What Role Has Hybridization Played in the Replacement of Native Roanoke Bass with Invasive Rock Bass?

2018 ◽  
Vol 147 (3) ◽  
pp. 497-513 ◽  
Author(s):  
Jackman C. Eschenroeder ◽  
James H. Roberts
Keyword(s):  
Rock Bass

scholarly journals River Otter, Lontra canadensis, Food Habits in the Missouri Ozarks

2008 ◽  
Vol 122 (4) ◽  
pp. 303 ◽  
Author(s):  
Nathan M. Roberts ◽  
Charles F. Rabeni ◽  
John S. Stanovick ◽  
David A. Hamilton
Keyword(s):  
Smallmouth Bass ◽  
Lontra Canadensis ◽  
Micropterus Dolomieu ◽  
Widespread Occurrence ◽  
River Otters ◽  
Lepomis Megalotis ◽  
Rock Bass ◽  
Longear Sunfish ◽  
The Mean ◽  
Ambloplites Rupestris

The reintroduction of River Otters (Lontra canadensis) between 1982 and 1992 resulted in widespread occurrence of the species throughout the Missouri Ozarks. This study examined otter diets from the vicinity of two Ozark streams in relation to seasonal and spatial trends. Otter scats (N = 4750) were collected and analyzed from the Osage Fork River and Big Piney River during the summer and winter seasons of 2001 and 2002. During the winter (January-March), fish occurred in 86% of the samples. During the summer (June–August), occurrence of fish dropped to approximately 15% for both rivers. Seven families of fish were identified in the diets, with Centrarchidae being most common regardless of river or season. Within the Centrarchidae, the genus Lepomis (mostly Longear Sunfish, Lepomis megalotis) was most common, with Micropterus (mostly Smallmouth Bass, Micropterus dolomieu) and Rock Bass (Ambloplites rupestris) also well represented. The mean age of Ambloplites consumed (mean = 3.3 years) was consistently older than that of either Micropterus (mean = 2.54 years) or Lepomis (mean = 2.78 years). Crayfish were recovered from a mean of 85.2% of scats in the winter and 99% in the summer. Smaller fish and crayfish were more common from the upper reaches of the streams while larger fish were prevalent in the lower reaches.

Sexual differences in accumulation of mercury in four species of centrarchid fishes

1988 ◽  
Vol 66 (4) ◽  
pp. 944-949 ◽  
Author(s):  
Paul F. Nicoletto ◽  
Albert C. Hendricks
Keyword(s):  
Lepomis Macrochirus ◽  
Mercury Content ◽  
Lepomis Gibbosus ◽  
South Fork ◽  
The South ◽  
Male And Female ◽  
Rock Bass ◽  
Males And Females ◽  
Redbreast Sunfish ◽  
Ambloplites Rupestris

A 3-year study of fish from the South River, and the South Fork of the Shenandoah River, and the Shenandoah River in Virginia revealed significant differences in the muscle mercury content of males and females. Female rock bass, Ambloplites rupestris, redbreast sunfish, Lepomis auritus, pumpkinseed, Lepomis gibbosus, and bluegill, Lepomis macrochirus contained higher levels of mercury than the males of each species. An analysis of these species indicated that sex-related differences in mercury levels were not due to differences in body size but may have been related to the onset of reproduction. For example, mercury levels in 1-year-old male and female redbreast sunfish were not significantly different: females averaged 0.66 μg Hg/g and males averaged 0.63 μg Hg/g. However, at 2 years of age, when redbreast sunfish first reproduce, females contained significantly more mercury than males: females averaged 0.84 μg Hg/g and males averaged 0.60 μg Hg/g. Analysis of the other species yielded similar results.

Body and Fin Form and Strike Tactics of Four Teleost Predators Attacking Fathead Minnow (Pimephales promelas) Prey

1984 ◽  
Vol 41 (1) ◽  
pp. 157-165 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Rainbow Trout ◽  
Fathead Minnow ◽  
Pimephales Promelas ◽  
Rigid Bodies ◽  
Smallmouth Bass ◽  
Response Threshold ◽  
Salmo Gairdneri ◽  
Large Prey ◽  
Caudal Fin ◽  
Rock Bass

Experiments with teleosts attacking fathead minnow (Pimephales promelas) prey showed that piscivore locomotor tactics vary with body/fin morphology. Predators were tiger musky (Esox sp.), rainbow trout (Salmo gairdneri), smallmouth bass (Micropterus dolomieui), and rock bass (Ambloplites rupestris) representing several morphological series from more flexible to more rigid bodies, elongate to gibbose bodies, soft-rayed to acanthopterygian median/paired fin patterns, and more to less myotomal muscle. Two predicted optimal tactics were common to the four predators: (1) strike at the prey center of mass and (2) strike prey from the side. Other tactics varied among the predators. Tiger musky always used S-start fast-starts, rainbow trout used steady swimming with body/caudal fin movements, and smallmouth and rock bass used steady swimming with body/caudal fin movements for closer prey and started attacks on distant prey with pectoral propulsion. Tiger musky overshot prey, this being prevented by the use of paired fins as brakes in the two centrarchids. Rainbow trout regularly chased prey, but effective braking coupled with suction feeding appeared to make chases less necessary for smallmouth and rock bass. Speeds in strikes increased according to rock bass < smallmouth bass < rainbow trout < tiger musky consistent with expectations based on morphology. Each species used attack speeds likely to minimize closure times, which is the general optimal strategy for interceptors. Tiger musky attacked at maximum speeds but rainbow trout and smallmouth and rock bass attacked at speeds very much lower than their maximum potential. The prey has a low response threshold for these three species compared with tiger musky when high speeds and associated large prey reaction distances would increase closure times.

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