Mid-summer Inside Coho

Every year is different, with fishing almost always showing changes between seasons. The Department of Fisheries and Oceans (DFO) works up a formal forecast for some salmon stocks e.g. Fraser sockeye or WCVI origin chinook, but most salmon get little more than what is called an “Outlook” characterization, largely based on broodyear size, assessment of freshwater conditions (mostly water levels neither too high or low at critical times) before the fish of concern migrate to sea and some kind of estimate of marine survival, based on the adult returns in the previous year.

Stock assessment staff have been frequently taken to task for failing to accurately describe some salmon returns in recent decades but I’ve never been too inclined to join the chorus. There’s always uncertainty when dealing with any wildlife resource, thus there’s always going to be population fluctuations with fish and in this time of changing climate – both atmospheric and oceanic – those fish like salmon that inhabit multiple habitats during the course of their lives are surely going to be affected in ways and to degrees with which even the best science can be challenged to describe beforehand.

Sadly, because fisheries research is well down the list of government priorities seemingly regardless of which party is in power, in Canada we don’t have the best of science. My own experience is of seeing hard working DFO research staff perpetually trying to do too much with too little and no amount of excellence or dedication can overcome the lack of enabling resources that lie at the root of this issue.

The boo-birds get going when the return of a particular salmon stock or stock aggregate fails to meet pre-season expectations but occasionally, although less frequently, more fish show up than were forecast. The 2010 return of sockeye to the Fraser River is Exhibit A for this kind of happenstance but there have been other, if less spectacular, examples, even in recent years. Everyone likes a good news story and so far I’d say that the inside (Strait of Georgia) coho fishing qualifies as one so far this summer, especially in comparison to the pre-season forecast.

The background is that once again over the past two years coho all around southern BC have declined in abundance for no obvious specific reason or combination of reasons. It is especially discouraging because, after a prolonged period of very low abundance, in the early years of this decade there seemed to be a significant and widespread revival of SBC coho underway. As has been the case for 20 or more years the most particularly afflicted fish are what is known as the Interior Fraser coho stock aggregate, which is to say all the coho that spawn upstream of the Hells Gate canyon, including the large Thompson River watershed. In 2012 (and 2013) approximately 55,000 coho spawned in this large area, somewhat above the rebuilding goal.

Three years later barely 12,500 coho returned to the same general area even though there was very little fishing associated mortality in 2015 to account for this steep decline. Fisheries biologists use the term “recruits per spawner” as one metric to describe how a stock of salmon is doing and even my fishing guide math tells me that less than 0.25 is a direction that doesn’t bode well for the future. If you wondered why there’s widespread non-retention of wild coho around southern BC again this year this last piece of data is a primary reason why. Although many other coho stocks did less poorly last year none did well and the auguries for this year weren’t anything to get excited about.

DFO does produce what is called the “Marine Survival Forecast for SBC Coho” which is generally available in the late spring of each year. The 2016 version begins by noting that “Indicator marine survivals and aggregate abundances from 2015 were universally much lower than 2014 and less than the lower 50% confidence interval bound”, continuing on with “This complete failure of existing forecast models, coupled with the oceanic climate indices that indicated poor survival conditions for the 2015 returns suggests that these factors have a more significant effect on the productivity of coho than in previous years” and then “The 2016 forecast for coho indicators are showing a continuation of the low marine survivals seen in 2015.”

In addition this forecast also describes a prediction of the “Distribution Index” (predominantly inside or outside Vancouver Island), which is “a moderate ‘outside’ distribution of coho in the Strait of Georgia, similar to 2015. This suggests that inside origin coho will be re-entering the Strait of Georgia later in the summer of 2016 than an ‘inside’ distribution year.”

So what’s happened? Coho showed up on the south side of Nanaimo in mid-June and have distributed fairly widely in a south to north direction, as well as over to the mainland side of the Strait of Georgia. Although their presence in the Campbell River area at the top end of the strait has been inconsistent local abundances not far away have been just that – abundant. One acquaintance in Nanaimo reported hooking 70 coho one July afternoon, another saying that even beginners out in rental boats near Comox were getting a dozen or more – shades of the 1980’s!

In addition to numbers the percentage of adipose fin-clipped hatchery origin coho is quite high with numerous stories describing a 20 – 30% mark rate. This is very encouraging and supports the idea that the mark selective fishery model can work.

It will of course be most interesting to see how the rest of the summer plays out for coho fishing in inside waters. The percentage of hatchery fish will inevitably decline as those caught are removed and those wild fish released will hopefully be a little wiser and not so ready to bite but now that they’re here the coho won’t leave and if there’s groceries (e.g. “firecracker” or herring of the year) around so will the coho. Tight lines!