There wasn't a huge amount of information going way back in time, but the basis for that conclusion was what was called a “bulk biomass” model. That was developed by some scientists at DFO. They considered three things that could influence cod: the fishery, capelin availability, and predation by seals. They considered these three things together. In their analysis, they couldn't find any indication that northern cod population dynamics were actually being driven by seal predation. It didn't seem to be having a major impact. Capelin availability and the fishery were far more important than seals were in driving the changes we were seeing in northern cod.
If you look at my presentation, you'll see the increase that we've seen in northern cod in the past decade. That has come about when the harp seal population—I emphasize the harp seal; this is not the grey seal—was close to an all-time high for the recent period. The stock has managed to improve considerably in the presence of a very large harp seal population. Again, that supports the idea that seal predation is not a major issue. The seal population was much lower back in the eighties, when this stock was very high.
I'm not the best person to ask about how much data we had back then. Seal diet is an extremely difficult thing to study in the open ocean. It's very hard to get samples of seal stomachs from seals out in the open ocean. It has always posed a very significant challenge to the scientists trying to estimate the impact of seal predation.