Prawns are members of the Decapods Crustacean family thus they are a shellfish, live independently and are bottom feeders. Prawns live four to five years; they breed and grow fast. They all start out as males and in the fourth year of life change over to females. The body colour is a pinkish to reddish brown with distinctive white spots on the first and fifth abdominal segment. They are usually between 1.5" to 9" long.
You will need a trap; bait holder, line, line weight., and a buoy. Most Marine supply stores will carry some type of trap. There are two styles of traps, round or rectangular, the mesh should be ½' or so and have at least two or three cone shape openings. Some boaters prefer the rectangular shape because most are designed to fold up for storage. The round ones are generally of a commercial grade, and do not fold up, thus they will take up more room on your boat. The line should be up to 400' long and can be poly, nylon or special trap line, (line made not to float). Line weights are made with a quick clamp to hook onto the line, and finally a float or buoy.
Here are some tricks to set you up. Add weight to the trap, you want the trap to go straight down and stay on the bottom, I use boat zinc's attached with zap straps, others have used anchor chain, or just scrap steel, whatever you use just attach it to the outside bottom of the trap. Bait holders can be fine nylon mesh bag or plastic screw top jars with slots. Bait can be fish guts, any seafood waist, rotting food like chicken works, but the best product I have found is commercial prawn bait, it’s just like dried dog food pellets impregnated with fish oil. I have found it for sale in most costal marine stores. Tie the bait in the middle of the trap, away from the top and sides. Attach your line to the top of the trap and start to lower over the side. You will want to find a spot on the chart anywhere between 150 to 350 feet deep. Let out all your line. Here is where your line weight comes into play. If you put out 400 ft of poly line, but it is only 200 ft deep you will have 200 ft of poly floating on the surface just waiting for someone else to run over or get caught in their props. The trick is to keep all unused line below the surface.
In deep water I attach the line weight 50 ft from the buoy, in shallow water move it further down to say 100 ft deep, what you really want is a straight line from the line weight to the buoy. The buoy or marker you use should never have more buoyancy than the weight of the trap, you do not want a large buoy pulling up on a trap and bouncing it along the bottom, first it will scare prawns away and second you will lose the trap if a wind comes up and the wave action again pulls the trap off the bottom. I use a small 6" buoy, sometimes a little harder to find but after losing traps with large buoys attached, I have learned that lesson.
Rules say you must have a name and phone number written on the buoy, that will also help you in finding your trap if there are many other people prawning in the same area.
Once set it is time to wait. There is no set time frame on how long to keep the trap down, some people check every 6 hours, others every 12 hours: I usually leave mine down for 24 hours. Often if bad weather comes up it can be days before I get back to the trap but probably the best time frame is 12 to 24 hours. When it is time to pull up the trap, you must remember prawns are not like crabs, they can swim, or squirt backwards with their tails, so they can get out of the traps through the holes they come in. To avoid prawns getting away, once you start to pull up the trap you cannot stop till the trap is in the boat. That way the upward motion of the trap keeps the prawns trapped on the bottom of the trap. Be prepared to find strange thing in the trap, I have pulled up octopus, star fish, cods, and a few other things I was never able to identify as the octopus had eaten all the prawn tails!
To prepare the prawns to eat you have to separate the heads from the tails. I keep the heads and usethem for crab bait, or just throw them back into the same water they came from. There are several ways to cook and eat the prawns, sometimes we just quick fry with shell on in garlic butter, other times a 1 minute boil in water than shell and use in salads or pasta dishes or on top of a steak. We find it easiest to boil than let them cool off before we shell them. I will leave it up to you to find your favorite way to eat fresh prawns.
Recently there have been several stories written about whales getting trap lines caught around their tails or side fins. We are not sure how this happens but if you have too much line (Especially Poly Line) drifting around between the trap and the buoy this may become too easy to catch on the fin. One solution it to put the line weight down much deeper so the line is then on a straight line from it to the buoy. Another solution, although this is not proven, would be to use the new super strong power curdy line which is very thin and made to sink if lost instead of poly or normal lead laced trap line.
Please remember, seafood is not an endless supply of food, do not take more than you need or can eat. What you leave behind you can always catch another day. Have fun!