As well as recommending a particular level for the total allowable catch to be set for each managed fishery, ICES specifies a lower level which should allow the stock of fish to expand and an upper level at which it would decline. The agreed TAC tends frequently to be in the upper end of this range. This is not always due to the difficulties of international negotiation, however. Much of the analysis is done by scientists from national research organisations working in joint teams under the auspices of ICES.