Economic Evaluation of a Small-Scale Recirculating System for Ongrowing of Captive Wild Black Sea Bass Centropristis striata in North Carolina

An economic analysis of a hypothetical small‐scale marine recirculating aquaculture system (RAS) is conducted for ongrowing small, wild black sea bass Centropristis striata at the University of North Carolina Wilmington, Center for Marine Science (UNCW‐CMS) aquaculture facility in Wrightsville Beach, North Carolina (NC). The analysis is based on production data from field trials and marketing data from the sale of tank‐grown product. The growout facility consists of four 16.7‐m³ (dia. x ht. = 5.58 × 1 m) fiberglass tanks supported by state‐of‐the‐art RAS components, including particle traps and swirl separators, drum screen filter, trickling biological filter, UV sterilizer, heat pump, protein skimmer, and oxygen cone. Wild‐caught, above minimum legal size black sea bass (24.2 cm TL, 350 g, 0.77 lb) were purchased from a commercial fisherman for $3.14/ kg ($1.4011b), stocked at a density of 21.1 kg/m³, and grown to a final weight of 1 kg (2.24 lb) in 200 d at 23 C resulting in 1.8 production cycles per year. Fish were fed a commercial pelleted diet ($0.94/kg; $0.42/Ib) with a feed conversion ratio of 1.5. Final harvest density was 60 kg/m³ (0.50 lb/gal), and total harvestable weight was 3,982 kg (8,919 Ibs) of fish per cycle, or 6,760 kg (15,022 lb) per year. The economic analysis assumes that the facility owner manages and operates the system on coastal property zoned commercial/industrial, where full strength seawater is available on demand from natural sources. Under the base case scenario, initial investment in construction and equipment is $84,506 (10‐yr life), fish are grown to a harvestable weight of lkg/fish (2.24 lb/fish), product price (farm gate basis) is $10.10/kg ($4.50/lb), and breakeven price is $7.02/kg ($3.13/lb). Depreciation, fingerlings, interest paid, electricity, and feed, account for 19.6%,17.4%, 16.9%, 16.6%, and 12.3%, respectively, of total annual costs. Measures of financial performance for the base case, 10‐yr scenario are: annual return to management, $18,819; net present value (5% discount rate), $145,313; internal rate of return on initial investment, 37%; and discounted payback period on initial investment, 3.2 yr. Sensitivity analysis showed that product price changes have the largest impact on annual returns, while changes in daily growth rate, initial weight, and survival have a strong impact on financial performance. Moderate effects are seen with changes in fingerling costs, feed costs, feed conversion ratio (FCR), final weight, and interest rates.     

Evaluation of a virus-insecticide combination for cotton pest control in Togo

A low dose of cypermethrin combined with Mamestra brassicae virus was applied weekly against the bollworms Helicoverpa armigera (Hübner) and Diparopsis watersi (Rothschild) in smallholder cotton plots in northern Togo in 1989 and 1990. The timing of treatments was based on action thresholds. One or two additional sprays of Bacillus thuringiensis were applied to control Syllepte derogata F., or dimethoate to control aphids. No significant yield differences were observed between the plots treated with the pyrethroid-virus combination and the control plots, treated with the recommended insecticide schedule. However, the latter had a significantly higher percentage of healthy bolls. The virus applied was not reisolated from insects collected in the field.     

The potential impact of summer flounder (Paralichthys dentatus) aquaculture on regional flounder price

Abstract

Increasing consumer demand for flounder and dramatic reductions in ocean flounder harvests have raised interest in summer flounder (Paralichthys dentatus) aquaculture. Flounder farmers have several potential markets, including regional seafood dealers and high‐end niche (e.g., sashimi and ike‐jime) buyers. Prices paid by buyers are exogenous to typical aquacultural budgeting models, yet they are a key determinant of potential profitability. We develop a simple economic model to assess the impacts of aquaculture industry supply on prices paid by regional seafood dealers. The model is parameterized for a region with established flounder dealers and active field research in flounder production methods. We derive the price elasticity of regional seafood dealer demand for farmed flounder, and we examine the impacts of changes in production cost and ocean harvest on regional price and the level of aquacultural production that maximizes returns to the aquaculture industry.     

A live weight–heart girth relationship for accurate dosing of east African shorthorn zebu cattle

The accurate estimation of livestock weights is important for many aspects of livestock management including nutrition, production and appropriate dosing of pharmaceuticals. Subtherapeutic dosing has been shown to accelerate pathogen resistance which can have subsequent widespread impacts. There are a number of published models for the prediction of live weight from morphometric measurements of cattle, but many of these models use measurements difficult to gather and include complicated age, size and gender stratification. In this paper, we use data from the Infectious Diseases of East Africa calf cohort study and additional data collected at local markets in western Kenya to develop a simple model based on heart girth circumference to predict live weight of east African shorthorn zebu (SHZ) cattle. SHZ cattle are widespread throughout eastern and southern Africa and are economically important multipurpose animals. We demonstrate model accuracy by splitting the data into training and validation subsets and comparing fitted and predicted values. The final model is weight^0.262?=?0.95?+?0.022 × girth which has an R ² value of 0.98 and 95 % prediction intervals that fall within the ±20 % body weight error band regarded as acceptable when dosing livestock. This model provides a highly reliable and accurate method for predicting weights of SHZ cattle using a single heart girth measurement which can be easily obtained with a tape measure in the field setting.     

Crystal structure of the GpIbalpha-thrombin complex essential for platelet aggregation

Direct interaction between platelet receptor glycoprotein Ibalpha (GpIbalpha) and thrombin is required for platelet aggregation and activation at sites of vascular injury. Abnormal GpIbalpha-thrombin binding is associated with many pathological conditions,including occlusive arterial thrombosis and bleeding disorders. The crystal structure of the GpIbalpha-thrombin complex at 2.6 angstrom resolution reveals simultaneous interactions of GpIbalpha with exosite I of one thrombin molecule,and with exosite II of a second thrombin molecule. In the crystal lattice,the periodic arrangement of GpIbalpha-thrombin complexes mirrors a scaffold that could serve as a driving force for tight platelet adhesion. The details of these interactions reconcile GpIbalpha-thrombin binding modes that are presently controversial,highlighting two distinct interfaces that are potential targets for development of novel antithrombotic drugs.     

Presence and accumulation of fungitoxic substances against Ceratocystis ulmi in Ulmus americana: possible relation to induced resistance1

This paper reports the differential accumulation of inhibitory compounds in American elm seedlings after inoculation with a non-aggressive and an aggressive strain of C, ulmi.