Steven G. George's research while affiliated with Engineer Research and Development Center - U.S. Army and other places

Publications (19)

Article
The Bonnet Carre' Spillway diverts water from the Mississippi River through a floodway into brackish Lake Pontchartrain to reduce river stages at New Orleans and prevent flood damage. Pallid Sturgeon Scaphirhynchus albus, a federally listed species under the Endangered Species Act, and Shovelnose Sturgeon Scaphirhynchus platorynchus, listed under t...
Article
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A major spawning event of Silver Carp was documented in a tributary of the Lower Mississippi River. Peak spawning occurred during a rapid rise in river stage, a rapid rise in water temperature up to 18°C–19°C, and most commonly in a sinuous river reach with complex hydraulic patterns. Spawning behavior is described.
Preprint
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The Bonnet Carre’ Spillway diverts water from the Mississippi River through a floodway into Lake Pontchartrain to reduce river stages at New Orleans and prevent flood damages. Pallid Sturgeon, a federally listed species under the Endangered Species Act, and Shovelnose Sturgeon, listed under the Similarity of Appearance rule, are entrained through t...
Article
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Benthic fish assemblages were compared in 2016-2017 among three different bank types in the Lower Mississippi River (LMR) using hoopnets: Articulated Concrete Mattress (ACM) along main channel banks, natural banks along main channel, and natural banks in a secondary channel. Species richness was highest in secondary channels (21 species), followed...
Article
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Two Hypophthalmichthys molitrix (silver carp) were collected in the Pearl River on 6 September 2012 during a natural fish kill in the decommissioned lock chamber of Lock-and-Dam No. 1 located at river kilometer (RKM) 47.5 in St. Tammany Parish, 9.4 km NW of the city of Pearl River, LA. Fish were a male 987 mm TL, 10.9 kg, and a female 1042 mm TL, 1...
Article
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On 24 February 2014, commercial fishers caught an unusually large Hypophthalmichthys nobilis (Bighead Carp) from an oxbow lake in northwestern Mississippi. We examined it to determine age, gonadal development, and fecundity. The specimen was 1316 mm total length, 49.7 kg, and 11 years old. It had asymmetric ovaries that collectively represented 15....
Article
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We observed a large adult Paddlefish entrained from the Mississippi River through the Bonnet Cane spillway, south Louisiana, which was injured and underweight. We captured, measured (23 metrics), and tagged the fish. After it had spent a week at large on the fioodway, we recaptured and released it back into the Mississippi River. The specimen was r...
Article
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An individual of Oncorhynchus mykiss (Rainbow Trout) was collected in a diversion canal of the Mississippi River known as Davis Pond located at river kilometer (RKM) 191.03 in St. Charles Parish near Luling, LA. This locality is the southern-most record for Rainbow Trout in the Mississippi River Basin and represents a range extension of 733.5 RKM s...
Article
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Harvesting of liver samples for toxicologic and other laboratory analyses is frequently undertaken in free-ranging fish to evaluate accumulations of various pollutants and chemicals. However, commonly used, lethal techniques for collecting liver tissues are unacceptable when dealing with protected species. We report the use of a nonlethal, single-e...
Conference Paper
Three floodways along the lower Mississippi River were operated during the 2011 flood: New Madrid, Morganza, and Bonnet Carre. There was concern that the federally endangered pallid sturgeon (Scaphiryhnchus albus) would be entrained through the floodways resulting in injury or death. Varying levels of sampling effort were conducted in each floodway...
Article
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We report the Silver Lamprey (Ichthyomyzon unicupis) from Arkansas for the first time. Fifteen adult I. unicuspis attached to paddlefish (Polyodon spathula) were collected in Apr. 2005 from the White River near the confluence of the Black River, Independence and Jackson counties. Twelve (80%) of the I. unicuspis possessed 3 teeth (including the ape...
Article
Stomach contents of 3 Scaphirhynchus platorynchus (Shovelnose Sturgeon) collected in the Lower Mississippi River in January 2010 yielded 44 specimens of cicada nymphs, Diceroprocta sp. The fish were collected during a sudden rise in water level. The floodplain-dwelling cicada were likely washed out of their terrestrial habitat and into the river, w...
Article
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This study summarizes recent observations of silver carp, Hypopthalmichthys molitrix, in small wetlands of the Lower Mississippi River and suggests management actions for their control based on wetland hydrology and pattern of fish movements.
Article
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Paddlefish rostra vary in size and shape suggesting existence of multiple morphotypes. Measurements for 118 adult paddlefish from a Mississippi delta river indicate that the rostrum becomes shorter, narrower, and straighter as a fish grows. Negative allometric growth of rostra, and high variation within size classes, may obscure existence of distin...
Article
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Two hundred of 295 shovelnose sturgeon Scaphirhynchus platorynchus captured in the Mississippi River near Rosedale and Vicksburg, Mississippi, were aged by examining sectioned pectoral fin rays. Ages ranged from 2 to 16 years, and the annual mortality was 20% for ages 7 and greater. The weight (W, g), to fork length (FL, mm) relation was W = 0.0000...

Citations

... Hypophthalmichthys molitrix (Valenciennes) (Silver Carp) invaded the Lower Mississippi River (LMR) system from aquaculture ponds in the 1970s Pegg 2001, Kelly et al. 2011). Since then, this species has become common in the Mississippi River (Haupt and Phelps 2016), its tributaries (DeBoer et al. 2018, Fuller et al. 1999, Hayer et al. 2014, Williamson and Garvey 2005, and other river basins in the southeastern US (Slack et al. 2016). ...
... The primarily cartilaginous skeleton, spiral valve intestine and notochord of the paddlefish bear a striking resemblance to the internal structures of chondrichthyans. Early taxonomists initially misclassified the paddlefish as a species of shark (Hoover et al. 2000). The paddlefish is now classified as a bony fish of the infraclass Chondrostei and placed in the order Acipenseriformes along with sturgeons and its only extant confamilial relative, the Chinese paddlefish (Psephurus gladius) (Moyle and Cech 1996;Ross 2001). ...
... cm) trees. Because of the potential inßuence of ßooding on emergence timing (Andersen 1994), predation on nymphs (Harrison et al. 2011), and our presumption that areas lower in elevation would be more prone to ßooding and would likely hold water for longer periods of time, we acquired elevation data at all traps. We obtained elevation data from the high resolution 1/3 Arc-second National Elevation Dataset (United States Geological Survey [USGS] 2009). ...
... Rates of movement of Moon Lake Paddlefish presumably vary depending on whether they are moving downriver, through the smaller waterways (presumably at higher rates), or upriver, through the Mississippi River (presumably at lower rates). Our rates approximate those for a single Paddlefish that moved upriver from Norco, LA, to Greenville, MS, at an overall rate of 2.5 km/day (Hoover et al. 2013). Slower daily rates of movement, ≤5 km/d, suggest that Paddlefish in the lower Mississippi River expend a great deal of energy during their upriver movements and/or are making extensive lateral movements into littoral areas and backwater habitats to feed or rest. ...
... In the southern portion of the Mississippi River, the Silver Lamprey is rare and historically considered restricted to the mainstem Mississippi River (Pflieger 1997). However, our discovery of Silver Lamprey in the Meramec River (a Mississippi River tributary) is consistent with Robison et al. (2011), who recently confirmed the presence of Silver Lamprey at multiple locations within the White River system, a tributary of the Mississippi River in Arkansas. These recent findings suggest Silver Lamprey may be more widespread, albeit still rare, in southern Mississippi River tributaries than historically documented. ...
... data indicate that the Big Sunflower River supports a diverse assemblage of fishes, with 57 species captured in 114 collections (). Available evidence suggests that fish populations increased and became more speciose between 1972 and 1992 due to reductions in DDT and municipal wastewater loads (Yarborough et al., 1994; Lucas and Pennington, 2001). George et al. (1995) examined paddlefish (Polyodon spathula) in a 60-km reach of the Big Sunflower immediately upstream of our study area and found a stable or increasing population in good condition relative to other major rivers. ...
... of YOY fish at Tanis enabled us to make a reasonable estimate of the elapsed time between hatching and death. A wide range of YOY body sizes relative to growth rate were compiled from the literature for modern Acipenseriformes 12,[14][15][16]30,31,40 , comprising a sufficiently broad spectrum of slow and rapid growth to encompass the imprecisely established ranges of the ancestral Cretaceous taxa. The body sizes of YOY fish from Tanis were compared with these ranges to estimate the time since hatching (Fig. 3). ...
... The Paddlefish, a "living fossil" with closely-related ancestors alive in the Cretaceous Era, has a rostrum unlike any other fish, supported by a lattice-like skeleton of cartilage made up of star-shaped elements called stellate "bones" [2]. The rostrum is unusually large and variable in shape [3,4]. It has multiple vital functions, as a sensory antennae detecting vibratory and electrical signals [5][6][7] and as a locomotor structure providing lift and enhanceed swim speed [8,9]. ...
... Endoscopy has been described in catfish (Ictalurus punctatus) (Boone et al. 2008), trout (Oncorhynchus mykiss) (Moccia et al. 1984), wolf fish (Hoplias aimara) (Weber 2011b), eel (Anguilla Anguilla) (Macri et al. 2014), and sturgeon (Hernandez- Divers et al. 2004;Divers et al. 2013;Falahatkar and Poursaeid 2014) among others, to determine sex, evaluate coelomic organs, remove ingested foreign bodies, and obtain biopsies (Boone et al. 2008;Stetter 2010;Divers et al. 2013). Celioscopy may be performed with the endoscope inserted directly into the coelomic cavity or within the swim bladder (Stetter 2010;Stevens et al. 2019). ...
Reference: Fish Surgery
... However, floods have also facilitated invasion of backwaters by bigheaded carps (Pongruktham, Ochs, & Hoover, 2010;Varble, Hoover, George, Murphy, & Killgore, 2007). Between floods, backwater habitats are an isolated habitat where local competition both within and between species could affect juvenile survival and adult fecundity. ...