Seasonal home ranges and fidelity to breeding sites among ringed seals

Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of 98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter—spring period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from\1 to 13.9 km2 (median = 0.628) while the home ranges of 28 adult females ranged from \1 to 27.9 km2 (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km3 for subadults and adult males and 0.13 (SD = 0.04) km3 for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring home ranges in summer but returned to the same small (1–2 km2) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound season— including the breeding season—limits their foraging activities for most of the year and may minimize gene flow within the species.

Attenuation of ruminal methanogenesis

Ruminal methanogens reduce carbon dioxide to methane (CH 4 ), thereby preventing hydrogen use by bacteria for VFA synthesis resulting in a 2 to 12% loss in feed gross energy. Methane is a greenhouse gas that contributes to global warming. The objectives of this work were to determine: (1) the extent to which ruminal cultures acquire resistance to a nitrofuranyl derivative of para-aminobenzoate (NFP) and an extract from the plant Yucca shidigera (Yucca); (2) the effect of distillers dried grains plus solubles (DDGS) on ruminal CH4 production; (3) the effect of brome hay-based diets, corn-based diets, and in vivo 2-bromoethansulfonate treatment on ruminal methane (CH4 ) production; and (4) the effect of the above treatments on the methanogen population. Ruminal cultures treated with NFP for 90 d maintained a diminished capacity to generate CH4 , but cultures became resistant to the inhibitory effects of Yucca treatment within 10 d. Both treatments decreased (P < 0.01) the relative abundance of total Archaea and the order Methanomicrobiales, but Yucca treatment increased (P < 0.01) the relative abundance of the order Methanobacteriales. The replacement of brome hay and corn with DDGS in lamb diets decreased (P < 0.01) and increased (P < 0.05), respectively, the amount of CH4 produced per unit of digested DM. The substitution of DDGS for brome hay increased (P < 0.01) the relative abundance of the order Methanomicrobiales. The replacement of brome hay with corn decreased (P < 0.05) the amount of CH4 produced per unit of digested DM, and also decreased (P < 0.05) the relative abundance of both Archaea and the order Methanomicrobiales. However, the abundance of the order Methanobacteriales increased (P < 0.05) as corn replaced brome hay. Intraruminal administration of 2-bromoethansulfonate decreased (P < 0.05) CH4 emissions, and decreased (P < 0.05) the relative abundance of Archaea and Methanobacteriales. In conclusion, NFP may be efficacious for chronically inhibiting ruminal methanogenesis, and the replacement of dietary forage with DDGS attenuates CH4 emissions from ruminant animals. Changes in domain- and order-specific ribosomal DNA indicators of methanogens are not consistently correlated with changes in CH4 production.