A variety of marine mammal species can be found on the menus of more than 100 countries around the world, including polar bears, sea lions and dolphins, researchers from the Wildlife Conservation Society said in a statement released on Wednesday.

Researchers found after conducting a comprehensive study consisting of roughly 900 informational sources that since 1990, people in at least 114 countries have consumed one or more of the 87 marine mammal species.

The findings come amid the global controversy surrounding the great whale species between pro and anti-whaling advocates, and researchers said that people are largely unaware of the doom of smaller marine mammals because “deliberate and accidental catching and killing dolphins, porpoises, manatees and other warm-blooded aquatic species are rarely studies or monitored”.

"International regulatory bodies exist to gauge the status of whale populations and regulate the hunting of these giants," said lead study author Dr. Martin D. Robards of the Wildlife Conservation Society.

"These species, however, represent only a fraction of the world's diversity of marine mammals, many of which are being accidentally netted, trapped, and—in some instances—directly hunted without any means of tracking as to whether these off-takes are sustainable," he added.

The list of marine mammals hunted for human consumption include more obscure species like the pygmy beaked whale, South Asian river dolphin, narwhal, Chilean dolphin, long-finned pilot whale, Burmeister's porpoise. Species of seals and sea lions, the polar bear, and three species of the manatee and its close relative the dugong are considered a prized delicacy in parts of the world and are therefore “widespread targets” of human consumption, researchers said.

The study demonstrated an escalation in the exploitation of smaller cetaceans, especially coastal and estuarine species since 1970. Researchers said that these animals are often caught accidentally as “bycatch” in nets meant for fish and other species. However once they’re caught, the small cetaceans are increasingly being consumed as food in areas of food insecurity and poverty.

In regions like Congo, Gabon, and Madagascar scientists find a worrying trend of increased captures and dolphin consumption, and dolphin meat is sometimes sold in markets known for their association with illegal trade of terrestrial ‘bushmeat’.

Researchers said that the “last strongholds for the rare Atlantic humpback dolphin” is located on the coasts of Gabon and Congo, and although fishermen in Gabon rarely catch the Atlantic humpback dolphin, the groups of dolphins that cross the border to Congo risk capture in coastal gillnets set by artisanal fisherman.

"The Atlantic humpback dolphin may well be the rarest mammal in the Congo basin region," said WCS Conservation Scientist Tim Collins. "Unfortunately, few have ever heard of it, least of all the fisherman eating them out of existence."

"Obviously, there is a need for improved monitoring of species such as Atlantic and Indo-Pacific humpback dolphins and other species," said Dr. Howard Rosenbaum, Director of WCS's Ocean Giants Program. "In more remote areas and a number of countries, a greater immediate need is to understand the motivations behind the consumption of marine mammals and use these insights to develop solutions to protect these iconic species that lead to more effective management and conservation."

Researchers said there could be more instances of aquatic mammals being accidentally caught or hunted because they only included information with actual evidence of human consumption of marine mammals and did not count instances where marine mammals were caught for fishing bait, feed for other animals, medicines and other uses.

The study was published in the most recent edition of Biological Conservation.