Well, as anyone trading prawn into the UK will know, while the global shrimp industry currency is the dollar, Brexit may deliver some sterling opportunities.
Your ready reckoner should go all the way up from local pvp through retailers (50% profit margin) or foodservice (food cost 20%) – through to distributor (+15% profit), storage costs, import costs, duties, logistics, exporter, farmer. Last jump to farmer is in local currency.
Exporter currency and financials costs are variables. Storage costs over time, import, duties, logistics frozen known per kg – so fixed.