Sea Otter Recovery Prevents Century-Old California Kelp Forest Decline, Preserving Ecosystems [Study]

Sea otter recovery along the coast of California has been linked with the propagation of kelp forests in the waters of the Golden State. This is according to a new study led by the non-profit public aquarium Monterey Bay Aquarium in California. Researchers found that the recovery of the southern sea otter population prevented a century-old California kelp forest decline, which helped preserve ecosystems.

Kelp forests are mostly found along the west coast of North America and it consists of the large brown algae called "kelp" that can grow in dense groups like a forest on land, according to the National Ocean Service of the National Oceanic and Atmospheric Administration (NOAA). These algae live in relatively cool temperatures and shallow waters close to the shore, where sea otters can also be found.

The new research paper identified several environmental stressors, including extreme ocean warming, responsible for the destruction and retreat of California kelp forests, which also serve as ecosystems for marine animals. However, scientists have long confirmed that these underwater forests are vulnerable to climate change, whether driven by natural factors or human activities.

What is a Kelp Forest?

A kelp forest is a haven for a diversity of plants and animals, including birds and mammals such as seals, sea lions, whales, great blue herons, and shore birds, according to the National Ocean Service. As a natural food source and shelter for thousands of species, kelp forests can grow up to 18 inches per day and even tower above the ocean floor.

Although kelp forests serve as large, natural structures beneath the sea surface, they are susceptible to the impacts of the current climate crisis and rise of global sea temperatures caused by global warming. Due to this vulnerability, kelp forests such as those off the coast of California have witness significant decline since the early 1900s.

California Kelp Forest Decline

In the new study published in the journal PLOS Climate on January 18, scientists from the Monterey Bay Aquarium observed significant California kelp forest decline or regional kelp canopy changes from 1910 to 2016. As an exception, the central coast saw a significant increase in kelp forest canopy since it is the only region of California where southern sea otters survived after being hunted nearly to the brink of extinction for their fur in the 1800s.

Now, the researchers confirmed in their study that kelp forests can even more endure climate change in areas where sea otters have reoccupied the California coastline over the past century. In general, sea otter recovery has contributed in preventing the century-old California kelp forest decline. The findings are important since it can guide conservation efforts and policies towards the protection of kelp forests.

Furthermore, the Monterey Bay Aquarium study also sheds light to the possibility that the environmental repercussions for California kelp forests are also the same for other areas where these underwater towers grow across the Eastern Pacific Coast.