Science Spotlight

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:

• The south coast mainland and the Channel Islands both experienced a reduction in kelp when compared to 2015 levels. The south coast mainland had almost half the canopy level surveyed the previous year.
• Along the central coast, kelp canopy levels were almost double that seen the previous year.
• North central canopy levels, while still low, were just over five times the 2015 survey levels.
• The north coast canopy levels were just over twice the 2015 measured canopy levels – but are still below the normal range for this area.

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.

Fate has not been kind to the San Joaquin kit fox (Vulpes macrotis mutica).

Shrinking habitat caused by urbanization and agricultural expansion landed this Central Valley native on the federal Endangered Species List decades ago. California’s total population of San Joaquin kit foxes may now be down to a few thousand animals. To make matters worse, its favorite food, the kangaroo rat, is likewise endangered as the desert habitat it prefers continues to disappear.

Wildlife biologists took heart, however, in a population that seemed to be thriving within the city limits of Bakersfield. Unlike San Joaquin kit fox populations in other parts of the Central Valley range, the Bakersfield foxes adapted quite nicely to urban life. Their number – estimated between 200 and 400 animals – has evidently seemed to be holding steady and possibly increasing.

Their cute and cuddly appearance make them popular with city residents. Earlier research showed the population was healthy and genetically robust. Wildlife biologists were counting on those urban foxes to ensure the species’ survival should kit fox populations completely collapse elsewhere.

Today, those Bakersfield kit foxes are under siege, suffering from an outbreak of highly infectious sarcoptic mange. Mange – a skin condition caused by parasitic mites -- leads to hair loss, open wounds from scratching and, ultimately, death. The first case was detected among the kit fox population in March 2013, and since then, more than 200 cases have been documented. The epidemic has grown worse every year.

Given the importance of the Bakersfield population, CDFW, the U.S. Fish and Wildlife Service, the California State University, Stanislaus, the University of California, Davis (UCD), and various nonprofit wildlife groups have all joined forces to combat the mange.

Jaime Rudd, an environmental scientist in CDFW’s Wildlife Investigations Lab in Sacramento, is leading CDFW’s efforts while simultaneously writing her UCD Ph.D. dissertation on the outbreak. Rudd is researching ways to prevent mange from spreading to healthy animals, and assisting Stanislaus State’s Endangered Species Recovery Program with trapping and treating diseased foxes.

Severely diseased kit foxes are trapped and transported to the California Living Museum, a Bakersfield wildlife rehabilitation facility and zoo. There, the kit foxes are hospitalized, given life-saving antibiotics and fluids and treated with a topical pet product that kills the mites. The foxes often need months of treatment before they are healthy enough to release. And although the intervention saves individual lives, the process is costly and time-consuming – and doesn’t prevent the treated fox from getting mange a second or third time.

Rudd is making good use of her undergraduate degree in molecular biology, analyzing the DNA of the mites to see if they might be related to those in dogs and coyotes, which could be spreading the mange to the foxes.

“Essentially, we want to look at their molecular signature to see if these mites are related,” Rudd said.

Rudd is studying a group of wild kit foxes living on the CSU Bakersfield campus, which no doubt are supplementing their diet with burger bits and pizza crusts discarded by college students. Rudd is monitoring the group with trail cameras, outfitting some foxes with radio tracking collars and others with the type of preventative flea and tick collar you might use on a pet dog or cat.

“We want to evaluate the efficacy of these collars,” she said. “If they’re only going to work for two months, the collars won’t help us slow down the spread of mange, so is it really worth the effort of putting them on? But if they’re going to work for five months or more, then it might be worth the effort.”

If there is any hope sustaining Rudd and her colleagues in this important, though often disheartening, work, it’s this: “The fact we are not seeing mange in the outlying populations is cause for optimism,” she said. “If nothing else, we can at least try to keep it from leaving the city.”

The Pacific herring – much like squid and anchovy – is an important forage fish that supports a commercial fishery and provides a prey source for all manner of fish and wildlife, including whales, seals, sea lions, sturgeon, salmon, pelicans and numerous other species of birds and invertebrates.

The largest population of Pacific herring in California spawn in San Francisco Bay, and since 1972, CDFW has been responsible for monitoring and managing their numbers. CDFW uses annual vegetation dive surveys and spawn (herring eggs) surveys to calculate a population estimate each year. CDFW also uses commercial fishery and mid-water trawl survey information to look at the composition and general condition of the spawning population.

CDFW has just completed and posted online the 2016-17 San Francisco Bay Season Summary for the Pacific herring fishery. The good news is that the spawning population, estimated at 18,300 tons, is up slightly from the 2014-15 and 2015-16 seasons. But it is still far below the historical average of 49,400 tons. Less than ideal ocean conditions are cited for the below-average numbers.

CDFW closely regulates the commercial Pacific herring fishery in the San Francisco Bay, setting quotas, season dates and using the commercial catch data to help further analyze the size, age and condition of the spawning population. Typically about six inches long, the fish primarily are harvested for their roe, which is prized in Japan. CDFW maintains a blog on the species called the Pacific Herring Management News.

This summer marked the end of an incredible journey for four dozen of California’s designated state freshwater fish, the golden trout, as they returned home after 10 months away. The fish traveled more than 500 miles in tanks and buckets, by hand and by mule, en route to their native waters 9,000 feet up in the Sierra Nevada range.

The journey began last fall after CDFW scientists observed that ongoing drought conditions were severely impacting the rare trout’s mountainous habitat. A decision was made to rescue 52 fish – a representative population that could repopulate the stream and save the species if drought conditions worsened.

Golden trout are one of California’s most iconic trout species. They are native to only two stream systems in the southeast Sierra Nevada – Golden Trout Creek, and the South Fork Kern River in Tulare County. Volcanic Creek, which is home to the rescued fish, connects with Golden Trout Creek during runoff and high-water level years.

The journey began in September 2016, when fisheries biologists made the two-day trek into the mountains to gather the trout. The captured fish were transported to the American River Trout Hatchery near Sacramento, where technicians monitored them, often around the clock. After nine months at the hatchery, the fish were ready to start the long trek back to their home waters. Crew members transferred the fish from the hatchery to a fish tanker truck and hauled them more than seven hours overnight to the trailhead at an elevation of 10,000 feet in the southern Sierra.

The crew met up with a CDFW team that would escort the fish on horseback, 16 miles into the Inyo National Forest. Federal laws forbids motorized vehicles on wilderness land, which left the team no option but to transport the fish by mule train in fish cans.

The operation took tremendous teamwork from multiple divisions in CDFW and the National Forest Service. Ultimately, the CDFW team successfully returned 48 fish to their natural element. Four died in captivity over the winter. CDFW officials consider that a normal mortality rate. Scientists remain optimistic that these iconic fish will continue to thrive and perhaps even be on-track for a brighter future.

See related VIDEO.

California’s coastal waters are home to seven species of abalone, and all but one are endangered or listed as species of special concern. The white abalone in particular has been nearly decimated by overfishing and disease, and scientists can find no evidence that the remaining population is reproducing in the wild. In order to avoid loss of the entire species, CDFW and partner agencies have formed the White Abalone Recovery Consortium, which will employ captive rearing and restoration stocking efforts and extensive public outreach in order to save these animals from extinction. It will be an ongoing, long-term project, but all signs point to future success – already there are more white abalone thriving in the captive breeding program than the entire population living in the wild.

Read more about the efforts to restore California’s white abalone – and learn what you can do to help! – on the CDFW Marine Management News Blog.