Jeremy Cooper
Diving conditions have been fantastic this summer, providing an ideal opportunity to refine and perfect your pāua harvesting technique. Adopting “best practice” harvest and handling techniques not only helps protect local pāua populations, it also ensures that your catch is of the highest quality.
Good harvesting and handling practice is mainly a matter of remembering that pāua are sensitive creatures that need to be handled with care. Like many of us, pāua don’t respond well to stress. Their defence mechanism in response to handling, noise, bright light or vibration is to clamp down firmly. Recent research has shown that this clamping down process triggers physiological changes in a pāua – its heart immediately shuts down and its blood volume reduces resulting in a loss of up to 10% of green-weight within half an hour. When a pāua loses blood it takes an enormous amount of its energy to replace the loss with new blood. Pāua blood doesn’t clot so even the smallest cut may result in a pāua bleeding to death over a period of several weeks. It’s easy to see why even a minor injury can lead to the eventual death of a pāua that has been roughly handled before being returned to the sea.
The best way to avoid injuring or killing paua unnecessarily is to not remove undersized paua from the rocks. This is not always easy, but it can help to only remove the biggest paua you see in an area and check their size first, and move on if they are under 125mm. This will also help you ‘get your eye in’. If you are in a plentiful area removing only the very biggest paua will help you avoid returning undersized and potentially damaged paua.
The most important way of preventing this damage is to use the right harvest tool. Sharp-edged tools such as screwdrivers can break the shell or rupture internal organs and should never be used. The ideal tool has a blunt chisel end, a blade length longer than the pāua you are harvesting (to increase leverage) and a solid handle that will not slip in your grip. MPI Fishery Officers provide free pāua knives that are perfect for the job.
Everyone has their preferred way of harvesting pāua, but you should aim to lever the pāua off the reef in a single continuous motion before it gets a chance to clamp down. Try to target the back (blunt end) of the shell, as injuries to the front end (the head) are more likely to cause fatal injury. If you can’t remove it on the first attempt, leave it, because once a pāua has clamped down you will probably damage it if you persist in trying to remove it.
Any undersized pāua must be returned to the sea immediately, so they should ideally be measured underwater. MPI’s pāua knife is great for this task as it has a built-in measurer. However, if you have taken your pāua out of the water to measure, keep them damp and in the shade because a warm, dry, undersized pāua won’t survive once it is returned to the sea.
The pāua minimum legal size limits are 125mm for blackfoot pāua, 80mm for yellowfoot, and 85mm for blackfoot in the Amateur Taranaki Pāua Fishery Area. These size limits refer to the greatest overall length of the pāua shell measured on a plane parallel to the ventral (i.e., foot) surface of the pāua. Accurate measuring tools should have a “book end” against which one end of the pāua can be placed while keeping the entire foot flat on the measuring surface.
When returning undersized pāua, it’s best to position them the right way up and as close to their original location as possible. Hold the pāua against a smooth rock surface until it clamps on. Never throw undersized pāua over the side of your boat – if they land upside down or on sand or gravel all you’re doing is providing an easy feed for predators such as starfish or reef fish.
By law, pāua must be landed whole. This means that you can’t shuck pāua at sea – any pāua on your boat must always have their shell attached so that they can be measured by Fishery Officers. To keep your pāua in the best possible condition while heading home, make sure they are well covered and out of the sun. Damp sacks or wet seaweed are ideal for keeping your catch in good condition but don’t leave your pāua lying in water and keep them away from contamination such as fuel, dirt or fresh water. Once they’ve been landed, pāua should be shucked, tenderised and chilled as soon as possible.
Having the right tools for harvesting and measuring is the best first step divers can take for improving their pāua harvest technique – so ask about the free pāua knife next time you see an MPI Fishery Officer.