Will she fall for anchovy extract? Could a mixture of raspberry jam and shrimp scampi reveal her charms? Surely the lure of passion fruit will prove too much?
Cartwright's excitement reached fever pitch yesterday as he tried out his seduction technique by throwing his most tempting dishes into a large gravel pit near Staines, west London. For, as the coarse fishing season opened, Cartwright (as he has for the past 10 years) was sitting patiently trying to catch Mary, the largest carp in the UK.
Most of Britain's 4 million fishermen are content to angle for anything with fins. But a select group will spend the rest of the year living in tents on a diet of beans and sausages, hoping for just one giant fish.
Cartwright, who leaves the waterside only to restock his larder and to collect his dole money, is an extreme example of carp fever, the most popular branch of coarse fishing, where the fish are not killed but weighed and lovingly
His love affair with Mary over the past decade has not been unrequited. He has caressed her scaly body three times. On each occasion, she had packed on a couple more pounds and edged nearer the 51lb 8oz British record that is his obsession. When he captured her at the end of last year, Mary was 1lb under that weight.
He has high hopes that his extraordinary vigil will be rewarded in the next couple of weeks. But she will not be easy to catch. She will turn her fins up at ordinary bread or worms. So Cartwright will be using a marble-shaped bait called a boilie - a carefully-prepared mixture of sweeteners, vitamins, minerals, enzyme additives and emulsifiers.
Electronic indicators will warn Cartwright if the fish grabs his bait while he is sleeping.
Such refinements have brought fierce condemnation from many anglers, including record holder Chris Yates, of Tisbury, Wiltshire: 'Carp fishing was always regarded as the most demanding branch of angling, and yet nowadays on many waters, it is about as exciting and demanding as playing snap with a tortoise.'