NOAA Report: Southern California Bight lost 58 percent of wetlands

STATEWIDE–Nearly 450 estuaries up and down the West Coast of the United States lost about 85 percent of its vegetated wetlands, according to a National Oceanic and Atmospheric Administration (NOAA) report. The hardest hit areas were the Central California Coast, Sacramento-San Joaquin Delta and San Diego Bay.

The Central California Coast suffered a 91.7 percent loss of its tidal wetlands, which include estuaries. Only the Sacramento-San Joaquin Delta area suffered a greater loss of tidal wetlands (96.8 percent). San Diego Bay lost 75.5 percent of its tidal wetlands. Other areas with a high loss of tidal wetlands were Humboldt Bay (85.9 percent), Southern California Bight (58.7 percent) and Newport Bay (41.9 percent).

NOAA’s report was published in mid-August. The report stated 85 percent of all historical tidal wetlands in California, Oregon and Washington have been lost.

Estuaries are where juvenile and steelhead salmon transition from saltwater to freshwater waterways; they also support a variety of migratory birds, fish, shellfish and terrestrial wildlife.

“More than a century of development has erased roughly 85 percent of original vegetated estuarine wetlands, especially around major river deltas,” NOAA staff said in a statement about the estuaries and tidal wetlands report. “The lost estuary habitat includes areas that were long ago diked and drained for agriculture, and forested wetlands that had not been widely recognized as estuary acreage.”

Scientists who studied the estuary habitats along the U.S. West Coast said these historical estuaries once occupied up to two million acres, which is about three times the size of Rhode Island.

“Scientists have data on the historic and current wetlands in 55 of the larger estuaries. Those estuaries have lost about 85 percent of their original vegetated wetlands. These 55 estuaries represent about 97 percent of historical estuary area on the West Coast, so their losses reflect almost all of the estuary losses,” NOAA staff said about the loss of tidal wetlands report.

The report itself specifically placed responsibility of estuary and tidal wetlands loss on human activity and development.

“Estuaries have long attracted human settlement due to their proximity to the ocean and their abundance of productive flat land, and human modifications to the landscape have resulted in extensive loss of estuarine wetlands,” scientists stated in their report.

Authors of the report moderated their findings by stating the numbers paint broad brushstrokes but policymakers should pursue additional studies before enacting specific regulations. The report, however, could still be a guide to “help interested groups improve action plans for estuarine wetland habitat restoration and conservation” and serve as a baseline “for understanding and predicting future changes with projected sea level rise.”

The report was titled “Insights into estuary habitat loss in the western United States using a new method for mapping maximum extent of tidal wetlands” and was authored by Laura Brophy (Institute of Applied Ecology), Correigh Greene (NOAA Fisheries), Van Hare (Pacific States Marine Fisheries Commission) and Brett Holycross (Pacific States Marine Fisheries Commission), among others.

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