VICTORIA — The highest number of coho salmon in a decade have returned to the Goldstream River on Vancouver Island, even though the fish left in 2011, the same year that thousands of litres of fuel spilled into the waterway.
However, few of the returns have tags that were attached to fish released shortly before the spill, adding to fears that any fish in the river at the time of the spill would have perished.
“The numbers are really encouraging for coho,” said Peter McCully, Goldstream Hatchery technical adviser.
About 900 fish have been counted so far. Returns are usually in the range of 75, but have occasionally risen to 500 fish.
Other southern Vancouver Island rivers are also seeing promising early coho returns.
No one knows for certain why the returns are good this year, but there must have been favourable survival conditions in the ocean, McCully said.
“With our natural human arrogance we think we know what’s going on and, every so often, Mother Nature gives us a quick kick in the pants,” he said.
There are interesting changes in how the fish are behaving this year, McCully said.
“It looks like the run is earlier than usual. Normally we don’t see them turning up in good numbers until November,” he said.
“Some have also taken on their spawning colours. The coho we would normally get at this time of the year are bright silver.
“Something is changing,” McCully said. Although hatchery volunteers are delighted with the number of coho, the lack of tags is not good news for any fish that were in the river in April 2011, when a Columbia Fuels truck rolled over and spilled 43,000 litres of gasoline and 700 litres of diesel, much of which leaked into the river.
“When the spill occurred in 2011, we had started releasing our juveniles about three weeks before,” McCully said. “There were 8,000 fish released the day of the spill. Altogether, 34,000 fish were released prior to the spill.”
Most of those had clipped adipose fins and nose tags, but less than two per cent of the returns are tagged.
“It supports the worst fears that everything downstream of that spill was compromised,” McCully said.
That could include steelhead and cutthroat trout as well as salmon.