Southern hemisphere humpback whales (Megaptera novaeangliae) rely on summer prey abundance of Antarctic krill (Euphausia superba) to fuel one of the longest‐known mammalian migrations on the planet. It is hypothesized that this species, already adapted to endure metabolic extremes, will be one of the first Antarctic consumers to show measurable physiological change in response to fluctuating prey availability in a changing climate; and as such, a powerful sentinel candidate for the Antarctic sea‐ice ecosystem. Here, we targeted the sentinel parameters of humpback whale adiposity and diet, using novel, as well as established, chemical and biochemical markers, and assembled a time trend spanning 8 years. We show the synchronous, inter‐annual oscillation of two measures of humpback whale adiposity with Southern Ocean environmental variables and climate indices. Furthermore, bulk stable isotope signatures provide clear indication of dietary compensation strategies, or a lower trophic level isotopic change, following years indicated as leaner years for the whales. The observed synchronicity of humpback whale adiposity and dietary markers, with climate patterns in the Southern Ocean, lends strength to the role of humpback whales as powerful Antarctic sea‐ice ecosystem sentinels. The work carries significant potential to reform current ecosystem surveillance in the Antarctic region.

An animal's body condition provides valuable information for ecophysiological studies, and is an important measure of fitness in population monitoring and conservation. While both the external body shape of an animal and its internal tissues (i.e. fat content) can be used as a measure of body condition, the relationship between the two is not always linear. We compared the morphological body condition (external metric obtained through aerial photogrammetry) of migrating humpback whales (Megaptera novaeangliae) with their outer blubber lipid concentration (internal metric obtained through blubber biopsy sampling) off the coast of southwest Australia early and late in the breeding season (spanning ∼4.5 months). The external body condition index of juvenile and adult humpback whales decreased by 26.9 (from 18.8% to −8.1%) and 12.0 percentage points (from 8.6% to −3.4%), respectively, between the early and late phase. In contrast, we found no intra-seasonal change in blubber lipid concentration, and no difference between reproductive classes (juveniles, adults and lactating females); however, the small sample size prevented us from effectively testing these effects. Importantly, however, in the 33 animals for which paired metrics were obtained, we found no correlation between the morphometric body condition index and the blubber lipid concentration of individual whales. The lack of a linear relationship suggests that changes in outer blubber lipid concentration do not reflect external changes in body shape, thus limiting the utility of outer blubber lipid reserves for individual body condition evaluation. The wider spectrum of change in body morphometry captured with aerial photogrammetry supports the use of body morphometry as a reliable and well-tested method.

The ability to accurately gauge the body condition of free‐swimming cetaceans is invaluable in population and conservation biology, due to the direct implications that this measure has on individual fitness, survival, and reproductive success. Furthermore, monitoring temporal change in body condition offers insight into foraging success over time, and therefore the health of the supporting ecosystem, as well as a species’ resilience. These parameters are particularly relevant in the context of widespread and accelerated, climate‐induced habitat change. There are, however, significant logistical challenges involved with research and monitoring of large cetaceans, which often preclude direct measure of body condition of live individuals. Consequently, a wide variety of indirect approaches, or proxies, for estimating energetic stores have been proposed over past decades. To date, no single, standardized, approach has been shown to serve as a robust estimation of body condition across species, age categories, and in both live and dead individuals. Nonetheless, it is clear that streamlining and advancing body condition measures would carry significant benefits for diverse areas of cetacean research and management. Here, we review traditional approaches and new applications for the evaluation of cetacean energetic reserves. Specific attention is given to the criteria of measure performance (sensitivity and accuracy), level of invasiveness, cost and effort required for implementation, as well as versatility e.g. applicability across different species, age groups, as well as living versus deceased animals. Measures have been benchmarked against these criteria in an effort to identify key candidates for further development, and key research priorities in the field.

The ability to accurately evaluate the energetic health of wildlife is of critical importance, particularly under conditions of environmental change. Despite the relevance of this issue, currently there are no reliable, standardized, nonlethal measures to assess the energetic reserves of large, free‐roaming marine mammals such as baleen whales. This study investigated the potential of adipocyte area analysis and further, a standardized adipocyte index (AI), to yield reliable information regarding humpback whale (Megaptera novaeangliae) adiposity. Adipocyte area and AI, as ascertained by image analysis, showed a direct correlation with each other but only a weak correlation with the commonly used, but error prone, blubber lipid‐percent measure. The relative power of the three respective measures was further evaluated by comparing humpback whale cohorts at different stages of migration and fasting. Adipocyte area, AI, and blubber lipid‐percent were assessed by binary logistic regression revealing that adipocyte area had the greatest probability to predict the migration cohort with a high level of redundancy attributed to the AI given their strong linear relationship (r = −.784). When only AI and lipid‐percent were assessed, the performance of both predictor variables was significant but the power of AI far exceeded lipid‐percent. The sensitivity of adipocyte metrics and the rapid, nonlethal, and inexpensive nature of the methodology and AI calculation validate the inclusion of the AI in long‐term monitoring of humpback whale population health, and further raises its potential for broader wildlife applications.

Background Ethanol (EtOH) intake correlates with increased risk-taking, and sex differences exist in both EtOH use and risk-taking in humans and rats. However, the interaction of sex and gonadal hormones to affect risk-taking under the influence of EtOH has not been determined. This was the focus of the current study. Methods Adult Long-Evans rats (n=18 males and females) were gonadectomized and received hormone replacement at physiologic levels or blank implants (n=7–9/group). Risk-taking was assessed with probability discounting, requiring rats to choose between a small/certain reward and a large/uncertain reward delivered with decreasing probability throughout each daily session. Before testing, rats received saline or EtOH (0.5 or 1.0 g/kg) ip. Results In males, EtOH increased preference for the large/uncertain reward lever (F2,28=10.462, p<0.05). However, there was no effect of EtOH on lever preference in females (F1,30=0.914, p>0.05). At baseline, ORCHX+T males showed a greater preference for the large/uncertain reward lever then ORCHX males (F1,14=13.805, p<0.05). In females only, EtOH decreased choice latency relative to baseline (F1,10=7.25, p<0.05). EtOH decreased loss sensitivity in both sexes, with all rats exhibiting decreased lose-shift ratios (males: F2,18=5.10, p<0.05; females F2,10=4.37, p<0.05). Conclusions These results show that EtOH, sex, and hormones interact to influence decision making. EtOH increases risk taking in males, but not in females. However, EtOH selectively decreases choice latency in females, and decreases loss sensitivity in both sexes. These findings are relevant to understanding human behavior, particularly in adolescents who experience increased hormone levels and often drink EtOH and engage in risky behavior.

Southern hemisphere humpback whales have evolved energetically demanding capital breeding and migratory life-history behaviours. It has been hypothesised that not all individuals of a population participate in the seasonal migration each year, or only undertake partial migrations.Given the cost of migration and reproduction, we explored the possibility that specifically, not all mature females participate in the seasonal migration every year, or significantly delay or shorten their migration, in response to poor feeding conditions. That is, females must attain a minimum threshold of accumulated energy reserves to commit to a reproductive event that likely occurs as a product of mating during migration. With a 1:1 male to female birth ratio, yet a male bias observed along the main migratory corridor; this study utilised inter-annual migratory cohort sex ratios to explore their potential to serve as measures of population fecundity, as a function of ecosystem health. The sex ratios of randomly biopsied adult humpback whales, sampled at a defined location and set time-points along the main migratory corridor from 2008 to 2016 were investigated. Northward migration sex ratios in 2009, 2014 and 2016 revealed a lower male bias suggesting good female participation in the migration and therefore apparent optimal provisioning during the two preceding summers. By contrast, the 2011 southward migration, revealed the highest male bias recorded of 5.75:1. Southward migration sex ratios were found to oscillate closely with measures of population adiposity, a sentinel parameter employed for longterm surveillance of the Antarctic sea-ice ecosystems under the Southern Ocean Observing System-endorsed Humpback Whale Sentinel Program. Anomalously poor humpback whale body condition recorded in 2011 was attributed to poor Antarctic feeding conditions during the extreme La Niña event of 2010/11. These findings lend support for the application of migratory cohort sex ratios, standardised by time and location, as a measure of relative inter-annual

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Background: Optimal timing for resection of asymptomatic congenital lung malformations (CLMs) remains controversial. The aim of this study is to define optimal timing for surgical intervention of patients with CLMs and define clinical variables that affect surgical outcomes. Methods: An IRB-approved retrospective analysis was conducted for patients undergoing surgery for CLMs between 2012 and 2017. Subjects were divided into cohorts based on timing of operative intervention. "Early intervention" was defined as surgery within 4 months of birth; "intermediate intervention"-between 4 and 6 months; and "late intervention"−6-12 months. Surgical outcomes including intraoperative estimated blood loss (EBL), surgical time, post-operative pneumothorax, length of time chest tube stayed in, and hospital length of stay were compared among the three groups using Fisher's exact test or Chi-squared test for categorical variables and one-way analysis of variance test for continuous variables. Results: We analyzed 63 patients who underwent surgery for CLM. There were no significant differences in baseline characteristics. Timing of surgery did not significantly correlate with post-operative outcomes. Specifically, there was no difference in operative time, EBL, post-operative pneumothorax, or length of hospital stay among the early, intermediate, and late intervention groups. Even after controlling for cyst-volume ratio (CVR), timing of surgery still did not affect post-operative outcomes. Conclusions: Surgical outcomes for resection of CLMs are not significantly affected by timing of surgery. We advocate for early intervention to decrease the incidence of associated complications that can occur with later intervention.