Erosion control practices applied to granitic roadfills for forest roads in Idaho: Cost effectiveness evaluation

Cost effectiveness of six alternative road embankment construction practices and 16 alternative fill-slope stabilization practices was evaluated as means for controlling erosion on forest roads built on granitic soils in Idaho (USA). A total of 63 bordered erosion plots 1-8 m wide by 4-6 m long, were used. Eroded material was collected in troughs at the bottom of each plot in the spring and fall. Measurements began in the fall of 1981 and continued until the fall of 1983. Costs were obtained by tabulating actual labor, equipment, and supplies used to install the treatments. Rainfall erosivity values accumulated for the snow-free periods between erosion measurements proved to be a statistically significant covariate for the analysis of treatment effects. There were no significant differences between the three embankment construction practices (sidecast, layer placed, and controlled compaction). But surface rolling did significantly increase erosion in all cases. Nine of the post-construction soil stabilization measures significantly reduced erosion, and one measure significantly increased erosion (P < 0-5). Stabilization measures that combined mulches with revegetation appeared to be more beneficial for erosion control than either mulches or revegetation alone. Rankings of the erosion control effectiveness of individual soil stabilization practices were different from the rankings of the cost effectiveness of the practices. Application of alternative treatments is discussed.     

Tagging of juvenile lobsters (Homarus gammarus (L.)) with visible implant fluorescent elastomer tags

Visible implant fluorescent elastomer (VIFE) tags were implanted beneath the epidermal layer within the abdomen of 25 juvenile lobsters. After three molts the tag retention was 100% and the total survival 92%. The results suggest that VIFE tags could be an effective tool when assessing the feasibility of enhancing natural lobster stocks.     

Water Quality and Microbial Dynamics in Shrimp Ponds Receiving Bagasse-Based Feed

Pond water quality and associated microbial biomass were studied in relation to the type of feed applied during the culture of the marine shrimp Penaeus vannamei . The feeds tested included conventional feedlot manure as well as two feeds based on bagasse, a sugarcane waste product. Physical and chemical parameters were studied during a 100 day trial in 200 m² earthen ponds. Both bagasse-based feeds supported a significantly larger microbial community as measured by specific biomass numbers ( P < 0.01), ATP content ( P < 0.001) and amount of the particulate organic matter present on pond bottoms ( P < 0.025). For both bagasse-based treatments, the estimated bacterial cell number in the flocculent layer was 3.11 ± 10¹²/m², compared to the much lower cell number of 7.53 ± 10¹⁰/m² for control ponds. Harvest data suggest that bagasse forms a potential base for feeds when applied to extensive shrimp cultures.     

Use of Bagasse as a Feed Input to Semi-Intensive Shrimp Growout Ponds

Efforts to reduce the cost of growout feeds for aquaculture have traditionally focused on the use of agricultural wastes as direct or indirect nutritional supplements to support semi-intensive production levels. The merits of a low cost, sugar cane bagasse-based feed for semi-intensive production of Penaeus vannarnei were evaluated. Shrimp averaging 0.24 g each were stocked into 200 m² earthen ponds at 20/m² and cultured for a 12 week period. Two bagasse-based feed treatments, a manure-based treatment and a no-feed input control, were compared in replicate ponds. One bagasse treatment (artificial manure) was designed to mimic manure and stimulate autotrophic and heterotrophic growth. The other bagasse treatment (bagasse alone plus inorganics) was designed to stimulate primarily autotrophic growth. Both bagasse treatments produced average growth rates of 0.78 g/wk, which were significantly greater than that of the manure treatment (0.57 g/wk). Lack of difference between the two bagasse treatments suggests that additional supplements used in making artificial manure probably were unnecessary to the nutrition of the shrimp. At harvest, bottom organics in the bagasse-fed ponds were at least twice as great as manure-fed ponds, and may have contributed to the lower survival associated with these treatments.     

Evaluation of CYP1A Protein Induction, Biotransformation Capacity and DNA Adduct Formation in a Rat Hepatoma Cell Line (Fao), as Biomarkers of Organic Contamination in Environmental Soil Samples

Induction of cytochrome P4501A (CYP1A) immunopositive protein was evaluated in the rat hepatoma cell line Fao, as a biomarker of organic pollution in extract of environmental soil samples, exposed to different sources and degrees of chemical contamination. Soil samples were collected in one area in Russia (Monchegorsk) and two areas in Southern Norway (Fiskaa and Birkenes). In addition, one reference soil sample was collected in Central Norway (Høoylandet). Contents of selected polycyclic aromatic hydrocarbons (PAHs) in the samples were also evaluated. To further evaluate the inducibility of the most potent soil extract (Fiskaa), S9 fraction of Fao cells, pretreated with this extract, was used as an activation system in the Ames Salmonella assay. The DNA adduct forming capacity of the soil extracts, analyzed by the ³²P-postlabeling technique, was also investigated in Fao cells. The Fao cell line has previously been found to be a very sensitive biomonitoring system, that responds to environmentally relevant concentrations of planar model contaminants with increased level of CYP1A immunopositive protein and DNA adducts. In the present study the Fao cell line also showed its potential for use in evaluating the CYP1A inducing potency of environmental samples. All soil extracts induced CYP1A protein in the Fao cells, although the level of induction varied between the soil samples. The Fiskaa soil extract was the most potent CYP1A inducer and this extract also contained the highest level of PAHs. No significant correlation was observed between the level of the total of 16 PAHs and CYP1A protein level. However, a significant correlation was observed between CYP1A protein level and the level of Benzo[a]pyrene (B[a]P), which is a very potent CYP1A inducer. The S9 fraction of pretreated Fao cells activated B[a]P to mutagens in a concentration-dependent relationship, although the response was weak. No DNA adducts were detected in cells exposed to the soil extracts. This demonstrates the necessity of determining several biomarker parameters simultaneously as one single biomarker may fail to respond to potentially harmful compounds.     

Effect of ultrasonic cavitation on small and large organisms for water disinfection during fish transport

Motivated by the need for additional tools to disinfect discharge water from well boats, and to prevent distribution of salmon lice, the effect of ultrasonic cavitation on the planktonic stages of the salmon louse, nauplii and copepodids, as well as marine heterotrophic bacteria, and the marine green microalgae Tetraselmis suecica, has been investigated. Survival and morphology were registered after different exposure times. Efficacy of the ultrasonic cavitation treatments varied with exposure time. A reduction in survival was registered even for the shortest exposure time (5 seconds) for both naupliar and copepodid stages of the salmon louse (36.7 ± 11.5 and 67.20 ± 7.2% survival respectively). Survival reached zero after exposure times of 20 and 60 seconds for the nauplii and copepodid stages, respectively. A reduction in 70% was observed for bacteria at all exposure times (5 to 300 s), while a reduction of 95% was observed after 300 s for algal cells. The logged energy transfer to the samples was on average 17.5 J/s. In conclusion, cavitation treatment is destructive for the planktonic stages of salmon lice, and may contribute to reduce discharge of pathogens and parasites from well boats when adapted for this purpose and combined with existing water disinfection methods.     

Piscine orthoreovirus (PRV) in red and melanised foci in white muscle of Atlantic salmon (Salmo salar)

Melanised focal changes (black spots) are common findings in the white skeletal muscle of seawater-farmed Atlantic salmon (Salmo salar). Fillets with melanised focal changes are considered as lower quality and cause large economic losses. It has been suggested that red focal changes (red spots) precede the melanised focal changes. In the present work, we examined different populations of captive and wild salmon for the occurrence of both types of changes, which were investigated for the presence of different viruses by immunohistochemistry and RT-qPCR. The occurrence of red or melanised foci varied significantly between the populations, from none in wild fish control group, low prevalence of small foci in fish kept in in-house tanks, to high prevalence of large foci in farm-raised salmon. Large amounts of Piscine orthoreovirus (PRV) antigen were detected in all foci. No other viruses were detected. Red focal changes contained significantly higher levels of PRV RNA than apparently non-affected areas in white muscle of the same individuals. Some changes displayed a transient form between a red and melanised pathotype, indicating a progression from an acute to a chronic manifestation. We conclude that PRV is associated with the focal pathological changes in the white muscle of farmed Atlantic salmon and is a premise for the development of focal melanised changes.