I doubt the Indians had killed off the grizzlies 10K YBP because the glaciers were still retreating from the Sound. But, yeah, I am pretty sure the number of fish was astounding.

Some bottom sampling was done on Karluk Lake, on Kodiak I. in AK. They were able to reconstruct sockeye escapements from about 0CE. The lowest runs were in the fist millennium (about 400,000 escapement) and around the 15-1600s I think the hit 4 million. Now, managers tell us the lake capacity is 1-2 million spawners.

For those who like steelhead fishing look at Kamchatka and then look at the salmon runs there, Even with occasional poaching problems the Russians are intentionally targeting some pretty sweet ecological levels of escapement for all species.