The Sea Shepherd conservation activist ship Allankay is in Tāmaki Makaurau after a full programme in the seas around Antarctica earlier this year and is welcoming visitors on board for a free tour of the vessel this weekend.

The group have been following trawlers fishing for krill in the Southern Ocean, highlighting the danger the activity causes to whales and other cetaceans.

Krill are small crustaceans about 5cm long and are fished to meet growing demand in the health supplement market as a source of omega-3. Unfortunately, they are also a major food source for humpback and other baleen whales, which are sometimes killed as bycatch.

In March this year the crew of the Allankay witnessed and documented the death of a humpback as the Chilean-registered supertrawler Antarctic Endeavour hauled up the creature around Coronation Island, between South America and Antarctica.

“That morning, there were so many whales around that we couldn’t even count them all as they dodged between fishing vessels,” Dr Lucia Morillo, a biologist onboard the Allankay, said.

Sea Shepherd highlights the impact of krill fishing and is offering ship tours during its Auckland visit to encourage the protection of wildlife.

“I noted the presence of two humpback whales in my observation log. We were less than two nautical miles away from Antarctic Endeavour at the time. I wonder now if one of those humpback whales ended up in their net.”

The incident was reported to Chile’s Fisheries and Aquaculture Service and a criminal complaint against the ship and her crew has been lodged.

Sea Shepherd has been sounding the alarm on the risk that the krill fishery poses to whale survival, by shadowing the krill fishing fleet and documenting the conflict between feeding cetaceans and a growing fleet of supertrawlers.

“Being part of the Operation Antarctica Defence made me realise how crucial it is to protect this fragile ecosystem,” Sèrgio Carlos, captain of the Allankay, said this week, adding that defending krill, the foundation of the Antarctic food chain, means defending whales, penguins and the overall balance of life in Antarctica.

“Every effort we make sends a clear message: the Southern Ocean must be respected and preserved.”

The conservation group hit the headlines 15 years ago when they attempted to interrupt Japanese whaling ships in Antarctic waters.

In January 2010, New Zealander Pete Bethune scuttled his boat, the Ady Gil, under orders from Sea Shepherd founder and former president Paul Watson after the Shonan Maru II crushed it.

Bethune was convicted in a Japanese court for throwing acid and illegally boarding one of the Japanese fleet. Watson was arrested in Greenland last July under an international warrant issued by Japan. Both men have now left the Sea Shepherd organisation.

The Allankay is welcoming people on board this weekend between 10am and 5pm at the Halsey St Wharf, behind the Viaduct Events Centre.