The sun breaks through the cloud as the first children arrive. It’s a perfect day for a Wildlife Watch expedition and although I don’t know the beach at Coverack well, a quick paddle in the rippling shallows has already yielded sand eels, an attractive pink thin tellin shell and plenty of shore crabs so it’s shaping up well.

I always look forward to meeting my Wildlife Watch groups and this one doesn’t disappoint. My assistant, Vicky, does a fabulous job of welcoming everyone and helping set up and the children are enthusiastic and curious, raring to get stuck in. It’s especially good to see how well the kids care for the animals, making sure they have enough water in their tubs, replacing any stones and seaweed they move and not detaching animals that might get damaged like anemones and limpets.

One lad is particularly adventurous and knowledgeable, so we have fun investigating a gully between two huge rocks. We find the inner face of one rock is covered in a massive sheet of breadcrumb sponge and there are especially large strawberry anemones in the pool beneath. My new friend stays there trying to catch an elusive fish while I help others identify creatures.

Soon, the finds are coming in to our makeshift shore laboratory. Glittering sand eels, a feisty velvet swimming crab with devilish red eyes, a whole troop of hermit crabs and colourful brittle stars which we watch walking on their long arms.

My new friend comes over with a shore crab. He’s learned that they keep their eggs under their tails and is excited to find one he thinks is in berry. He seems disappointed when I reveal that, although she has something under there, it’s not eggs. But this is something far more exciting. It’s a parasitic barnacle, Sacculina carcini, which I’ve been searching for and never seen. The yellow mass under the crab’s tail is the barnacle’s fruiting body, the barnacle’s eggs – not the crab’s.

Unfortunately for the crab, once it is infected it can no longer moult and grow or lay eggs. The barnacle will take a lot of energy from the crab as it spreads through its body. It can even trick male crabs into behaving like females to ensure that they will successfully release the barnacle’s young when the eggs are ready to hatch. It’s amazing to see, even if it’s not good news for the crab.

As always, I get more than a little distracted doing my own rock pooling. I can’t help myself. I briefly feel guilty that I’m not available enough to the children while I’m crawling about among the slippery boulders, but then I spot a miniscule thing moving on the rock and it has my entire attention.

The thing looks like a tiny lobster. I scramble to grab a suitable pot and when I look back at the rock I can’t see it any more. I stare at the area where I saw it but it’s just not there. I look all around the surface of the rock in vain, gently tip a little sea water down it to see if anything moves but I’m scared I might wash it off accidentally.

When I finally relocate my mini crustacean, it is nearly at the edge. With a lot of care and determination, I succeed in catching it in my pot. It’s only about 5mm long, but seems to be a tiny squat lobster, the smallest I’ve ever seen.

Back at the trays, we all gather round to take a close look at all the animals and learn about their lives and strange habits. We have a fabulous diversity of creatures to watch before they’re returned to the shore.

I slip my baby squat lobster into a petri dish to take some photos. It looks a bit strange, as though something has got caught on its back legs. When I look a couple of minutes later, the thing that’s stuck to it has grown. It’s hard to see as the whole animal is only a few millimetres long, but when the ‘thing’ comes away I’m in no doubt. The squat lobster is growing and has just shed its old skin.

The old carapace is an exact replica of the animal, only colourless and transparent. As the new, soft shell of the squat lobster begins to harden it seems to grow before our eyes.

It’s something I’ve never seen before. It’s what’s so special about events like this. Even though I’m here to help others learn and see new things, I’ve seen something new myself.

If you’d like to come to a Wildlife Watch event with the Cornwall Wildlife Trust this summer, you’ll need to book quickly as they are filling up. Find the whole list on the Cornwall Wildlife Trust’s website. Maybe I’ll see you there?