Comparative ecologies of domestic and naturalised rainbow trout in northern Lake Huron

Northern Lake Huron (Ontario, Canada) supports the largest concentration of freshwater salmonid cage culture farms in Canada and receives inputs of domestic‐strain rainbow trout (Oncorhynchus mykiss) through escapement. We assessed the potential effects of these domestic fish on the naturalised rainbow trout of this ecosystem by comparing their respective ecologies. Mature adults were sampled from spawning tributaries, primarily in spring, and to a lesser extent in fall. Fish of domestic origin comprised ~80% of rainbow trout sampled from sites near cage culture facilities but <20% of rainbow trout sampled from more distant sites. Domestic adults in spawning condition (gametes free‐flowing) were present in the spawning tributaries in both spring and fall sampling seasons, whereas naturalised fish in spawning condition were only observed in the spring. Domestic adults were younger and smaller (in length), appeared to have shorter lifespan and had a higher male to female ratio compared with their naturalised counterparts. Growth rates (change in length with age) of naturalised and domestic females in the wild were similar, but domestic males grew more slowly than naturalised males. Domestic females also produced smaller eggs than naturalised females. Food web positions (inferred from δ¹³C and δ¹⁵N) of domestic and naturalised fish were very similar but varied more strongly with body size in the former. Domestic‐strain rainbow trout of cage culture origin can survive, grow and attempt to spawn in northern Lake Huron and have the potential to compete for food, mates and spawning habitat with naturalised rainbow trout.     

The role of flow dependency and water availability in fish assemblage homogenization in tributaries of the Chattahoochee River,Alabama, USA

The availability of water is becoming more variable as flow regime alterations intensify both locally and on a global scale. This pattern has been observed in the tributaries of the central Chattahoochee River System as water withdrawal and natural drought have caused flows to diminish. Stream discharge has steadily decreased in the study area by 31% over the last 50 years, and during this time, fish assemblage homogenization has occurred throughout the system. Our primary objective was to assess whether spawning mode and water availability are catalysts for fish assemblage change in tributaries of the Chattahoochee River System. We found that species which prefer or have adapted to low flow conditions (e.g. blacktail shiner Cyprinella venusta, redbreast sunfish Lepomis auritus and blackbanded darter Percina nigrofasciata) are becoming dominant and replacing historically dominant fluvial specialists. When examining short‐term changes between a dry year (2009) and a wet year (2010), some species preferring higher flows such as the highscale shiner Notropis hypsilepis were detected during the wet year, suggesting that the amount of water is important for the presence of these species in upstream reaches where they were historically abundant. Species that can reproduce successfully in low flow conditions are thriving and expanding their native ranges as more habitat becomes suitable. Species that require higher flows for part of their life cycle, however, appear to be declining from upstream areas as water availability continues to decrease, despite temporary recovery from downstream refugia during wet years.     

Genetical investigations into photosynthetic rate in Brassica 1. A simple technique for measuring photosynthesis of leaves of kale

Summary An inexpensive method for comparative assessment of net assimilation rate in kale or other plants with large leaves is described. The technique is based on the measurement of dry weight of leaf disks after exposure to light and is capable of providing statistically significant evidence of small differences among genotypes or among leaves grown under different conditions.     

Intraspecific hybridization in Pinus caribaea var. hondurensis I. Performance for growth and form traits

Inter-provenance hybrids of Pinuscaribaea var. hondurensis wereprogeny tested in Queensland, Australia inorder to assess the feasibility ofincorporating some desirable traits intothe local breeding population, consistinglargely of a single upland provenanceMountain Pine Ridge (MPR). Data onphenotypic traits up to seven years fromplanting revealed that an inter-provenancehybrid, MPR × coastal had greater diameter,straightness and wind-firmness, and fewerramicorns than the MPR control provenance.The data were mostly consistent for twowidely separated sites, and also whenpooled across those sites (p <0.05). In addition, hybrid vigor for treevolume was apparent (p < 0.05).Trees of coastal × Guanaja Island, and purecoastal provenances were as large as thoseof the MPR provenance but had fewerramicorns. Even though the coastal ×Guanaja provenance seemed to produce treesthat were more crooked than the MPRprovenance, there was evidence at leastwithin one site to suggest that the hybridtrees were superior in terms ofwind-firmness (p < 0.01). Breedingfor hybrid vigor and pedigree selection ofthe priority hybrid, MPR × coastal aresuggested as future measures. Pureprovenance populations of coastal andGuanaja island are to be bred as sublinesto the MPR breeding population for futureuse in inter-provenance hybridization andfor gene conservation.     

Estimating Amenity Benefits of Coastal Farmland

This paper investigates differences in non‐market farmland amenity values estimated using distinct methodologies, with a focus on the potential causes and policy implications. The paper compares farmland amenity values generated by a hedonic property value model and a contingent choice model, both estimated from data collected in the Peconic Estuary System of Suffolk County, NY. The analysis demonstrates that a combination of non‐market valuation methodologies can provide policy insights not otherwise available to those relying on any single approach, and illustrates types of information that may be obscured by methodologies used in isolation.     

Determination of 4,4'-dinitrocarbanilide (DNC), a component of Nicarbazin,in Canada goose (Branta canadensis) eggshells using high-performance liquid chromatography

A method was developed using high-performance liquid chromatography to assay 4,4'-dinitrocarbanilide (DNC), the active ingredient in Nicarbazin, in eggshells collected from Canada geese fed a formulated feed fortified with Nicarbazin at doses of 0, 125, 250, and 500 microg/g. The method was developed using chicken eggshells fortified with DNC. The method was used to quantify DNC in both the shell-associated membranes and the calcified shell extracellular matrix. These values were compared to those obtained for a composite sample consisting of both the membranes and the calcified shell extracellular matrix. The validated method was used to quantify DNC in eggshells from geese fed fortified feed to ascertain the effect of Nicarbazin feed concentration on shell DNC concentration. DNC levels in the eggshells were highly correlated with feed dose.     

Development of porcine rapid identification method (PRIME) by modified agar-gel immunodiffusion

A porcine rapid identification method (PRIME) has been developed for detection of pork in a wide variety of meat products. The test is an adaptation of previously developed field screening immunodiffusion tests for beef and poultry detection. The PRIME test was demonstrated to be specific, sensitive, and accurate in the analysis of samples in the laboratory and in a commercial meat processing establishment.     

Soil organic matter, effects on soils and crops

Abstract. Manurial treatments and cropping history have remained unchanged for many years in classical and long-term experiments at Rothamsted and Woburn, in some cases for more than 100 years. Soil samples taken periodically have been analysed to follow changes in organic carbon content with time and treatment. Data presented here clearly show effects of carbon input and soil texture on equilibrium organic matter content.
Until recently increasing amounts of soil organic matter had little effect on yields of arable crops especially if fertilizer nitrogen dressings were chosen correctly. However the yield potential of many crops has increased and various agronomic inputs have become available to achieve that potential. Yields of many crops are now larger on soils with extra organic matter both on the sandy loam at Woburn and the silty clay loam at Rothamsted. Some of the effect appears to be related to extra water holding capacity, some to availability of nitrogen in ways which cannot be mimicked by dressings of fertilizer N, and some to improved soil physical properties. Responses to fertilizer N have been larger on soils with more organic matter.     

Hierarchical scheme for LC-MSn identification of chlorogenic acids

The fragmentation behavior of 18 chlorogenic acids that are not substituted at position 1 has been investigated using LC-MS(4) applied to a methanolic coffee bean extract and commercial cider (hard cider). Using LC-MS(3), it is possible to discriminate between each of the three isomers of p-coumaroylquinic acid, caffeoylquinic acid, feruloylquinic acid, and dicaffeoylquinic acid, and a hierarchical key has been prepared to facilitate this process when standards are not available. MS(4) fragmentations further support these assignments, but were not essential in reaching them. The distinctive behavior of 4-acyl and 3-acyl chlorogenic acids compared with the 5-acyl chlorogenic acids is a key factor permitting these assignments. The fragmentation patterns are dependent upon the particular stereochemical relationships between the individual substituents on the quinic acid moiety. Fragmentation is facilitated by 1,2-acyl participation and proceeds through quinic acid conformers in which the relevant substituents transiently adopt a 1,3-syn-diaxial relationship. Selected ion monitoring at m/z 529 clearly indicated the presence in coffee of six caffeoylferuloylquinic acid isomers, whereas previously only two or three had been demonstrated. The hierarchical key permitted specific structures to be assigned to each of the six isomers. These assignments are internally consistent and consistent with the limited data previously available.