Keeping Up With the Kelp

Under the sea, Sprague dives through massive, 80-foot-tall towers of kelp. When he looks up, he sees light shining through a canopy of kelp bunched on the water’s surface. Looking down, he sees fish, sponges, sea urchins, and other critters. Then he gets to work. First, Sprague lays out plastic tubes on the ocean floor to create 1-meter squares. Next he counts how many organisms are inside the square. He then moves the tubes and repeats this process in the new square. Finally, he estimates the density of the kelp and animals living in each column of water within the square meter. 

Gathering this data is important because the researchers will notice right away if the kelp or animals start dying. Sprague is like an underwater doctor, monitoring his patient. “It’s like a checkup,” he says.

In the early 1990s, the scientists found that the kelp forest ecosystem was struggling: The kelp was dying and fish were scarce. Overfishing of spiny lobsters and fish like the California sheephead led to a takeover by kelp-eating sea urchins. So in 2003, California created 13 protected marine areas around the Channel Islands to protect the kelp forest ecosystem, with no fishing allowed.

Since then, the Channel Islands’ kelp forests and many other species have started to recover. Sprague sees the comeback firsthand every dive. “That’s one of the most rewarding parts of the job,” he says.

Under the sea, Sprague dives through massive towers of kelp. Some are 80 feet tall. When he looks up, he sees light shining through bunches of kelp on the water’s surface. Looking down, he sees fish, sponges, sea urchins, and other critters. Then he gets to work. First, Sprague lays out plastic tubes on the ocean floor. He arranges them into a 1-meter square. Next he counts how many organisms are inside the square. He then moves the tubes to make a new square. He repeats the process. Finally, he tallies the organisms he found in each square meter. He uses this to estimate how many kelp and animals live in the column of water above the square.

Gathering this data is important. It means the researchers will notice right away if the kelp or animals in the area start dying. Sprague thinks of himself like an underwater doctor, monitoring his patient. “It’s like a checkup,” he says.

In the early 1990s, the scientists found that the kelp forest ecosystem was struggling. The kelp was dying and fish were becoming scarce. People had caught too many spiny lobsters and fish like the California sheephead. That allowed kelp-eating sea urchins to thrive. In 2003, California created 13 protected marine areas around the Channel Islands. Fishing isn’t allowed in these areas in order to protect the kelp forest ecosystem.

Since then, the Channel Islands’ kelp forests have started to recover. So have many species that live among the kelp. Sprague sees the comeback for himself on every dive. “That’s one of the most rewarding parts of the job,” he says.