Pāua are ancient snails with basic and inefficient blood and
They are easily stressed by handling, noise, bright light and vibration and their defence mechanism in this situation is to clamp down. Recent research has shown that this clamping down process triggers several physiological events that can take a couple of days to get back to normal. Their heart immediately shuts down and their blood volume is reduced by up to 10 percent of their green weight within half an hour. Pāua blood is clear in colour as it travels to the gills and light blue in colour as it travels out of the gills. Its blood circulation system is unique to this species. It does not clot and there are very few biological mechanisms (e.g., valves) to stop the blood draining out. Even the smallest cut may result in the pāua bleeding to death. When this occurs, pāua will attempt to stem the flow of blood by contracting the muscle around the wound while the cut heals. Unfortunately, this response can also restrict its movement and ability to feed.
When you combine the lack of a blood clotting mechanism, lack of feeding, the immense energy required to replace blood volume and the number of things that can trigger stress in pāua; it is easy to see why injury can lead to death of undersized pāua in the months following handling. Therefore special care needs to be taken to avoid damaging pāua both during harvest and post-handling.
There are a number of ways to ensure that damage to undersized pāua is minimised. You can help ensure your future pāua harvests by following these ten simple guidelines:
PĀUA DIVER'S CODE
Pāua less than the minus legal size are next year's harvest. There are a number of ways to ensure that undersized pāua are not removed from reef surfaces, and ways to care for the young pāua if they are inadvertently removed. Divers can help ensure the future pāua harvest by following a few simple rules:
Use instruments with an underwater measuring device/mark. If you measure your pāua underwater, you will have less change of taking and damaging undersized pāua.
Use tools that are less likely to cut and damage pāua. This will avoid damaging any undersized pāua you may inadvertently harvest.
Take care when removing pāua in case some are undersized. Pāua blood does not clot. Even the smallest cut may result in pāua mortalities. Returned undersized pāua are unlikely to survive when damaged. If they do survive the cut, they are likely to die of infection.
You should measure your pāua underwater. However, if you have taken pāua from the water to measure onboard the boat, ensure you keep them damp and in the shade. Pāua dry out and die quickly if not protected from the heat and sun. Heat-damaged pāua will be in a weakened state and susceptible to predators if placed back on the reef.
Undersized pāua should be returned promptly by a diver, the right way up onto the reef surface. Do not throw pāua over the side of the boat. Unless pāua are returned to the reef, they are likely to be preyed on by starfish, reef fish and other predators before they have a chance to clamp to a rock surface. It is unlikely that pāua thrown overboard will survive.
Take only a few pāuafrom a bed and move onto another area. If pāua are cleared from large areas, they may not reproduce, resulting in depleted pāua areas.
Where possible, avoid fishing in areas favoured by customary and recreational pāua fishers. The pāua fisheries are a shared resource that everyone has the right to access. Avoiding commercial fishing in such areas lessens the pressure applied to local "food patches".
Pāua's size should be measured in as close to a straight line as possible, across the greatest overall length of the shell. 125mm is the minimal legal size (MLS) in most pāuaQMAs, although some areas opt to take pāua greater than 125mm for the greater health of the fishery. Check your local area's rules before diving.
If you see any suspicious or illegal activity, report it to the Ministry for Primary Industries (MPI). The sooner you this, and the more accurate and detailed the information you provide, the better the chance of the offenders being caught and prosecuted. Record/provide the following information: - Exact location, time and date - Vessel name and number - Description of vessel type, colour and length - Vehicle plate number and a description of make, model and colour - Number and description of people involved (names and addresses if known) - Details of what you observed or heard about or found - Images / video if possible