Fishing Magdalena Bay's Offshore Thetis Bank Logo
Fishing Magdalena Bay's Offshore Thetis Bank


Photo fishing boat Mary Lee at Magdalena Bay, Mexico.

Baja On The Fly's chartered boat, the Marylee out of La Paz, is shown in late November 2001 at its Santa Maria Bay anchorage. The Marylee fished with fly tackle for six weeks at the Thetis Bank off Magdalena Bay, Baja California Sur, Mexico this season.


By Gene Kira, Dec. 16, 2001, as published in Western Outdoor News:

The 2001 Thetis Bank fall fish pile-up in Pacific Ocean waters off Baja California's Magdalena Bay was still going strong last week, even as winter winds made their seasonal influence more and more dominant, and the few sport fishing boats remaining at Bahia Santa Maria pulled anchor and left. In fact, there were more striped marlin out there than at any time this season, even though virtually nobody was fishing for them anymore.

"When we left, we turned off the lights and locked the doors," said Gary Graham of Baja On The Fly, who on Dec. 12 wrapped up six straight weeks of fishing the Thetis Bank on the fly. "We were the last boat out there."

The 2001 fishing season offshore of Magdalena Bay was not outstanding compared to 1999 and 2000, when perhaps 200 striped marlin could be enticed to crash the pattern in a week's trolling. Nevertheless, the Thetis Bank fall bite is so phenomenal that even in an off-year, the numbers were impressive. Graham lost four days to weather this year, but still came up the following results for 26 fishing days: 188 striped marlin raised to the fly; 126 cast to; 52 hooked; and 28 landed and released. That makes a six-week average of more than one fish landed per fishing day on the fly. Spectacular anywhere else, but only so-so for the Thetis Bank.

Early this season, Graham said, many sport fishing captains felt that the Thetis Bank was going to be a bust, even though there were flurries of ten-fish days reported here and there. As the season began about November 1, the water was still cold and mixed up from the after-effects of September's powerful Hurricane Juliette, and the massive concentrations of sardines usually found off Magdalena Bay were nowhere to be seen. The sky was empty of the thousands of frigate birds that are usually seen circling above the water after flying out from their roosts in the Magdalena Bay mangrove channels.

But all along, Graham--who originally discovered the Thetis Bank fall bite by accident in 1979 and has studied it ever since--maintained correctly that the spectacular Magdalena Bay marlin concentration would happen eventually, even though it would be much later than normal. "Remember, we didn't have any big fronts moving through until November, and that's what usually starts the marlin moving south," he said. "Also, this was one of the worst marlin years on record for Southern California, so you have to factor that in. This year started out fairly normal, but Hurricane Juliette made it all go sideways, and it's only now recovering."

This year, Baja On The Fly's chartered boat, the Marylee fished more days on the Thetis Bank than any other, and recorded a steadily increasing intensity of action from its Nov. 1 starting date to the last fishing day of Dec. 12. As the last trip was ending, Graham finally observed what he was willing to call "large concentrations" of striped marlin, about 20 miles west of the entrada.

One oddity of this year's bite, according to Graham, was the extreme and almost uncanny precision and stability of the locations where fish were found. If fish crashed the pattern at a certain set of GPS numbers, oftentimes they would be found at that exact location time and time again.

Even after a gap caused by bad weather or poor water conditions, the fish would reappear on those identical numbers, sometimes days later. Graham, it should be noted, fishes with a GPS unit linked to a recording laptop computer, running Nobletech mapping software. The coordinates and details of every event and observation are punched into a permanent record.

A large-scale chart of the ocean around Magdalena Bay, overlayed with Graham's GPS coordinates of every fish caught this year showed that they were concentrated very tightly in a sharply-defined triangular area, with one corner on the Thetis Bank itself, another corner on Cabo San Lazaro, and the third corner located 20 miles outside the main entrance of Magdalena Bay on a heading of 230 degrees. During the entire, six-week 2001 season, virtually every striped marlin caught was inside this elongated triangle.

Another difference in this year's bite, noted Graham, was that the striped marlin seemed more lethargic than usual. For the first time, he was forced to add deboned mackerel to the teasers in order to draw strikes. In previous years, the marlin would aggressively strike the flies again and again on the same follow, as long as they were presented properly. Another notable difference this season was the presence of significant numbers of tuna, wahoo, and yellowtail in the main marlin fishing zone. Usually, it's almost pure marlin. There were also some dorado present, but not in numbers.

This season, the Thetis Bank fish pile-up was fished by more boats than ever, Graham said, including charter boats coming up from Cabo, private yachts from San Diego, the large Riviera Boat tournament, and several long range party boats that didn't fish for especially for marlin. In contrast to other seasons when only a handful of boats visited the area, this year up to about 15 boats at a time were anchored in Santa Maria Bay.

As a final comment, Graham said he is concerned that there may be a correlation between what seems like an increased sardine harvest by the net boats operating out of San Carlos, and the big drop in sardine numbers observed offshore this season. "We didn't see sardine bait balls like we normally do," he said. "If this continues, it's sure to have a big effect on the fishery."

(Related Magdalena Bay (Bahia Magdalena) articles and reports may be found at's main Magdalena Bay (Bahia Magdalena) information page. See weekly fishing news, photos, and reports from the major sportfishing vacation areas of Mexico including the Magdalena Bay (Bahia Magdalena) area in "Mexico Fishing News.")