The Seattle Mariners are entering familiar waters. And the seas ahead look rough.

Last week, for the second home game of the season, the M’s drew a record-low crowd to Safeco Field. Just 10,745 showed up, and that was the official paid attendance, including however many season-ticket holders didn’t go.

The next day, the crowd got even smaller — a new record low of 10,493. Felix Hernandez, with his first home start of the season, drew 22,917 to the “Supreme Court” and left the Mariners’ promotion people with a couple-thousand leftover yellow T-shirts.

The low attendance has continued: 15,029 last Friday, 23,461 on the first home Saturday, 16,981 on Sunday and a paltry 12,379 on Tuesday when Doug Fister and the Tigers shut down the flailing M’s. If you watched Tuesday’s game on TV, you know the crowd looked embarrassing; heck, Safeco Field’s capacity is 47,476.

Already, at 19,324, the Mariners’ average attendance per game is the worst it’s been since 1990 — nine years before they moved from the Kingdome. And yes, while it is too early in the 2013 season to make any conclusions — Wednesday’s was only the ninth home game of the year — what we’re seeing this April is part of a continuing downward trend in the number of people who go see the Mariners play live.

That’s not exactly news; with the exception of 2007, M’s attendance has dropped each season since 2002. But what’s notable is just how few people are going to Safeco now. And oh, with a record of 6-9 through Tuesday and a team batting average of .219, the Mariners still look awful, too.

The last time the Mariners played this poorly and had home attendance this low, in the late ’80s and ’90s, the team was dangerously close to being moved out of town.

Here’s a refresher. After the 1988 season, when the yellow-”S” M’s finished 68-93 with an average attendance of 12,622 per game at the Kingdome, owner George Argyros sold the team to a group led by Indianapolis communications tycoon Jeff Smulyan. The team continued to flounder, and even after the franchise barely registered its first winning season in 1991, Smulyan repeatedly threatened to relocate the Mariners.

Attendance and revenue remained poor, as did the quality of baseball on the field. Midway through 1992, Smulyan sold the still-struggling M’s to the team’s current owners, a group headed by (now former) Nintendo Chairman Hiroshi Yamauchi. The new owners campaigned for a new baseball stadium, but Seattleites resisted by voting down a tax increase in September 1995.

Then came October, when the M’s surged into the playoffs on their magical 1995 comeback. With new excitement and support for the Mariners, legislation finally got pushed through (some would say “around” the voters) to build Safeco Field — “the house that Griffey built.”