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Moored boat owners have long understood that maintaining their vessel's antifouling system is essential to the smooth running of their boat.
Failure to keep the antifouling coating in good nick generally has pretty dire consequences, and these usually don't take too long to appear.
Large unsightly growths along and below the waterline are just the start. Speed drops, fuel consumption skyrockets and little greeblies sneak into skin fittings and seals and do considerable damage.
But keeping your antifouling in good shape has another benefit, it seems: It helps to protect our marine environment.
According to MAF Biosecurity, the Government agency responsible for protecting us against these sorts of things, our waters and coastal environments are coming under increasing threat from "foreign" marine organisms.
More to the point, at least two-thirds of these are suspected of having arrived on the hulls of visiting vessels; anything from large merchant ships to small cruising yachts.
One particularly nasty example is the Australian sea squirt, Eudistoma elongatum. This unsightly white sausage-like organism has, over the past few summers, steadily infected Northland bays and harbours.
It probably arrived in New Zealand on the hull of an ocean-going vessel and is now too widespread in the North to tackle effectively.
The fouling sea squirt Styela clava (just as nasty as its Australian cousin) is now widespread throughout the Hauraki Gulf and has also been found in Lyttelton and in two marinas in Northland.
It, too, was almost certainly spread on boats, possibly pleasure boats with hulls where the antifouling not been properly maintained.
Also in Lyttelton, Biosecurity is trying to decide how to battle a new invader, the Sabella spallanzannii fanworm. It was discovered during routine surveillance of the area.
Unfortunately, once they arrive in new waters, unpleasant marine organisms such as these sea squirts (and worms, sea stars, crabs, clams and various weeds) often seem to really prosper. In doing so they can, not surprisingly, cause irreversible damage to their new environment.
Some of these pests can literally overrun our native ecosystems, adversely affect our fish stocks, marine farming and tourism. They can also be incredibly unsightly.
Sadly, once established here, they are extremely difficult to control or eliminate. It seems all any of us can realistically do is prevent them (and any other fouling pests) from hitch-hiking to other areas on our hulls.
Obviously, the best way to do this is simply to ensure our hulls are clean and well protected with an effective antifouling coating.
Biosecurity has recognised this and therefore, as part of its strategy to minimise the spread of these harmful organisms, has begun to encourage boat owners to regularly clean and properly antifoul their hulls.
As part of the campaign, all cans of antifouling from New Zealand's specialist marine paint manufacturer, Altex Coatings, are now being sold with a new "Clean Boats - Living Seas" sticker on the can.
On the sticker is the address of a new web page (www.livingseas.co.nz).
This features detailed hull cleaning information and also links to Biosecurity's website (www.biosecurity.govt.nz) where there is a comprehensive array of information on marine pests, as well as advice on cleaning and antifouling.
The agency has also produced illustrative guides and a new instructional DVD.
Information brochures are also being prominently displayed in chandleries and marine supply stores around the country.
Biosecurity's Lesley Patston says the role boaties can play in protecting the environment cannot be over-estimated. She urges owners to regularly clean their boat's bottom.
"Do not allow any build up of growth beyond a slime layer.
"Particular attention should be paid to what are known as 'niche' areas - parts of the boat that stick out or retain water," she says.
"These are areas such as the keel, intakes and outlets, propellers and shafts, rudders and casings. They are prime areas for harbouring pests.
"Ensure your antifouling is in good condition and re-applied as recommended by the manufacturer or retailer. Renew if it's been scraped or damaged or if persistent fouling is occurring.
"Finally and most importantly, check your boat is clean before you move location. If it's not, clean it!"
Patston also urges owners to put any debris removed from the hull into rubbish bins on land, to prevent it getting back into the water.
Biosecurity is also working hard to stop marine pests arriving here in the first place.
The Government has just agreed to sign an international agreement on ballast water. Once in force, this will see ships required to treat ballast water on board before it is discharged.
As well, New Zealand is leading work through the International Maritime Organisation, pushing for the development of consistent, internationally agreed biofouling management measures for all vessels.
Biosecurity is developing new standards requiring all arriving vessels to demonstrate their cleaning history and that they have a clean hull.
Australia already has such a protocol in place and advertises it widely among the cruising fraternity.
Patston says Biosecurity also needs boat owners and their crew to keep an eye out for new pests.
"Because boaties are out and about on and around the sea, they are well placed to notice things that may seem unusual. If anyone comes across a marine plant or sea life that looks out of the ordinary, it would be great if they could note its location (as accurately as possible), collect a sample (if they can) and phone us on our freephone, 0800 80 99 66.
"The sooner [we hear] about potential marine pests, the better chance we have of successfully controlling or eradicating them."
