32 research outputs found

    Albatrosses Following Fishing Vessels: How Badly Hooked Are They on an Easy Meal?

    Get PDF
    Fisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km) showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit

    Very high power added efficiency PHEMT amplifiers for GSM and DCS 1800 applications

    Get PDF
    A InGaAs/AlGaAs power amplifier MMIC kit designed for GSM handset phone systems has been developed. It includes two power amplifiers (PA), one GSM 900MHz and one for 1800MHz. Both parts are manufactured using a 0.5µm gate length PHEMT process. Under a low single supply voltage of 3.5V the GSM PA provides 35dBm with 60% PAE and the DCS PA achieves 33dBm with 54% PAE, they are housed in small leadless packages

    Preliminary investigation of the costs of incubation in the Australasian Gannet (Morus serrator) breeding in Port Phillip Bay, Victoria

    Full text link
    To optimise lifetime reproductive success, individuals must balance current reproductive effort against future reproductive prospects. In birds, incubation and chick-rearing must involve costs, and manipulation of the length of incubation offers an insight into some costs affecting adults. An experiment was conducted at a colony of Australasian Gannets in Port Phillip Bay, Victoria, in which length of incubation was manipulated so that some adults experienced short (10&ndash;20 days duration), long (70&ndash;80 days) or normal (~45 days) incubation periods. Adults with a manipulated incubation period did not show significant differences in weight change (taken here to reflect cost) during incubation or chick-rearing compared with controls. Manipulation of length of incubation did not significantly affect the hatching success or the growth rate of chicks involved and is not, therefore considered to impose an increased reproductive cost. This suggests that the Australasian Gannet has the capacity to maintain body condition and successfully rear young despite modified duration of incubation.<br /
    corecore