After being hunted to near extinction in the 19th century, sea otters from southeast Alaska to central California have made a remarkable recovery. But it’s one that is causing anxiety for those who make their living harvesting sea otters’ prey, including Dungeness crabs. While it has long been assumed that a steadily increasing population of sea otters would lead to lower crab catches, a new study shows that—in California at least—that’s just not the case.

Instead, says Andre Boustany, the lead author of the new study and a fisheries scientist with the Monterey Bay Aquarium in California, Dungeness crab landings have actually been increasing in areas that have sea otters. “It doesn’t seem like they have a measurable impact on crab populations.”

The study assessed commercial Dungeness crab landings in California ports from 1980 to 2018, breaking out three regions with sea otters: Half Moon Bay, Monterey Bay, and Morro Bay. Boustany says that despite the presence of sea otters, Dungeness crab populations are increasing in those areas because of improving environmental conditions that are more favorable to larval crabs. Similarly, he says, the decreasing Dungeness crab harvest in Northern California ports, where there are no sea otters, is likely due to climate change and higher levels of ocean acidification.

While sea otters are ravenous eaters—every day they consume around 25 to 30 percent of their body weight—Dungeness crab is not exactly their favorite food. Based on observing 117 otters conduct 57,186 feeding dives, the scientists found that Dungeness crab makes up as little as 1.6 percent of a sea otter’s diet on average.

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In the June 23, 2019 travel section of the San Francisco Chronicle I took readers from tide pools to rocky reefs 30 feet below the ocean surface to show how they can witness the effects of climate change on the Northern California coast. For the first article I followed world-class free diver and spearfisherman Greg Fonts underwater to see how sub-tidal ecosystems have changed after kelp forests shrunk by 90 percent in less than a decade. In the second, I explored tide pools off Bodega Bay with UC Davis marine ecologist Eric Sanford to observe intertidal creatures who have moved north to the Sonoma Coast as the ocean has warmed.

Also in the section, I profiled the Monterey Bay Aquarium’s top diver George Z. Peterson and got his top-five scuba diving spots in California. If these stories interest you then check out my article on abalone diving I wrote while a staff writer at The Press Democrat in 2017.

Without abalone, spearfishing hooks North Coast anglers
On a cool, overcast day in May, spearfisherman Greg Fonts floats facedown on the surface of the Pacific Ocean 300 yards off the coast of Fort Bragg, rocking in the swell in a thick wetsuit. A small dive flashlight dangles from his right wrist. His left hand holds a long speargun, an arrow-tipped steel bolt locked in place along the stock with thick rubber tubing.

Through his dive mask, Fonts spots a school of blue rockfish swimming over the rocky reef 20 feet below — a good sign that lingcod may be nearby. With large fang-like teeth, lingcod are marine predators prized for their large fillets of mild, flakey meat. After a deep inhale, Fonts removes his snorkel and duck-dives. With a few kicks of his long flippers, he descends to the reef. Read more…

How is climate change affecting oceans? Check the tide pools
On a sunny afternoon in mid-April, Professor Eric Sanford crouched in a tide pool off Bodega Bay and turned over algae-covered rocks in search of a chocolate porcelain crab, a dime-size crustacean with blue speckles.

The creature has been spotted in small numbers around Bodega Bay for decades. But five years ago a severe marine heat wave, dubbed “the blob,” caused a sharp increase in its numbers north of the Golden Gate, says Sanford, a marine ecologist who researches climate change and coastal ecosystems at UC Davis’ Bodega Marine Lab. Read more…

5 best scuba diving spots in California, from Monterey Bay Aquarium’s dive director
George Z. Peterson’s job as director of dive programs at the Monterey Bay Aquarium is — in his words — quite simple: “I’m there to get people stoked on the ocean.” No day is the same, says the 49-year-old Peterson, who has worked at the aquarium since 2003. He has brought more than 41,000 kids underwater through the aquarium’s youth dive program, keeps the glass of the massive tanks clean and sea creatures fed with help of more than 100 volunteer divers, and coordinates dives and safety procedures for the aquarium’s 50-plus scientists and research staff who dive for their work. Read more…