El Niño is caused by warming of the ocean surface temperatures in the tropical Pacific and weaker trade winds.
“When we’re in an El Niño year, they’re not quite as strong so they’re not pushing away the water so it stays put and keeps the water right off the coast a lot warmer than normal,” said Vivian Rennie, KSBY News meteorologist.
Rennie said the change happens gradually, with weaker trade winds happening from April through July and the impacts coming later.
“Typically, we won’t see any impacts of this until September, October, November, could be slightly earlier this year but we’re still technically in that neutral category. We’re not technically in an El Niño just yet,” Rennie said.
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While rainstorms can impact us on land, the warmer water impacts ocean productivity since warmer waters tend to have less nutrients.
“The plankton, the little single-celled algae that are the base for most marine food webs don’t do as well and so all of the things that eat those, that eat those, that eat those, then tend to do less well," said Benjamin Ruttenberg, Cal Poly Center for Coastal Marine Sciences Director. "So there just tends to be a lot less food available.”
Ruttenberg said that gray whales will be migrating back from Alaska to Baja in the Fall and will need to feed, but if El Niño develops, it will mean less food.
He added that we could see lots of birds, sea lions, and whales much closer to shore because that’s where their food will be, which brings the possibility of additional interactions.
“There were lots of interactions between fishing gear, dungeness crab pots particularly, and whales during the last El Niño event because their food was enclosed, the whales were enclosed right in the places where those crab pots normally get deployed,” Ruttenberg said.
It can also bring tropical species to the Central Coast.
“Seahorses appeared on the Central Coast during the last El Niño. You know, they normally don’t get any further north than San Diego and even that is pretty rare," Ruttenberg said.
