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Gadget is the Globally applicable Area Disaggregated General Ecosystem Toolbox
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userguide: Weightjones uses maxcons, not consumption #38

Closed lentinj closed 4 months ago

lentinj commented 4 months ago

@bthe Any thoughts on this? the C in the WeightJones documentation seems flat out wrong to me.

Instead of C, we actually use Fphi[i] * MaxCon[i]: https://github.com/gadget-framework/gadget2/blob/508b993a2cbbc3304cad25f8ee3f65cca1df0466/src/growthcalc.cc#L340

These come from getFphi / getMaxConsumption: https://github.com/gadget-framework/gadget2/blob/508b993a2cbbc3304cad25f8ee3f65cca1df0466/src/stockmemberfunctions.cc#L99-L100

...from fphi / maxcons: https://github.com/gadget-framework/gadget2/blob/508b993a2cbbc3304cad25f8ee3f65cca1df0466/src/include/stockpredator.h#L64-L75

From the calculation of max consumption: https://github.com/gadget-framework/gadget2/blob/508b993a2cbbc3304cad25f8ee3f65cca1df0466/src/stockpredator.cc#L158-L162

Hopefully it's true, since it'll be easier to implement in gadget3 :)

bthe commented 4 months ago

Yes, that sort of makes sense to use the feeding level and max consumption, the total consumption is on the stock (at size l) level while the growth should be on the individual level (I guess). But I do have the feeling that the energy content of the prey should be included somewhere, most likely in the feeding level.

On a side note, @vbartolino any idea where the original article is? A quick search on google scholar didn't yield much.

vbartolino commented 4 months ago

On a side note, @vbartolino any idea where the original article is? A quick search on google scholar didn't yield much.

this should be described in Jones_1978_cond_consumption.pdf

lentinj commented 4 months ago

the total consumption is on the stock (at size l) level while the growth should be on the individual level (I guess).

True, although you could work out average consumption of an individual, I was hoping to avoid doing so. And turns out it was worth digging into.

I do have the feeling that the energy content of the prey should be included somewhere, most likely in the feeding level.

The feeding level is in joules, not total biomass as it would be for a (total)fleet. Although I might be misunderstanding the question :)

bthe commented 4 months ago

The feeding level is in joules, not total biomass as it would be for a (total)fleet. Although I might be misunderstanding the question :)

Sorry, yes. Misread the equation ;)