Part 2: Diving in Neah Bay: surveying the rocky reef ecosystem

Join Dr. Shawn Larson, curator of conservation research at the Seattle Aquarium, as she shares the latest on one of our many field research efforts in this special two-part guest post.

August 2019
Day 2: August 23

The next day we woke up bright and early. The marina was about a 40-minute drive from where we were staying in Sekiu, and we wanted to be on the water by 8am to see how the currents were running compared to the printed predictions. It turned out they were about two hours off, so we waited until 10am. Once the current seemed to slow down as viewed from the surface, we sent two divers down to Site 4, which was the only site with a starting block on the west side of the reef (toward the Strait of Juan de Fuca), thus making it easier to dive in the sheltered part of the current on a strong ebb tide.

They found the block almost immediately, and even though the water was still moving, it was workable and they were able to conduct two full transects. The second dive team immediately rolled in after the first team, and they experienced almost no current at all. Now that we had found the magic time when the water wasn’t moving that much for a little while, we motored quickly over to Site 1 and sent in two teams back-to-back to collect the four transects from that site. Day two worked out very well for us with two site surveys—and we even saw a mature big skate swim through our transect at Site 1!

 

Big skate swimming underwater
Big skate at Site 1.

 

Day 3: August 24

The last day, we repeated the same pattern as the day before, and once the water slowed we rolled divers in to pick up Sites 2 and 3. We were successful, and the visibility was better than it had been the previous day. We even saw the specific yelloweye rockfish (Sebastes ruberrimus) at Site 2 that we’ve been documenting since its birth five years ago. We have watched this fish, a member of a species classified as “threatened” under the Endangered Species Act, since it was about one inch long (its first year of life). Over the years it has stayed in the same three-foot-square (one-meter-square) area near the same boulder and has added about an inch of growth every year; it now approaches six inches long. These fish are slow growing and long lived (known to live to a maximum age of 118 years) and thus vulnerable to overfishing, which is why we think they remain threatened. It’s nice to see this fish every year and watch it grow.

At the end of the day we went back to Site 5 and had our divers finish the last surveys at that site. The trip was complete, and it was a very successful one.

 

Rockfish swimming among kelp and rocks.
Yelloweye rockfish at Site 2.

 

The goals of these surveys are to document changes in fish diversity and density over time as well as to document shifts in species or fish assemblages. But we also can document individuals as well as invertebrates and habitat quality, such as percentage of kelp cover. The surveys in Neah Bay started in 2005, with Site 5 added in 2010. We then added nine additional survey sites in Puget Sound starting in 2009, with one or two added each year until 2013. This broader sampling allows us to compare what’s happening in these reef systems in the Strait of Juan de Fuca (adjacent to the open ocean) with what’s happening in Puget Sound, which helps us see if there are correlations and connections. The data we gather has been used to inform rockfish abundance in these areas by the Washington State Department of Fish and Wildlife as well as by the National Oceanic and Atmospheric Association. The data gained is critical to the management of these reef systems.

Did you know that our Window on Washington Waters exhibit was built to resemble a Neah Bay habitat? Come check it out—and learn more about rockfish and other fascinating animals that live in our local waters—during your next visit to the Aquarium!

 

Research vessel on dry land.
The Aquarium’s research boat.

 

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