The forest under the surface of Puget Sound is declining. This team seeks clues as to why

Heidi Wilken looks out from her crew’s small motorboat to the rocky shore of Owen Beach, watching as they float beyond a nearby fallen tree. At first glance, the greenish waters that surround the boat on this overcast morning may seem relatively empty – but as Wilken knows, a dive below the surface reveals a world of seaweed, invertebrates and fish.

Today, her work begins 30 feet underwater.

Wilken is the lead dive safety officer at Point Defiance Zoo & Aquarium, and this summer, she’s working with her team to complete their first kelp surveys at two new sites in Tacoma.

Kelp is a large brown seaweed that provides critical habitat for species like salmon and rockfish. Sometimes referred to as forests of the sea, kelp ecosystems play a key role in producing oxygen and increasing biodiversity. Across much of Puget Sound, they’re fighting to survive.

According to the Puget Sound Kelp Conservation and Recovery Plan, bull kelp forests in South Puget Sound have declined by 62% since 1870. A recent study from the Washington Department of Natural Resources indicates that South Puget Sound contains only 1% of the state’s kelp, with some sites seeing a total loss of the resource.

“The loss of it has impacts all the way from tiny little fingerling fish all the way up to orca, and so having those thriving and healthy ecosystems, it’s just so important for us,” Wilken said.

Point Defiance’s kelp survey, now in its second year, is part of a collaborative recovery effort outlined by the Puget Sound Kelp Conservation and Recovery Plan. The plan was prepared in 2020 by the Northwest Straits Commission, NOAA’s National Marine Fisheries Service, Puget Sound Restoration Fund, Washington State Department of Natural Resources and Marine Agronomics. It “provides a research and management framework for a coordinated and collaborative approach to protecting and restoring kelp forests of Puget Sound.”

Point Defiance’s kelp and rockfish surveys are funded through the Dr. Holly Reed Wildlife Conservation Fund, which comes from private donations and coin collections at the aquarium and zoo. This year’s $24,162 budget funds staff time, boat fuel, dive equipment and tools.

Last year, Point Defiance divers surveyed kelp at Foulweather Bluff on the Kitsap Peninsula. This year, they’re continuing their work at the bluff in August, but they’re also adding survey sites at Owen Beach and Titlow Beach, offering a unique opportunity to better understand kelp trends close to the Tacoma community.

Kelp surveys begin in the summer, when bull kelp, an annual variety of surface kelp, is at its peak.

At a given site, Wilken and her fellow divers will perform anywhere from four to 10 dives at deep and shallow depths, counting the kelp, fish and invertebrates (like sea snails and sea stars) that they see. To prepare, the divers suit up in wetsuits, masks and flippers, each carrying a 50- to 60-pound pack and oxygen tank along with an assortment of other tools, like a bright orange safety whistle, compass, cutting tool and giant tape measure called a transect.

“You start to feel a little like a Christmas tree down there with all these things attached to you and dangling,” Wilken said.

This year, bull kelp populations at Owen Beach and Titlow Beach appear to be healthy, said assistant dive safety officer Adam Schare, but that hasn’t always been the case. Just a few weeks ago, Schare saw hundreds of salmon fishing boats off the shore of Owen Beach. To him, those boats are one reminder of why protecting local kelp populations is so important.

“They wouldn’t be able to be successful in their catches if there’s no habitat for these fish to hide in,” Schare said. “So we’re seeing that the kelp is doing very well, but there’s always more to do.”

While monitoring efforts at Point Defiance are shedding light on local kelp populations, they’re also increasing researchers’ understanding of kelp conditions more broadly. Data collected by Point Defiance divers is added to a shared database with other partner agencies, helping to paint a clearer picture of trends around Puget Sound.

“You can imagine how big Puget Sound is,” said Jeff Whitty, Puget Sound Kelp Conservation and Recovery Plan project coordinator at the Northwest Straits Commission. “Having a SCUBA survey over the entire Sound is not going to be possible if you’re alone, but when you’ve got a big team with you, it’s manageable.”

Whitty said although research exists on kelp populations around Puget Sound, some areas don’t have enough data to identify trends. Much of the historical record is based on floating kelp species, while understory kelp, which isn’t visible above the water, has largely gone unaccounted for.

Thanks to coordinated kelp surveys, some of those gaps are now beginning to be filled. Whitty has seen a move in the right direction toward all of the Kelp Plan’s goals, but strides in monitoring and education have been especially noticeable.

“There’s been an amazing amount of progress in the last three years,” he said. “For just three years, it’s been mind-boggling how much they’ve accomplished.”

Like Whitty, Wilken recognizes the importance of teamwork when it comes to advancing kelp recovery. When she and her crew descend through the waters at Owen Beach, clipboards and grease pencils in hand, they play one small role in that mission.

“We are one piece of a really big collaboration and partnership,” Wilken said. “Whether it’s collecting the data or analyzing the data or trying to figure out how to grow kelp in a lab and plant kelp back out, they’re all pieces that are hopefully going to contribute to turning this around and seeing more kelp again.”