Food of Bluegill and Longear Sunfish in DeGray Reservoir, Arkansas, 1976

Stomach contents were examined from 544 bluegill (Lepomis macrochirus) and 709 longear sunfish (L. megalotis) collected from nearshore areas of DeGray Reservoir April-November 1976. Major foods of bluegill (percentage of total weight of food in parentheses) were insects (33), bryozoa (7.3), planktonic crustaceans (6.5), and plant materials (15.4). The major food items contributing to the diet of longear sunfish were insects (52.6%), crayfish (12.5%), fish (7.4%), and plant material (6.7%). Although bluegill and longear sunfish are closely related species, their diets were not as similar as expected: bluegill consumed zooplankton, adult dipterans, and adult ephemeropterans associated with limnetic areas; while longear sunfish consumed terrestrial insects, immature stages of aquatic insects, and macro-invertebrates associated with littoral areas

Loss of Larval Fish by Epilimnial Discharge From DeGray Lake, Arkansas

Weekly samples of larval fish were collected from water discharged from the epilimnion of DeGray Lake into the tailwaters, for power generation, from April through August, 1976 and 1977. Peak rates of loss measured were 1.4 larvae/m³ in May, 1976 and 2.7/m³ in April, 1977. Sunfish, shad and crappie made up 97% of an estimated 83.3 million fish lost in 1976, and 98% of 122.4 million lost in 1977. The most critical period for larval fish loss extended from the last week of April to the first week of June. No definite relationships were noted between length of the power generation period or power generation rate, and rate of larval fish discharge. Diel collections showed the rate of larval fish discharge to be lower and more uniform during darkness than during daylight

Fishes of the Caddo River, Arkansas, After Impoundment of DeGray Lake

Fifty-five collections of fishes were made with small-mesh seines and electrofishing gear in the Caddo River and four of its tributaries during 1974-75. Eighty-two species representing 17 families were collected; 14 of the species had not previously been reported from the Caddo River

Water Quality in the Gillham Lake-Cossatot River System During Dry and Wet Periods

Water samples were collected in the Cossatot River-Gillham Lake system during an extended dry period and after heavy rains to determine the spatial variations in certain water quality characteristics. Of particular interest was the influence of the reservoir discharge on the water quality of the tailwater compared with the effects of four tributaries entering the tailwater below the reservoir. The water quality of the Cossatot River below Gillham Lake at low-flow (dry periods) and during the first 3 days after heavy rainfall (wet period) was influenced more by the tributaries entering the tailwater than by the reservoir water release. We estimated, however, that the amount of particulate inorganic matter released to the tailwater from the reservoir after the initial 3-day wet period would be greater than the amounts entering the tailwater from the tributaries

Food of Largemouth Bass (Micropterus salmoides) in DeGray Reservoir, Arkansas, 1976

Stomach contents were examined from 748 largemouth bass, Micropterus salmoides (\u3c125 mm total length), collected from DeGray Reservoir during April-November 1976. Fish constituted 59% by weight of the total diet and occurred in 81% of the stomachs; crayfish made up nearly 38% of the weight and occurred in 24% of the stomachs. Sunfish, the principal fish food (about 28% by weight), were observed in 36% of the stomachs. Shad were the second most important prey (23% by weight and 29% frequency in occurrence). Crayfish constituted about 42% of the total weight of the food of bass 200 mm long or longer, but only 12% in bass less than 200 mm. Crayfish consumption was greatest during the fall

Evaluation of a Frame Trawl and Tucker Trawl for Sampling Young-of-the-Year Fish

Relative efficiencies of two trawls — a 1.88 m² frame trawl and a 2 m² Tucker trawl— were compared for sampling young-of-the-year (YOY) shad, Dorosoma sp., crappies, Promoxis sp., and sunfishes, Lepomis sp. Seven tests with six replicate hauls for each net in each test were analyzed by non-parametric techniques. Relative efficiency ratios, calculated from mean density estimates, were compared. The Tucker trawl was the more efficient for sampling YOY shad, its relative efficiency increasing as shad length increased. Results for the other two taxa were less consistent. The larger size range of YOY shad captured compared with the size ranges of fish of the other two taxa, seemingly increased the avoidance capabilities of the shad. The absence of a bridle and otter boards on the Tucker trawl and towing the net away from the effect of the propeller wash contributed to its efficiency

Student Perceptions Of Appropriate Classroom Policies Of College Professors

Student perceptions of classroom management practices and policies employed by college educators have not been widely studied.  Faculty have broad discretion to determine classroom management practices and policies, and faculty are generally evaluated at least annually with student evaluations of teaching as a significant component of  the evaluative process.  The focus of this paper is whether students perceive faculty as having the freedom or discretion to adopt specified behaviors or policies unrelated to course content decisions.&nbsp

Genomic prediction in an admixed population of Atlantic salmon (Salmo salar)

Reliability of genomic selection (GS) models was tested in an admixed population of Atlantic salmon, originating from crossing of several wild subpopulations. The models included ordinary genomic BLUP models (GBLUP), using genome-wide SNP markers of varying densities (1 to 220k), a genomic identity-by-descent model (IBD-GS), using linkage analysis of sparse genome-wide markers, as well as a classical pedigree-based model. Reliabilities of the models were compared through 5-fold cross-validation. The traits studied were salmon lice (Lepeophtheirus salmonis) resistance (LR), measured as (log) density on the skin and fillet color (FC), with respective estimated heritabilities of 0.14 and 0.43. All genomic models outperformed the classical pedigree-based model, for both traits and at all marker densities. However, the relative improvement differed considerably between traits, models and marker densities. For the highly heritable FC, the IBD-GS had similar reliability as GBLUP at high marker densities (>22k). In contrast, for the lowly heritable LR, IBD-GS was clearly inferior to GBLUP, irrespective of marker density. Hence, GBLUP was robust to marker density for the lowly heritable LR, but sensitive to marker density for the highly heritable FC. We hypothesize that this phenomenon may be explained by historical admixture of different founder populations, expected to reduce short-range LD and induce long-range LD. The relative importance of LD/relationship information is expected to decrease/increase with increasing heritability of the trait. Still, using the ordinary GBLUP, the typical long-range LD of an admixed population may be effectively captured by sparse markers, while efficient utilization of relationship information may require denser markers (e.g., 22k or more)