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Sea Otters Are Reintroduced to Monterey Bay, Central California Coast, After Sea Star Wasting Syndrome in 2013 Allowed Urchins to Devastate Kelp Forests. Between 2014 and 2020, the Area Decreased by 51% and, in Some Areas, Disappeared by 95%. The Plan Is Controversial, Considered a Last Resort.
The Sea Otters are being returned to the ocean in Monterey Bay, California, after between 2014 and 2020 the area of giant kelp forests decreased by an average of 51% and, in parts of the northern coastline, over 95% of these forests disappeared.
The crisis accelerated after 2013, when the sea star wasting syndrome spread and killed millions of sea stars, including the sunflower sea star, which kept the sea urchins in check. With the imbalance, the urchins exploded and California was forced to bet on the return of Sea Otters, in a decision that divides opinions.
Monterey Bay and the Kelp Forests That Sustain the Coast
Monterey Bay is located on the central California coast, where cold waters and nutrient-rich currents create one of the most productive marine ecosystems in the United States.
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In this scenario, the kelp forests function as “green cathedrals” of the Pacific: formed by the largest brown algae in the world, they can reach up to 60 meters and create a three-dimensional habitat that shelters hundreds of species.
In addition to supporting life, these forests help weaken waves and currents, reducing erosion and protecting the coastline.
They also filter seawater and play a significant role in the carbon cycle, capturing CO2 at rates that can exceed many terrestrial forest ecosystems.
The Collapse in a Few Years and the Warning from the Numbers
In recent years, what was once considered a resilient system has collapsed at an accelerated pace.
According to the National Oceanic and Atmospheric Administration and Atmospheric Administration cited in the material, between 2014 and 2020 the area of giant kelp forests in Monterey Bay fell by an average of 51%.
In many regions along the northern California coastline, over 95% of the kelp forests have completely disappeared, leaving behind rocky and exposed seabeds.
What draws attention is not just the scale, but the speed, described as a rupture that occurred in just a few years.
The Sea Star Disease and the Domino Effect That Opened the Way for Urchins
The text points to a central trigger: in 2013, a disease known as sea star wasting syndrome spread along the Pacific coast of North America, causing mass deaths in a short period.
Scientists from the Monterey Bay Aquarium report that millions of sea stars disappeared, including the sunflower sea star, a keystone species in the ecosystem.
Before the outbreak, these sea stars acted as ecological guardians, keeping sea urchin populations in check.
When this crucial link vanished, the system that seemed stable for decades lost its brakes, and the urchins went from common herbivores to a destructive force on the seafloor.
Urchins Explode and Turn Forests into “Barren” Land
Without sufficient natural predators, the urchins multiplied unchecked. In parts of Monterey Bay, the density may have exceeded 100 individuals per 10 square feet, reaching levels up to 60 times higher than normal in some areas.
With jaws and feeding behavior focused on the base of the algae, the urchins gnawed at the attachment structures that anchor the kelp to the rocks, toppling entire forests and creating barren areas where young kelp can no longer establish.
It was this explosion of urchins that pushed California towards the return of the Sea Otters.
Human Actions and the “Century of Errors” That Fragilized the System
The basis states that the devastation is not only a result of the disease.
It would have been exacerbated by accumulated errors over the centuries: large-scale fishing would have reduced species that feed on urchins, such as rockfish and cod, while Sea Otters were hunted nearly to extinction for their fur.
With these layers of natural control dismantled, the ecosystem would have persisted for decades in a “false equilibrium.”
When the sea star disease struck, the shock exposed the fragility and accelerated the collapse of the kelp forests.
Why Sea Otters Enter as a “Mechanism” of Self-Regulation
In coastal ecosystems, Sea Otters are described as the most effective natural predators of sea urchins.
They dive, pull prey from the bottom, float on their backs, and use rocks as tools to crack shells, a behavior uncommon among marine animals.
The basis highlights one appetizing data point: each otter can consume up to 25% of its body weight per day.
Where urchins are abundant, the Sea Otters concentrate on them as the main food source, and cited research indicates that in these areas, urchin biomass drops drastically, making room for young kelp to settle and rebuild the forest.
Limits of the “Last Resort”: Where Sea Otters Do Not Resolve Alone
Despite their effectiveness, the material emphasizes that the return of Sea Otters does not solve everything. In areas where kelp forests have completely vanished, the seabed has turned into bare rock, and the urchins survive in a state of starvation.
In this scenario, Sea Otters hunt fewer urchins because the energy required to catch them exceeds the nutritional value offered.
The conclusion presented is straightforward: Sea Otters are a necessary but not sufficient condition. They protect remaining forests and help maintain the system in balance, but cannot alone regenerate ecosystems that have already collapsed.
Human Intervention: Manual Removal of Urchins from the Seafloor
Faced with the limit, the basis reports that divers and volunteers have begun to intervene directly in barren rocky areas, removing urchins manually or with tools.
The work is done site by site, requires care because of the spines, and needs to be repeated to reduce density to acceptable levels.
The effectiveness, according to the text, is more about precision than speed.
Where removal is consistent, urchin numbers drop in a few months, and signs of kelp recovery emerge, creating conditions for nature and Sea Otters to sustain the rest of the process.
Relevant Side Effect: Sea Otters and the European Green Crab
The material also cites a possible additional benefit of the return of Sea Otters: they may help control the European green crab, described as an aggressive invasive species that would have arrived via ballast water and spread through estuaries and coastal marshes.
As Sea Otters often forage in estuaries and brackish waters, exactly where these crabs concentrate, they would function as a biological barrier, reducing pressure on oyster beds, seagrass meadows, and juvenile organisms.
The “Substitute Mothers” Program and Survival Rate After Release
To reintroduce Sea Otters, the text states that it is not enough to release them. Orphaned pups raised by humans tend to lose critical instincts and not survive in the wild.
Therefore, the Monterey Bay Aquarium developed an initiative for substitute mothers: orphaned pups are paired with an adult female who cannot be released due to health constraints.
These mothers would teach essential skills such as hygiene, temperature maintenance, swimming, diving, and using rocks as tools.
Are you in favor of reintroducing Sea Otters as a last resort, even with controversy, or do you think direct human intervention should be the main focus in this recovery of the coast?
Totalmente a favor
O ser humano na sua ignorância e falta de empatia com outros seres vivos, não só p/ c/ os animais, eliminam, matam até quase sua total extinção, poluem, não sabem respeitar o espaço de outros seres vivos até serem prejudicados. Daí tentam consertar. Onde existe programa de recuperação de áreas destruídas deveriam gastar um pouco mais de investimento para a divulgação nas escolas e até tvs para o público saber o q está ocorrendo no planeta.
Gostei de saber o q está ocorrendo na baía de Monterey/Ca, e ao mm tempo triste. Ñ tem pedaço do planeta onde a Natureza não esteja sendo destruída por causa do homem.
Se é o homem q destrói, é o homem q tem q consertar.