By the time you read this, I'll be at the head office of Princes in Liverpool where a frenzy of sharks is demanding an end (a fin-ish?) to the dreadful fishing methods that kill other marine species like sharks, rays and even turtles which Princes relies on for its tinned tuna.

Some of the unlucky sharks killed in tuna nets are hanging from the iconic Liver Building, while other sharks are protesting outside. Of course, they're not real sharks, but Greenpeace volunteers are reminding everyone why Princes - the largest supplier of tinned tuna in the UK, responsible for one in every three tins of tuna sold - came last in our UK tinned tuna league table. There's even the Jaws theme booming out of a loudspeaker.

Despite receiving over 75,000 emails from Greenpeace supporters around the world - not to mention the attention drawn to the fishing industry by Hugh's Fish Fight - Princes has done little to improve its sustainability practices. Oh sure, there are some labelling changes in the pipeline, but that doesn't change what's in the tin and how it got there.

The fact remains, Princes still relies on fish aggregating devices (FADs) used with purse seine nets and they know that's a sure-fire way to haul up plenty of bycatch along with the tuna. Hence the sharks outside Princes's head office - some of them may look cuddly and cute, but they mean business.

But while we're outside head office, I'd like your help to come up with a new advertising slogan for Princes. I don't think the current one - "Yours to enjoy" - gets across what the company is really doing. It's fairly bland and meaningless however you look at it, but given what's going on behind the scenes  it doesn't really do justice to the mass destruction of ocean life, which is what the Princes brand really stands for.

Does it explain how Princes is refusing to move to more sustainable fishing methods in contrast to other suppliers like Sainsbury's, Marks & Spencer and Waitrose who have done so, for instance? Or that Princes is the only tinned tuna company in the UK still selling bigeye tuna. Why does no one else want to sell bigeye tuna? Because scientists have classified it as "facing a high risk of extinction".

And what is a PR agency like Citypress (@citypress) doing trying to defend the dreadful practices of Princes? There's only so far you can spin a fishy tale about Princes having "strict standards" when it comes to sustainability.

I know we can do better than "Yours to enjoy". Send us your new advertising slogan for Princes. It will be emailed to Princes, and we'll feature some of the best ones here and on Twitter.

It's time Princes changed its tuna once and for all. Add your voice to the growing movement demanding Princes stop canning ocean destruction here.

Jamie Woolley is based in Greenpeace UK's London office.