Travel company Thomas Cook has agreed to suspend its online promotion of controversial attraction park SeaWorld.
The move follows months of campaigning by animal rights charity PETA.
PETA organized actions outside branches of Thomas Cook, and encouraged 22,000 of its supporters to send emails.
The move is another blow to SeaWorld, which has seen attendance rates drop since the release of documentary Blackfish.
In 2017 park experienced a massive 16 percent fall in net profits compared to a year before.
Many people boycotted the park after watching Blackfish
According to PETA: "This is a step in the right direction, but the company must go the whole way by dropping all ticket sales to the marine park if it’s to be an industry leader in animal welfare.
"Orcas are highly intelligent animals who live in large, complex social groups and swim up to 140 miles a day in the ocean.
"At marine parks such as SeaWorld, they’re confined to tiny concrete tanks, where they’re deprived of physical and psychological stimulation and forced to spend their days swimming in endless circles.
"At least 41 orcas and dozens of other dolphins have died in captivity at its facilities so far."
A PETA spokesperson added: "By suspending online promotions of SeaWorld, Thomas Cook has shown that it understands that holding orcas captive for entertainment is unacceptable.
"PETA commends this decision, and we’re now calling on the travel provider to end ticket sales to the marine park altogether. In doing so, it would become an industry leader in animal welfare and set the bar high for others to follow."
A Thomas Cook spokesperson said the company 'has taken steps' to remove promotional material including adverts, social media promotional campaigns and blog content across its websites and social media channels.
They added: "This is in line with our animal welfare policy."