Run Timing – Then And Now

A few weeks ago, a fellow angler and I were talking about how the salmon and steelhead weren’t showing up the same time of year they used to. This friend told me, “You know, the steelhead fishing was really good around Thanksgiving, and the run was over by January.” That got me to thinking about when fish should be showing up. Were the runs years ago healthier than today?

When Do Fish Come Back?
Anadromous (sea run) fish return to their home river anywhere from months before they spawn to hours before they spawn. For instance, on the Columbia River, steelhead bound for rivers in Idaho (Columbia River tributaries) enter freshwater many months before they actually spawn. And on Oregon coastal rivers, salmon and steelhead may spawn just hours after entering freshwater. In other words, the length of the journey to spawning grounds dictates (in part) when fish enter a river. Anadromous fish, particularly fall chinook salmon, may also hold in lower stretches of coastal rivers until water levels raise enough to allow them to access suitable spawning gravel. An example of this is as follows: a fall fish may enter the river in September and slowly work its way upriver, and when freshets raise the water level in early November, the fish enters a tributary and spawns during the middle of November.

Run Timing – An Inexact Science
While it’s tough to predict when the “peak” of the run will be, research on salmonids gives us some clues as to when most of the fish will be in the river. On Oregon coastal rivers, run distribution is on a Bell Curve. When examining fall chinook salmon, this means that some fish will be present in the bay and river during July, and some fish will be present in January, but the peak of the run will be present some time during October or November. We make this assumption based on sport catch and results of spawning fish surveys. When we take a look at winter steelhead, the timing is different. Most of these fish spawn in the spring (March and April). And while some steelhead are in the rivers in November and some fish are in the river in May, the peak of the run will probably be in January and February. A Thankgiving peak run just doesn’t sound quite right to me, at least not on the Oregon coast.

What Affects Run Timing?
It’s not that my friend was wrong. I’m sure he had the dates right. But there are many things that can impact run timing of salmon and steelhead. Probably the biggest single impact on run timing in the past was poor hatchery practices. And this is how it works: the eggs of fish used by the hatchery were taken from the first fish that made it to the weir. So, over a few generations the hatchery, by just taking these early fish, inadvertently selected for early arriving fish. Today, hatchery practices are changing. Those in charge realize that fish should be selected throughout the run to ensure that fish come back during the entire time they would naturally.

See you on the water,
Action Jackson

(Please send comments or questions to Action Jackson at 268-6944 or www.actionjacksonfishing.com)