Recent Susquehanna River survey shows an abundance of and sizable smallmouth bass

Within an hours drive of the Lehigh Valley, some of the best smallmouth bass fishing can be had in the Susquehanna River that runs past Harrisburg. And in a pair of recent reports, Pennsylvania Fish and Boat Commission (PFBC) biologists concluded that the Susquehanna River is home to a healthy, abundant population of smallmouth bass and channel catfish.

From October 22-28, 2018, fisheries biologists conducted nighttime electrofishing surveys targeting adult smallmouth bass at four historic sampling sites located within the middle portion of the Susquehanna River between Clemson Island and the Pennsylvania Turnpike Bridge. Sites surveyed were near Clemson Island, Rockville, the Dock Street Dam and the Pennsylvania Turnpike Bridge near Highspire, Dauphin County. Of note, the catch rate of smallmouth bass in 2018 was the fifth-highest on record since standardized surveys began in the middle section of the Susquehanna River in 1990. In addition, the surveys revealed a strong population of adult bass ranging in size from 6 to 20-inches, as well as record numbers of trophy-sized bass measuring 18-inches or longer. 

“The findings of this survey continue to reveal a strong smallmouth bass population,” said Geoff Smith, PFBC Susquehanna River Biologist. “Because we’re seeing fish in all size categories, we believe the population will remain strong for years to come.” 

In a second report, PFBC biologists outlined the findings of adult channel catfish surveys conducted between 2016 to 2018. During this time, biologists surveyed eleven sites; six in the middle section of the Susquehanna River extending from Sunbury to York Haven, and five in the lower Susquehanna River from York Haven to the Columbia-Wrightsville Bridge.
 
Using commercial catfish bait, biologists collected thousands of channel catfish ranging in length from 12 to 31-inches. While equipment used in the survey is not capable of collecting younger fish, typically those under 12-inches, the number of catfish in the angler-preferred length of 24-inches or longer was good in both the middle and lower sections of the river with no evidence of overfishing.

This is good news especially since back in 2014 it was announced that a malignant, or cancerous tumor was found on a single smallmouth that was caught by angler in the middle of the Susquehanna.

According to PF&BC biologists, cancerous growths and tumors on fish are extremely rare in Pennsylvania and throughout the U.S., but they do occur. However, this is the only documented case of this type of tumor being found on SMB in Pennsylvania. 

Since 2005, PFBC biologists have observed more than 22,000 adult SMB as part of routine surveys in the Susquehanna River basin, and have not documented any fish with obvious signs of tumors. 

I asked Michael Parker, PF&BC media relations manager, if it was ever determined what was the cause of this disease. In checking with agency biologists, Parker reported that the primary reason for the response of the population is improved recruitment after several years of reduced disease-related mortality of young-of-year smallmouth bass that resulted from largemouth bass virus in concert with a host of other factors. Since 2012, the agency has observed a few moderate to strong year classes come into the population as disease prevalence has waned. During that time, disease prevalence has remained around 10% or less as opposed the highs of the mid-2000s when proportion of fish in our surveys observed with lesions was 67% at the middle Susquehanna River. Parker added that they now have a more robust population with multiple year classes, including a large number of juvenile fish, that can withstand the fluctuations in the population (natural or otherwise) should they occur. 

My other question, was a cure ever found and have anymore been found since one was caught in in 2005? According to biologists, no, the cause or cure of the tumor is still uncertain. No other fish have been found with a similar tumor since that fish was caught. But the agency will continue to monitor the situation. 

As this latest study shows, smallmouths are thriving with good numbers and large sizes in the Susquehanna. And once the weather breaks, anglers may want to wet a line there and see for themselves what a bona fide smallmouth fishery this is. 
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