Mud Crabbing from a kayak

Author: JayPenfold

Category: Technique & strategies

Created on Thursday, 20 October 2011 12:07

Written by Jay Penfold

Kayak fishing isn't all about fins and scales, especially once you approach the subtropics. It's also about the estuaries' other serious delicacy: the Mud Crab. Delicious simply boiled and eaten warm or dissected and stir fried hot in a wok with Asian flavours, the tough as nails Mud Crab is a wonderful, tasty, messy meal that retails live for in excess of $60/kg. 

Scylla serrata, or the Black Mud Crab, is a short lived omnivorous crustacean that dwells intertidally in burrows by day and forages after dusk and just before dawn.  The larger nipper is used to crush shellfish and for self defense.  Mud Crabs are found from The Bega River in Southern NSW to the Gulf of Carpentaria and as far as Broome in WA.  Mud Crabs are thought to live only four years, reaching maturity in 18-24 months after spawning deep at sea. A mature Male Mud Crab may weigh as much as 3kg, 40% of which is in the nippers. A female Mud Crab may carry between 2 and 8 million eggs per spawn event. Mud Crabs grow through a series of moults where they shed their shell to be replaced by a larger one. This soft new shell is quickly filled by the expanding muscle tissue. At maturity, Mud Crabs cease to moult and most will not grow any larger.

Season: There is an old saying that Mud Crab season is "any month with an 'R' in it" This is not the case. Mudcrabs can be caught all year round, but numbers and the condition of the crab may vary from one part of the year to the next.  A crab caught in moult will have a softer shell and relatively little muscle tissue in it as the crab grows. These are best thrown back. It only takes two to three weeks for the crab to fill out again. Moulting occurs from September to January.  Water temperatures of under 20 degrees celcius shut down the feeding activity of Mud Crabs. 

Traps: There are several different kinds of trap that can be deployed, only one of which really stands out as being specifically kayak friendly, so we shall speak mostly of this. There are dillie nets, a single ring of steel with a “witches hat” of fine 50mm mesh with a float affixed atop, holding the net into position. Dillie nets may not be left alone (you must sit on them), and are a nightmare to untangle crabs from.  Round traps, consisting of two hoops of steel strung with a 50mm mesh, are difficult to stow on the kayak and heavier too.  Rectangular traps, collapse (and stow) easily, are easy to remove catch and by catch from and light and easy to manage.

Handling a trap  on the kayak: The best way I have found of stowing a trap on the kayak is either aft of the rear well, or on top of the open front Hobie Revolution hatch, with the hatch open. With the buoy rope coiled neatly on top, all it takes is a well aimed knock to send it to the destination required, with the respective ends of the trap pointing up and downstream. Bait it and organise it one the river bank prior to setting out and lay your trap where you can check on it periodically. Traps are best left overnight as Mud Crabs, like many other crustaceans, are nocturnal feeders.

Handling crabs on the kayak: This is a personal thing dependent on the fisherman's ability and risk profile. I prefer to have an iced ice box on the back of the kayak to shake the crab(s) into, Or a square bucket containing ice bricks in the forward hatch that may be used both to scoop crabs out and store/sort the catch.This has two advantages. One, no need to physically handle the crab and risk a puncture/crush wound. Two, this allows the crabs to be chilled to hibernation, or cooking state on the trip home. It is not advisable to drop the crabs into the foot well and try to tie them up, unless you are more than proficient at cornering and tying them. They may (and have) end up around your testicles. A bad place for crabs, period. An oversized heavy duty gardening glove is an indispensable piece of kit to minimise injury potential.  Handle crabs from the very back to avoid a bite. Never grab hold of the nippers themselves as the crab will drop them clean off in an attempt to flee. Recently shed limbs allow  cooking water to enter the carapace and make the crab flesh soggy and unpalatable.

Trap deployment: Mud Crabs live predominately in mangrove fringed areas of the river. Your trap is ideally positioned adjacent to these in water over one metre deep but not exceeding four. Deeper holes may attract foraging crabs, but they reside in shallower water. Crabs tend to move up and down the river geography with the tide, so ensure you have an opening upstream and downstream, not across the current. When deploying your trap, be aware of the tidal variation. Make sure that your trap will be covered by water at all times. A crab left in the sun will perish fast if not covered by water.  Don't deploy your trap in the middle of a waterway where it becomes a navigation hazard to other vessels.

Crab Bait: anything oily is great. Whole mullet, fish frames not limited to but including trevalley, jewfish, tuna and chicken. Ensure to fasten tight in the center of the trap with a bait pin to maximise potential for crabs to search and gain entry without getting a free feed. If eels become a problematic bycatch/predator, secure the bait in a piece of gutter guard (the plastic mesh that is supposed to keep leaves out of gutters but doesn't). 

Rigging your trap: The best way to rig a trap is to use 8mm silver nylon anchor rope, a length of about five meters should suffice. Pass one end through a 150mm float and splice together. Wrap splice with electrical tape to secure. Attatch a name plate on which (NSW regulations) the initials CT for crab trap, your name and address must be written using cable ties. A weight such as a snapper lead must then be spliced a meter under the float into the rope to keep it from becoming a navigation hazard.  splice a loop at the tail end of the silver rope to fix the bridle part of the rig. take a 2m length of 3mm nylon rope, fold it in half and seal the ends over a flame. Pass both of the lengths through the tail end loop and then through a bobby float to keep the bridle free above the trap. Tie each end of each bridle length on opposite corners lengthways utilizing a bowline knot and some half hitches to secure it. Add a bait pin to the centre of the trap running through the intersection of the structural crossbars, pin a bait and happy crabbing!

State Regulations: It is important to check your State regulations both on the set up for your trap, the number of which type you may carry and the size/sex of crabs that you may take.

NT: Min !40cm male, 140cm female, bag limit of 10

QLD: Min 15cm carapace width, Bucks (males) only to be kept, bag limit max 10

NSW: Min 8.5cm carapace height, Both sexes may be taken, bag limit max 5

Information on how to cook a Mud Crab can be found here.

NT DPI and fisheries have a great diagram on tying a mud crab here.