Up and down the West Coast, ichthyologists—professional fish nerds—can barely contain themselves. Whale sharks normally in the Sea of Cortez have been seen as far north as Malibu. Spotter planes have photographed giant manta rays flapping their way north. Sport fishermen who normally have to travel to Baja for wahoo and blue marlin are now catching them by the boatload off the coast of San Diego. And a rainbow of reef fish that are hundreds of miles beyond their normal range are poking around the piers of Southern California.
Mike Couffer, a semiretired biologist from Newport Beach, has been scuba diving nearly every day to see the mohawk-style fins of star-studded grouper, tiny iridescent orange creolefish, three-banded butterflyfish, and other exotic fish hardly ever seen in this area. “It’s just nuts, what’s going on out there,” he told me. The balmy waters produced during this year’s El Niño have essentially imported a whole ecosystem from Mexico. In recorded history, “this is the most profound movement of tropical fishes into California that anyone’s ever seen,” Milton Love, a research biologist at UC Santa Barbara’s Marine Science Institute, told me.
From his office window, Owyn Snodgrass, a NOAA Fisheries research biologist, can see the Scripps Pier in La Jolla. He told me that his father, a former aquarium curator, used to drop a probe twice a day off that pier to take the temperature of the Pacific Ocean, contributing to a daily record that stretches back to 1916. This year, an extraordinary amount of warm water has built up in the equatorial Pacific and beyond, driving what promises to be the most intense El Niño ever recorded. When Snodgrass and I talked on Tuesday, the water temperature at the pier was 75 degrees, 11 degrees warmer than the daily average and the warmest November 3 ever recorded. This would have surprised him more if daily records hadn’t already been broken 65 times this year. As we spoke, Snodgrass was keeping an eye on a livestream showing the water under the pier. He watched a razor surgeonfish swim by. “That has never been documented in California waters,” he said…