All animal cruelty charges laid by the Ontario Society for the Prevention of Cruelty to Animals against Marineland have been dropped by the Crown, citing no reasonable chance of conviction.

During a brief hearing in a Niagara Falls, Ont., court on Thursday, the Crown said it could have proceeded on three of the charges against the theme park, but did not believe that would have served the public interest.

The OSPCA disagreed with the Crown's decision, saying in a statement to CBC News that it was not informed of the decision until after the court proceedings.

"We are extremely disappointed in this outcome and feel that this matter is of public interest as all animals rely on humans for appropriate care for their general welfare and the public demands this," said Alison Cross, spokesperson for the OSPCA.

She said the OSPCA had "conducted a thorough investigation in this case," and said members of the public with concerns for the animals' welfare should contact 310-SPCA to report any new information.

Marineland also released a statement, saying the company had suffered "reputational damage" from "five years of baseless accusations by ill-informed, radical activists."

"The Crown conducted its own independent review of the OSPCA charges and has effectively agreed with Marineland by determining all the charges ought to be withdrawn."

The statement from Marineland also reiterated a previous statement that the OSPCA was continuing a "publicity campaign at the behest of a band of discredited activists with little relevant expertise or knowledge" that it accused the OSPCA of "being in bed with."

Marineland was facing 11 animal cruelty charges relating to the treatment of the park's land animals, including black bears, elk, red deer, fallow deer, guinea hens and a peacock.

The OSPCA laid the charges last November and in January.

Marineland denied any wrongdoing, saying its herds of elk, red deer, fallow deer and bison are "uniformly healthy, well fed, with good coats." It also said its bears are healthy, as are its birds. It also said the complaints were initiated by a disgruntled former employee.

The OSPCA previously said a conviction on all counts at provincial court in Niagara Falls could result in a fine up to $60,000, a lifetime ban on owning animals and up to two years in jail.

With files from Mahnoor Yawar