Cornwall Wildlife Trust is urging the public to respect basking sharks as the ocean giants are attracted to Cornish seas which are currently teaming with plankton.

Thanks to a spell of calm weather and long days, Cornwall’s seas are currently full of the shark's main source of food.

Basking sharks and the world’s second largest shark and are totally harmless, gentle giants which come here each year to feed on tiny planktonic animals.

They need to maximise the time they spend feeding on plankton as the energy reserves that they build at this time of year are needed to keep them going through the winter. A basking shark swims slowly through the water on or near the surface with its gaping jaws wide open, using its comb like gills to trap nutritious zooplankton.

It is thought that every hour a basking shark filters a volume of seawater equivalent to an Olympic sized swimming pool, (2000 cubic meters). Despite their gentle reputation basking sharks are powerful creatures and they have been reported to occasionally leap out of the water, a behaviour known as breaching which can make encounters with them dangerous.

"People naturally get excited when they see these incredible creatures but we can also easily disturb them as more and more people are using our coastal waters recreationally each year," said a spokesperson for the trust. "The law (Wildlife & Countryside Act 1981) states that it is an offence to intentionally or recklessly harass any basking shark. A conviction carries the maximum sentence of £5000 and/or six months imprisonment. Recent amendments to the Wildlife & Countryside Act means that ignorance is no longer deemed a suitable excuse; it is up to us to act responsibly around marine wildlife."

Cornwall Wildlife Trust volunteers run a 24 hour marine wildlife hotline to report instances of marine wildlife being disturbed or harassed as part of the work of the Cornwall Marine and Coastal Code Group (CMCCG), 03452012626, with reports backed by video and photo footage where possible.

The information collected can help guide the CMCCG direct their efforts of education and engagement and work within disturbance hotspots around our county.

Abby Crosby, Marine Conservation Officer for Cornwall Wildlife Trust and secretary for the Cornwall Marine and Coastal Code Group says

“We are delighted that basking sharks inspire and excite people, and appreciate that nine times out of ten people do not realise that their actions may be detrimental to the species. Our Cornwall Marine and Coastal Code guidelines are therefore designed to give people all the information they need so that they can enjoy these sightings and encounters whilst protecting the animal they are enjoying. Whether on the sea, by the sea, or even under the sea, there is information for all water users”.

Basking shark code of conduct:

• Do not move closer than 100 metres to them.

• Watch their movements and quietly position yourself alongside their anticipated path 100+ metres away, if using a motor switch your engine into neutral and then drift. Check carefully before re-engaging the engine.

• If the sharks choose to swim past you that is OK but do not change direction to follow them or make sudden movements.

• Keep well clear of large groups – they are likely to be gathering to breed

• Avoid sharks swimming close together nose to tail, as you may disrupt courtship behaviour

• Keep clear of areas where they’ve been seen breaching

• Ensure all encounters are on their terms by only being close to them if they choose to be close to you

If you see a basking shark close its mouth or dive down it may have been disturbed from its feeding.

For more information about the Cornwall Marine and Coastal Code Group, go to cornwallmarinelifecode.org.uk