8 out of 10 cats don't know where their fish comes from

You may have made you home and car energy efficient but what about your pet?

The authors of a recent book, Time to Eat the Dog? warned that the energy required to feed a cat is the same as that required to build and drive a Volkswagen Golf for 6,000 miles a year.

Now there is a way do reduce your cat's carbon paw print.

Later this year the UK's 8m cat owners will, for the first time, be able to feed their kitties their favourite fish with a clear conscience.

The manufacturers of Whiskas and Sheba are to become the first to sell products using Marine Stewardship Council-certified fish, which is caught sustainably and without threatening further dwindling stocks.

While eight out of 10 cats are likely to have no opinion on the provenance of their fish, Mark Johnson of manufacturer Mars Petcare said people were increasingly aware of the importance of sustainability.

"The End of the Line film [a documentary about overfishing] has had a big impact," said Johnson, the company's UK general manager.

We are now the first pet company to make a commitment to sustainable fish, and we hope that will act as a catalyst for the whole industry."

Supermarkets have been quick to respond to rising human demand for sustainable fish, with the Co-operative eliminating threatened species from its own-brand products and Marks & Spencer recently becoming the first high-street name to sign up to WWF's new seafood charter.

But pet lovers have so far been limited to giving their animals human food such as sustainably caught tinned tuna: an expensive way to limit their pets' ecological impact.

(Well, in Charlie's case it's a good thing he is not keen on fish! I hear rabbits and poultry are much lower impact than fish and red meat.)

While cats and dogs may seem unlikely environmental villains, UK pet owners buy 1.5m tonnes of food a year and globally there are an estimated 750m pets who consume 20m tonnes annually. 

The new MSC-certified Whiskas and Sheba will be on sale in December - with a pledge to source all its fish globally from sustainable sources by 2020. For more visit The Guardian website.