San Diego Offshore Fishing ReportWeek of Sep 14 · out of San Diego Bay Inlet

Friday is GO all day inshore — 3–7 knot NNW winds and a long-period 3-foot SW swell in the morning, building to 14 knots WNW with gusts to 20 and 3.9-foot seas by afternoon. Get out early, fish the morning and midday, and expect a livelier ride home.

The headline is the LJ 100. Three signals converge here: a moderate SST front carrying a 1.4°F break (warm side NE), a gradient peak marking the steepest part of that break, and a moderate CHL color break that jumps 7.3x from 0.16 to 1.16 mg/m³ across a 13-mile transition with the green water lying to the northeast. The spot sits five miles northwest of the LJ 100 and five miles northwest of the La Jolla Canyon, with Carlsbad Canyon six and a half miles to the north — so this break is lying over the canyon complex, and the surface current arrows along this stretch are pushing north-northwest along the edge, which keeps the boundary tight and rakes bait along the canyon walls. Water on the warm northeast side of the break is running about 73°F at the surface; the cool southwest side is the clean blue water the tuna want.

How to fish it: the productive green water is NE and inshore, and that's where the anchovy will be stacked. Bluefin and yellowtail are sight feeders here, so set up on the clean southwest side of the break and let the bait come to you. The warm layer holds only to about 31 ft (73°F) and the temperature falls fastest from 31 to 61 ft (down to 69°F) — that 30–60 ft band is where the anchovy pin up and where the bluefin will be, so fish flylined anchovies for the surface stage and drop a sinker-rigged anchovy to 40–60 ft if they won't come up. Yellowtail will work closer to the green edge itself; a live Pacific mackerel or a yo-yo iron worked through the thermocline layer covers them. On the warm northeast side, glass for kelp paddies — this 73°F water in September is mahi water, and any paddy along the break line is worth a stop with live anchovy or sardine. The moon is a half-lit waxing crescent, eight days before full, so there's no overnight gorging to worry about — expect a steady daytime bite with a bump in the early-afternoon moonrise window around 1:30–2:30 PM, which is right before the wind builds.

Farther west, the NW Harbor off the north end of San Clemente Island shows the tightest edge on the chart — a moderate SST front with a 1.5°F break compressed into a 5-mile transition, warm side NE, sitting in 71°F water with the current pulling northwest around the island. That's textbook bluefin and yellowtail temperature and the break runs along the island's steep deep-water side. Bluefin work the cool side; yellowtail and Pacific bonito will be on the warm side and tight to the edge on anchovy. The catch is distance: the spot is 76 miles from San Diego and the run crosses midshore water that carries a CAUTION call Friday with a confused cross-sea and a 6 PM deadline. Only consider it as a long-range or overnight play with a settled boat, and weigh the shorter La Jolla run first.

A second thermal front also lies west of La Jolla around 117.7°W in the 30-mile range, connecting the inshore and midshore water — troll the corridor between the LJ 100 and that line if the canyon break goes quiet.

Friday is CAUTION midshore — a usable window from midnight to 6 PM, but a south swell crossing a WNW wind-wave makes for awkward motion all day, and after 6 PM seas build to 5 feet with 22-knot gusts. Fish it only if you can be back before late afternoon. Saturday is similar with a window closing around 1 PM; Sunday is the best of the three midshore days with an all-day window and easing seas.

The one spot with signal is the E Butterfly, sitting two miles southeast of the E Butterfly high spot on the Butterfly Bank, with San Salvador Knoll ten miles to the east-northeast. The SST feature here is broad — a 1.5°F step spread across an 18-mile transition with the warm side to the northeast — so treat this as a gradual warming across the bank rather than an edge to troll. What earns it a look is that this warming has held position for two days, giving the anchovy time to gather around the bank's structure, and the water is clean blue 72°F at the surface (midshore chlorophyll averages just 0.12 mg/m³) — exactly the visibility bluefin want. There's a light 0.2-knot current setting toward the southeast across the bank, which will push bait onto the down-current side.

Fish it like a bank: meter the up-current and down-current edges of the high spot for anchovy balls and bluefin marks. The warm layer here holds to about 35 ft (72°F) and the fastest temperature drop runs from 31 to 61 ft (down to 69.6°F) — bluefin will be hanging in and just under that 30–60 ft band, so flyline anchovies on the surface fish and send sinker-rigged anchovies to 50–60 ft when they're down. Yellowtail should be on the structure itself in this 72°F water — a yo-yo iron or a live Pacific mackerel dropped to the top of the bank covers them. And with 72–73°F water and September timing, any kelp paddy you find drifting across the bank on the southeast set is a mahi stop; work live anchovy or sardine up-current of the paddy. With a half moon and no night feeding pressure, the daytime bite should be steady; the moonrise bump around 1:30–2:30 PM is a good final push before you point it home ahead of the evening deterioration.

Offshore is NO-GO on all three days. Friday brings a confused cross-sea — SSW swell crossing NW wind-wave — with 18-knot NW winds, gusts to 24 and seas building to 5.7 feet by evening. Saturday and Sunday offer only brief lulls, never a settled window long enough for a 12-hour run. Postpone any trip beyond 60 miles until this pattern breaks.

There is also no ocean reason to force it. No qualifying spots set up in the offshore zone: the water out there is uniformly clean 70.5–71.2°F blue (chlorophyll averaging 0.087 mg/m³) with no temperature breaks, color changes or eddies to concentrate bait. That temperature is right in the bluefin and albacore window, but without an edge or a bait signal the fish will be scattered. When the weather settles, look for the warming trend now over the Butterfly Bank to push farther offshore and create an edge worth hunting; until then, the inshore canyon break off La Jolla is the far better use of a September day.