The Mystery of the Disappearing Eelgrass in Morro Bay

NOAA News –

Eelgrass has mysteriously disappeared from the large tidal flats of Morro Bay, California, prompting a new research collaboration to investigate the reasons for the collapse, the potential adverse effects on local fish and wildlife, and how to bring the eelgrass back. Scientists hope what they learn will also help inform eelgrass recovery efforts up and down the West Coast.

Eelgrass provides one of the richest and most productive coastal habitats in the world and is found in cold, shallow waters, primarily in the northern hemisphere. Halfway up the California Coast, Morro Bay has long been known for its vast beds of native eelgrass (Zostera marina), which help protect shorelines, improve water quality, sustain marine and estuarine food webs, and support many fish and invertebrate species. As one of many examples, threatened and endangered species such as steelhead benefit from the food-rich habitat and shelter that eelgrass provides.

But something is happening to Morro Bay eelgrass. It has declined by 97 percent, from 344 acres in 2007 to about 13 acres by 2015. While natural cycles normally drive increases and decreases in eelgrass abundance over time, such catastrophic crashes are rare.

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