Biology subjects

Pace, R. M.

Publications and source records attributed to Pace, R. M..

5 recordsLinked to original sources

bioRxiv2024

A multistate capture-recapture model to estimate reproduction of North Atlantic right whales

The recent steep decline of critically endangered North Atlantic right whales (Eubalaena glacialis) can be attributed to high mortality combined with low reproduction. While the former is a clear result of anthro-pogenic activity, the latter involves more complexity. Evidence suggests that both short-term fluctuations in prey availability and long-term decline in health are responsible for depressed right whale calving rates. To facilitate an assessment of extinction risk, we developed a multistate capture-recapture model that estimated the probability of calving using extensive sightings data from 1990-2019. The model estimated sub-lethal effects of severe injury on calving probability, and modeled temporal variability in calving as related to indices of prey availability (Calanus spp. biomass) and an apparent regime shift. The average annual probability of calving for known-breeding females, given average prey conditions, decreased from 0.217 [0.162, 0.281] to 0.142 [0.067, 0.252] after the 2010 regime shift. The model indicated strong evidence of a relationship between calving probability and the prey index from the eastern Gulf of Maine, though this relationship effectively disappeared after 2010; moderate evidence for a relationship with prey from the southwest Gulf of St. Lawrence remained. Weak evidence of reduced calving probability due to severe injury resulted from low sample sizes, given increased mortality for individuals observed with severe injuries. The regime effect is hypothesized to be capturing a long-term decline in health due to a combination of decreasing habitat quality resulting from climate change and potentially chronic sublethal injuries (e.g., entanglements). Our reproduction model provides demographic parameter estimates that can be used in population projections for North Atlantic right whales, though uncertainty remains in the mechanisms responsible for recent declines in calving.

ecology↗

bioRxiv2024

Associations between SARS-CoV-2 Infection or COVID-19 Vaccination and Human Milk Composition: A Multi-Omics Approach

The risk of contracting SARS-CoV-2 via human milk-feeding is virtually non-existent. Adverse effects of COVID-19 vaccination for lactating individuals are not different from the general population, and no evidence has been found that their infants exhibit adverse effects. Yet, there remains substantial hesitation among this population globally regarding the safety of these vaccines. Herein we aimed to determine if compositional changes in milk occur following infection or vaccination, including any evidence of vaccine components. Using an extensive multi-omics approach, we found that compared to unvaccinated individuals SARS-CoV-2 infection was associated with significant compositional differences in 67 proteins, 385 lipids, and 13 metabolites. In contrast, COVID-19 vaccination was not associated with any changes in lipids or metabolites, although it was associated with changes in 13 or fewer proteins. Compositional changes in milk differed by vaccine. Changes following vaccination were greatest after 1-6 hours for the mRNA-based Moderna vaccine (8 changed proteins), 3 days for the mRNA-based Pfizer (4 changed proteins), and adenovirus-based Johnson and Johnson (13 changed proteins) vaccines. Proteins that changed after both natural infection and Johnson and Johnson vaccine were associated mainly with systemic inflammatory responses. In addition, no vaccine components were detected in any milk sample. Together, our data provide evidence of only minimal changes in milk composition due to COVID-19 vaccination, with much greater changes after natural SARS-CoV-2 infection. IMPORTANCEThe impact of the observed changes in global milk composition on infant health remain unknown. These findings emphasize the importance of vaccinating the lactating population against COVID-19, as compositional changes in milk were found to be far less evident after vaccination compared to SARS-CoV-2 infection. Importantly, vaccine components were not detected in milk after vaccination.

molecular biology↗

bioRxiv2024

Before and after delisting: population dynamics of North Atlantic humpback whales over two decades in the Gulf of Maine

Whales are long-lived, slow-reproducing species that were decimated by commercial whaling. Although some populations seem close to recovery, others are challenging to assess. We studied humpback whales (Megaptera novaeangliae) in the Gulf of Maine, an area of the North Atlantic (NA) with well-documented threats. Long-term studies and mark-recapture data were used to estimate humpback whale apparent survival, abundance and population growth from 2000 through 2019. Estimates were derived from a hierarchical, Bayesian state-space model with sex, age, and random time effects on survival while accounting for individual capture probability. Abundance increased from 744 (95% CI: 726-762) in 2000 to 1,706 (95% CI: 1,639-1,771) in 2019, with 4.6% mean annual growth. However, adult males exhibited higher survival and outnumbered adult females by the end of the study. Over time, fewer calves were observed, calf survival varied and the juvenile class declined. These are rare insights into the dynamics underlying whale abundance trends and they revealed similarities to an endangered species that is declining due to environmental and human impacts. The results inform a listing change under the U.S. Endangered Species Act, a mortality event of unprecedented magnitude off the U.S and humpback whale recovery from historical whaling in the NA.

ecology↗

bioRxiv2023

A multistate capture-recapture model to estimate cause-specific injury and mortality of North Atlantic right whales

Understanding the causes of mortality for a declining species is essential for developing effective conservation and management strategies, particularly when anthropogenic activities are the primary threat. Using a competing hazards framework allows for robust estimation of the cause-specific variation that may exist across multiple dimensions, such as time and individual. Here, we estimated cause-specific rates of severe injury and mortality for North Atlantic right whales (Eubalaena glacialis), a critically endangered species that is currently in peril due to human-caused interactions. We developed a multistate capture-recapture model that leveraged 30 years of intensive survey effort yielding sightings of individuals with injury assessments and necropsies of carcass recoveries. We examined variation in the hazard rates of severe injury and mortality due to entanglements in fishing gear and vessel strikes as explained by year and the age and reproductive status of the individual. We found strong evidence for increased rates of severe entanglement injuries after 2013 and for females with calves, with consequently higher marginal mortality. The model results also suggested that despite vessel strikes causing a lower average rate of severe injuries, the higher mortality rate conditional on injury results in significant total mortality risk, particularly for females resting from a recent calving event. Large uncertainty in the estimation of carcass recovery rate for vessel strike deaths permeated into the apportionment of mortality causes. The increased rates of North Atlantic right whale mortality in the last decade, particularly for reproducing females, puts the species at risk of severe decline. By apportioning the human-caused threats using a quantitative approach with estimation of relevant uncertainty, this work can guide development of conservation and management strategies to facilitate species recovery.

ecology↗

bioRxiv2018

Strong and lasting impacts of past global warming on baleen whale and prey abundance

AbstractThe demography of baleen whales and their prey during the past 30 thousand years was assessed to understand the effects of past rapid global warming on marine ecosystems. Mitochondrial and genome-wide DNA sequence variation in eight baleen whale and seven prey species revealed strong, ocean-wide demographic changes that were correlated with changes in global temperatures and regional oceanographic conditions. In the Southern Ocean baleen whale and prey abundance increased exponentially and in apparent synchrony, whereas changes in abundance varied among species in the more heterogeneous North Atlantic Ocean. The estimated changes in whale abundance correlated with increases in the abundance of prey likely driven by reductions in sea-ice cover and an overall increase in primary production. However, the specific regional oceanographic environment, trophic interactions and species ecology also appeared to play an important role. Somewhat surprisingly the abundance of baleen whales and prey continued to increase for several thousand years after global temperatures stabilized. These findings warn of the potential for dramatic, long-term effects of current climate changes on the marine ecosystem.\n\nOne Sentence SummaryThe effects of past global warming on marine ecosystems were drastic, system-wide and long-lasting.

evolutionary biology↗