What scientists call the upcoming “very strong” El Niño of 2026 could affect a variety of species that inhabit the ocean and coastal land on the Central Coast.
Faculty and students in the Cal Poly Center for Coastal Marine Sciences are preparing to monitor the negative effects of the upcoming super El Niño. The effects of El Niño and its resulting storms could be detrimental to the Central Coast’s marine life ecosystem and give the community a glimpse of what the oceans will look like in a few decades, according to Director of the Center for Coastal Marine Sciences Ben Ruttenberg.
El Niño is a naturally occurring climate pattern where trade winds of the Pacific Ocean reverse direction and send warm waters to the eastern Pacific, such as California, where the water is normally cold. These warm waters are detrimental to the productivity of marine systems as they lose the cold, nutrient-rich water.
The new warm water sits on top of the cold water, acting as a barrier that stops the nutrient-rich cold water at the bottom from mixing easily with the surface. The cold water at the bottom is where organic matter like dead plants, animals and waste accumulate and break down.
The warm waters specifically harm the kelp forests that drive the productivity of marine ecosystems through habitats and food sources.
“[When] those waters get warmer, the kelp forest then does less well, and so the entire ecosystem that relies on the kelp forest is also going to do less well,” Ruttenberg said.
When the kelp forests are less productive, the phytoplankton and zooplankton populations decrease. These two species feed the smaller prey of the ecosystem and ultimately leave some species without a consistent food source. The lack of productivity can disrupt all levels of the food chain.
Strong storms are also expected during El Niño, bringing heavier rainfall to California.
In addition to El Niño, Stefan Talke, a civil and water resources engineering professor, said the Central Coast is currently at the peak of two tide cycles.
“We’re at the peak in a 20-year cycle of tides right now, and so the tides are bigger than they would ordinarily be, and we’re in the peak of a 4.4-year cycle,” Talke said. “So just that effect alone, the predictions I’ve seen are anywhere from six to 12 additional inches [of sea level].”
The two cycles of tides are in relation to the Moon’s orbit. When the Moon is closest to the Earth in parts of these two cycles, the tides rise.
The predicted sea level is the natural equivalent to at least three or four decades of sea level rise but will eventually recede after El Niño. The rising of the tide will cause more marine life to come closer to shore, which is a natural phenomenon called habitat compression.
Ruttenberg said the Central Coast normally has cold, nutrient-rich water that goes far out from the coast, so most marine life is well spread out offshore. However, with the reverse trade winds, it is very warm offshore with very few nutrients, and it tends to be a bit cooler near the coast. This means that many marine life will gravitate closer to the coast, compressing their normal spread out habitat to just near the coast.
“All those fish come in, and then the birds come in, and the whales come in, so they tend to be much, much closer to the shore,” Ruttenberg said. “Things like whales then are much more likely to be close to the coast, which means they’re much more likely to be interacting with things like boats and fishing gear.”
Along with habitat compression, some species may experience habitat loss.
“The extreme [tide] highs also come [with] extreme lows. When we get those extreme low tides, there’s less water in these kelp forests, and so that wave energy tends to impact them more,” Ruttenberg said. “It’s more likely to tear that kelp out.”
The habitat loss may specifically hurt sea otters, which rely heavily on kelp forests for food, protection and rest along the coast.
Along with the kelp forest, the estuaries they tend to live in, such as Morro Bay, can also face negative effects.
Estuaries are an enclosed body of water on the coast where freshwater and saltwater meet. Morro Bay is a local estuary currently home to more than 40 southern sea otters. In the upcoming El Niño storms, the estuaries will see more freshwater input that will affect the salinity and turbidity of the water, according to Morgan Martinez, a biological sciences graduate student.
The murkier water and decrease in salt concentration may affect the sea otter’s prey community by reducing overall species diversity and changing which prey items are available. Sea otters must consume about a quarter of their body weight to fuel their high metabolic rate and stay warm, as they do not have blubber. A drop or shift in prey forces otters to adapt their diet, change their foraging behavior or face population limits.
The storms will also increase runoff, so different chemicals will run off of our land and into estuaries. Some examples of the chemicals are toxoplasmosis that comes from both wild and domestic cat feces, as well as pesticides from our crops.
“The goal is to monitor it, understand it better, so that we can make better models and predict what’ll happen the next time something like this happens,”
Ben Ruttenberg, director of the Center for Coastal Marine Sciences
“We might see things that are harmful coming from land increasing more in that estuary,” Martinez said. “One of those things that comes from runoff is toxoplasmosis…So, it’s definitely possible that we might see an increase of those parasites affecting our sea otters.”
It is impossible to predict which species may experience the most effects. The disruption may lead to a large domino effect in the food chain and the greater ecosystem.
“In general, we expect, you know, seabirds, seals and sea lions, many of these species that rely on these bay fish to do much less well,” Ruttenberg said.
While San Luis Obispo may see a decline in some species, tropical species have also moved closer to the California coast during El Niño. The coast has already seen sharks and manta rays off of Malibu and bluefin tuna and garibaldi fish in Morro Bay, according to Ruttenberg.
In September 2026, Orange County had the first recorded olive-ridley sea turtle nesting on the West Coast.
Ruttenberg said because there have only been a few very strong El Niños, there is not much data on what may happen to marine life during them. With complex marine systems, it can be difficult to make strong predictions.
Whether the predictions are short-term or long-term, the Center for Coastal Marine Sciences is currently focused on monitoring and recording as much data as possible, according to Ruttenberg.
“What’s happening with the ocean productivity, all of the coastal impacts, the coastal engineering monitoring, that’s definitely going to continue,” Ruttenberg said. “The goal is to monitor it, understand it better, so that we can make better models and predict what’ll happen the next time something like this happens.”
This story originally appeared in the October printed edition of Mustang News. Check out more stories from the issue here.