Hydrological Forecasting in the Oder Estuary using a Three- Dimensional Hydrodynamic Model

A three-dimensional operational hydrodynamic model, developed at the Institute of Oceanography, University of Gdańsk was used to forecast hydrological conditions in the Oder Estuary. The model was based on the coastal ocean circulation model known as the Princeton Ocean Model (POM). Because of wind-driven water backup in the Oder mouth, a simplified operational model of river discharge, based on water budget in a stream channel, was developed. Linking these two models into a single system made it possible to forecast water levels, currents, water temperature, and salinity in the estuary. A good fit between the observed and computed data allowed to consider the model as a reliable environmental tool. Obtaining a hydrological forecast via a quick website access gives potential users an opportunity to predict the day-by-day course of processes that may affect different areas of human life and activities, e.g., navigation, port operations, flood protection of coastal areas; the predictions may also be used in studies of coastal processes in the estuary.     

Interannual variation in condition of the mackerel icefish

Mackerel icefish Champsocephalus gunnari are widespread on the South Georgia (54° S, 36° W) shelf. Analysis of condition indicated a strong interannual variation. High condition indices, indicative of good feeding conditions, were present when krill were abundant in the region. Years when krill were scarce and condition index was consequently low, were consistent with years when indices from land-based krill predators also indicated that krill were scarce.     

Body condition helps to explain metabolic rate variation in wolf spiders

1. Metabolism is the fundamental process that powers life. Understanding what drives metabolism is therefore critical to our understanding of the ecology and behaviour of organisms in nature. 2. Metabolic rate generally scales with body size according to a power law. However, considerable unexplained variation in metabolic rate remains after accounting for body mass with scaling functions. 3. We measured resting metabolic rates (oxygen consumption) of 227 field‐caught wolf spiders. Then, we tested for effects of body mass, species, and body condition on metabolic rate. 4. Metabolic rate scales with body mass to the 0.85 power in these wolf spiders, and there are metabolic rate differences between species. After accounting for these factors, residual variation in metabolic rate is related to spider body condition (abdomen:cephalothorax ratio). Spiders with better body condition consume more oxygen. 5. These results indicate that recent foraging history is an important determinant of metabolic rate, suggesting that although body mass and taxonomic identity are important, other factors can provide helpful insights into metabolic rate variation in ecological communities.     

A predictive model for freshwater bioassessment (Mondego River,Portugal)

We sampled macroinvertebrates at 75 locations in the Mondego river catchment, Central Portugal, and developed a predictive model for water quality assessment of this basin, based on the Reference Condition Approach. Sampling was done from June to September 2001. Fifty-five sites were identified as “Reference sites” and 20 sites were used as “Test sites” to test the model. At each site we also measured 40 habitat variables to characterize water physics and chemistry, habitat type, land use, stream hydrology and geographic location. Macroinvertebrates were generally identified to species or genus level; a total of 207 taxa were found. By Unweighted Pair Group Method with Arithmetic mean (UPGMA) clustering and analysis of species contribution to similarities percentage (SIMPER), two groups of reference sites were established. Using Discriminant Analysis (stepwise forward), four variables correctly predicted 78% of the reference sites to the appropriate group: stream order, pool quality, substrate quality and current velocity. Test sites’ environmental quality was established from their relative distance to reference sites, in MDS ordination space, using a series of bands (BEAST methodology). The model performed well at upstream sites, but at downstream sites it was compromised by the lack of reference sites. As with the English RIVPACS predictive model, the Mondego model should be continually improved with the addition of new reference sites. The adaptation of the Mondego model methodology to the Water Framework Directive is possible and would consist mainly of the integration of the WFD typology and increasing the number of ellipses that define quality bands. Handling editor: K. Martens     

An Experimental study of reduced parental effort and future reproductive success in the puffin, Fratercula arctica

1. The puffin, a long-lived seabird, was studied on the Isle of May, East Scotland between 1990 and 1992. During two of these years, parental effort was experimentally decreased by supplementary feeding of young. This aimed to identify inter-year reproductive costs, and show whether they took the form of reduced adult survival, reduced fledging success and/or a reduction in the 'quality' of offspring in the following year.
2. The feeding treatment significantly reduced the daily number of feeds delivered by experimental parents by 67% in 1990 and 87% in 1991.
3. The proportions of experimental and control parents returning to the colony in the year following manipulation did not differ significantly, although in 1991, 2·5 times as many controls (young unfed) as experimental birds (young fed) failed to return.
4. The fledging success of experimental pairs in the year following manipulation (68%) was significantly higher than that of controls (24%).
5. Experimental pairs raised young with significantly higher body condition (Residual Peak Mass) than that of controls in the year following manipulation (1992).
6. Experimental parents did not differ from controls in their body condition (Lipid Reserve Mass) or rate of reserve depletion, either in the year of manipulation or in the following breeding season; hence there was no evidence for a role of the measured component of body condition in the cost mechanism.
7. The study demonstrated inter-year reproductive costs for puffins and supported the hypothesis that long-lived species reduce the 'quality' of their offspring or abandon a breeding attempt rather than compromise their survival and future opportunities to reproduce.     

Song and immunological condition in male barn swallows (Hirundo rustica)

Male secondary sexual characters may have evolved as intra-or intersexual signals of male phenotypic or genetic quality.In birds, singing performance may have the function to honestlyreveal health and vigor of individual males. Infectious diseasesand poor body conditions would therefore be expected to negativelyinfluence singing performance. Since bird pathogens are knownto elicit both a humoral and a cell-mediated immune response,it can be predicted that a negative relationship exists betweensinging performance and activity of the immune system. Thisprediction was tested for the first time in this correlationalstudy. The relationships between song rate and features andhematological variables (concentration of leukocytes in peripheralblood, ratio of gamma-globulins to total plasma proteins, bloodcell sedimentation rate, hematocrit) and body condition wereanalyzed in a population of bam swallows (Hirundo rustica).Song rate was negatively correlated with lymphocyte concentrationand with the ratio of gamma-globulins to plasma proteins. Spectrographicanalysis showed that features of song were not significantlycorrelated with hematological variables or body condition. Thelevel of circulating testosterone was not correlated with songrate nor hematological variables. This study is the first toshow a correlation between a bird's singing performance andhematological profile and suggests that song rate of male barnswallows may reflect their health status. Song in this speciesmight thus have evolved because it allows prospecting femalesto assess aspects of phenotypic and/or genetic quality of potentialmates     

Effects of light-emitting diode light v. fluorescent light on growing performance,activity levels and well-being of non-beak-trimmed W-36 pullets

More energy-efficient, readily dimmable, long-lasting and more affordable light-emitting diode (LED) lights are increasingly finding applications in poultry production facilities. Despite anecdotal evidence about the benefits of such lighting on bird performance and behavior, concrete research data were lacking. In this study, a commercial poultry-specific LED light (dim-to-blue, controllable correlated color temperature (CCT) from 4500 to 5300 K) and a typical compact fluorescent light (CFL) (soft white, CCT=2700 K) were compared with regards to their effects on growing performance, activity levels, and feather and comb conditions of non-beak-trimmed W-36 pullets during a 14-week rearing period. A total of 1280-day-old pullets in two successive batches, 640 birds each, were used in the study. For each batch, pullets were randomly assigned to four identical litter-floor rooms equipped with perches, two rooms per light regimen, 160 birds per room. Body weight, BW uniformity (BWU), BW gain (BWG) and cumulative mortality rate (CMR) of the pullets were determined every 2 weeks from day-old to 14 weeks of age (WOA). Activity levels of the pullets at 5 to 14 WOA were delineated by movement index. Results revealed that pullets under the LED and CFL lights had comparable BW (1140±5 g v. 1135±5 g, P=0.41), BWU (90.8±1.0% v. 91.9±1.0%, P=0.48) and CMR (1.3±0.6% v. 2.7±0.6%, P=0.18) at 14 WOA despite some varying BWG during the rearing. Circadian activity levels of the pullets were higher under the LED light than under the CFL light, possibly resulting from differences in spectrum and/or perceived light intensity between the two lights. No feather damage or comb wound was apparent in either light regimen at the end of the rearing period. The results contribute to understanding the impact of emerging LED lights on pullets rearing which is a critical component of egg production.