Recent accomplishments of CDFW's scientific community
Banded black brant feeding on eelgrass
Volunteer John Roser in the field at Morro Bay
Flock of black brant in flight above Morro Bay
Black brant in Morro Bay
John Roser began hearing the stories shortly after he moved to Los Osos, San Luis Obispo County, on the shores of Morro Bay in the mid-1990s.
Longtime birders, waterfowl hunters, biologists and other coastal residents were all saying the same thing: It seemed fewer black brant were showing up on the bay each winter.
The coastal sea goose is a cultural icon of the area, the signature species of the Morro Bay Winter Bird Festival and a temporary visitor welcomed by locals as the geese arrive each fall from their summer breeding grounds in the Arctic. When the geese are present in big numbers, you can hear their cacophony almost anywhere on the bay from November through April or until the warm environs of Baja California lure the birds farther south on their migration.
Roser, who holds a degree in biology from Cal Poly San Luis Obispo and spent 25 years as an environmental educator, set out to see if the old-timers’ stories were true. For the past 21 years, he has provided CDFW and brant biologists throughout the Pacific Flyway with their most credible and reliable source of data on wintering brant in Morro Bay.<
“I’m retired, and I wanted to take on a volunteer project that would make a difference in this community,” Roser said of his motivation. “I wanted to create a Morro Bay specific data set significant enough that it would be valuable in brant studies and research across the Pacific Flyway.”
Roser’s retirement project has led him on a brant-like odyssey.
He banded brant one summer in Alaska, worked in Humboldt Bay with leading brant researcher Jeff Black and his Humboldt State University graduate students, and traveled to Baja California to help biologists read bands on birds at the extreme end of their southern range. Much of Roser’s winter observations take place at CDFW’s Morro Bay Wildlife Area.
“John is our go-to guy on the ground in Morro Bay for sure,” said Melanie Weaver, the head of CDFW’s Waterfowl Program. “We only have two employees in our program, myself included, so we depend on regional staff and volunteers like John to help compile survey data. John is part of the local community, he cares, and he is close to the resource.”
The data Roser supplies are incorporated into CDFW’s Mid-winter Waterfowl Survey, which is used to set hunting regulations for the following waterfowl season.
What attracts brant to Morro Bay is the same thing that prompts the birds to stop at other coastal bays along their southward migration: eelgrass. The underwater seagrass grows in shallow marine environments and is the birds’ primary food source.
Roser’s initial research in 1997 confirmed the reports he was hearing: The wintering brant population in Morro Bay had declined significantly and corresponded with a crash in eelgrass acreage in the bay.
While CDFW surveys from the 1930s through 1960s documented Morro Bay’s wintering brant population as high as 11,800 birds, Roser’s first survey in 1997 recorded a population high of fewer than 700 birds.
The eelgrass crash in the mid-1990s was temporary and well-understood, caused by an influx of sediment from a fire-ravaged landscape, a deluge of freshwater from a rainy year and warming El Nino ocean conditions. As environmental conditions normalized in subsequent years, the eelgrass rebounded, and the brant returned. Roser counted a population high of 4,600 birds in Morro Bay in 2001.
The story since then, as told in Roser’s annual reports to CDFW, is of another dramatic crash in eelgrass acreage in Morro Bay and a corresponding drop in the numbers of brant wintering there. Unlike the eelgrass crash of the mid-1990s, the latest decline has been more persistent and perplexing.
Biologists measure Morro Bay’s eelgrass acreage each year. Eelgrass spanned 344 acres as recently as 2007 but had dwindled to just 14 acres by 2017. Not surprisingly, Roser’s 2016-17 brant survey recorded a population high of just 319 birds and a low of 43. Roser’s brant-use-day metric has fallen by 90 percent since the nearly 500,000 brant use days he recorded in 2001. In the past five years, brant use days have measured around 50,000 a year. Money from the purchase of the California duck stamp-validation, required to hunt waterfowl in California, is funding research into the eelgrass decline along with restoration efforts.
In addition to fewer numbers of brant frequenting Morro Bay, Roser has noticed behavioral changes in the birds that still show up. Increasingly, the brant are foraging on secondary food sources that include salt marsh vegetation and green algae species such as sea lettuce with eelgrass in short supply.
Roser takes some solace that the overall Pacific Flyway brant population is holding steady if not increasing, estimated between 130,000 to 165,000 birds. Roser says waterfowl biologists are seeing flyway-wide changes in brant behavior that they suspect may be linked to climate change.
Fewer brant are migrating to Mexico for the winter. More are remaining in Alaska and their northern range throughout the year as warming Arctic conditions require fewer calorie demands and less ice exposes more eelgrass. Ten years ago, less than 10 percent of the population wintered in Alaska. By 2017, almost 40 percent of the Pacific Flyway population spent the winter there.
“This bird is tied to Morro Bay, our culture and our identity,” Roser said. “A robust wintering brant population needs abundant eelgrass beds. Eelgrass needs a healthy bay and watershed. Our actions as stewards of Morro Bay really do reverberate across the globe.”
CDFW photos: courtesy of John Roser
Top photo: Pair of black brant on Morro Bay
Beneath the waters off the California coast are vast forests that are home to an astounding variety of animals. Their sunlit canopies can soar 150 feet from the ocean’s floor. But instead of trees, these forests are made of kelp.
Worldwide, kelp is used in a host of everyday products like toothpaste, pudding, ice cream and even pharmaceuticals. Although kelp is valuable to humans, it is critical to sustaining life for many ocean-dwelling wildlife species ranging from microscopic plankton to sea otters, pelagic birds and predatory fishes. When a kelp forest is depleted, the entire underwater ecosystem can be thrown out of balance. This is why CDFW scientists are tracking and studying the amount of kelp growing in coastal waters.
In 1989, CDFW marine biologists began using aerial surveys to monitor the size of the kelp forests off of California’s coast. A second survey was conducted a decade later, and since 2002, CDFW has made an effort to conduct these surveys annually (although budget issues sometimes require skipping a year).
The surveys are conducted along the entire coastline and offshore of the Channel Islands. CDFW conducted the earliest surveys on its own, but now contracts out for this work. The contractor uses an aircraft with a specialized camera system that picks up the infrared image of the kelp. Those images become Geographic Information System (GIS) shapefiles that capture a snapshot of what the kelp canopy looks like on a given day. The images enable the viewer to see and compare the spatial area of a specific kelp forest over time.
A graph depicting CDFW’s historic aerial kelp survey data is located on the Kelp and Other Marine Algae webpage.
CDFW’s most recent (2016) kelp survey includes the following findings:
Rebecca Flores Miller, a marine environmental scientist with CDFW’s Marine Region office in Monterey, was the coordinator for the 2016 kelp survey.
“Kelp does fluctuate normally, anyway … there is a seasonality with it,” she explains. “However, during El Nino and warm water conditions as we’ve had in the recent past, the canopy doesn’t grow as well.”
Coastal development can also negatively affect the kelp canopy, as it sometimes leads to pollution, increased turbidity (which reduces the light needed for photosynthesis) and siltation (which can hinder growth or bury young kelp). An increase in urchin populations can also have a dramatic impact on kelp, and recently, a wasting disease decreased the numbers of sea stars (a predator of urchins) statewide.
“All of these things are connected within the ecosystem,” Flores Miller says.
Kelp survey data is available to anyone who is interested – members of the general public, other governmental agencies, universities and researchers.
The dataset has many uses, both within and outside of CDFW. It is used during the review process for commercial kelp bed lease requests. It has been a critical piece of the Marine Protected Area planning process. It has been used to help predict the abundance of many kelp forest-dependent species valued by humans, such as abalone. And it has helped scientists understand issues such as the recent abalone die-off in northern California.
CDFW Photos: giant kelp and bull kelp (by Rebecca Flores Miller), and image of kelp forest near Cambria taken during the 2016 aerial kelp survey.
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