Social, economic and cultural perspectives of European inland fisheries: review of the EIFAC symposium on fisheries and society

The contributions presented at the EIFAC Symposium on Fisheries and Society in 2000 are reviewed. There have been considerable advances in many sectors of inland fisheries over the past decade. Nowadays the value of inland fisheries to society is generally better understood and increasingly recognized. However, it was recognized that the allocation of fishery resources and their management could still be made more effective through more extensive application of the recent approaches and techniques discussed during the Symposium and reviewed in the paper.     

Evaluation of two N cycle models for the prediction of N mineralization from grassland soils in the UK

Abstract. The ability of two nitrogen cycle models, of contrasting complexity, to predict N mineralization from a range of grassland soils in the UK, was evaluated. These were NCYCLE, a simple mass balance model of the N cycle in UK grasslands, and CENTURY, a more complex model simulating long-term C, N, P & S dynamics in grassland ecosystems. The models were tested using field measurements of net N mineralization from a range of grassland soils (differing in soil type, history & management practice), obtained over a 2 year period using a soil core incubation technique. This method was considered to measure the total net release of mineral N from the soil organic matter over a specified time, including N which may have been recycled several times. NCYCLE consistently under-estimated mineralization rates at all sites. By contrast, there was some correlation between CENTURY predictions of net N mineralization and field measurements. This may have reflected the different abilities of the two models to simulate N recycling. Neither model, however, was able to predict adequately the effect of cultivation and reseeding on net N mineralization.     

Factors Affecting the use of Dreissena polymorpha as a Bioindicator: the PCB Pollution in Lake Como (N. Italy)

The aim of this study was to assess the PCB pollutionof the South-Western branch of Lake Como by using thezebra mussel (Dreissena polymorpha) as abioindicator since its recent reintroduction. Someenvironmental and physiological variables influencingaccumulation processes of organochlorine compounds inDreissena were investigated because climaticfactors may affect life cycle, reproductive stage andage. PCB levels were highest in the soft tissues ofDreissena close to the industrialized area ofComo (2298 ng g^-1 of lipids) and slowly decrease goingnorth, reaching approximately half this value at theclosing section of the lake branch. Nonetheless, thePCB concentrations are well below the dangerous levelsfor the aquatic environment.     

Prevalence of ovine and bovine respiratory syncytial virus infections in cattle determined with a synthetic peptide-based immunoassay.

Subgroup-specific peptide-based enzyme-linked immunosorbent assays from the G-protein of the ovine and bovine respiratory syncytial virus (RSV), respectively, were used to determine the prevalence of the ovine and bovine subgroup strains of RSV infections in cattle. A total of 1,102 bovine serum samples were obtained from 6 diagnostic laboratories located in the northwestern and the southeastern USA and were tested for antibody to either the bovine or ovine subgroups of RSV. Antibody to viruses from each subgroup was present in samples from each region and all states tested. The Southeast had a higher prevalence of the bovine subgroup strains (69.5%). Then did the Northwest (40.9%). The prevalence of the ovine strain was similar for the two regions (16.7% in the southeast, 14.9% in the northwest). The overall prevalence was 56.6% for the bovine strain and 15.9% for the ovine strain. These results suggest members of the ovine subgroup of RSV circulate in the cattle population but with less frequency than those viruses of the bovine subgroup.     

Sinnesphysiologische Untersuchungen an Schmetterlingsraupen und ihre praktische Bedeutung

Ohne Zusammenfassung     

Interaction of low-pathogenicity reoviruses and low levels of infection with several coccidial species

Various combinations of reoviruses and coccidia were studied to see if interactions would occur. Two reoviruses were used: virus 2035, a moderate to low pathogen, and virus 2177, a nonpathogen. Coccidia used were Eimeria acervulina, E. mitis, and E. maxima at dosages of 10(3) or 10(4) sporulated oocysts/chick and E. brunetti at 10(4) sporulated oocysts/chick. In Hubbard-Hubbard cockerels, a combination of virus 2035 and E. acervulina (10(4) oocysts/chick) or E. maxima (10(3) oocysts/chick) significantly (P less than or equal to 0.05) increased the frequency of stunting (% of chicks with body weight less than 80% of controls) and further depressed weight gain over that seen with either virus or coccidia alone. Conversely, virus 2177 ameliorated the same effects in Shaver-Arbor Acre cockerels given 10(4) oocysts/chick of E. mitis or E. maxima. The interaction could not be attributed to changes in the degree of coccidial infection based on oocyst production. Reovirus did not generally change the effect of coccidia on levels of plasma pigment and plasma protein. In Hubbard-Hubbard cockerels, coccidia-induced effects were not ameliorated by virus 2177, suggesting that breed difference in interaction can be expected.