Ted R. Angradi

Multimetric macroinvertebrate indices for mid-continent US great rivers

Abstract We developed a set of great-river macroinvertebrate indices of condition (GRMINs) for the littoral benthos of mid-continent great rivers in the US (Missouri, Upper Mississippi, and Ohio). We used a multiscale (site, reach, landscape), multimetric abiotic stressor gradient to select macroinvertebrate assemblage metrics sensitive to human disturbance. We used the same stressor gradient to derive reference expectations by empirical modeling. We developed GRMINs for each of 5 reaches: the upper Missouri River, the lower Missouri River, the unimpounded Upper Mississippi River, the impounded Upper Mississippi River, and the Ohio River. We created 2 versions of each index. One version was based on the absolute value (AV) of the correlation between invertebrate metrics and the stressor gradient and potentially included all types of metrics (e.g., diversity, composition, tolerance to pollution, feeding guild). The second version included no tolerance-value-based metrics (NTV). Each index included up to 10 metrics. The indices were reliable for general assessment of great-river aquatic conditions except in the unimpounded Upper Mississippi River. The AV and NTV versions of the GRMIN were highly correlated (r  =  0.94). The indices revealed longitudinal variation in condition on great-river reaches and among-river variation in relative condition. No sites near or <100 km downriver of Kansas City, Missouri, on the Missouri River or Minneapolis–St. Paul, Minnesota, on the Upper Mississippi River were in least-disturbed condition. GRMIN indices are an indicator of biotic response to general human disturbance. They are appropriate for local and regional-scale ecological assessments and long-term monitoring.

Multispatial-scale variation in benthic and snag-surface macroinvertebrate assemblages in mid-continent US great rivers

Abstract We sampled macroinvertebrate assemblages in the littoral benthos and on the surface of snags in the Upper Mississippi, Missouri, and Ohio rivers. Snag assemblages differed from benthic assemblages. Tubificids, Caenis, Tanytarsus, Cryptochironomus, Limnodrilus, and Chironomini were consistently more abundant in the benthos; Nais, Cricotopus/Orthocladius, Nematoda, and Rheotanytarsus were consistently more abundant on snags. Filterers were more abundant and gatherers were less abundant on snags than in the benthos. Snag assemblages differed among rivers and among reaches within rivers. Variation among reaches was the result of direct and indirect effects of high-dam reservoir impoundments (upper vs lower Missouri River) and low-dam impoundment for navigation (impounded vs free-flowing Upper Mississippi River). The maximum relative abundance of filterers in the lower Missouri River, which was the only long unregulated reach we studied, was related to particulate organic C and sestonic chlorophyll a concentration, which increased with distance downriver from the lowest main-stem dam. Snag diameter, snag-surface characteristics, and water depth did not affect the composition of snag assemblages, but the dominant taxa on snags in fast-velocity locations were different from the dominant taxa on snags in slow-velocity locations. Relatively few taxa showed strong longitudinal patterns in relative abundance within a reach, and only on the Missouri River. We hypothesize that the many navigation dams on the Ohio and Upper Mississippi rivers suppress the development of environmental gradients and inhibit the formation of longitudinal patterns in macroinvertebrate assemblages. Snag assemblages were dominated by a few taxa (genus-level and higher), a characteristic that might constrain the sensitivity of the assemblages to some human impacts. Sampling snag assemblages has potential for great-river bioassessment, but further research is necessary on sampling methods and sensitivity of assemblages to stressors.

Occurrence of the Quagga Mussel (Dreissena bugensis) and the Zebra Mussel (Dreissena polymorpha) in the Upper Mississippi River System

ABSTRACT The quagga mussel (Dreissena bugensis) was first found in the Ohio River and the upper Mississippi River in the mid-1990s. It has since gone unreported in the Mississippi River system possibly due in part to its phenotypic variability and close morphological resemblance to the more commonly occurring zebra mussel (Dreissena polymorpha). Sampling of the upper Mississippi River system during 2004–2006 revealed that the quagga mussel occurred at several localities outside its previously reported distribution in the Ohio River and upper Mississippi River. Few zebra and no quagga mussels were found in the Missouri River. Quagga mussels were not abundant in our survey, comprising less than 1% of identifiable Dreissena specimens.

Invasion of the Upper Mississippi River system by saltwater amphipods.

Abstract: Zoobenthic surveys of the large rivers of the Upper Mississippi River basin (Missouri, Upper Missis-sippi, and Ohio Rivers) in 2004-2006 revealed new invasions by euryhaline amphipods. The gammarid amphipods Echinogammarus ischnus and Gammarus tigrinus were discovered in the Ohio and Upper Mississippi Rivers in 2004. The corophiid amphipod Apocorophium lacustre was fi rst found in the Ohio River in 1996, and fi rst detected in the Upper Mississippi River in 2005. None of these invaders was collected in the Missouri River. The presence of breeding adults of all three species suggests they are permanently established in the Ohio and Upper Mississippi. The range and occurrence of all three species increased in the basin from 2004 through 2006. The contribution of the three invaders to total amphipod catch in the Upper Mississippi River increased from 23 % in 2005 and 2006. The establishment of nonindigenous amphipods will likely contribute to alterations of food webs and native faunal diversity in the invaded rivers.

Muskie Lunacy: Does the Lunar Cycle Influence Angler Catch of Muskellunge (Esox masquinongy)?

We analyzed angling catch records for 341,959 muskellunge (Esox masquinongy) from North America to test for a cyclic lunar influence on the catch. Using periodic regression, we showed that the number caught was strongly related to the 29-day lunar cycle, and the effect was consistent across most fisheries. More muskellunge were caught around the full and new moon than at other times. At night, more muskellunge were caught around the full moon than the new moon. The predicted maximum relative effect was ≈5% overall. Anglers fishing exclusively on the peak lunar day would, on average, catch 5% more muskellunge than anglers fishing on random days. On some lakes and at night, the maximum relative effect was higher. We obtained angler effort data for Wisconsin, Mille Lacs (MN), and Lake Vermilion (MN). For Lake Vermilion there was a significant effect of the lunar cycle on angler effort. We could therefore not conclude that the lunar effect on catch was due to an effect on fish behavior alone. Several factors affected the amount of variation explained by the lunar cycle. The lunar effect was stronger for larger muskellunge (>102 cm) than for smaller fish, stronger in midsummer than in June or October, and stronger for fish caught at high latitudes (>48°N) than for fish caught further south. There was no difference in the lunar effect between expert and novice muskellunge anglers. We argue that this variation is evidence that the effect of the lunar cycle on catch is mediated by biological factors and is not due solely to angler effort and reflects lunar synchronization in feeding. This effect has been attributed to variation among moon phases in lunar illumination, but our results do not support that hypothesis for angler-caught muskellunge.

An assessment of stressor extent and biological condition in the North American mid-continent great rivers (USA)

We assessed the North American mid-continent great rivers (Upper Mississippi, Missouri, and Ohio). We estimated the extent of each river in most- (MDC) or least-disturbed condition (LDC) based on multiple biological response indicators: fish and macroinvertebrate, trophic state based on chlorophyll a, macrophyte cover, and exposure of fish-eating wildlife to toxic contaminants in fish tissue (Hg, total chlordane, total DDT, PCBs). We estimated the extent of stressors on each river including nutrients, suspended solids, sediment toxicity, invasive species, and land use (agriculture and impervious surface). All three rivers had a greater percent of their river length in MDC than in LDC based on fish assemblages. The Upper Mississippi River had the greatest percent of river length with eutrophic status. The Ohio River had the greatest percent of river length with fish with tissue contaminant levels toxic to wildlife. Overall, condition indices based on fish assemblages were more sensitive to stress than macroinvertebrate indices. Compared to the streams in its basin, more of the Upper Mississippi and Missouri Rivers were in MDC for nutrients than the Ohio River. Invasive species (Asian carp and Dreissenid mussels) were less widespread and less abundant on the Missouri River than on the other great rivers. The Ohio River had the most urbanized floodplains (greatest percent impervious surface). The Missouri River had the most floodplain agriculture. The effect of large urban areas on river condition was apparent for several indicators. Ecosystem condition based in fish assemblages, trophic state, and fish tissue contamination was related to land use on the floodplain and at the subcatchment scale. This is the first unbiased bioassessment of the mid-continent great rivers in the United States. The indicators, condition thresholds, results, and recommendations from this program are a starting point for improved future great river assessments.

Macroinvertebrate assemblage response to urbanization in three mid-continent USA great rivers

We sampled macroinvertebrates in the benthos and on the surface of woody snags in three mid-continent USA great rivers, the Upper Mississippi River, the Lower Missouri River, and the Ohio River, all of which flow through several large urban areas. We defined urban and non-urban zones of each river based on mean percent impervious surface extracted from recent land cover data. We estimated that 28-36 % of the rivers, by length, was urbanized. Based on multivariate ordination, the overall structure of the great river assemblages was not different between urban and non-urban zones for either the benthos or snags in any river. Most taxa (82 %) did not exhibit a significant positive or negative effect of urbanization in either river. Many of the taxa that were responsive to zone type were relatively rare (river- and habitat-specific relative abundance < 5 %). For responsive taxa, the effects of urbanization were generally weaker on the Upper Mississippi and Ohio Rivers than on the Lower Missouri River and weaker for snag-surface assemblages than for the littoral benthos. Among the taxa that were more abundant in urban sections were several insect taxa generally considered intolerant of pollution. We speculate that urbanization, possibly due to nutrient enrichment and resulting increased food resources (algae, seston), may improve conditions for these taxa. There appeared to be a threshold in mean percent impervious surface for a great river subcatchment near 5 % above which urban-intolerant taxa were always rare and urban tolerant taxa were often abundant.

Trophic status of three large Missouri River reservoirs

Abstract Bolgrien, D.W., J.V. Scharold, T.R. Angradi, T.D. Corry, E.W. Schwieger and J.R. Kelly. 2009. Trophic status of three large Missouri River reservoirs. Lake Reserv. Manage. 25:176–190. Probability-based surveys conducted between 2001–2004 characterized the three large reservoirs of the Missouri River—Lake Oahe, Lake Sakakawea, and Fort Peck Lake—as mesotrophic to eutrophic, phosphorus (P) limited, and generally supporting cold water habitat (bottom waters <15°C and dissolved oxygen [DO] concentrations >5 mg/L) in midsummer. Riverine zones were shallower, warmer, more eutrophic, and had lower DO and higher suspended matter concentrations than lacustrine zones. Similar, although more variable, differences were found between bays and open-water areas. Between sampling years, water levels decreased in each reservoir. In the first year of sampling, area-weighted mean reservoir trophic status index based on chlorophyll (TSIchl) was about 37 in all three reservoirs. Sixty percent of Oahe and Sakakawea and 40% of Fort Peck had TSIchl> 50. Trophic status index based on Secchi depth (TSISD) averaged about 50 in each reservoir across years. Because mean TSIchl< TSISD, light attenuation was considered to be silt, not algae, dominated. Trophic status index based on total P (TSITP) and the ratio of N:P concentrations indicated that the reservoirs were very P limited. Mean bottom temperature and DO concentration in Oahe were unchanged between years at about 19°C and 7.5 mg/L, respectively. Bottom temperatures in Sakakawea increased (from 15°C to 21°C) and DO concentration decreased (from 7.3 mg/L to 6.0 mg/L) with lower water levels. In Fort Peck, bottom temperature remained about 18°C, but DO concentration fell from 7.23 mg/L to 4.96 mg/L. Results show that surveys successfully characterized important environmental conditions throughout these large reservoirs.

Assessing the condition of the Missouri, Ohio, and Upper Mississippi rivers (USA) using diatom-based indicators

Diatom-based indicators were developed to assess environmental conditions in the Missouri, Ohio, and Upper Mississippi rivers. Disturbance gradients, comprising the first two principal components derived from a suite of stressor variables, included a trophic gradient (Trophic) and a gradient reflecting agriculture and other development activities (Ag/Dev). Diatom-based indicators were developed by creating models using weighted average calibration and regression-based transfer functions to relate planktonic and periphytic diatom species assemblages to each disturbance gradient. The most predictive disturbance models combined phytoplankton and periphyton assemblages into a single bioindicator model (observed versus inferred: Trophic