On a remote Scottish island in the Hebrides, boisterous children gather around a life-size blow-up minke whale. As they bounce around on the billowing monster, marine education officer Caroline Lathe explains the mammal’s main features. Two blow holes are for breathing and expelling moist air from their lungs, while the hair-like baleen filters plankton.

This is as close as most of the children have been to a whale, yet minkes regularly cruise the Isle of Colonsay’s coastline.

Caroline is hoping the children will grow to appreciate the marine riches on their doorstep. “Our main aim is conservation through education,” she says. “We aim to raise awareness of marine habitats so that people know more about the dangers of allowing them to be damaged.”

We’ve sailed to Colonsay aboard Silurian, a 53ft floating classroom. The Hebridean Whale and Dolphin Trust (HWDT), Caroline’s employer, bought the ketch in 2002 when its role as a filming platform for the BBC’s Blue Planet series drew to a close. Now equipped with anemometers (for measuring windspeed), temperature and salinity probes, a plankton-catching net, and microscope, plus computers and software for gathering marine mammal survey data, her use alternates between monitoring cetacean numbers and movements, and spreading the marine conservation message around the islands of Argyll.

Eight miles long by three miles wide, Colonsay is a windswept island lying 20 miles south-west of the trust’s base in Tobermory, Mull. We have come to visit the pupils at Kilchattan primary school. Only 100 people live on the island, so it is not surprising the school has only a dozen pupils. Although most of them have grown up by the sea and know people who own boats, their experience of marine mammals is limited. Some recall seeing dolphins and porpoises, but few have seen a live whale.

Once acquainted with Matilda the minke, the pupils follow Caroline back into their cheerful, yellow-painted classroom to learn how cetaceans communicate using clicks. In pairs, they invent their own codes then try to locate their partner using sound alone.

The wind was so strong when we arrived at Colonsay that the Silurian had to leave us to seek shelter on the nearby Isle of Jura. On calmer days, the trust invites schoolchildren to come aboard for a hands-on lesson. Teachers on the islands have welcomed this opportunity, because organising school trips can be tricky.

“Having the trust come to visit us is great for the children, particularly now conservation plays such a large part in the curriculum,” enthuses Kilchattan’s headteacher, Carol Macneill.

Around 10 children can come aboard at any one time. In the cosy saloon, they learn about the species that patrol Scottish waters. Killer and minke whales, Risso’s, common and bottlenose dolphins, and harbour porpoises are all regular visitors, feeding on fish, squid, krill and plankton.

Microscopes, petri dishes and pipettes laid out on the Silurian’s varnished wooden table enable the children to catch plankton from a tank and inspect the tiny translucent creatures for themselves. Coloured charts help them tell their copepods (minute marine crustaceans) from their daphnia (waterfleas), while a minke whale painted in rich blue hues on the ceiling casts a watchful eye over them.

On deck, the children gather round a “touch tank” to examine treasures retrieved from local waters. There are whelks and crabs, lobsters and seaweed, and sometimes starfish such as the brittle and the sun star.

Pupils can use the hydrophone to eavesdrop on life beneath the waves.

“Dolphins make whistles and clicks, while humpbacks make moaning sounds described by scientists as song,” explains first mate Jamie Speirs. “Sperm whales make a click which sounds like an engine starting, or castanets.

Even if there are no cetaceans around you can hear crabs and shrimps breaking things with their claws.”

Reunited with the Silurian after our Colonsay visit, the trust staff celebrate having visited every Argyll island school on Mull, Jura, Gigha, Islay, Colonsay, Lismore, Coll, Iona and Tiree - at least once since 2002.

During the winter months, marine conservation lessons are available on the mainland, but as spring gets under way, the Silurian will be back on the water. Caroline even hopes one day to sail her into Glasgow to spread the conservation word among inner-city pupils.

HWDT Tel: 01688 302 620; email: education@hwdt.sol.co.uk; http:whales.gn.apc.org