposits, some of which contain micro-and megafossils. These deposits are overlain with Pleistocene alluvium. The Bay was formed by the down-cutting of a river, possibly the Santa Ana, after the Pleistocene uplift of the area.

Today there is no permanent freshwater flow into the Upper Bay though a number of creeks discharge into the Bay during the rainy season. While there is a tidal flushing in the upper reaches, freshwater discharges of flood proportions, as in 1968, have resulted in heavy sedimentation. Being relatively shallow, there is a great variation in the water temperature in the Bay; during all but the winter months it is warmer than the ocean temperature.

Integrity: Much of the Upper Bay has been disturbed or altered by various developments, including channelization and diking. There is a road along the edge of the marsh. Agricultural and urbanized areas surround the Bay. The lower Bay is completely developed.

Use: Educational, research, observational. It is widely used by Southern California educational institutions and natural science organizations, and numerous studies have been conducted here.

Ref: Stevenson, R. E. and K. O. Emery, 1958. Marshlands at Newport Bay, California. Allan Hancock Foundation Occasional Paper No. 20. Los Angeles.

Vogel, R. J. 1966. Salt Marsh Vegetation of Upper Newport Bay, California. Ecology 47, pp. 80-87.

Anon. 1970. Report on Natural Resources of Upper Newport Bay and Recommendations Concerning the Bay's Development. Calif. Dept. of Fish and Game, Sacramento .

November 1975