Hi there, i have population mapping/creation utility at home I can recommend to you (after I finish work).
how many times does a cray need to shed/long it needs to live before it can breed? - This suprisingly is slightly variable, but is generally accepted to be 3rd instar at the very earliest.
How many eggs do they produce? - This is also variable, and depends on the size/instar of the crayfish. But it probably wavers between a few hundred to 5700/6000+
How many would a smaller one of a year of so produce? A year or so, in warm conditions (as we have experienced over the past few years) would probably be instar 3 at the most - so call it 300.
What is the average increase per year of eggs produced by a female? -- hmmmm, well a large female would probably be on the 5-6000 mark. I don't think there is any accurate data for this.
How many eggs will hatch? -- in ideal conditions (alkaline, warm water - probably all of them), however here the fungus can play a role, and signals do lose a random percentage to fungal infection. the female carries the berried eggs until they are ripe/sometimes beyond. Most often late stage eggs are shed into the milder currents. So a high percentage - 60-70%.
How many babies will then live to cause damage to the ecosystem (ie, when they are at, say, 3cm long)?
Predation of signals is very very low in britain, predators of the white claw can predate upon signals to about the 3rd instar, but after that point, predation is human/signal/mink etc. so once again a high percentage ~70%
What is a fairly average growth rate?
Full size in 2.5-3 years.
How many Crayfish (as a %) are removed by predation and other factors? - this is unknowable, and is a variable factor of population models. This is one factor which muct be manipulated in order to create such a model. Crayfish population growth is generally exponential. Predation of the different age ranges would differ. I can't (and I don't think anyone else can) accurately provide this info.
How long would they usually live for?
approximately 6 years at most.
How many young Crays would an Adult consume?
Not that many, other prey is much easier/less well defended. Signals are primarily scavengers, and do not like to risk claws/appendages/antennae to difficult prey. Most large crays in dense populatyions will have only 1 or no claws left due to territorial combat with other crays, and are therefore innefective predators. fish, insects etc. are much easier prey.
Please be as accurate as possible, 4000+ wont do. Something like 4200 would.
I have been as accurate as I can. The population growth type of crayfish is not 'scramble' type but build and spread. I.e. dense population centre, that will eventually spread creating other dense populations (e.g. along a river) which then become dense and create the same. High levels of crayfish urea in the water may be inducer to migration/exploration by larger crays.
Hope that helps. It is best to download a population model if possible, and program, which has adjustable levels. Also remeber any model made will not account for males produced, and will only consider females and their egg production/survival.
Good luck! I shall be eager for your creation.
I am trying to produce a formular which will prove who ever is right.
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I said disputing not disrupting :>
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