Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

People gather near a facility, where nearly 100 orcas and beluga whales are held in cages, during an operation to transport and release two orcas in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Employees take part in an operation to transport and release two orcas at a facility, where nearly 100 orcas and beluga whales are held in cages, in Srednyaya Bay in Primorsky Region, Russia June 20, 2019. REUTERS/Yuri Maltsev 

Greenpeace activists hold a protest against the "whale prison", a facility in Primorsky Region where nearly 100 whales including orcas and beluga whales are held in cages, in Vladivostok, Russia May 13, 2019. REUTERS/Yuri Maltsev 

Greenpeace activists hold a protest against the "whale prison", a facility in Primorsky Region where nearly 100 whales including orcas and beluga whales are held in cages, in Vladivostok, Russia May 13, 2019. REUTERS/Yuri Maltsev 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls TPX IMAGES OF THE DAY 

People look from the river bank after a Beluga whale was spotted in Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

A Beluga whale swims in the River Thames near Gravesend, east of London, Britain, September 26, 2018. REUTERS/Peter Nicholls 

People look from the river bank after a beluga whale was spotted in the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches near a buoy on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches near a buoy on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches near a buoy on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

A beluga whale breeches near a buoy on the River Thames near Gravesend east of London, Britain, September 25, 2018. REUTERS/Toby Melville 

Visitors take pictures while Beluga whales and their trainers present "The heart of Ocean" show at the Harbin Polarland in the northern city of Harbin, Heilongjiang province January 6, 2015. The polar land themed park combining animal shows and polar land sights has had increased visitors during the annual Harbin International Ice and Snow Festival, the park said.
REUTERS/Kim Kyung-Hoon (CHINA - Tags: ANNIVERSARY SOCIETY TRAVEL) 

Beluga whales and their trainers present "The heart of Ocean" show at the Harbin Polarland in the northern city of Harbin, Heilongjiang province January 6, 2015. The polar land themed park combining animal shows and polar land sights has had increased visitors during the annual Harbin International Ice and Snow Festival, the park said. REUTERS/Kim Kyung-Hoon (CHINA - Tags: ANNIVERSARY SOCIETY ANIMALS TRAVEL TPX IMAGES OF THE DAY) 

A young boy yells to his parents as a beluga whale plays with a ball in its enclosure behind him, at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

Visitors watch a beluga whale as it plays with a ball in its enclosure at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

A visitor (L) has her photograph taken next to two beluga whales as they swim in their enclosure at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

A security guard walks past a beluga whale as it swims in its enclosure at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

A keeper checks on two beluga whales as they swim in their enclosure at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

A keeper checks on two beluga whales as they swim in their enclosure at the Beijing Aquarium June 21, 2012. The aquarium is the largest in China, and promoted as "the world's largest inland aquarium", with more than 1,000 marine species and freshwater fish on display. REUTERS/David Gray (CHINA - Tags: SOCIETY TRAVEL ANIMALS) 

A Beluga whale (Delphinapterus leucas) swims at the National Museum of Marine Biology and Aquarium in Checheng Township, in Pingtung July 13, 2011. Fully grown Belugas turn white as an adult. An endangered species, it is estimated that there are about 40,000 Beluga whales alive in the wild. REUTERS/Joel Boh (TAIWAN - Tags: ANIMALS TRAVEL SOCIETY) 

A Beluga whale swims by the underwater viewing window at the Vancouver Aquarium as Canadian Prime Minister Stephen Harper announces federal funding for the aquarium in Vancouver, British Columbia August 9, 2010. REUTERS/Andy Clark (CANADA - Tags: POLITICS ANIMALS) 

A Beluga whale swims by the underwater viewing window at the Vancouver Aquarium as Canadian Prime Minister Stephen Harper announces federal funding for the aquarium in Vancouver, British Columbia August 9, 2010. REUTERS/Andy Clark (CANADA - Tags: POLITICS ANIMALS) 

A Beluga whale swims by the underwater viewing window as British Columbia Premier Gordon Campbell speaks at the Vancouver Aquarium in Vancouver, British Columbia August 9, 2010. Campbell was attending an announcement the aquarium was to be given federal funding. REUTERS/Andy Clark (CANADA - Tags: POLITICS ANIMALS) 

A Beluga whale swims by the underwater viewing window at the Vancouver Aquarium as Canadian Prime Minister Stephen Harper announces federal funding for the aquarium in Vancouver, British Columbia August 9, 2010. REUTERS/Andy Clark (CANADA - Tags: POLITICS ANIMALS IMAGES OF THE DAY) 

A Beluga whale swims by the underwater viewing window at the Vancouver Aquarium as Canadian Prime Minister Stephen Harper announces federal funding for the aquarium in Vancouver, British Columbia August 9, 2010. REUTERS/Andy Clark (CANADA - Tags: POLITICS ANIMALS) 

Aurora, a 20-year-old Beluga whale gives birth at the Vancouver Aquarium in Vancouver, British Columbia, June 7, 2009. Aurora was in labour for about three hours before delivering the new calf. REUTERS/Andy Clark (CANADA ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, gives birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, gives birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, swims with her newborn calf after giving birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, gives birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, swims with her newborn calf after giving birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, gives birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, gives birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS) 

Aurora, a 20-year-old Beluga whale, swims with her newborn calf after giving birth at the Vancouver Aquarium in Vancouver, British Columbia June 7, 2009. Aurora was in labour for about three hours before delivering the calf. REUTERS/Andy Clark (CANADA SOCIETY ENVIRONMENT ANIMALS IMAGES OF THE DAY) 

A white whale balances an orange on its head to resemble a special New Year's rice cake called "Kagami-mochi" at Hakkeijima Sea Paradise aquarium in Yokohama, southwest of Tokyo December 30, 2008. The performance will be held officially at the aquarium from New Years to January 12, 2009. REUTERS/Yuriko Nakao (JAPAN) 

A 125-pound (57kg) beluga whale male calf, who was born on July 17 at the Shedd Aquarium, swims in Chicago, in this file image from August 4, 2006. A new count by the National Marine Fisheries Service puts the Beluga whale population at 302, less than half the number in 1994 and well below the 1,000 to 2,000 believed to have been swimming in earlier years in the glacier-fed channel that runs from Anchorage to the Gulf of Alaska. REUTERS/John Gress/Files (UNITED STATES) 

A couple watch beluga whales at Hakkeijima Sea Paradise in Yokohama, south of Tokyo in this file image from November 24, 2004. A new count by the National Marine Fisheries Service puts the Beluga whale population at 302, less than half the number in 1994 and well below the 1,000 to 2,000 believed to have been swimming in earlier years in the glacier-fed channel that runs from Anchorage to the Gulf of Alaska. REUTERS/Kimimasa Mayama/Files (JAPAN) 

Yulka, a beluga whale, swims at the Oceanografic in Valencia August 11, 2006. Yulka is the first beluga whale to be pregnant while in captivity in Europe, according to the veterinarians of the Oceanografic. REUTERS/Heino Kalis (SPAIN)