 There is a loss of perception of change that occurs when each generation redefines what is "natural".Most modern fisheries' stock assessments do not ignore historical fishing and account for it by either including the historical catch or use other techniques to reconstruct the depletion level of the population at the start of the period for which adequate data is available.Anecdotes about historical populations levels can be highly unreliable and result in severe mismanagement of the fishery.