"Not a lot of meat on that one," she says, before dropping Lucky back into the water, with a plop.
But that's not such bad news for our hungry group, as there are plenty of other spoils to be found on a stroll along the pale yellow sands of Elie Beach on the East Neuk of Fife. We're taking part in a Forage Rangers seaside session, which has been organised by Milne and her friend Fiona Houston, who are joint authors of foraging reference book, Seaweed and Eat It.
The theme of this lesson seems particularly timely, as many of us will be spending our summer holidays "a-la-plage" in the UK this year. Armed with the right knowledge, there's no reason why more of us couldn't head out at low tide with wellies on, bucket in hand, looking for dinner.
You see, what this lot really, really want to find is a lobster. This is possible, but not guaranteed, as Milne says: "It's a bit like going on safari, you're not always going to see a leopard."
We'll be far luckier if we think vegetarian as, in contrast, edible algae is everywhere. If we want to harvest it, we're told that we have to avoid effluent (EU Blue Flag beaches, like the one at Elie, are preferable), only pick living seaweed and cut the plants with scissors, so they can regenerate. Aside from that, go crazy. After all, as Milne says, "You can eat all varieties of seaweed, it's just that some taste better than others."
The first species that we stumble upon is flat-stranded kelp, which can be found in huge quantities on almost every British beach. It looks a bit like discarded Super 8 film reel and can be used to wrap sushi, or flavour the Oriental cooking stock, dashi. As Milne says; "My Chinese friend was gobsmacked that we don't eat it."
The unseasoned flavour isn't, however, the most compulsively delicious thing we've ever tried. My boyfriend, Rolf, chews a corner, before describing it as "salty apple skin". I concur, although, one of the dogs that's tagging along on our session, an elderly bull terrier named Myrtle, can't stop gorging herself on this iodine-rich plant.
"That's a good sign that it's fresh," says Houston.
Perhaps Myrtle is lacking in vitamins as, despite its lack of flavour, kelp is packed with nutrients. This makes it of special interest to one of today's participants, Tara Graham, 36, from St Andrews.