Downeast Fishing Report: July 25, 2008
The hot and humid weather that comes with a Maine summer is upon us now. During the last few weeks we have been sampling brooks and streams in the area around the Stud Mill Road, north of Route 9. The sun was bright, the air was muggy, the alders were thick, and the deer flies were abundant but we gained valuable information about many little streams and the areas where they cross the Stud Mill Road.
After about a week of electrofishing our observations led us to make some conclusions about streams in the area. The things we were seeing are quite common throughout most of the region. First and foremost, we observed where we found brook trout and where we didn’t. The number one factor in determining where trout were found was water temperature. As long as the water temperature was less than about 70 degrees we found trout. (We did not electrofish any stream with a temperature greater than 73 degrees since if salmonids are in the stream they will be greatly stressed already and the stress caused by electrofishing could kill the fish.) Even in streams that didn’t look like the “classic” brook trout stream, as long as the water temperature was acceptable, we found trout.
One example is a small brook that is only about 4-5 feet wide and about a foot deep. This brook meanders through some tall grasses and alders, the flow is quite slow and almost appears stagnant. We recorded a water temperature of about 70 degrees, which indicated that this brook has spring influence contributing cold water from underground. The bottom of the brook was very soft and had at least one foot of soft organic sediment (muck!) on bottom. We electrofished a section of 150 feet and were pleasantly surprised with the result. In that section we netted 127 brook trout, ten times more than I would have guessed! The brook was not very well shaded, except for a few alder trees here and there, but it did have undercut banks that provided good shade and cover for brook trout. Only four of the 127 fish were over six inches, the majority of the fish were ones that hatched out this spring and at this time of year are between an inch and a half and three inches in length. This brook truly is a small wild trout hatchery.
Another observation we made is that a very high percentage of the brooks we sampled showed signs of road washouts at some time in the past. In most cases gravel and rocks from the road had filled in portions of the streams downstream of the road. Sometimes this sediment could be seen 75-100 feet downstream of the road. The washouts were likely caused by undersized culverts that could not pass high flows adequately or by beaver activity.
When water levels reach their summer lows, the affects of these washouts can cause isolated pools with water flow traveling underground through the rocks. This causes a barrier to fish movement and, if the flow is slow enough, the pools can become stagnant, devoid of dissolved oxygen, and can warm up rapidly. Unfortunately, many of those fish will not survive through the summer.
Lots of people drive over brooks just like the ones we sampled last week and would never think that they could hold so many wild brook trout. They truly are an amazing little fish and an important part of this state.