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Monitoring Fishes of the Monongahela River
May 19 – July 14, 2009
Sampling Gear: Nighttime Boat Electrofishing

Since the late 1990s scientists from West Virginia University’s Water Research Institute, University of Pittsburgh, and Carnegie Mellon University have monitored chemistry and water levels in more than 1,200 abandoned underground mines within the Monongahela River basin. Their findings revealed the magnitude and severity of increasing water levels in abandoned underground mine pools. Findings revealed that abandonded mines are flooded with billions of gallons of acidic, highly toxic water. If released, this water would most likely discharge into both Dunkard Creek and Ten Mile Creek, and then into the Monongahela River. Such an event, depending upon magnitude, could potentially be catastrophic to fish and other aquatic life (Click here for more information). Although the Monongahela River was nearly dead in the 1960s it has improved to the point of supporting over 70 species of fish, including a much-improved sauger and smallmouth bass fishery. Results of recent fish density surveys are documented below, preliminary results suggest the basin is in early stages of pollution recovery, and any water quality degradation could easily reverse the recovery process.

In response to the potential dire consequences of a flooded mine pool breach, Area 8 fisheries biologists were assisted by biologists from the Ohio River Valley Water Sanitation Commission (ORSANCO), U.S. Environmental Protection Agency’s Freshwater Biology Team (USEPA), PA Department of Environmental Protection Southwest Regional Office (PADEP), and West Virginia Division of Natural Resources (WVDNR) in conducting a much-needed biological monitoring investigation of the Monongahela River, including a comprehensive inventory of its fish populations. In May 2003, these agencies conducted nighttime boat electrofishing (NTBEF) surveys at the tailwaters of Grays Landing, Maxwell, and Braddock navigation dams in Pennsylvania (Click here for more information), as well as Opekiska and Morgantown navigation dams in West Virginia (Figure 1). Electrofishing surveys (NTBEF) were also conducted upstream and downstream of Dunkard Creek and Tenmile Creek. In September 2003, Monongahela River lockchamber surveys were completed to append the NTBEF data (Click here for more information).

Figure 1. Navigation dams of the Monongahela River (from U.S. Army Corps of Engineers).

Figure 1

In October 2008, PADEP biologists first observed elevated conductivity readings and total dissolved solids (TDS) values at several locations on the Monongahela River. They later found that several wastewater treatment plants along the river were accepting contaminated frac-flowback water from Marcellus Shale natural gas drilling operations. Unable to completely treat this water, plant outflows caused the spikes in the conductivity and TDS readings. In response to concerns regarding potential Marcellus Shale impacts, as well as to update the 2003 fisheries data, NTBEF surveys were repeated at Monongahela River navigation dam tailwaters in May and July 2009 (Figure 2). In September 2009, a few months following our surveys, a major fish kill occurred on Dunkard Creek (Click here for more information). The following is a summary of our 2003 and 2009 NTBEF efforts on the Monongahela River.

Figure 2. A longnose gar collected in 2009 from the tailwaters of the Braddock Locks and Dam.

Figure 2

In 2003, a total 2,093 of fish representing 45 species were caught during NTBEF surveys at the three Pennsylvania navigation dams. In 2009, a total of 4,501 fish representing 57 species were collected from these same sites, including a paddlefish collected at Maxwell (Figure 3).

Figure 3. A young paddlefish, measuring 9 inches from the eye to the fork of the tail fin, captured in 2009 from the tailwaters of the Maxwell Locks and Dam. This is the first paddlefish collected in Pennsylvania using electrofishing gear, and was most likely a fish originally stocked in West Virginia by WVDNR that moved downstream.

Figure 3

The top 10 species collected in terms of total abundance for each year are the following:

2003 2009
Fish Species # Collected Fish Species
Emerald shiner 378 856 Emerald shiner
Sauger 284 363 Mimic shiner
Smallmouth bass 278 310 Golden redhorse
Spottail shiner 206 247 Channel shiner
Common carp 184 185 Smallmouth bass
Golden redhorse 124 130 Sauger
Walleye 69 66 Silver redhorse
Rock bass 52 64 Bluegill
White bass 52 49 Common carp
Bluegill 51 48 Logperch

The emerald and mimic shiners that top the list provide a forage base for piscivorous game fish such as smallmouth bass, which are also considered pollution intolerant by ORSANCO.

In 2009, the number of percids (sauger, walleye, and saugeye) that we collected during the NTBEF surveys was highest at Braddock. The largest walleye was 17 inches long and was captured near the confluence of Dunkard Creek. Smallmouth bass were the most abundant bass species collected in the Monongahela River, along with a few largemouth and spotted bass. We collected the highest number of smallmouth bass at Braddock with Grays Landing coming in a close second. The largest smallmouth bass was 19 inches long and collected at Grays Landing. Compared to smallmouth bass, largemouth bass, white bass, hybrid striped bass, rock bass, and catfish were collected in lower numbers.

Summary of game fish and panfish species, sizes, and numbers collected in 2009:

Fish Species Grays Landing Maxwell Braddock
Number Collected Size Range (inches) Number Collected Size Range (inches) Number Collected Size Range (inches)
Sauger 24 9-13 32 8-13 33 7-13
Walleye 1 14 4 8-15 4 8-12
Saugeye 1 9 - - 2 11
Smallmouth bass 53 2-19 35 3-16 57 3-14
Largemouth bass 7 10-14 2 9 1 9
Hybrid striped bass 3 7-8 1 11 - -
White bass - - 1 13 - -
Rock bass 15 2-8 10 5-8 6 7-8
Bluegill 12 5-8 3 6-8 4 7-8
Black crappie 4 7-13 - - - -
Muskellunge 1 22 - - - -
Channel catfish 5 17-20 7 14-21 8 14-19
Fish Species Upstream and Downstream Tenmile Creek Upstream and Downstream Dunkard Creek
Number Collected Size Range (inches) Number Collected Size Range (inches)
Sauger 11 11-13 30 6-13
Walleye - - 2 13-17
Smallmouth bass 36 5-13 4 3-13
White bass - - 5 6-12
Rock bass 5 4-7 3 2-5
Bluegill 24 2-7 21 2-8
Channel catfish 1 17 5 14-19
Flathead catfish 1 14 - -

Overall, abundances of legal-size walleye (Figure 4), sauger (Figure 5), and smallmouth bass (Figure 6) were higher in 2003 than 2009. The one exception was smallmouth bass at Grays Landing (Figure 6). The following graphs compare 2003 and 2009 catch-per-unit-effort (CPUE; reported as number of fish collected per hour) values for the three Pennsylvania navigation dams on the Monongahela River.

Figure 4. Comparison of 2003 and 2009 CPUE values for legal-size walleye.

Figure 4

Figure 5. Comparison of 2003 and 2009 CPUE values for legal-size sauger.

Figure 5

Figure 6. Comparison of 2003 and 2009 CPUE values for legal-size smallmouth bass.

Figure 6

In addition to game fish stock assessments, Monongahela River fish assemblages were evaluated using two different biological indices. The Modified Ohio River Fish Index (MORFIn), originally developed by ORSANCO to assess the condition of fish assemblages of the Ohio River, was computed for each site, as well as the Shannon-Wiener Diversity Index (SWDI). MORFIn is a multimetric index comprised of 15 individual biological metrics, including number of great river species, number of pollution intolerant species, and percent relative abundance of piscivores. ORSANCO has found that the 15 MORFIn metrics generally respond predictably to human disturbances. The Shannon-Wiener index (SWDI) is frequently used to quantify diversity of ecological communities and to provide important information about rarity and commonness of species in an assemblage. The ability to quantify diversity in this way is an important tool for biologists trying to understand community structure.

Both indices were compared between years (pooled 2003 scores and pooled 2009 scores), and in both cases there were no statistically significant differences (using nonparametric Mann-Whitney confidence interval and test procedures to make inferences about the difference between 2003 and 2009 population medians). The results of these indices are displayed in the following graphs (Figure 7 and Figure 8).

Figure 7. Comparison of 2003 and 2009 Shannon-Wiener Diversity Index scores.

Figure 7

Figure 8. Comparison of 2003 and 2009 Modified Ohio River Fish Index scores.

Figure 8

In addition to Monongahela River fisheries data, water quality data (collected by others) and river invertebrate samples (e.g., aquatic insects, crustaceans, and mollusks) collected by PFBC in 2009 will also be evaluated to formulate a more detailed evaluation of aquatic communities in the Monongahela River. The Pennsylvania Fish and Boat Commission is also directing a multi-agency survey effort in late September 2010 to repeat the 2003 lockchamber surveys at Opekiska, Morgantown, Grays Landing, Maxwell and Braddock. All these data and those collected by others will serve the PFBC in developing a weight-of-evidence approach to evaluate changes in Monongahela River biological assemblages, as well as using these assemblages (e.g., fish, invertebrates) as potential biological indicators for ecological impact assessment.

— Prepared by Three Rivers Fisheries Biologist Aide Matt Kinsey and Three Rivers Fisheries Biologist Bob Ventorini

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