We do a fall survey in the bulk of the area. The fall survey will estimate the number of males that are over 95 millimetres across the carapace. That would be the commercial biomass that would be available to the fishery. Then the fishery is prosecuted, and they'll remove or they'll ask for almost 21,000 tonnes. Some people would look at the biomass before the fishery, subtract the fishery, and the biomass that results from that should be a numerical value. It's just straightforward math.
Crabs in their terminal moult live about six years, and that's without fishing. They're going to die. The age structure and so on will give you some idea, but you also get natural mortality caused by a number of different factors. That's not easily predicted by science, because you have trends, but that's the “lost crab”. It's the crab that will normally die over the course of the time period between surveys. Not every crab that's not killed in the fishery is there to carry on. They have a natural life cycle.
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