Influence of Foliar Exposure, Adjuvants, and Rain-free Period on the Efficacy of Glyphosate for Torpedograss Control

The proportion of torpedograss tissue exposed to glyphosate at application rates of 0.28, 0.56, 1.12, 2.24, and 4.48 kg/ha affected control as measured by regrowth. The effect of tissue exposure was more pronounced as application rate decreased. This study suggests that higher rates of glyphosate need to be used during higher water levels, when less torpedograss tissue is exposed to herbicide spray and lower rates may be used during periods of low water levels. Addition of the water conditioning agent Quest (R) (0.25% v/v) to glyphosate spray mixtures diminished the influence of simulated rain events following glyphosate application. Twelve other adjuvants did not influence the effect of simulated rain events.

Seasonal variation of some trace metal concentrations in some fish species on stretch of River Kubanni, Zaria

In a semi-urbanized stretch of river Kubanni, Zaria, seasonal variations of some tree metals (copper, zinc and lead) in fish species (Clarias sp., Tilapia sp and Alestes sp) were investigated over a period of eight months. Water and fish were sampled monthly, pooled separately and seasonal analysis of each trace determined using atomic absorption method. The concentration of each of the elements in water higher in the dry season than during the rainy season. The dry and rainy season concentrations of copper, zinc and lead were 6.85~c10.66 mu gg super(-1)&1.45~c1.10 mu gg super(-1); 2.13~c1.68 mu gg super(-1)&0.1 5~c0.05 mu gg super(-1); and 0.52~c0.50 mu gg super(-1) & 0.31~c0.14 mu gg super(-1) respectively. Similarly, all the three accumulated more zinc and lead in the dry season than during the rainy season. Tilapia species and to some extent, Alestes species being pelagic had a higher concentration of trace metals than Clarias species which is a bottom dwelling fish Tilapia species may therefore be a better indicator species than Clarias species for monitoring trace metals in water bodies. Reasons for the observed variations in the trace metals were discussed

On the feeding of the larvae of Chironomidae during the planktonic period of life [Translation from: Nauch.Dokl.vyssh.Shk.Biol.Nauk 1 19-21, 1965]

It is known that the larvae of Chironomidae in the first stages of life after leaving the egg case, swim for a long time in a body of water. Positive reaction in light, the capability of directed swimming and passive floating in suspension allow the larvae to temporarily carry out a planktonic way of life. This study describes the behaviour of Chironomus dorsalis larvae after leaving the egg case. The feeding of chironomid larvae in the first stages of development was also described.

Ecological study of the River Lambourn. Report for the period October 1970 to March 1972

A small investigation of the ecology of the river Lambourn was carried out during 1967-70. During this period it became clear that detailed and reliable information could only be obtained by a much larger investigation. The present study was planned to meet the minimum requirements. No pumping is expected during this period and, since the pumping carried out during the pilot scheme was on a small scale, it is reasonable to assume that the river is still relatively unaffected by pumping.The present investigation has two main objectives both of which depend on obtaining a detailed picture of the ecology of the river at the present time. First, it will provide basic information on the state of the river prior to the development of the pumping scheme which will be available for comparison at any later date. Secondly, it may be possible to use some of the data to predict the ecological changes which may occur if the flow of the river is altered by the pumping scheme. This report is part of a series of fives studies on the River Lambourn which were undertaken between 1970 and 1979. [PDF contains 83 pages]

Ecological study of the River Lambourn. Report for the period October 1970 to September 1973

Few detailed studies have been made on the ecology of the chalk streams. A complex community of plants and animals is present and much more information is required to achieve an understanding of the requirements and interactions of all the species. It is important that the rivers affected by this scheme should be studied and kept under continued observation so that any effects produced by the scheme can be detected. This need has been recognised by the Thames Conservancy and the Water Resources Board who jointly sponsored this investigation on one of the chalk streams involved in the scheme. The present investigation has two main objectives both of which depend on obtaining a detailed picture of the ecology of the river at the present time. First, it will provide basic information on the state of the river prior to the development of the pumping scheme which will be available for comparison at any later date. Secondly, it may be possible to use some of the data to predict the ecological changes which may occur if the flow of the river is altered by the pumping scheme. The study covers suspended solids, invertebrates, fish.This report is part of a series of fives studies on the River Lambourn which were undertaken between 1970 and 1979. [PDF contains 24 pages]

Ecological study of the River Lambourn. Report for the period October 1973 to September 1977

The investigations described in this report were carried out to fulfill three distinct but interrelated objectives. In 1973 the Thames Conservancy were making plans for a second stage of their groundwater scheme which would take water from the chalk aquifers in the valley of the Kennet and they wanted basic information on the ecological state of this river and its upper tributaries. Little appeared to be known about limestone streams and a preliminary study of one of the streams in this area was desirable as a basis for planning more detailed studies if these were needed later. At a progress meeting held in March 1976 the problems and opportunities presented by the developing drought conditions were considered. It was concluded that the ecological effects of the exceptionally low natural flows should be studied and that it would be important to assess the ecological impact of the groundwater scheme if it was brought into operation that year. This could only be done on the Lambourn and the Winterbourne and it was decided that considerable effort should be diverted there for this purpose and that the field observations should be extended to cover any recovery period after the end of the drought. To make this possible it was agreed that the studies of invertebrates and detritus on the Kennet should be reduced considerably and that the proposed study of the limestone stream should be abandoned. The revised objectives were as follows: A detailed ecological study of several sites on the Kennet and its tributaries above Kintbury, extending over at least two years and involving observations on wate r weeds , invertebrates, fish, detritus and the trophic relationships within the river community. Quantitativ e and qualitative sampling of water weeds and invertebrates during one year at a number of sites on several chalk streams to determine whether the patterns and relationships found in the Lambourn are also found at the other sites. Observations on the Lambourn at Bagnor were to continue for most of the period to look for long-term fluctuations and to enable these sites to act as controls with which the other sites could be compared. Further detailed studies on the Lambourn and the Winterbourne to assess the impact of low flows, trial pumping and the operation of the groundwater scheme.

Nitrates in surface waters, inputs and seasonality: Progress report for the period April - December 1987

The objective of this short project progress report is to investigate, in a catchment on which earlier nitrate data are available for comparison, seasonality and budgets, in relation to land use, of nitrate inputs, concentrations and loads. Sampling was undertaken from 1984-87 in the River Frome catchment and data on nitrate concentrations analysed.

Impact of watercress cultivation on river water quality: progress report for the period, January - December 1987

The objective of this short project progress report is to investigate the possible water quality implications of modern watercress growing practices. Chalk receiving watercourses are usually of high supply, amenity, game fishing and fish farming value. Any headwater pollution load, therefore, needs characterising and quantifying. Two sites of watercress farming were studied in 1986-87 and nutrient levels examined. Different approaches of watercress farmers in Dorset and Hampshire are summarised.

Final report on the updating service on environmental chemicals in freshwater for the period 9.1.89 to 9.7.89

This report presents five batches of data which have been despatched to the Joint Research Centre, Ispra. The data as been allocated to various ECDIN (Environmental Chemicals Data and Information Network) files. The data comprises environmental chemicals in the freshwater environment, taking in paricular consideration: aquatic toxicity, bioaccumulation, metabolism and elimination biodegradation.

Catch rates and demographics of loggerhead sea turtles (Caretta caretta) captured from the Charleston, South Carolina, shipping channel during the period of mandatory use of turtle excluder devices (TEDs)

Trawling was conducted in the Charleston, South Carolina, shipping channel between May and August during 2004–07 to evaluate loggerhead sea turtle (Caretta caretta) catch rates and demographic distributions. Two hundred and twenty individual loggerheads were captured in 432 trawling events during eight sampling periods lasting 2–10 days each. Catch was analyzed by using a generalized linear model. Data were fitted to a negative binomial distribution with the log of standardized sampling effort (i.e., an hour of sampling with a net head rope length standardized to 30.5 m) for each event treated as an offset term. Among 21 variables, factors, and interactions, five terms were significant in the final model, which accounted for 45% of model deviance. Highly significant differences in catch were noted among sampling periods and sampling locations within the channel, with greatest catch furthest seaward consistent with historical observations. Loggerhead sea turtle catch rates in 2004–07 were greater than in 1991–92 when mandatory use of turtle excluder devices was beginning to be phased in. Concurrent with increased catch rates, loggerheads captured in 2004–07 were larger than in 1991–92. Eighty-five percent of loggerheads captured were ≤75.0 cm straight-line carapace length (nuchal notch to tip of carapace) and there was a 3.9:1 female-to-male bias, consistent with limited data for this location two decades earlier. Only juvenile loggerheads ≤75.0 cm possessed haplotypes other than CC-A01 or CC-A02 that dominate in the region. Six rare and one un-described haplotype were predominantly found in June 2004.

Genetic improvement of freshwater prawn, Macrobrachium rosenbergii (de Man) in India. Phase two: annual report for period January to December 2012

Macrobrachiurn rosenbergii is one of the widely cultured freshwater prawn species globally. India was the third largest producer of this species in 2007 and its aquaculture production rose to 43,000 metric tons (t) in 2005 froin less than 500 t in 1995. However, since then production has been declining and in 2008-09 it was 12,856 t, a reduction of more than 70% compared to 2005. There are several contributing factors to this decline, such as slow growth rate, poor survival, disease outbreaks, increase in cost of production, and availability of low risk alternative fish species. However, there is a consensus that poor seed quality leading to unsatisfactory growth and survival rates in ponds is one of the major reasons. Hence, the development of a systematic selective breeding program aimed at improving growth rate and ensuring high survival rate of this species was deemed a high priority. The Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar, India in collaboration with the WorldFish Center, Malaysia initiated a selective breeding program for this species in 2007.

Changes in size and age at maturity of the northern stock of Tilefish (Lopholatilus chamaeleonticeps) after a period of overfishing

The modern fishery for Tilefish (Lopholatilus chamaeleonticeps) developed during the 1970s, offshore of southern New England, in the western North Atlantic Ocean. The population quickly became over exploited, with documented declines in catch rates and changes in demographic traits. In an earlier study, median size at maturity (L50) of males declined from 62.6 to 38.6 cm fork length (FL) and median age at maturity (A50) of males declined from 7.1 to 4.6 years between 1978 and 1982. As part of a cooperative research effort to improve the data-limited Tilefish assessment, we updated maturity parameter estimates through the use of an otolith aging method and macroscopic and microscopic evaluations of gonads. The vital rates for this species have continued to change, particularly for males. By 2008, male L50 and A50 had largely rebounded, to 54.1 cm FL and 5.9 years. Changes in female reproductive schedules were less variable among years, but the smallest L50 and youngest A50 were recorded in 2008. Tilefish are dimorphic, where the largest fish are male, and male spawning success is postulated to be socially mediated. These traits may explain the initial rapid decline and the subsequent rebound in male L50 and A50 and less dramatic effects on females. Other factors that likely contribute to the dynamics of maturity parameter estimates are the relatively short period of overfishing and the amount of time since efforts to rebuild this fishery began, as measured in numbers of generations. This study also confirms the gonochoristic sexual pattern of the northern stock, and it reveals evidence of age truncation and relatively high proportions of immature Tilefish in the recent catch.

High-resolution record of climate change in the Owens Lake Basin, California, for the period 52,500 to 12,500 YBP

EXTRACT (SEE PDF FOR FULL ABSTRACT): High-resolution oxygen-18 and total inorganic carbon (TIC) studies of cored sediments from the Owens Lake Basin, California, indicate that Owens Lake was hydrologically open (overflowing) most of the time between 52,500 and 12,500 carbon-14 YBP. ... The lack of a strong correspondence between North Atlantic climate records and the Owens Lake delta-oxygen-18 record has two possible explanations: (1) the sequence of large and abrupt climate change indicated in North Atlantic records is not global in scope and is largely confined to the North Atlantic and surrounding areas, or (2) Owens Lake is located in a part of the Great Basin that is relatively insensitive to the effects of climate perturbations recorded in the North Atlantic region.