نتایج جستجو برای: stocking
تعداد نتایج: 3536 فیلتر نتایج به سال:
Genetic admixture between wild and introduced populations is a rising concern for the management of endangered species. Here, we use a dual approach based on molecular analyses of samples collected before and after hatchery fish introduction in combination with a simulation study to obtain insight into the mechanisms of admixture in wild populations. Using 17 microsatellites, we genotyped pre- ...
Knowledge of the relationship between stocking rate or grazing intensity and plant production is fundamental to the sustainable management of rangelands. The general management paradigm is that plant production declines as stocking rate increases. Our objective was to determine the impact of stocking rate on herbaceous production of a sand sagebrush (Artemisia filifolia Torr.)grassland. Stockin...
three stocking densities (20, 40, and 60 sheep/ha) were applied in four stocking periods (0, 2, 4, and 6 weeks) on a medicago truncatula cv. paraggio pasture. treatments were arranged in a split plot system and compared through a completely randomised block design with four replications.grazing period had a significant effect (p
The effect of stocking density and dietary aflatoxin B1 along with including rosemary and thyme powders on digestive enzymes activity of rainbow trout was evaluated. 600 fish with an average weight of 90±3 were randomly allotted into six experimental groups consisted of (1) stocking at 15 kg.m-3- feeding diet devoid of aflatoxin, (2) stocking at 45 kg.m-3-feeding diet devoid of aflatoxin, (3) s...
The most important decision for successful range management is setting a proper stocking rate. The stocking rate affects rangeland health and productivity, livestock production, and economic returns. Because of its importance, much rangeland research has focused on answering the question, "what is the proper stocking rate?" However, like many important questions in life, it is not easily answer...
Simple grazing models with two herbivores are used to assess the effects of pasture pests on stability and productivity of continously-growing pastures. Algebraic and graphical methods are also presented for estimating losses from pasture pests at different stocking rates directly, from data on productivity/stocking rate relationships. Pests are considered as competing grazing herbivores and de...
Feeding frequency and stocking density are important factors affecting growth and maturation of cultured fishes. The aims of this investigation were to determine the effects of stocking density (10, 20, 30 and 40 fish per aquarium) and feeding frequency (2, 3 and 4 times per day) on growth parameters and hematocrit of the Rutilus rutilus caspicus. The experiment was continued for 45 days in two...
We investigated the spatial and temporal relationship of catch rates and angler party location for two days following a publicly announced put-and-take stocking of rainbow trout (Oncorhynchus mykiss). Catch rates declined with time since stocking and distance from stocking. We hypothesized that opportunity for high catch rates would cause anglers to fish near the stocking location and disperse ...
Three trials were conducted to assess the effects of stocking density on physiological adaptive responses of broilers. Male broilers were reared in floor pens under conditions similar to those used commercially in the United States. Accepted indicators of adaptation to a stressor were measured on d 49 including plasma concentrations of corticosterone, glucose, cholesterol, and total nitrites as...
Predator-prey systems have been studied extensively. See, for instance, [1, 6, 8–10] and the references cited therein. Most of the previous papers focused on the predator-prey systems without stocking. Brauer and Soudack [2, 3] studied some predator-prey systems under constant rate stocking. To our knowledge, few papers have been published on the existence of positive periodic solutions for del...
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