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This Heatwave Was Just the Warm-Up: El Niño Hasn't Even Reached SoCal Yet

A finescale triggerfish crossed a Scripps Pier camera this month, in water running well above its August normal, and NOAA says El Niño has not started working on this coast yet. The region is still in the opening act.

Nick Meyers, Nautical Nick11 min read

A pair of finescale triggerfish over a shallow reef. The species belongs to warm water well south of California, and it is the kind of visitor that turns up here when the ocean runs hot. AI-generated illustration, Nautical Nick.

This Heatwave Was Just the Warm-Up: El Niño Hasn't Even Reached SoCal Yet

The fish crosses the frame for a few seconds and is gone. It is deep-bodied and blunt-headed, with a high-set eye and a stiff forward dorsal spine that locks upright and gives its family the name trigger. The animal is a finescale triggerfish (Balistes polylepis), a species whose center of abundance lies well south of California, off Baja California and into the Gulf of California. It was not the subject of the shot. Nobody was looking for it. It swam through a camera pointed at the water for other reasons and turned up later in a screenshot, at 8:11 on the morning of August 2, in water this site graded at 30 feet of visibility. The identification is this site's own, made after an initial call of shovelnose guitarfish was corrected, and no one at Scripps has reviewed it.

The back half of a finescale triggerfish, pale and mottled with a dark-edged fin, passing the underwater camera beneath Scripps Pier.

The back half of a finescale triggerfish was accidentally caught on camera during a regular visibility check at 8:11 on the morning of August 2. Scripps Pier underwater camera.

Strays like that are the ocean reporting on itself, and the report is currently unusual. The water at the end of Scripps Pier has been running well above its August normal. Between August 6 and 17 the daily surface reading averaged 73.3 degrees Fahrenheit, against a 1991 to 2020 average of 70.8 for the same dates, which makes this stretch one of the 6 warmest in 109 years of August records at the pier and warmer than the same dates in 1997, 1998, 2014, and 2015. NOAA's Climate Prediction Center has an El Niño Advisory in effect, and in its August 13 discussion put the chance of a very strong El Niño, the periodic warming of the equatorial Pacific, above 90% for this fall and winter, with a 69% chance that October through December produces an event stronger than any since 1950. According to NOAA, that is not what is warming this coast yet. The heat arriving now comes from 2 tracked marine heatwaves, or prolonged stretches of abnormally warm surface water, in the California Current, and the agency expects El Niño's influence on regional temperatures to begin in fall 2026 and carry into winter. The tropical arrivals have started ahead of the forcing usually blamed for them.

Where the Heat Is Coming From

The distinction is mechanical. El Niño begins as a shift in the equatorial Pacific, and its effect on California arrives indirectly and late, through coastal waves and atmospheric changes that take months to travel north. A marine heatwave is generated locally. NOAA's California Current tracker attributes the present anomaly to a breakdown in upwelling, the process by which winds drag cold, deep water up to the surface along the coast. When those winds go slack or reverse direction, upwelling shuts down and the surface layer heats up.

The result has been sustained. Melissa Carter, the biological oceanographer who manages long-term monitoring at Scripps Institution of Oceanography, has said in comments reported by Nature World News that every monitoring station along the Southern California coast was showing record-high temperatures by November 2025, and that the condition has been essentially continuous since. The same account, citing reporting by CNN, counted 36 separate days in the first 4 months of 2026 that set records at Scripps Pier for the warmest water ever measured on each of those calendar dates. On April 27, according to KPBS, the pier read 66 degrees Fahrenheit (18.95 Celsius), roughly 3 degrees Fahrenheit above the seasonal average for the date.

Those records carry weight because of how long the ledger is. The Scripps Pier shore station has logged ocean temperature continuously since 1916, the longest such record on the West Coast. A date record there stands against more than a century of comparisons.

That same ledger puts this August in proportion. The first 4 days of readings this month ran 4 to 7 degrees above normal, the warmest of them 77.5 on August 7. Then the surface came off the top. By August 16 and 17 the pier was reading 70.3 and 69.4, just under the average for those dates, which is a reminder that a marine heatwave is a running condition rather than a fixed one.

Line chart of daily surface temperature at Scripps Pier from August 6 to 17, 2026, running above the 1991 to 2020 average of 70.8 degrees for most of the period and dipping below it on the final 2 days.

Daily surface temperature at Scripps Pier for August 6 to 17, against the 1991 to 2020 average for the same dates. The 12 day average of 73.3 runs 2.5 degrees above that normal. Data from the Shore Stations Program at Scripps Institution of Oceanography. Tap the chart to open it full size.

What 1997 Carried North

The benchmark for what warm water delivers to California reefs was set 28 years ago, and it was catalogued carefully. The ichthyologists Robert Lea and Richard Rosenblatt documented the fishes that arrived during the 1997-98 El Niño for CalCOFI Reports, and the tally ran to 29 families of Panamic fishes, the tropical assemblage normally found from Baja south, recorded off California. Among them were 10 species new to the state. The authors concluded that the event surpassed both the warm-water period of 1957-59 and the El Niño of 1983-84.

By their count, San Diego produced a large share of the records. On May 12, 1998, 6 pink cardinalfish (Apogon pacificus) measuring 1 to 2 inches (27 to 50 millimeters) were collected from La Jolla Canyon at 39 feet (12 meters), the first California record of the species. A juvenile threebanded butterflyfish appeared inside the San Diego-La Jolla Ecological Reserve in November 1997. A longnose puffer was photographed off La Jolla on January 24, 1998, and 11 days later a juvenile of the same species washed up at La Jolla Shores. A Mexican barracuda was taken by a sport angler at Bird Rock in January 1998, a fish easily mistaken for the ordinary Pacific barracuda it was swimming among.

San Diego Bay produced a different roster. A cocinero, a tropical jack, taken there on August 12, 1997, was the first California record. Mexican lookdown, a deep-bodied silver jack of the same family, appeared through the winter and into April 1998. Bonefish larvae and juveniles turned up in bays and estuaries. Between April 1997 and January 1998, at least 10 juvenile scalloped hammerheads, all under 3 feet (1 meter), were caught in the bay, enough for Lea and Rosenblatt to raise the possibility that under sufficiently warm conditions the bay can briefly serve as nursery habitat.

Identification card for the scalloped hammerhead shark, Sphyrna lewini, showing the broad notched head and slender grey body.

The scalloped hammerhead. At least 10 juveniles, none longer than 3 feet, came out of San Diego Bay between April 1997 and January 1998. AI-generated illustration, Nautical Nick.

The Small Ones Carry the Signal

Lea and Rosenblatt were specific about how these fish got north. Poleward transport of larvae and early-stage juveniles, they wrote, is "an extremely important mechanism." Species that associate with flotsam, including jacks, goatfishes, and tripletails, likely rode drifting debris. The free-swimming animals, the sharks and the barracudas, moved north under their own power through water masses that suited them.

Most of the tropical fish that reach California, then, arrive as something close to plankton and settle onto a reef. A 2-inch (5-centimeter) cardinalfish wedged into a crevice at 40 feet (12 meters) carries more information than a large pelagic fish cruising past, because the small one had to be carried there by moving water.

That mechanism also introduces a lag, and the lag is easy to misread. Writing in CalCOFI Reports, the fisheries researcher Jorge Adrián Rosales-Casián described 11 finescale triggerfish captured off San Martín Island, Baja California, on July 30 and 31, 2011, the first record for the San Quintín area. He attributed their presence to the moderate El Niño of 2009-10, which is to say the fish appeared well after the event that likely moved them. A stray caught on camera in August 2026 is not automatically a fish that arrived in August 2026.

Identification card for the finescale triggerfish, Balistes polylepis, a deep-bodied fish with blue mottling along its flank and a stiff forward dorsal spine.

The finescale triggerfish, deep-bodied and blunt-headed, with the forward dorsal spine that gives the family its name. Its center of abundance lies off Baja California and in the Gulf of California. AI-generated illustration, Nautical Nick.

The triggerfish is a recurring visitor to California in warm years, not a singular event. Its documented range extends far north. In 2016 the journal Northwestern Naturalist published the first records of finescale triggerfish in British Columbia. The species works as a warm-water tracer because it appears often enough to be measurable.

What the Same Water Is Costing

Warm water carries tropical strays north because it suits them, and it does not suit a great deal else. The heat that may deliver a butterflyfish to a La Jolla reef this fall is currently starving seabirds.

Tammy Russell, a seabird researcher at Scripps, told NBC San Diego that birds have been washing up on beaches across Southern and Central California in elevated numbers for months, emaciated and significantly under normal body mass, and testing negative for avian influenza. Starvation is the working explanation. Warm surface water disperses and displaces the forage species seabirds depend on, including anchovy, sardine, smelt, and krill, and murres, auklets, and cormorants have been traveling farther to find them. A rare fish sighting and a beach full of dead birds are 2 readings from the same instrument.

More than a dozen dead gulls scattered across wet sand at the waterline on an overcast beach.

Seabirds have been coming ashore along the Southern and Central California coast for months, emaciated and testing negative for avian influenza. Starvation is the working explanation. AI-generated illustration, Nautical Nick.

The 1997 Records Point at 2 Sites

The historical record concentrates in 2 places in San Diego County, for different reasons.

La Jolla's rocky reef and the head of the canyon produced the cardinalfish, the butterflyfish, the puffers, and the barracuda in 1997-98. Those records were small, cryptic species, meaning fish colored and shaped to disappear against the reef, recorded under ledges and inside crevices between 10 and 60 feet (3 to 18 meters).

San Diego Bay produced the jacks, the bonefish, the lookdown, and the hammerhead pups. Shallow, warm, and structurally complex, the bay behaved during that event like the northern edge of a tropical system.

Timing is part of the pattern. Lea and Rosenblatt noted that in 1997, reports of Panamic fishes off California became frequent around midsummer and continued through the end of 1998, which places the current moment early in the comparable window.

The camera at the end of Scripps Pier is not looking for any of this. It records water, continuously, the way the thermometer beside it has since 1916. A triggerfish crossed it once this month. Whether that frame proves to be an isolated stray or the first entry in a long list depends on water that, by NOAA's own forecast, has not finished warming.

Rippled sand on the seafloor visible beneath Scripps Pier in clear blue water, with small fish near a piling.

The same camera on the morning of August 6, with the bottom in plain view and the water graded at 35 feet. Scripps Pier underwater camera.

Sources

This Heatwave Was Just the Warm-Up: El Niño Hasn't Even Reached SoCal Yet | Nautical Nick