Mar 31, 2023

State of the Bay 2023

State of the Bay 2023 is Here!

Every three years, the Estuary Program gathers the available data and research to compile a report examining the health of the Morro Bay estuary and the lands that surround it. The State of the Bay report provides important information about environmental trends and guides local efforts to protect and restore this special place. In this blog, we will introduce some of the topics in the 2023 State of the Bay report and how you can join our upcoming events this spring. 

The 2023 State of the Bay report is now available. We also created an online version with expanded content. 

Exploring Water Quality

Clean water is essential for humans and for the wildlife that call those waters home. Monitoring the health of our bay and creeks  has been an ongoing project at the Estuary Program for over 20 years. Our dedicated staff and volunteers track a variety of data points throughout the watershed to help determine the health of aquatic ecosystems.  

This map shows oxygen levels at seven sites around the estuary. Oxygen levels tend to be higher toward the front bay where the cold well-oxygenated waters of the Pacific Ocean are easily pushed into the bay through the deeper channels. Our data shows lower oxygen levels in the back bay. The shallower depths in this part of the bay prevent those ocean waters from coming in with the tide, leading to stagnant water with less oxygen. These conditions can be harmful to the most sensitive wildlife.
Nitrate levels are monitored in creeks throughout the Morro Bay watershed. While nitrates are essential for plant growth, excess amounts can lead to harmful algal blooms and low oxygen levels. Our data shows Good (low) levels of nitrates in upper Los Osos and Chorro Creeks, as well as the smaller creeks that drain into Chorro (Dairy, Pennington, and San Luisito Creeks). Middle and lower Chorro Creek and Warden Creek have Very Poor nitrate levels, which means the high concentrations of nitrates could make it difficult for wildlife to thrive. The creek segments are greyed out in areas where we lack adequate data to make an assessment.


Another way MBNEP staff determine creek health is by looking at the presence of benthic macroinvertebrates, bottom-dwelling animals visible to the naked eye that lack a backbone. Some of these insects are very sensitive to pollution, so finding them in a creek typically indicates good water quality.

MBNEP staff and volunteers regularly collect and test water samples at popular recreation sites throughout the bay to determine if bacteria levels are safe for swimming. From our monthly data at eight shoreline sites, bacteria levels are typically safe for swimming. However storm runoff can bring contaminants into the bay, so Surfrider and Heal the Bay recommend staying out of the water for 72 hours following a storm.

Clean water is also essential for aquaculture operations in the bay. Two commercial oyster farms, the Morro Bay Oyster Company and Grassy Bar Oyster Company, produce Pacific oysters for sale in restaurants and stores throughout our area and beyond.  

The Morro Bay Oyster Company is one of our bay’s commercial farms. The oyster farmers regularly monitor water quality to ensure that the waters are clean enough for safe consumption of the oysters that grow there. Wild native oysters have been making a comeback in the estuary after extreme decline due to disease and competition. In 2022, Cal Poly researchers found 458 wild oysters in the estuary, a great improvement from finding zero in 2009! Photo courtesy of Christa Ranee and the Morro Bay Oyster Company.

Wildlife: Protecting the Vulnerable  

We are fortunate that Morro Bay and its watershed provide lots of open space for wildlife. Changes in climate, loss of habitat, and other factors can pose a threat to vulnerable species. The Estuary Program and its partners conduct work to monitor steelhead and birds in the area.

Steelhead, pictured here in Santa Rosa Creek, migrate to their natal streams to spawn. Steelhead in our watershed face challenges from habitat loss and lack of stream flows. The Estuary Program has several ongoing projects related to steelhead, including managing invasive predators, monitoring water levels, and addressing barriers to seasonal migration.
The western snowy plover is a small shorebird that nests directly on the sand of some of our local beaches. Their nests are vulnerable to trampling, habitat loss, and predation. California State Parks manages their nesting areas to help protect this vulnerable species. Photo courtesy of California State Parks.

Habitat Health

The Estuary Program and its partners have worked to protect over 5,400 acres of habitat throughout the watershed. Thirty restoration projects have been completed, including floodplain and wetlands restoration, native plant reintroduction, and invasive species control. By protecting and restoring habitats, we work to ensure that the plants and animals in the area have the resources they need to better adapt to the challenges they face, including a changing climate.

Abundant Eelgrass  

Eelgrass is a flowering plant that puts down roots in our bay floor. Eelgrass is considered to be a valuable habitat type due to its ability to improve water quality, provide wildlife habitat, and sequester carbon. Our program has mapped eelgrass for two decades. The three maps above show eelgrass coverage in the estuary in 2007, 2017, and 2021. In response to the decline of eelgrass a dozen years ago, the Estuary Program and its partners conducted restoration efforts to help eelgrass remain viable in the bay. Our 2021 map indicated a full recovery of eelgrass, with 500 acres mapped.

To learn more about our many partners and volunteers that have made this work possible, visit our 2023 State of the Bay page on eelgrass. 

State of the Bay Events

The Estuary Program is hosting a wide variety of events this spring to share the results highlighted in our State of the Bay report. All events are free and open to the public. To learn more and to register, visit

Get Outside

April 22: Earth Day beach cleanup at Morro Rock and Baywood Pier. We will provide gloves, trash pickers, and bags. Register for the Morro Rock cleanup here, and the Baywood Park cleanup here.

April 29 & May 13: Nature journaling and hike. Staff from the Estuary Program and Creek Lands Conservation will lead a guided nature journaling workshop along with a short hike. Designed for all experience levels! Register for April 29 at Black Hill here & May 13 at Morro Rock here.

Learn More About the Science 

May 25: Science Explorations at the SLO Botanical Garden. Join us for an evening of scientific talks about research happening in the estuary and beyond. Register for free here.

For more information about these and other events, visit our events calendar.