Participants gathered at a workshop held in Prince Rupert, May 20 and 21 1998, to discuss changes to the Hecate Strait ecosystem. Hecate Strait is defined here as DFO statistical areas 5C and 5D and includes Dixon Entrance. A preliminary mass-balance model of Hecate Strait in the early 1900s was constructed from information provided by participants, and a preliminary mass-balance model representing the same area during the early 1990s. Changes in biomass from the previous model were based on input from workshop participants. Thus, it presents a test of whether ECOPATH can be used to develop a picture of how the ecosystem looked based almost entirely on local knowledge. Unless otherwise noted, biomass values were adjusted according to the consensus of the workshop participants. Most changes in biomass ranged from a 25% to a 100% increase, back through time. Where information was lacking, ECOPATH was allowed to calculate new biomass values. The results indicate that a coherent mass-balance model can be developed, based on the experience gained from long histories of personal association with an ecosystem.