'I initially didn't want to have anything to do with them, to tell you the truth'

Brent Hughes, an assistant professor of marine ecology and conservation at Sonoma State University, is a self-proclaimed "algal nerd." But last week, while speaking at a Garden Club of America event, he wasn't just talking gardens or algae -- he was talking otters.

Hughes' dive into studying otters was accidental. While studying eelgrass at San Jose State University's Moss Landing Marine Laboratories around 2008, he noticed the marine plant was actually starting to recover amid a large, normally destructive algal bloom.

"It was bizarre," Hughes told SFGATE over the phone after the Garden Club of America meeting. "We didn't immediately go, 'Oh, it must be the sea otters.' That was literally the last thing [we considered]."

He tried to find an explanation -- El Niño, seasonal temperature fluctuations -- yet there was nothing to account for the abnormality. The "a-ha" moment finally took place when he got hold of a data set from a tour operator at Elkhorn Slough Safari, which operates out of Moss Landing.

"Capt. Yohn was giving all the tourists on the boat little hand counters, you know, the clickers?" said Hughes. He instructed passengers to click every time they saw a sea otter, so they could later compare who saw the most. "He was doing this almost every day, sometimes several times a day, for 15 years, and he was actually recording the data."

Hughes had been on the brink of giving up on his eelgrass study and had no idea he was about to make a startling discovery when he overlaid the sea otter data with the area where the marine plant had recovered.

"They kind of followed each other in time, and it was almost like the two time series fit together like a glove," said Hughes, recognizing that the creatures were somehow positively impacting the underwater meadows. After that, he knew he had to keep following the furry carnivores.

"It was totally by accident and serendipity," he said. "I'm a little bit different from most sea otter biologists or ecologists because most people want to study sea otters, but I initially didn't want to have anything to do with them, to tell you the truth."

The discovery led Hughes and his team to start a study in 2013 about the salt marsh at Elkhorn Slough and the sea otters' impact on it, which was finally published this year in the February issue of the journal Nature.

Now, his focus is decidedly more esoteric: "I basically study sea otters where they don't currently exist."

North of San Francisco, people don't see sea otters in the wild often. They do show up once in a while -- usually juvenile males swimming up from Monterey -- but functionally, they don't reside here. So Hughes, along with a number of other scientists, agencies and nonprofit organizations, has been studying San Francisco Bay and other estuaries surrounding Point Reyes National Seashore.

"We're asking the question, 'Well, would this be good for sea otters?' And then if so, what would be the impact of the sea otter potentially returning here?" he said. Hughes and his team published a paper in 2019 in the journal PeerJ that shared a model predicting that San Francisco Bay could currently support about 6,600 sea otters. While the number seems exciting, it pales in comparison to the estimated tens of thousands of sea otters the region once had.

Hughes' other recent studies have focused on the risks facing the sea otter in San Francisco Bay -- and there are plenty. Between boat traffic and contamination, it'd be a very treacherous place for sea otters to reside. The possibility of a habitat farther north offers more hope.

While smaller, Drake's Estero in Marin County has almost no human traffic at all and could support a couple hundred otters, according to Hughes, which might be a good enough place to test whether a population up here would eventually expand. Drakes Estero also has another special feature of interest.

"It's just loaded with crab," said Hughes.

Sea otters love to eat crabs, particularly European green crabs, which are notorious marine invaders. European green crabs arrived in San Francisco Bay in the late 1980s and have now spread all the way up to Alaska. But it turns out that sea otters, who are voracious eaters that can eat a quarter of their body weight in a day, are really good at gobbling up these crabs.

In Moss Landing, the crabs have a favorite treat -- eelgrass sea hares, slug-like creatures that lick grasses clean of the microscopic algae coating their blades, allowing more sunlight to hit the plants. According to PBS, scientists believe that the symbiotic arrangement between eelgrass sea hares and eelgrass is no accident, and that the two species evolved together over millions of years.

When seagrasses flourish, amazing things happen. These marine pastures help control erosion and sequester carbon at remarkable rates -- in fact, they are among the most powerful carbon sinks in the world. (According to ClientEarth, "A carbon sink is anything that absorbs more carbon from the atmosphere than it releases.")

Hughes' research challenges old paradigms and shows that predators may be good for restoration, though he admits that the sea otters would variously impact whatever region they landed in. One of the biggest issues for Northern California reintroduction efforts would be their effects on crab fisheries and abalone.

Monterey once had an important recreational fishery for the iridescent mollusks, primarily red abalone, that was closed in 2017 due to dwindling populations. Today, shellfish divers are among the groups concerned about what the sea otters would do if they were to return.

"Sea otters will likely do great things for habitats. ... It might reduce this invasion, but there could be these other consequences," Hughes said. He highlights a unique aspect of the reintroduction process that could help account for these concerns -- a substantial amount of stakeholder involvement.

Back in 2021, Congress mandated a review of the sea otter reintroduction effort, and the U.S. Fish and Wildlife Service -- which is running the show -- must develop a cost and feasibility report, exploring the possibility of moving otters up to Northern California.

"They're not making any rash decisions and they're not trying to overstep the fishermen," Hughes said, adding that the process involves a lot of tribal input, as well.

"Hopefully, a decision will be made that, hopefully, everybody can agree to," Hughes said. "That's a really hard thing to do, but we'll see."