After having a debate on the water with a fisheries inspector regarding the size of some of my crabs, I found that my plastic crab measures are not accurate at all. I had 2 different and common types, one yellow and one orange. Neither were accurate, and both would get me into trouble.
The fisheries boys use a set of digital vernier calipers to measure your crabs... for sandies, 115mm minimum size means that 114.99 is undersize. (Their digital verniers read in 0.01mm graduations)
One of my crabs measured 114mm. I explained that I had very carefully gauged each crab with my plastic measure, and showed the inspector my measure. He then put my measure over his digital calipers, and the plastic measure was nearly a mm under legal size. Big Problem - my problem.
I certainly didn't think that a crab measure purchased from many reputable stores would be under legal size!!!
I later checked a range of plastic measures in a commonly known store, and found a large number of these measures that were under legal size. Another problem found with some plastic measure is the big flat on the sand crab measure. Sand crab carapace notches don't have a neat and square shaped notch, so even if the plastic measure was proper size, the crab would still be undersize. Pastic measures also change size in the sun, and not always bigger, as they can twist.
Cutting a long story short, I made myself a precision cut stainless steel crab measuring gauge that is 0.5mm over minimum legal size, and bevelled to suit sand crabs as well. My crab measuring problems are over. The half a mm over minimum legal size just removes all doubt.
When I got my stainless steel crab measure made, I got a batch of them done as it was more cost effective in a batch, and I'm sure other people don't want to get caught the way I did.
PM me or email me at mixoffshore@hotmail.com if you are interested in getting one of these stainless steel crab measures. (Current QLD Regulations)
cheers
Mick