Post-logging regeneration and recruitment of shihuahuaco (Dipteryx spp.) in Peruvian Amazonia: Implications for management

Over the past decade, shihuahuaco timber - comprising several species of Dipteryx (Fabaceae) traded internationally as “cumarú” or “Brazilian teak” - has become one of the most highly demanded types of hardwood from Peruvian Amazonia, particularly in the Chinese market. Dipteryx is an ecologically important canopy-emergent genus with widespread distribution in neotropical forests. To assess the response of Dipteryx to logging, we conducted inventories in three logging areas in the Regions of Ucayali and Loreto, Peru. The size-class distributions of Dipteryx populations in recently logged sites showed that initial post-logging conditions enhance recruitment of residual seedlings. These conditions are created by a combination of logging gaps and the activities of farmers migrating into logged lands. Through protection and liberation of shihuahuaco seedlings in post-logged forest as well as within and around agricultural fields, local residents and timber companies could favor the recovery of this valued resource. However, as logged land is increasingly converted to agriculture and pastureland, the reestablishment of mature seed trees is not assured.     

Modeling the relationship between food animal health and human foodborne illness

To achieve further reductions in foodborne illness levels in humans, effective pre-harvest interventions are needed. The health status of food animals that are destined to enter the human food supply chain may be an important, although often overlooked, factor in predicting the risk of human foodborne infections. The health status of food animals can potentially influence foodborne pathogen levels in three ways. First, diseased animals may shed higher levels of foodborne pathogens. Second, animals that require further handling in the processing plant to remove affected parts may lead to increased microbial contamination and cross-contamination. Finally, certain animal illnesses may lead to a higher probability of mistakes in the processing plant, such as gastrointestinal ruptures, which would lead to increased microbial contamination and cross-contamination. Consequently, interventions that reduce the incidence of food animal illnesses might also help reduce bacterial contamination on meat, thereby reducing human illness. Some of these interventions, however, might also present a risk to human health. For example, the use of antibiotics in food animals can reduce rates of animal illness but can also select for antibiotic-resistant bacteria which can threaten human treatment options. In this study, we present a mathematical model to evaluate human health risks from foodborne pathogens associated with changes in animal illness. The model is designed so that potential human health risks and benefits from interventions such as the continued use of antibiotics in animal agriculture can be evaluated simultaneously. We applied the model to a hypothetical example of Campylobacter from chicken. In general, the model suggests that very minor perturbations in microbial loads on meat products could have relatively large impacts on human health, and consequently, small improvements in food animal health might result in significant reductions in human illness.     

Production Characteristics of All‐male and Mixed‐sex Giant River Prawns,Macrobrachium rosenbergii,Grown in Earthen Ponds in Kentucky and Mississippi USA

Production and population characteristics of monosex male (all‐male) giant river prawns, Macrobrachium rosenbergii, were compared with a normal (mixed‐sex) population in separate studies in Mississippi and Kentucky (USA) under low and high density stocking conditions, respectively. In Study 1 (Mississippi), juvenile prawns were stocked into eight 0.05–0.06 ha ponds at 24,700/ha. The mean stocking weight of all‐male was 0.34 g and mixed‐sex was 0.39 g. Prawns were fed 23% crude protein “range cubes” and harvested after 120 d for the all‐male prawns and 112 d for mixed‐sex prawns. In Study 2 (Kentucky), juvenile prawns from each group were stocked into six 0.04 ha ponds at 60,000 juveniles per hectare. The mean stocking weight for all‐male was 0.38 g and for mixed‐sex juveniles was 0.34 g. Prawns were fed a commercial sinking pellet (33% protein) once daily at a standardized rate and harvested after 105 d. In both locations survival of mixed‐sex prawns and all‐male prawns was not significantly different and the final average weight of all‐male prawns was significantly greater than the average weight of mixed‐sex prawns. For the study in Kentucky, total production was not significantly different between treatments, whereas in Mississippi total production in the all‐male ponds was significantly higher than in the mixed‐sex ponds. For both studies, the production size index of all‐male prawns was significantly greater than that of mixed‐sex prawns. In terms of population structure, in all‐male ponds there was a significant increase in orange claw (OC) males compared with the mixed‐sex ponds both as a percent of sex and a percent of total population. The increase in OC numbers in all‐male populations may be due to a lack of females to stimulate the transition of males to the final, sexually mature, blue claw stage. As target weights increase from 20, 30, and 40 g, the all‐male populations were increasingly superior in terms of production (kg/ha) of those target sizes. The economic benefit of all‐male over mixed‐sex populations will be principally based on an examination of tradeoffs that primarily consider the cost difference of juveniles relative to the price differences for different final harvest weights.     

Development and Evaluation of Diets for Crustacean Aquaculture

Effective purified and unrefined diets have been developed and evaluated for use in studying the nutrition of lobsters ( Homarus sp.). A 4-month growth experiment showed that the purified diets yielded weight increases nearly 80% of that achieved on a live food diet, with concomitant high survival rates. Lower-cost unrefined diets supported growth over half of that observed on live food diets. Supplementation of a purified diet with an astaxanthin concentrate derived from crayfish waste enhanced growth significantly, and all the diets tested promoted growth and survival with only 0.2% dietary cholesterol.
Growth and survival are the most useful criteria for evaluating crustacean diets, but other factors such as proximate analyses of feeds, physical characteristics such as pellet leaching rates, and measurable physiological effects can provide important supplemental information. Our analysis of some of these factors suggests that pellet integrity and resistance to leaching may not be directly related either to growth, or to levels of binder in the diets.     

Experimental study of the effect of soaking temperature on the peeling parameters of two oak species (Quercus canariensis Willd. and Quercus afares Pomel)

ABSTRACT

Veneer checking is a common enough occurrence in woodworking. It appears as cracks in the veneer and generally following the grain. Their appearance and the variation of their depth and frequencies have tremendous impact on their utilization. Finding a means of identifying and characterizing the veneer checks is an important ongoing challenge. An automated device, named SMOF, was developed in LABOMAP (Arts et Metiers – France) and achieves this task. By using the SMOF device, the lathe checks occurred in veneers of two species: zeen oak (Quercus canariensis Willd.) and afares oak (Quercus afares Pomel) were detected, automatically imaged and then, the depth and intervals of checks measured. The results were described by statistical distributions that exhibited abnormalities, such as skewness and kurtosis, which were assessed by mode analysis. It has been established that hot soaking temperature (from 60°C to 90°C) reduce slightly the cutting forces for both species, no produce significant heart checks within the loose side of veneers. However, low soaking temperature (from 50°C to 65°C) allow avoiding deeper lathe checking, producing shallower ones acceptable for veneer production.     

Characterization of resistance to Aphis glycines in soybean accessions

The soybean aphid, Aphis glycines Matsumura, is a pest of soybean [Glycine max L. (Merrill)] in Asia, and its recent establishment in North America has led to large, recurring outbreaks that have challenged pest management practitioners there to seek environmentally responsible means for its control. Growth-chamber experiments were conducted to determine and characterize host-plant resistance among several soybean accessions. Soybean plants were first screened for resistance by rating the population growth of A. glycines in two tests. All plants of PI 230977 and 25% of PI 71506 plants were resistant (≤100 aphids per plant) in the first screening test. All ‘Dowling’, PI 71506 and PI 230977 were resistant (≤150 aphids per plant), and 50% of plants of line ‘G93-9223’ were resistant in the second test. Follow-up experiments showed that antixenosis was a modality of resistance based on reduced nymphiposition by A. glycines on Dowling, PI 230977 and PI 71506 in no-choice tests and on fewer numbers of A. glycines on Dowling, PI 230977, PI 71506 and G93-5223 in distribution tests. Antixenosis in Dowling and PI 230977 was stronger in the unifoliolate leaves than in other shoot structures, whereas distribution of A. glycines within plants of PI 71506 and G93-5223 suggested comparable suitability between unifoliolate leaves and other shoot structures of these accessions. Antibiosis to A. glycines was evident as a lower proportion of aphids that reproduced on PI 230977 and from fewer progeny on PI 230977 and Dowling than on 91B91. The number of days from birth to reproduction by A. glycines did not differ among accessions. Results confirmed Dowling and PI 71506 as strong sources of resistance to A. glycines. The levels of antixenosis and antibiosis to A. glycines in PI 230977 and antixenosis to A. glycines in G93-9223 suggest that these accessions may also be valuable to soybean breeding programs as sources of resistance.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.