Ever throw a nice little dinner party for a few close friends and have it balloon into a full-blown, packed-house rager? Well, for British Columbia’s Fraser River, this year’s sockeye salmon run has exceeded all expectations and a migratory soiree of mammoth proportions is in full effect.

Scientists are estimating this year’s run to be in the neighborhood of 34 million sockeye. That’s an incredible number considering last year saw very few sockeye in the Fraser with numbers hovering around 1 million. The anadromous species, which breeds in streams and rivers, but lives the majority of its life in the ocean, has seen its populations decline precipitously over the past century.

Speculation abounds as to why the sockeye migration has swelled so unexpectedly.

It seems the leading theory, at least in the news media, centers on the August 2008 eruption of the Kasatochi volcano in the Aleutian Islands of Alaska. The eruption spewed volcanic ash across the northern Pacific Ocean resulting in the proliferation of the diatoms (phytoplankton) sockeye feed on.

But, scientists warn that the large run is likely an anomaly and not an indicator of a trend. All scientific evidence shows a trend of smaller runs and dwindling numbers, the exact opposite of what is occurring this year. However, this massive run serves as a reminder of the size of historic runs. The hope is that, over time, the work of Earthjustice and other environmental organizations can protect the sockeye population and its habitat, making runs of 34 million the norm rather than the exception.