BUDGET ANALYSIS OF PENAEID SHRIMP HATCHERY FACILITIES

One of the critical factors in commercial penaeid shrimp culture production is the availability of postlarvae to stock grow-out ponds. This study investigates the economic feasibility of rearing penaeid shrimp from nauplii to postlarvae (hatchery phase). The facility design used is based on the hatchery operated by Texas A&M university at Galveston, Texas. The Generalized Budget Simulation Model for Aquaculture developed at Texas A&M University was used for the analysis. A ten-year planning horizon was used for the analysis. Six different systems ranging in size from 5 ten-metric ton tanks to 60 ten-metric ton tanks were examined. Annual cost and return budgets were developed for the six systems assuming they operated 6 and 12 months per year. Investment costs, break-even prices and quantities, and net present value were estimated for each system. Results show that commercial hatcheries, using 10-metric ton tanks, could be profitable above and including 20 tanks for those operating only six months annually and above and including 10 tanks for those operating 12 months annually.     

Preservation of striated-muscle urethral sphincter function with use of a surgical technique for perineal urethrostomy in cats

It has been reported that perineal urethrostomy resulted in impairment of striated-muscle urethral sphincter function in male cats, as measured by urethral pressure profilometry and electromyography (EMG). Our study was undertaken to describe and evaluate a surgical technique for perineal urethrostomy that reduces trauma to the urethral branches of the pudendal nerve. Perineal urethrostomy was performed on 10 healthy neutered cats after demonstrating that they had normal urethral sphincter function by urethral pressure profilometry (maximal urethral closure pressure [MUCP] = 151 +/- 52 cm of water) and EMG activity at the level of the striated-muscle sphincter before surgery. All cats had normal urethral sphincter function 1 week (MUCP = 194 +/- 19 cm of water, EMG activity present) and 3 weeks (MUCP greater than 200 cm of water, EMG activity present) after surgery. These results indicated that preservation of the urethral branches of the pudendal nerve during urethrostomy preserved striated-muscle urethral sphincter function.     

The Impact of Aquaculture Pond Engineering Design on the Returns to Shrimp Farms

The effects of pond design on the internal rate of return of a 40 ha shrimp farm is evaluated. The influence of four pond construction parameters (pond size, pond shape, levee crown size and canal bank slope) on the total amount of earth moved and construction costs is determined using an engineering design model. The bioeconomic model, MARSIM, calculates returns to farms with the design modifications. Of the four parameters, the pond shape is the most influential over the range considered (from 17% to 8%). Pond size is the second most important parameter (from 17% to 21%). Levee width and canal bank slope influence are of lesser importance (<1% change).     

Stocking Strategies and an Investment Analysis for Producing Penaeus setiferus as a Live Bait-Shrimp on the Texas Gulf Coast

An economic and investment analysis was performed to determine the viability of bait-shrimp farming in Texas. A single pond analysis producing 5–5.5g shrimp always had higher returns above selected cost (RASC) than producing 4–4.5g shrimp. Stocking 0.01g shrimp had a higher RASC than stocking 0.25g, 0.50g or 0.75g shrimp. In the 20 pond analysis, which accounted for marketing considerations, stocking 0.25g shrimp had the highest RASC. The investment analysis, assuming average management, was declared bankrupt by the end of the fifth year. Under "excellent" management the internal rate of return was only 11.7%. It is unlikely that bait-shrimp farming will become a viable industry in Texas in the near future.     

Morphologies and origin of elemental carbon in the environment

Carbon particles extracted from sediments collected by box coring from southeastern Lake Michigan were compared with carbon particles extracted from oil, coal, and wood fly ash. Sediments deposited after 1900 contained coal, oil, and wood carbons; older sediments contained only wood carbon.     

Cooperation, control, and concession in meerkat groups

"Limited control" models of reproductive skew in cooperative societies suggest that the frequency of breeding by subordinates is determined by the outcome of power struggles with dominants. In contrast, "optimal skew" models suggest that dominants have full control of subordinate reproduction and allow subordinates to breed only when this serves to retain subordinates' assistance with rearing dominants' own litters. The results of our 7-year field study of cooperative meerkats, Suricata suricatta, support the predictions of limited control models and provide no indication that dominant females grant reproductive concessions to subordinates to retain their assistance with future breeding attempts.     

Microbial dehalorespiration with 1,1,1-trichloroethane

1,1,1-Trichloroethane (TCA) is a ubiquitous environmental pollutant because of its widespread use as an industrial solvent, its improper disposal, and its substantial emission to the atmosphere. We report the isolation of an anaerobic bacterium, strain TCA1, that reductively dechlorinates TCA to 1,1-dichloroethane and chloroethane. Strain TCA1 required H2 as an electron donor and TCA as an electron acceptor for growth, indicating that dechlorination is a respiratory process. Phylogenetic analysis indicated that strain TCA1 is related to gram-positive bacteria with low DNA G+C content and that its closest relative is Dehalobacter restrictus, an obligate H2-oxidizing, chloroethene-respiring bacterium.     

Detection of channel catfish virus DNA in acutely infected channel catfish, Ictalurus punctatus (Rafinesque), using the polymerase chain reaction

Channel catfish virus (CCV) causes an acute haemorrhagic disease in channel catfish, Ictalurus punctatus (Rafinesque), fry and fingerlings. The present study describes a polymerase chain reaction (PCR)-based assay for detection of CCV DNA in the tissues of acutely infected juvenile catfish. The assay is rapid, sensitive and specifically detects CCV DNA derived from epidemiologically distinct viral isolates. The use of two independent PCR primers sets, each specific for particular CCV genes (open reading frames 8 and 59), provides a means to confirm the results and minimize false-positive results. The method identifies CCV DNA in several tissues of acutely infected fish, including the brain, blood, intestine, kidney and liver. The CCV PCR assay is useful for the diagnosis of acute CCV disease and for studies to investigate the molecular basis of CCV pathogenesis.     

An analysis of a community food waste stream

Food waste comprises a significant portion of the waste stream in industrialized countries, contributing to ecological damages and nutritional losses. Guided by a systems approach, this study quantified food waste in one U.S. County in 1998–1999. Publications and personal interviews were used to quantify waste from food production, processing, distribution, and consumption. Approximately 10,205 tons of food waste was generated annually in this community food system. Of all food waste, production waste comprised 20%, processing 1%, distribution 19%, and 60% of food waste was generated by consumers. Less than one-third (28%) of total food waste was recovered via composting (25%) and food donations (3%), and over 7,000 tons (72%) were landfilled. More than 8.8 billion kilocalories of food were wasted, enough to feed county residents for 1.5 months. This case study offers an example of procedures to quantify and compare food waste across a whole community food system.