In 2023, Marineland was charged by the province of Ontario for providing inadequate care to their black bears under the Provincial Animal Welfare Services Act.

[34][35] Holer welded two large steel tanks together and brought in three sea lions and charged one quarter for admission and another to feed the animals.

In 1973, the aquarium purchased Kandy, a 4,000-pound (1,800 kg) female orca captured off Vancouver Island in 1973, to mate with Kandu,[42] but she died later that year.

In 1976, Marineland announced a CA$50 million expansion on 1,000 adjacent acres, to include a 400-acre "safari park" and amusement centre.

[49] In 1984, Holer announced the postponement of part of the expansion, citing an 86% increase in municipal property taxes, and threatened to move the facility across the river to the United States.

After spending 1996–1998 at Oregon Coast Aquarium, Keiko was returned to a sea pen in Iceland and was released to the ocean in July 2002.

[60] In 2015, the Government of Ontario banned the practice of breeding and keeping orcas in captivity, while allowing the existing one to remain at Marineland.

[69] The Mayor of Niagara Falls, Jim Diodati, sees Marineland at a "crossroads" with three options: to continue the current business model, to sell its 1,000 acres of land to real estate developers, or to become an amusement park without animals.

[76] In September 2019, it was announced that Marineland had sold two beluga whales to Oceanographic, a Spanish facility owned by Ocean Wise Inc., with the permission of the Canadian government.

[34] In 1983, Niagara Falls mayor Wayne Thomson resigned amid controversy over a vacation given as a gift by a Toronto development firm and a land purchase made by his then-fiancé Bonnie Dickson.

Marineland initially refused to return Ikaika, but was eventually ordered to by the Ontario Superior Court as well as pay $255,000 in compensation to SeaWorld for legal expenses.

[86] On March 5, 2013, the Toronto Star published an article quoting Hammond and a local resident alleging that John Holer had shot two Labrador Retrievers that had escaped a neighbour's house and entered Marineland property.

[91] Bob Barker urged Ontario Premier Kathleen Wynne to order Marineland to give up Kiska and other animals.

Affolter responded by asserting that "Black Water is meant as an educational, non-commercial film that dives into the moral question behind keeping cetaceans in captivity.

[97] On August 15, 2012, the Toronto Star published an article of Demers' account, alleging that many sea mammals at Marineland live in inhumane conditions and suffer from a variety of illnesses caused by problems with water quality and chronic understaffing.

[98] The Ontario Society for the Prevention of Cruelty to Animals declined to press charges, but did order changes in park procedures that were then implemented by Marineland.

It documented the relationship former Marineland trainer Phil Demers had with the walrus Smooshi before he quit in 2012 and became a vocal critic of the park.

[103] In June 2020, the film was named as the winner of 2020 Rogers Audience Award and as Overall Favourite at the Hot Docs Canadian International Documentary Festival.

[104] The CBC's Documentary Channel item about the film stated that Demers had "appeared four times on the Joe Rogan show, has testified before the Canadian Senate, and is being sued for $1.5 million for plotting to steal Smooshi, the walrus".

[107] In 2015, then-Senator Wilfred Moore of the Senate of Canada introduced Bill S-203, the Ending the Captivity of Whales and Dolphins Act.

[108] Progressive Conservatives in the Senate, led by Sen. Don Plett, used procedural obstruction to keep the bill from moving to a vote.

On November 10, 2016, however, the agency received a formal 35-page complaint—compiled by California-based group Last Chance for Animals—which included photographs and videos taken by a former Marineland employee whose identity has not been revealed to the public.

(The Canadian Press obtained a copy of the complaint file which was reviewed by some members of the news media; only excerpts have been published.)

[114] On November 25, 2016, the OSPCA charged Marineland with five counts of animal cruelty under the Ontario SPCA Act over their treatment of peafowls, guineafowls, and American black bears in the zoo portion of the park.

"[116] The company also posted a commentary on their Web site indicating that it is "being attacked by disgruntled former employees again, who are working with a professional activist group that raises just under 2 million dollars per year to share their distorted view of facts about others."

Deputy chief Jennifer Bluhm of the OSPCA provided the following comment: "While the investigation is still ongoing, these are all the charges we expect to be laid in this case."

The prosecutor stated that there was no likelihood of conviction and pursuit of the matters was found to not be in the public interest[122] The OSPCA inspected the park a week later and did not find any issues of concern.

"It was motivated by a series of improper objectives, including a desire to accomplish its own policy agenda, to mollify the animal activist community, to please its donors, and to effectively destroy Marineland."

However, in May 2021, an affidavit obtained by The Canadian Press revealed that inspectors had issued two orders to Marineland to repair water systems in animal enclosures.

"Marineland of Canada, Inc. in Niagara Falls, Ontario, has been charged with three counts of failing to comply with an order, related to the care of American Black Bears," said Brent Ross, a spokesman for the ministry.