Seasonal and diel patterns in the migrations of fishes between a river and a floodplain tributary

Nunn AD, Copp GH, Vilizzi L, Carter MG. Seasonal and diel patterns in the migrations of fishes between a river and a floodplain tributary. Ecology of Freshwater Fish 2010: 19: 153–162. © 2009 John Wiley & Sons A/S
Abstract –  The population behaviours associated with the migrations of fishes in lowland river ecosystems are amongst the most poorly-understood dispersal mechanisms of temperate freshwater organisms. This study evaluated the influence of four environmental variables (light levels, river discharge, water temperature and water velocity) on the timing, intensity and direction of fish movements between the River Avon (Hampshire, England) and a small floodplain tributary, Ibsley Brook, over a 12-month period. Using canonical correspondence analysis (CCA) to identify patterns of movement (by groups of species) and the relative strengths of explanatory variables in the data, the probability of fishes migrating between the river and tributary was determined using Bayesian modelling. The intensity and direction of fish movements between the river and tributary varied temporally, both on a diel and seasonal basis, and there were species- and age-specific patterns in behaviour. Diel movements appeared to be triggered by changes in light intensity and brook water velocity, whereas seasonal movements were mostly driven by changes in river discharge and water temperature, particularly those associated with floods. This study emphasises the importance of connectivity in river systems, as fishes migrated in all conditions, but especially during rapidly-rising discharge.     

Maintenance ration, protein synthesis capacity, plasma insulin and growth of Atlantic salmon (Salmo salar L.) with genetically different trypsin isozymes

Growth was found to be associated with the changes of trypsin activity in the pyloric caecal tissues and the level of plasma insulin in Atlantic salmon (Salmo salar L.). A decrease in trypsin activity accompanied by an increase in plasma insulin was detected one month before an enhanced growth was observed. There were significant relationships between weight specific consumption rate, plasma insulin levels and fish growth. The correlation of weight specific consumption rate was higher with growth rate (R²=0.7, p<0.0001) than with plasma insulin concentration (R²=0.4, p<0.0001).When the comparison was made between Atlantic salmon carrying and lacking the trypsin variant TRP-2*92, the fish with the variant had lower maintenance ration (p<0.05), higher capacity for protein synthesis in the white muscle (p<0.02), and a greater ability to utilize the feed at a restricted ration than the fish without the variant. In Atlantic salmon lacking the variant, both plasma insulin concentrations and growth rates were significantly lower (p<0.05) in the fish fed 0.5% bw day^–1 than those fed 1% bw day^–1. Whilst the growth rates of TRP-2*92 salmon fed the different rations became similar one month after similar levels of plasma insulin were observed between them. The TRP-2*92 salmon may be defined as a high protein growth efficiency fish with low protein turnover rate.Genetic variation in trypsin isozyme pattern affects feed utilization, plasma insulin levels and growth in Atlantic salmon.     

An autosomal recessive, lethal, neurologic disease of Gordon Setter puppies.

This report details clinical, necropsy, and pedigree data on an inherited, lethal, neurologic disease of young Gordon Setters. This disorder is characterized by an early age of onset, gait and postural abnormalities, progressive weakness, and recumbency by 5-6 weeks of age. Although clinically distinctive, postmortem changes in affected pups were minimal. Gross lesions were not observed. Microscopic changes were subtle and consisted of astrocyte swelling, primarily in the cerebrocortical and cerebellar white matter, and white matter tracts of the brainstem. Immunohistochemistry for glial fibrillary acidic protein revealed a marked increase in the number and staining intensity of astrocyte cytoplasmic processes in affected pups compared with age-matched controls. Neither cerebral inflammation nor neuronal necrosis was identified. Pedigree analysis of affected litters demonstrated an autosomal recessive mode of inheritance. A diagnosis of this heritable disease should be based on the early age of onset (3-4 weeks of age), characteristic clinical signs, rapid progression to recumbency by 5-6 weeks of age, identification of swollen astrocytes primarily in the cerebellar and cerebrocortical white matter and white matter tracts of the brainstem, and the exclusion of other disease processes.     

National document-handling systems in science and technology

As a result of the studies described here and the COSATI recommendations, as well as briefings and discussions at many levels of government and with professional and industrial organizations, the Office of Science and Technology has a blueprint for action and support for forward movement in the handling of scientific and technical documents.     

CONTROL OF REPRODUCTIVE FUNCTION OF CATTLE USING CLOPROSTENOL

Two intramuscular injections of cloprostenol were given 12 days apart to synchronise oestrus in a group of 47 heifers and following the second injection, 38 were found in oestrus in 2 to 6 days, 1 in 11 days and 8 in 22 to 27 days. The conception rate of the synchronised animals was 24 of 38 (63%). Twenty-nine heifers were given injections of cloprostenol in late pregnancy and parturition was induced with a latent period of 6 +/- 3 days when injected at 266 to 267 days. When injected at 254 to 262 days, 3 of 16 heifers (19%) were unresponsive and the remainder calved with a latent period of 12 +/- 6 days. The survival rate of calves from induced heifers was 71% with 80% survival from controls. Approximately 50% of the induced heifers, and none of the controls, retained their foetal membranes.