Encyclopedia of Puget Sound

Underwater monitoring of kelp forests

Puget Sound Restoration Fund has launched a network to track declining kelp populations in the Salish Sea. The three-year initiative aims to support and standardize underwater monitoring to improve kelp conservation in the region.

: Underwater view of a person in scuba diving gear holding a clipboard and grasping a stalk of brown kelp.
A diver records kelp growth. Photo: Kate Vylet (CC BY 2.0) https://flic.kr/p/2kfey4j

Underwater kelp monitoring gathers different data than aerial and surface kelp monitoring, according to the non-profit Puget Sound Restoration Fund (PSRF) which started the initiative last spring in partnership with Marauder Robotics, The Bay Foundation and Reef Check Foundation. Surface monitoring can tell scientists about the kelp canopy and the size of the beds, the partners say, but it cannot tell them about the understory, the invertebrates that live at the bottom of kelp forests, or details about the water column. 

In addition to dive monitoring led by Reef Check, the network will use automated underwater vehicles to collect continuous data at core sites beginning within the next two years.

The current project focuses on kelp within the Puget Sound region but its sponsors hope that the network can be expanded in the future to include the entire Salish Sea coast and organizations operating in British Columbia. Funding for the project comes from the Paul G. Allen Family Foundation. 

Many species of kelp are declining worldwide, partially due to warming waters associated with climate change. South Puget Sound has lost 80% of its bull kelp over the last 50 years, and kelp forests have declined by 36% in the San Juan Islands since 2010, according to PSRF's website. 

This article was based on findings presented at the 2022 Salish Sea Ecosystem Conference.