Believe show in Shamu Stadium at the SeaWorld Orlando theme park in Orlando, Fla.
Mix together killer whales, a negative documentary and bad weather, and what do you get? If you're SeaWorld (SEAS), all three ingredients apparently have created a visitor drought. 

The SeaWorld parks have seen a 6% decline in visitors during the first half of the year, although the cause of the downturn isn't entirely clear. SeaWorld rejects the notion that a documentary called "Blackfish," which is critical about the treatment of killer whales in captivity, had an impact on attendance, The Los Angeles Times reports.

Amid the dry spell, SeaWorld has cut some prices, offering San Diego residents a free children's ticket when an adult ticket is bought, or a $71 value, Bloomberg reports.

But SeaWorld is denying the ticket deal is a reaction to the visitor drought, telling The Times that it's "not slashing prices, period." The discounts are part of what it describes as a typical theme park marketing technique. 

Nevertheless, bargains on theme park tickets may strike some as unusual, given the never-ending upward price march for Walt Disney's (DIS) parks. A single-day ticket at Disneyland rose 6% earlier this year, and now requires $92 for entry.

SeaWorld was in the news earlier this year with the January premiere of "Blackfish," which continued to gain media coverage just as families were planning theme-park visits over winter and spring school breaks. The film, which will air on Time Warner's (TWX) CNN in October, was called a "disturbing film" by The Pittsburgh Post-Gazette, which notes SeaWorld declined to be interviewed by the filmmakers.

To be sure, given that the film wasn't widely released, it's unclear how many potential SeaWorld visitors would have heard about or seen the movie. 

SeaWorld has its own explanation about dwindling attendance: poor weather. Its parks in Florida and Virginia were impacted by unfavorable weather earlier this year, while Easter fell on a weekend that also happened to be spring break for college students, The Los Angeles Times notes. 

Regardless of the reason for the drop off, investors have taken notice. SeaWorld's stock has plunged 24% since mid-July, when shares crested following its April initial stock sale.

Follow Aimee Picchi on Twitter at @aimeepicchi.

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