Are you a biosecurity risk? It can be difficult for the untrained eye to tell from the surface if a boat is a biosecurity risk or not. The safest rule of thumb is to ensure your boat hull never carries more than a slime layer, and ideally this is regularly brushed or wiped off. Your boat should also have a regular out-of-water clean and a liberal coating of antifouling paint.
MAF Biosecurity New Zealand (MAFBNZ) is the government agency responsible for marine biosecurity. It has work programmes underway to help prevent marine pests arriving in New Zealand in the first place, to detect and take action against any new arrivals, and to help manage any that do become established pests. But protecting New Zealand is not just the Government’s job. As a boatie you can help prevent the spread of those marine pests already in our waters. And the more people we have keeping watch for anything that may be a new exotic pest, the greater our chances of detecting it early and managing it.
It is a scientific fact that marine pests travel on boat hulls. A 1998 report by the National Institute of Water and Atmospheric Research (NIWA) estimated that of the 148 known introduced marine species in New Zealand, 69 percent had arrived in hull fouling. The message is clear – keep your boat bottom clean. Pests are unlikely to hitch a ride on a clean hull.
A slime layer is easily removed with a water blast.nAny vessel that remains moored in seawater (yachts, launches, fishing/aquaculture boats, ferries, barges) can collect marine pests in the growth that accumulates on the bottom. These can then t allow in-water cleaning because of the risk of releasing contaminants in paint.
The only way to ensure a good thorough clean is to slip or haul out your boat. Regularly cleaning out of the water and replacing your antifouling paint should be a fact of life for boat ownership. And that’s not just for biosecurity. As most boaties know, keeping your hull clean improves performance, reduces running costs and prolongs the life of your vessel. The following are guidelines for cleaning your hull if you are doing it yourself:
- When out-of-water cleaning, where possible arrange to haul your boat out at a facility where waste hull-wash water is contained and treated before going back into the sea or is discharged to a municipal sewerage system. Once again, your local city or regional council or marina will be able to guide you on the best facilities for your needs.
- You should always haul out your vessel for cleaning if it is carrying any more than a slime layer.
- Remove all visible fouling, including mussels, barnacles, seaweed etc.
- Dispose of all debris removed to a rubbish bin that will go to land-based refuse dump. Some pests are very tough and can survive being out of water for a long time, and some are encouraged to reproduce after being out of the water for some time. So don’t dump debris where it might end up back in the ocean.
- Hose and brush down surface to remove all fouling. Water or sandblast where required.
- Pay particular attention to what are known as “niche areas” on your boat – areas that stick out or contain water where marine organisms could attach or hide. These include:
- keel and stabilisers;
- intakes and outlets;
- propellers and shafts;
- rudders and casings;
- earth plates, transducers and areas where antifoul has not been applied such as where the hull has rested during the last painting;
- anchors and anchor wells.
The best way to avoid fouling build up is to have your hull coated with an appropriate antifoul paint. Your antifoul should be replaced at the interval recommended by the manufacturer or retailer, or when the paint has been scraped or damaged. The antifouling paint used should be suitable for the material of the hull, the type of boat and the use it is put to. Factors considered in this are the speed of travel, time kept at mooring or berth, and the water conditions around your boat. Be sure to strictly follow the manufacturer’s and or retailer’s instructions. If you’re unsure on what antifouling paint to use, get advice from your local marine chandlery or marina slipyard.
If you are moving to a new area, ideally clean before you set off. Preferably slip or haul out your vessel for a thorough, out-of-water clean and antifoul before a voyage such as a holiday, working in another region or a relocation trip. Antifouling should help you avoid picking up any nasties while you are away.
If you are returning to New Zealand after sailing internationally, it is very important make sure you’re not bringing back hitchhiking marine pests. If possible, you should check and clean any debris from your hull before you leave your last offshore port or location. If you are unable to carry out a full haul out and antifoul application at this stage, you should arrange to haul out your vessel as soon as possible after arrival back in New Zealand. Haul out on arrival back here must be in a boat maintenance facility that has containment systems and treatment of all waste and cleaning run-off. The MAFBNZ inspector clearing your vessel on return will be able to advise you on a suitable facility and may direct you there if they consider you pose a biosecurity risk.
Most of you know salt water is hard on vessels and gear. Washing your boat, fishing gear and dive gear with fresh water after every use will prolong its life and reduce the risk of spreading marine pests.