Citizen divers aid understanding of fish in the Salish sea

Hundreds of fish species live in the Salish Sea, and many face a number of threats. Monitoring the health of these fish populations is crucial. But with nearly 5,000 miles of coastline and more than 400 islands, it’s no small task. 

Historically, monitoring fish populations has included fishery catch data, active trawl surveys, underwater video, satellite imagery, hydroacoustics and more. But citizen scientists are increasingly playing crucial roles, according to a study from the University of California, Davis.

The study, published in the journal Environmental Monitoring and Assessment, revealed that in just over two decades, volunteers with Reef Environmental Education Foundation (REEF)’s Volunteer Fish Survey Project helped monitor more than half of the total fish species known to occur in the Salish Sea.

The study found that the project’s surveyors also expanded the known range of multiple species within the ecosystem and documented the presence of a fish species not previously known to occur in the Salish Sea — the striped kelpfish (Gibbonsia metzi). This brings the total number of fish species known to use the Salish Sea to 261.

The research was led by SeaDoc Society, a program of the Karen C. Drayer Wildlife Health Center at the UC Davis School of Veterinary Medicine. SeaDoc has partnered with REEF for almost two decades to help train volunteer divers in the Pacific Northwest.

Citizen scientists survey Salish Sea

REEF is a marine conservation organization with a worldwide network of recreational divers and snorkelers who provide data to better understand status, trends, and distribution patterns of marine fishes and selected invertebrates and algae in oceans around the world. REEF citizen scientists have been surveying the Salish Sea since 1998. The region encompasses Puget Sound, the San Juan Islands and the waters off of Vancouver, British Columbia.

The study was also informed by a list of species published by fisheries biologists Theodore Pietsch and James Orr.

“I had so much fun exploring the REEF database and published compilation of Salish Sea fishes,” said lead author Elizabeth Ashley, a UC Davis research assistant with SeaDoc Society. “This study highlights that the incredible biodiversity of the Salish Sea merits the use of a diverse set of tools, wielded by both professional and citizen scientists, to fully understand and protect these fishes.”

Ashley and her co-authors compared data from 13,000 REEF surveys collected from about 800 sites in the Salish Sea over 21 years (1998-2019). Volunteers observed 138 of 261 recognized fish species in the Salish Sea and expanded the range of 18 species, meaning they were spotted in an area where they previously had not been documented to exist. 

Not all fish species have an equal chance of being spotted by a scuba diver. Some might live hundreds of feet deep, expertly hide themselves, or only rarely venture into the Salish Sea. The authors took this into account and categorized each fish based on its potential for encounter by a diver.

REEF divers sighted 85% of fish species that lend themselves to visual observation. For these fishes, experienced citizen scientists can expand what scientists know about range, life history, population status, size, age, behavior, and more. 

Citizen science monitoring is only minimally invasive since it relies purely on human observation. Trained divers can document what they see and enter it into the free international database housed at www.REEF.org.

“It’s exciting to see that the expertise within our community of citizen scientists has expanded what is known about fish assemblages of the Salish Sea and yielded a new discovery,” said co-author Christy Pattengill-Semmens, REEF's co-executive director. “Beyond providing much-needed data that can be used by researchers and management agencies, participating in citizen science programs like REEF’s Volunteer Fish Survey Project creates an authentic connection to nature and empowers participants to make a difference.”