| Any picture with a time and file size underneath it is linked to a Windows Media video. |
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The Sioux River is a moderately large stream flowing northeasterly through Bayfield County emptying into Lake Superior. The Sioux is 13.3 miles in length and considered class IA trout stream. Brook charr, rainbow trout, brown trout, and coho salmon are present in the stream with the latter three species also migrating from Lake Superior for spawning. Anadromous brown trout and coho salmon migrate up the Sioux in the fall with the peak run occuring in October and early November, though browns may enter the river as early as August and cohos may remain until early December. Anadromous rainbow trout migrate up the Sioux in both the fall and spring with the majority entering the stream in early April.
"The Big Rock" is a rather steep layer of bedrock over which the Sioux River flows. Below The Big Rock is a pool called "The Big Rock Hole." During periods of low water flow The Big Rock serves as an obstacle to the migrating trout and salmon. During these times large numbers of trout and salmon may concentrate in The Big Rock Hole. In addition, rather large fish can be seen attempting to "climb" The Big Rock to reach their preferred spawning grounds.
The Big Rock Hole is closed to fishing from September 30 through May 31 in an attempt to protect these fish from snagging and overharvest while in this concentrated and vulnerable area. A sign at the adjacent County Park describes The Big Rock in more detail.
On November 10, 2006 I was fortunate enough to find a large number of fish concentrated below The Big Rock. In addition, several large fish attemped to pass The Big Rock at this time. The pictures and videos below are my attempt to document these observations.
The Big Rock Hole appears to consist of two pools. The upper pool is the area just below The Big Rock and is rather shallow with a water velocity higher than the lower part. The fish seem to stage in this pool just prior to attempting to climb The Big Rock. The lower pool is a classic pool of moderate depth and very low water velocity.
The videos below document the coho salmon and brown trout in the lower pool in November, 2006. The video is highly "zoomed" from a "cliff" about 30 feet above The Big Rock Hole. The fish are visible but not highly defined because of the zoom and the glare on the water surface.
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| 1:15, 4.0 mb | 1:47, 5.6 mb |
| A bird's eye view of the trout and salmon concentrated in the pool below The Big Rock. | A bird's eye close-up view of trout and salmon concentrated in the pool below The Big Rock. |
In the fall, when water levels are relatively low, the Big Rock appears to have two "tracks" that fish use to attempt passage. The east portion of The Big Rock has much shallower water (not more than a couple of inches on this day) spread over a larger flatter area of bedrock. The west portion of The Big Rock has a bit of a trough in which the water is somewhat deeper (probably as much as seven or eight inches) with much higer velocity of water. Fish that attempted the east portion appeared larger and seemed to "beach" themselves for short periods before attempting further progress up The Big Rock. Fish using the west trough appeared somewhat smaller and were washed back downstream if they did not continue swimming. On this day in November 2006 I saw nine coho salmon attempt to "climb" The Big Rock; seven of these fish are captured in the videos below.
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| 4:39, 14.5 mb | 0:54, 2.9 mb |
| Four fish attempting to swim up the east side of The Big Rock. | Three fish attempting to swim up the west side of The Big Rock. |
I returned in April 2007 when The Big Rock was covered with more water moving at a higher velocity and steelhead (rainbow trout) were attempt the climb. Many fish attempted to climb The Big Rock using the western trough although several other fish attempted the climb outside of this trough. Video was more difficult to get at this time because the attempts seemd quicker and the rejection by the water on the Rock more swift.
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| 1:26, 4.7 mb | 4:03, 12.8 mb |
| Several steelhead attempting to swim up east side of The Big Rock. | Several steelhead attempting to swim up west side of The Big Rock. |
I also found several fish in a small side eddy to the western trough. These fish can be seen in the video to the right below.
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| 0:55, 3.1 mb | |
| Several steelhead in the eddy along the western trough of The Big Rock. |
The videos above are fairly low quality to save space and reduce download time.