I am from Hong Kong and I live here in South Korea. I can’t speak the language, but in the past few days the only sentence on my mind was:

 "Greenpeace neun hankuk chamchi op che Dongwon e sak sul i oe oepeul jung dan hal geosl chuk gu ham ni da" (Greenpeace urges the Korean tuna company Dongwon to stop destructive fishing.)"

 I kept practising it because I wanted to say those words to Dongwon Industries company representatives when we confronted them on Wednesday.

After launching Greenpeace East Asia’s first ranking of Korean tinned tuna in a report called “The Hidden Secret of Canned Tuna” (http://www.greenpeace.org/korea/news/publications/2012/1/hidden-secret-of-canned-tuna/), we followed it up with a protest at Dongwon’s South Korea headquarters.

Our activists climbed up the Dongwon headquarters in Seoul displaying a big fish bone in a fishing net and a banner saying “Dongwon, Korea’s No.1 Ocean Plunderer!” Activists involved in this protest came from South Korea, Hong Kong, Taiwan and even Fiji.

  Following the release of the ranking last week, we collected hundreds of messages from Korean consumers urging Dongwon (which has a commanding 50 percent market share here) to change their practices.

 Many consumers did not know about the hidden costs behind canned tuna and could not imagine that this common food item is now in trouble due to continued overfishing and wasteful fishing methods.

 When they saw our report and understood the issue, most people said they want big Korean companies to support the protection of our oceans. Some of the messages Korean consumers sent to Dongwon were:

 "Dongwon, please save the ocean because we trust you."

 "Don’t catch juvenile tuna."

 "Use the right method to catch tuna."

 We packaged consumers' messages into a giant tuna can and delivered it to representatives from Dongwon. We hope the company will listen to their customers' demands for sustainable tuna choices.

 Greenpeace East Asia will continue to bring consumers’ concerns to this company over the coming months, demanding change.

 As the biggest tuna company in South Korea, Dongwon should take the lead on sustainability and not lag behind its competitors, Sajo and Ottogi.

 Greenpeace is demanding Dongwon abandon destructive fishing practices, start sustainable fishing operations to ensure our oceans are healthy for future generations. We hope the industry can change its ways and ensure our next generation can also eat and enjoy seafood.

 Greenpeace is campaigning for tuna brands to improve their sustainability policies. Some of the steps they can take include eliminating the use of fish aggregating devices (FADs) with their purse seine fleet, and support the creation of a global network of marine reserves covering 40% of the world’s oceans.

 Both of these are necessary steps that will help our oceans recover and ensure an ample supply of fish for future generations.

Yuen Ping Chow is an oceans campaigner based in Greenpeace East Asia's Seoul office.