Aging is often perceived as a degenerative process caused by random accrual of cellular damage over time. In spite of this, age can be accurately estimated by epigenetic clocks based on DNA methylation profiles from almost any tissue of the body. Since such pan-tissue epigenetic clocks have been successfully developed for several different species, it is difficult to ignore the likelihood that a defined and shared mechanism instead, underlies the aging process. To address this, we generated 10,000 methylation arrays, each profiling up to 37,000 cytosines in highly-conserved stretches of DNA, from over 59 tissue-types derived from 128 mammalian species. From these, we identified and characterized specific cytosines, whose methylation levels change with age across mammalian species. Genes associated with these cytosines are greatly enriched in mammalian developmental processes and implicated in age-associated diseases. From the methylation profiles of these age-related cytosines, we successfully constructed three highly accurate universal mammalian clocks for eutherians, and one universal clock for marsupials. The universal clocks for eutherians are similarly accurate for estimating ages (r>0.96) of any mammalian species and tissue with a single mathematical formula. Collectively, these new observations support the notion that aging is indeed evolutionarily conserved and coupled to developmental processes across all mammalian species - a notion that was long-debated without the benefit of this new and compelling evidence.

In recent years, large numbers of late-run Fraser River sockeye salmon Oncorhynchus nerka have died in freshwater areas before they spawned. We used radiotelemetry techniques to determine river entry timing, migration rates, and survival for the summer and late runs of sockeye salmon in 2002 and 2003. Fishery removals and river detections accounted for 62% of the 873 fish tagged and released in marine areas in 2002. Some late-run fish migrated from release sites to the Mission hydroacoustic site in 8-10 d and migrated upstream with the summer run. Most late-run fish remained in the Strait of Georgia for 15-33 d and entered the river after the summer run. Tracking data indicated that individual sockeye salmon maintained essentially the same chronological order as they migrated up the Fraser and Thompson rivers. Summer-run stocks traveled faster between Mission and the Thompson Junction (33-39 km/d) than late-run fish (17-21 km/d). After accounting for fishery removals, the river survival rate for summer-run fish was 92%, and differences between the three release timing groups were not significant. In contrast, the first migration group of late-run fish that passed Mission had significantly lower survival (13%) than all other timing groups. The survival rate for the second and third river entry groups combined (74%) was significantly lower than that of the fourth group (92%). Period-specific survival rates were used to define a relationship between river entry timing and survival and to identify additional factors influencing river entry timing for late-run fish. These relationships may be useful in predicting river survival rates for late-run stocks in future years.

Tests of an unmanned airborne system (UAS) for surveys of marine mammals were conducted near Port Townsend, Washington. Sixteen surveys were conducted over a 10-d period to find 128 simulated whale targets (4 to 9 per survey). Various weather conditions were encountered, and searchwidths and altitudes were varied to establish optimal search parameters for future surveys. Logistic regression models were applied to estimate how detection rates were influenced by target color, degree of target inflation, shutter speed, searchwidth, and Beaufort wind force. Beaufort wind force was the strongest predictor of detection rates with color and degree of target inflation also included in the model that best fit these data. Overall detection rates of simulated large whale profiles using UASs were similar to published estimates of detection rates during manned aerial surveys for marine mammals, except the search area was much smaller (narrow strip width) when using the UAS. The best detection rates were obtained when Beaufort wind force was lowest (~ 2). The UAS tested showed promise for replacing manned aerial surveys for monitoring distribution and abundance of large marine mammals; however, improvements are required before the UAS would be an efficient tool for detection of all species. Side-by-side comparisons are needed between the UAS and manned aircraft to evaluate any differences in detection rates from the two platforms.

Aerial surveys in June and July, 1978 and 1979, documented an unexpectedly large population (at least 417 O O O) of ringed seals, some with pups, inhabiting the pack ice of Baffin Bay. Pack-ice seals are smaller than their fast-ice counterparts and have a different diet and gut parasite load. Age and reproductive data, although limited, indicate that the offshore seals are a normal breeding population, Pack-ice seals probably mix with fast-ice seals in coastal areas during the brief open-water season but morphological and ecological differences suggest that the populations are reproductively isolated. This study prompts reconsideration of the importance of offshore pack ice to ringed seals and, therefore, to the coastal hunting economy of Inuit in Greenland and Baffn Island.

Epigenetics has hitherto been studied and understood largely at the level of individual organisms. Here, we report a multi-faceted investigation of DNA methylation across 11,117 samples from 176 different species. We performed an unbiased clustering of individual cytosines into 55 modules and identified 31 modules related to primary traits including age, species lifespan, sex, adult species weight, tissue type and phylogenetic order. Analysis of the correlation between DNA methylation and species allowed us to construct phyloepigenetic trees for different tissues that parallel the phylogenetic tree. In addition, while some stable cytosines reflect phylogenetic signatures, others relate to age and lifespan, and in many cases responding to anti-aging interventions in mice such as caloric restriction and ablation of growth hormone receptors. Insights uncovered by this investigation have important implications for our understanding of the role of epigenetics in mammalian evolution, aging and lifespan.