The dog days of June continued for the Marlins on Sunday — and this time it spread to the stands.

Playing in front of 31,111 humans and 648 of their canine friends on the first Bark at the Park promotion at the new stadium, the slumping Marlins dropped their sixth game in a row, falling 4-2 to the Rays on a day when the big hit continued to elude Miami.

Rays starter James Shields authored the latest Marlins bummer.

He surrendered four hits, walked three and struck out five in 6 1/3 innings as Tampa Bay (35-25) became the second team in a row to sweep the Marlins on their home turf during their second-longest homestand of the season.

In the 54 innings the Marlins have played since returning from Philadelphia tied for first place in the National League East, they have had a lead for a grand total of a half inning (when they were up 1-0 on Atlanta in the fifth inning Thursday). At 31-29, they now trail the first-place Nationals by five games.

“It’s kind of weird how we play good one week and another week we play very bad,” said Marlins manager Ozzie Guillen, whose team prior to returning home this week had won 23 of their previous 32 games.

“I don’t know if I can say it’s a part of the game or this is the way baseball is, or that’s the ball team we have. … We play well for a month and all of a sudden we kind of lost the touch, the big pitch or the big RBI. Hopefully, we can turn this thing around and play better.”

During its six-game slide, Miami has been outscored 43-10, and the pitching staff has been raked (43 earned runs, 7.16 ERA) while a lineup in constant change has struggled to produce with runners in scoring position (5 for 50).

Sunday, the Marlins brought back first baseman Gaby Sanchez after his three-week stint in the minors and reinserted him into the starting lineup. He drove in the Marlins’ first run with a double to left off Shields with nobody out in the seventh.

The Marlins scored again in the eighth on Logan Morrison’s two-out RBI single to right off Joel Peralta.

“I was just laying off pitches I was swinging at earlier, getting into good counts,” said Morrison, who after being benched two nights in a row because he had been struggling at the plate, finished with his first three-hit performance since April 15th.

But nothing Morrison did Sunday was nearly enough as the Marlins finished 2 for 11 with runners in scoring position and squandered multiple opportunities.

Justin Ruggiano, who led off the sixth with a double, was gunned out at the plate with one out in the sixth after Omar Infante sent a bouncer to third. Giancarlo Stanton then ended the sixth by striking out swinging with runners on first and second.

In the seventh, the Rays worked themselves out of a situation with runners on first and second and no one out. After Shields struck out Brett Hayes, Rays manager Joe Maddon handed the ball to left-hander Jake McGee, who got pinch-hitter Greg Dobbs to fly out to left and Jose Reyes to bounce out to second.

Marlins starter Anibal Sanchez, meanwhile, pitched six innings and took the loss for the fifth time in his past six starts. He gave up seven hits, three walks and four earned runs — including three runs on a pair of home runs in the fourth.

Matt Joyce started the rally with a solo blast to center off Sanchez. Three batters later, second baseman Elliot Johnson crushed a changeup into the visiting bullpen in right field, a two-run blast that made it 4-0.

The Marlins’ pitching staff, which gave up just 13 homers in first 25 games at Marlins Park, has now given up 11 in their past six home games.

“That inning brought the team down, too many runs,” Sanchez said. “Right now the situation is we don’t score too many runs. … I know we showed we can play better than this. We just need to make some runs. This team is pretty good. We have to stay together.”