Four decades of opposing natural and human-induced artificial selection acting on Windermere pike (Esox lucius)

The ability of natural selection to drive local adaptation has been appreciated ever since Darwin. Whether human impacts can impede the adaptive process has received less attention. We tested this hypothesis by quantifying natural selection and harvest selection acting on a freshwater fish (pike) over four decades. Across the time series, directional natural selection tended to favour large individuals whereas the fishery targeted large individuals. Moreover, non-linear natural selection tended to favour intermediate sized fish whereas the fishery targeted intermediate sized fish because the smallest and largest individuals were often not captured. Thus, our results unequivocally demonstrate that natural selection and fishery selection often acted in opposite directions within this natural system. Moreover, the two selective factors combined to produce reduced fitness overall and stronger stabilizing selection relative to natural selection acting alone. The long-term ramifications of such human-induced modifications to adaptive landscapes are currently unknown and certainly warrant further investigation

Mass of 39Sc via the 40Ca(7Li, 8He) reaction

The Q value of the 40Ca(7Li, 8He) 39Sc reaction has been measured, and a value of -37.40(4) MeV was obtained. The corresponding mass excess of 39Sc is -14.14(4) MeV, which makes 39Sc proton unbound by 630(40) keV. Under the assumption of a quadratic form, the b and c coefficients of the isobaric multiplet mass equation for 39 (T = 3/2) were obtained. They agree well with systematics and the predictions of the isospin-nonconserving Hamiltonian model

The status of Arctic charr Salvelinus alpinus in Britain and Ireland

The Arctic charr occurs in lakes across Britain and Ireland and was previously described here as 15 separate species. Most authorities now agree that all these stocks belong to a single polymorphic species complex Salvelinus alpinus (L.). This fish is given little protection in British and Irish law and there has been a steady loss of natural populations in recent years in all the countries concerned. A few new stocks have been created either intentionally or accidentally. In Scotland, only a small proportion of the 258 recorded natural populations has been studied and at least 12 of these are now extinct. There are at least four introduced populations originating from native Scottish stocks, but the fate of stocks introduced from Canada for aquaculture is uncertain. In England, there are eight extant populations in Cumbria and four others extinct. The status of introduced stocks in England is uncertain but there is probably one population surviving in Yorkshire. In Wales, eight lakes with resident Arctic charr populations have been recorded, three of these populations are natural, one is extinct and four have been introduced. In Ireland, of the 74 known populations, approximately 30% are extinct. There is no evidence to indicate that introduced stocks (some of them from Iceland) in a small number of lakes have survived there. A range of factors is involved in the extinction of populations and these include pollution, eutrophication, acidification, afforestation, engineering, exploitation, aquaculture, introductions and climate change. Much research remains to be done and unique stocks of this valuable species will continue to be lost unless positive action is taken through local conservation management backed by appropriate national legislation

Valores de referência e influência da idade no eritrograma de fêmeas bovinas da raça Aquitânica Reference values and age effect on the erythrogram of bovine females of the Aquitanian breed

Determinaram-se os valores de referência e estudou-se a influência da idade sobre o eritrograma em fêmeas bovinas da raça Aquitânica. Amostras de sangue de 80 fêmeas bovinas, acima de 12 meses de idade, e não reagentes ao antígeno do vírus da leucose dos bovinos, foram colhidas utilizando-se EDTA como anticoagulante para realização das seguintes provas: contagem global das hemácias, determinação do volume globular, concentração de hemoglobina, cálculo dos índices hematimétricos absolutos - volume corpuscular médio (VCM), hemoglobina corpuscular média (HCM) e concentração de hemoglobina corpuscular média (CHCM). A idade exerceu influência significativa (P<0,05) sobre a maioria dos parâmetros hematológicos estudados, com diminuição da quantidade de hemácias e aumento do volume globular, quantidade de hemoglobina, VCM e HCM. Os valores foram: hemácias 6,68&plusmn;0,58&times;10(6)/mm³, volume globular 41,2&plusmn;4,5%, hemoglobina 12,8&plusmn;1,31g/dl, VCM 61,83&plusmn;6,54fl, HCM 19,28&plusmn;2,25pg, CHCM 31,4&plusmn;2,3%.<br>The reference values and the influence of the age factor on the erytrogram in bovine females of the Aquitanian breed were evaluated. Blood samples of 80 healthy females, all tested negative for bovine leucose virus, were utilized for the analysis. Erythrocyte counts, determination of the packed cell volume, concentration of hemoglobin, calculation of hematimetric absolute rates of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were evaluated. Significant influence (P<0.05) of age was observed for most of the hematological characteristics, with decreased of the number of erythrocytes and increase of packed cell volume, quantity of hemoglobin, MCV, MCH. The reference values were: erythrocytes counting 6.68&plusmn;0.58&times;10(6)/mm³, packed cell volume 41.2&plusmn;4.5%, hemoglobin 12.8&plusmn;1.31g/dl, VCM 61.83&plusmn;6.54fl, HCM 19.28&plusmn;2.25pg, CHCM 31.4&plusmn;2.3%