Even though everyone refers to the crabs that we catch in our waterways as blue manna crabs, the correct name is actually the blue swimmer crab and they are my favourite seafood. I prefer this beautiful crustacean over anything else and during late spring right through to the end of autumn I target these nippy little creatures. Most of you would head to Mandurah to catch this delicacy and so do I on many occasions during the year because I love to scoop them. I also head to the Swan/Canning rivers and drop nets for them. Our local crabs compared to their cousins down south are like comparing apples with oranges. Although this I am sure will start all sorts of arguments, I believe Perth crabs are the biggest and the tastiest. This month, I thought I would share with you some tips on how to catch these delicacies.
For starters some of you may not be aware that you find these crabs all over Australia. I have caught them all the way along our coast in places such as Albany, Walpole, Busselton, Geraldton, Shark Bay and Carnarvon. Some places around the coast are easier than others. The crabs in the Shark Bay area for example are as sweet as you will ever get but they are very small and there are loads of them at the right time. When I was running tours on Dirk Harthog Island we used to throw a few fish frames out the front of the camp site in Whitnell Bay and every day we would be able to scoop up a lunch or an entrée for the main meal. As a young bloke my Dad and I use to go down on the beach in Busselton and place large fish heads in the water with a stake pinning it to the ground and then after dark walk around with a torch scooping crabs.
In places such as Mandurah or Australind you need to get up early in the morning and then down on the estuary, then out with a scoop net towing a good tub behind you to catch your bag limit of 10. I have also found in these areas that night time is the best, but most people prefer the morning. When scooping in these areas sometimes they will be walking around and other times they will be buried. What you need to look for is a little mound of black sand or mud sticking out amongst the weed or sand. Poke it with your net and if one is there he soon will let you know. I have also found in these estuaries that if you find some muddy ground they can be all over the place. I remember back a few years ago my good mate Dave Benthien and myself had walked around the Mandurah estuary for a couple of hours for a few crabs and we were just about to pack it in thinking there was not much about when we walked into this major bog hole. What resulted was Dave and I had to use the scoop nets to protect ourselves from the masses of crabs. They were running up our legs nipping our feet to the point where Dave could not handle it any more and had to retreat. The result was our bag limit in a very short period of time. When the crabs are like this there is a very good chance that some are undersize, so carry a gauge with you and replace the small ones back as quickly as possible.
Many of us also use these estuaries for drop netting from a boat. I believe this year the blowies are that thick in Mandurah that they will strip a net clean of bait in about twenty minutes. So if you are going down with drop nets use bait baskets as this will protect your bait. Once again while drop netting you will find a lot of undersize critters so gauge them and put them back straight away. Crabs grow very quickly and a just undersize crab in summer will be size by the next month. I still have kids in my school groups that tell me they use a beer or soft drink can to measure their crabs. Here is a little tip; the legal size for a crab is 127mm and I think you will find a drink can is 130mm so you are ripping yourself off for a starter. Once you have used it, because they are aluminum now days it may have a dent in the side of it. Once you do that the ends come in and you may be taking undersize. For those of you that do want to stretch the limit by taking just size or undersize I quite honestly do not understand. If I have to put a gauge on one, I will put it back as they seem to be a waste of time. It is much more enjoyable to crack open 5 big boys than fiddle around with 10 just size crabs.
I have talked about the crabs around the state but not those in Perth. We should all know by now that Cockburn Sound is closed to all crabbing (recreational and commercial). This is a shame but it may be a huge benefit to the future of the fishery and may even have an impact on the Swan and Canning Rivers which are my favourite spots. For some reason the crabs in the metro area grow bigger thannywhere else and the reason for this I do not know. Here are a couple of suggestions. One is their life span is not very long. I have figures of 12 to 18 months and when crabs leave the estuaries they apparently do not return. The water in Mosman Bay and Blackwall Reach is very deep and maybe they stay there over winter and we get an extra year out of them. The other suggestion is the river is so rich with nutrients that they grow bigger. I do not know but big they are, so big that I have self imposed a possession limit on a boat in the river of 20 with 3 people aboard. In most cases I pull the pin at 15.
In the past there have been some spots around the river that you could scoop, although now days I think you would find it very hard work for little success. My preferred method is drop netting but it is nothing like drop netting in Mandurah and it makes me laugh when I see someone on their first expedition in the Swan leaving the ramp with nets with 3 or 4 meters of rope on them. All my nets have enough rope on them to stretch 100 feet or just less than 30 meters. The crabs are not always in this depth of water but at certain times of the year they are and when you are looking for them, you need to know you have the capability to go anywhere. Pulling a net in 25 meters of water can be quite exciting or very disappointing when you have pulled a net from the bottom to find all that is in it is a dirty great big jelly fish. On the other hand, if it is a 750 gram crab that’s a different story. There is some shallow water for crabbing in the river but you will still need at least 7 meters of rope per net.
In other estuary systems you will find the crabs very much confined to one area but in the Swan they are widespread so you need to cover a lot of ground. Be prepared to work very hard but the rewards are worth it. I believe one Swan River crab is worth at least 3 to 4 Mandurah crabs and I have caught many crabs where one is enough for me. I use a mixture of mullet and bullock’s spleen as bait, and during the summer months I throw all the females back. Late in the season and over winter I will keep large females as their breeding life is just about over and they are full of meat where the males are very empty. There are many people who never take females. In my opinion there is no point in putting an imbalance in the system. If all the males are gone and there are only females left there is no future in that. Remember to put all spawning females back and enjoy your next feed of chilli crabs which are my families favourite.