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:
USING THE RIGHT TOOLSHarvesting Tool : When harvesting pāua, use pāua friendly tools (that is, no sharp edges). There are a number of tools available that minimize the potential for damage. It is important that they have a blunt chisel end, a blade length longer than the pāua you are harvesting (to increase your purchase while extracting them from the reef) and a solid handle that will not slip in your grip. Measuring Tool: Most harvesters prefer the measuring gauge to be built into the handle of their harvesting tool, some prefer it to be set on the side of the blade and some prefer it to be attached to their kit. Whatever the preference, it is important that each diver has the ability to measure pāua for both legal minimum size and any agreed voluntary minimum harvest size; and that the construction of the measuring tool is of a standard so that it cannot be damaged or bent in a way that alters the minimum legal measure of 125 mm. Make sure that appropriate measuring tools for industry-agreed increased harvest sizes are available. Prior to each dive session you should check the harvesting tool for: Sharp edges which form because of the continual contact with the hard surface of the reef. Always have a grinding stone on board the boat to file these back to a blunt edge. Measuring tool. Have a piece of metal cut to exactly 125mm. Place this in the measuring gap on the harvesting tool to check that that it is accurate (a bend in the tool can alter this gap). An incorrect measuring gap could lead to under-sized pāua being kept or oversized pāua being put back.
THE CORRECT REMOVAL TECHNIQUEThere are various techniques for removing pāua: In a quick continual action, slide the tip of the tool under the pāua getting it as far under the foot as possible before applying upwards pressure on the handle. The idea is to lever the pāua off the reef before it gets a chance to clamp down. Be careful to ensure the tip of the tool is between the foot and the reef and not just under the skirt or damage will occur. If unsuccessful in removing a pāua on the first attempt, leave it, because once it has clamped down it is extremely unlikely it will be prised loose without suffering damage. Try to avoid the delicate head area, where the holes meet the front of the shell.
MEASURING PĀUA IN WATERIf you are in doubt about the size of a pāua, you need to measure it prior to putting it into your kit. If it is undersize, return it immediately to the reef. The size of pāua is measured in a straight line across the greatest overall length of the shell. All of the foot must be in contact with the measuring device.
MEASURING PĀUA IN THE BOATIf every pāua has not been carefully measured in the water, the catch will need to be remeasured in the boat. If using a dive tender, pāua should be re-measured by a Boatman as they are landed into the tender. Undersize fish must not be left to sit in the boat as exposure to the sun for any length of time will warm and dry them out leaving little chance of survival when they are returned to the water. It is illegal to leave pāua for a long period of time before measuring and returning them to the sea. The legal requirements are clear and stipulate that any undersized fish must be returned immediately to the waters from which it was taken.
RETURN UNDERSIZED PĀUA TO ENSURE SURVIVALThe boatman should ensure that any undersize fish are put into a kit and handed back to a diver for return to the reef as soon as possible. The pāua need to be positioned the right way up and as close to their original location as possible. Hold them against a smooth rock surface until they clamp on. Under no circumstances should pāua be thrown over the side as these will land upside down where they can be attacked by predators before they have the chance to right themselves. Pāua that are thrown back onto sandy or gravely substrate may not be able to right themselves at all and will become an easy meal for the first predator on the scene.
MEASURING PĀUA WITHOUT A BOATMANLeave the fish (pāua) in catch bags clipped to the side of tender/boat (i.e., in the water) until the fish is measured. Catch bags should be measured and undersized pāua returned to the bottom at least every hour.
STORAGE OF PĀUA ONCE HARVESTEDPāua that are stored on deck must be kept in the shade and protected from the elements. Wet sacks are ideal in keeping the catch in good condition. Pāua should be stacked into clean, inter-lockable, well drained containers (holes in the bottom) and kept away from all contamination e.g., fuel, dirt, fresh water and any other harmful substances. Pāua should be placed gently into bins. Avoid cramming or dropping the animals. To stop the pāua drowning they need to be stacked on their side with their vent holes up. Make sure the top layer of pāua does not go above the stack lugs on the bin so that the pressure of the bin above is taken by the stack lugs and not the pāua. During transportation the bins need to be held secure and covered. There should be no delay in getting the catch into the LFR’s chiller.
LANDING THE CATCHHarvesters, where possible, should notify the LFR of their intention to dive Care must be exercised when lifting and moving bins. Occupational Safety and Health (OSH) guidelines recommend that the bins should not weight more than 25kg. There is a detailed recommendation in the OSH “Code of Practice for Manual Handling” that allows you to better calculate what the maximum weight should be to suit your circumstances, see www.osh.govt.nz Pāua should be free from any foreign matter, weed, stones etc. and in good, live condition. Any blue material in the bottom of the bins means the pāua are bleeding and have been handled too roughly. At the end of the trip all pāua must be landed directly and expediently to an LFR All bins / containers must be CLEARLY labelled with: Vessel name and registration Date the pāua were taken Minimum harvest size area The pāua statistical area from which pāua were taken Harvester's QRN number, name and signature Labels must be of such material to stay clearly readable when wet.
BOATMAN'S RESPONSIBILITIESEmpty the pāua kit without force. This includes not dropping or banging the kit to loosen the pāua clump Use a harvesting tool to separate the pāua. Do not aggressively twist, wrench or pull pāua when trying to de-clump them as the internal muscles and organs will be damaged. Any undersized pāua with these injuries will die when they are returned to the reef Use a dedicated measuring tool that is strongly constructed so that daily use will not alter or damage the measuring gap Ensure that pāua are flat on the surface of the tool when measuring Place undersize pāua in a kit ready to be returned to the reef by the next available diver Ensure all pāua are protected from the elements at all times. Pāua are extremely fragile. All care must be taken during the handling of them so that when undersized pāua are returned to the reef they have the greatest chance of survival.
IMPORTANT HARVESTING PRACTICESHarvesting crews must ensure that their harvesting does not cause serial depletion of substocks within PAU7, especially in easily accessible beds. Too much pressure on individual substocks results in excessive handling of the fish leading to major mortality. Sustained fishing pressure causing serial depletion also results in very low CPUE data for those areas which consequently affects the total PAU7 CPUE, making CPUE inaccurate and misleading when building a sustainable fishery.
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