Bois Brule River Spring Steelhead

The past is prologue...

I'm not sure which philosopher said that but he must have been a steelheader. I finally got a chance to plug the 2009 spring data into my historical data from the Brule River, so I thought I'd post it.

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What you are looking at is a snapshot of the spring 2009 return data vs. the historical flow and return data for spring conditions on the Brule. Let's face it, the North Shore lags the South Shore by a period of time when it comes to steelhead runs, and lots of us can't wait to get a line in the water after a long winter.

Now, keep in mind that this is NOT -repeat NOT- a prediction of when the run is going to occur. It is simply a representation of past flow, run return and ice-out activity. The complex interactions between flow, temperature, photoperiod (length of daylight), year-class strength, recruitment etc. all play a part in the year-to-year fluctuations in the size and actual timing of steelhead returns. Yet having access to past data can give you a good idea as to when to start watching conditions more closely in a given year as annual runs and peaks tend to fall somewhere within the historical period with a few exceptions.

As you can see, 2009 return activity fell largely within the historical averages although the late returns were slightly higher than the historical means. Start, peak and end dates also closely followed the historical model. Again, this tends to hold true much of the time which is why the historical data is helpful.

Couple points regarding the Brule:
Remember that the bulk of the steelhead return to the Brule in fall, then winter over in the stream. This is one reason the Brule fishes well early. Conditions in the upper Brule, namely temperature, can lead to spawning activity as early as mid-March. However the spring-run fish historically tend to peak closer to mid-April as shown. It is therefor not uncommon to find a mix of spawned out as well as fresh fish early on which may lead to some confusion. Don't automatically assume that the run is already winding down just because you get a post-spawn hen shortly after opener, in fact the best is typically yet to come.

If you had a thermometer stuck in the lower river, that is to say a point north or downstream of Highway 2, you would be looking for average daily temps to be breaking that magic 40 degree mark any time around the first week in April. Once that happens, spring run activity begins in earnest. Once the average daily stream temps maintain between 40-49 (the temperature at which most return/spawning activity occurs), fishing the back-side of bumps in flow will be your best shot at finding active, fresh-run steelhead.

One thing to watch out for early on the Brule which also occurs on the North Shore:
High daytime air-temperatures and sun in spring are normally a good thing. On days like this, stream temperatures can increase rapidly leading to very active fish. However, when there is still a lot of snowpack, warm days can absolutely kill fishing leaving you scratching your head as to what the heck happened.

On those early-season warm days, increased air-temps and sun lead to increased melting of snowpack and remaining ice. As melt accelerates towards early afternoon, flows increase but stream temps actually decrease due to the addition of near-freezing water into the system. This lowered stream temp changes what the fish are doing. As long as you recognize it soon enough, you can still salvage your day. This is just one reason why it's critical to carry a thermometer.

Given lowered stream temps, you can do several things:
1. Look for slower, deeper holding water out of the main current. Dark bottomed holes are a good bet because they tend to absorb sunshine which can warm surrounding water, and even a 1-2 degree temp change can make the difference. Steelhead will hold in slower water when it's colder in any event due to their metabolism and absent slightly warmer water.
2. You can stream-hop looking for smaller streams that tend to warm more readily. This is a lot more practical on the North Shore where streams are a lot closer together.

Just about 5 weeks and counting!
Regards-
NMF

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