Warren County anglers should have am appreciation for river smallmouth bass fishing. The Allegheny is a fine smallmouth river. But in comparison to the Susquehanna River up to just a few years ago, smallmouth bass fishing here in the Allegheny River was a notch lower. The Allegheny River smallmouth bass fishery is good, the Susquehanna was world class.
Now, however, something is very wrong with the Susquehanna River smallmouth bass fishery. According the Pennsylvania Fish and Boat Commission Executive Director John Arway, world class no longer applies to that fishery.
Problems dramatically got worse in the 2000s. The least successful spawn was recorded in 2005 on the Susquehanna.
Problems with smallmouth bass intensify heading down the river. By comparison, the West Branch and North Branch have not declined as drastically. Unfortunately, the middle and lower parts of the Susquehanna were the heart of the great smallmouth fishery.
Some anglers, even guides, have yet to realize the full extent of the problem. It is young-of-the-year smallmouth that are dying in great numbers. Larger smallmouth remain in reasonably good health and fair numbers. During spring and fall these adult smallmouth congregate so they are easy to locate and easy to catch.
Various factors combined to bring about the decline of the Susquehanna River smallmouth bass fishery. Environmental conditions, some natural, some caused by man, weakened the smallmouth which increased their susceptibility to diseases.
At first scientists thought that Columnaris bacteria was the cause of mortality in young-of-the-year smallmouth bass. Later they learned that another problem was Aeromonas bacteria
"It's the two of them," Arway said.
Arway explained that the most effort was spent studying the relationship between oxygen and the health of smallmouth bass. The bass were being weakened by low levels of dissolved oxygen. This, however, is just one link in a chain of factors leading to severe mortality on young-of-the-year smallmouth.
Increased algae growth was lowering the level of dissolved oxygen. This was happening at night, to the greatest extent in side waters which are used extensively by young smallmouth bass. At night algae continues to photosynthesize, but it does not produce oxygen.
Nitrogen and phosphorus levels were going down. This would be thought to reduce the growth of algae in the river.
"That's the strange twist to this story," Arway said.
That twist was that although the total phosphorus load in the river was going down, dissolved phosphorus was increasing. No cause has yet been found for this.
This is only part of the reason behind low oxygen content. Warmer that normal water was a contributing factor.
Another factor was chemicals including birth control and antibiotics were suppressing the natural immunity of the bass.
Dr. Vicky Blazer, a scientist who works with the U.S. Geological Survey, discovered higher levels of transgender fish than anywhere else she had studied. Transgender fish are males that produce eggs, or females with testosterone.
Although not all of the answers to the current problem have been learned, Arway says it is time to take the next step.
"We've got to take some action, and the first thing is to admit the river is in trouble," he said.
What that means specifically is to get the Susquehanna River on the list of impaired waters in Pennsylvania.
Only when the Susquehanna River is on the list of impaired waters, and that is approved at the federal level, can steps toward fixing the river and restoring the smallmouth bass fishery to world class status begin.
That will require the cooperation of both state and federal agencies. The Pennsylvania Fish and Boat Commission is limited in what it can do.
"We need to protect the fish that are left. That's the only action the Fish and Boat Commission can do," Arway said.