Multi-year longitudinal profiles of cortisol and corticosterone recovered from baleen of North Atlantic right whales (Eubalaena glacialis)

© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in General and Comparative Endocrinology 254 (2017): 50-59, doi:10.1016/j.ygcen.2017.09.009.Research into stress physiology of mysticete whales has been hampered by difficulty in obtaining repeated physiological samples from individuals over time. We investigated whether multi-year longitudinal records of glucocorticoids can be reconstructed from serial sampling along full-length baleen plates (representing ~10 years of baleen growth), using baleen recovered from two female North Atlantic right whales (Eubalaena glacialis) of known reproductive history. Cortisol and corticosterone were quantified with immunoassay of subsamples taken every 4 cm (representing ~60 d time intervals) along a full-length baleen plate from each female. In both whales, corticosterone was significantly elevated during known pregnancies (inferred from calf sightings and necropsy data) as compared to intercalving intervals; cortisol was significantly elevated during pregnancies in one female but not the other. Within intercalving intervals, corticosterone was significantly elevated during the first year (lactation year) and/or the second year (post-lactation year) as compared to later years of the intercalving interval, while cortisol showed more variable patterns. Cortisol occasionally showed brief high elevations (“spikes”) not paralleled by corticosterone, suggesting that the two glucocorticoids might be differentially responsive to certain stressors. Generally, immunoreactive corticosterone was present in higher concentration in baleen than immunoreactive cortisol; corticosterone:cortisol ratio was usually >4 and was highly variable in both individuals. Further investigation of baleen cortisol and corticosterone profiles could prove fruitful for elucidating long-term, multi-year patterns in stress physiology of large whales, determined retrospectively from stranded or archived specimens.This work was supported by the Eppley Foundation for Research, the NOAA Marine Mammal Health and Stranding Program, the Woods Hole Oceanographic Institution Ocean Life Institute, and the New England Aquarium

Lifetime glucocorticoid profiles in baleen of right whale calves: Potential relationships to chronic stress of repeated wounding by Kelp Gulls

Baleen tissue accumulates stress hormones (glucocorticoids, GC) as it grows, along with other adrenal, gonadal and thyroid hormones. The hormones are deposited in a linear fashion such that a single plate of baleen allows retrospective assessment and evaluation of long-term trends in the whales´ physiological condition. In whale calves, a single piece of baleen contains hormones deposited across the lifespan of the animal, with the tip of the baleen representing prenatally grown baleen. This suggests that baleen recovered from stranded carcasses of whale calves could be used to examine lifetime patterns of stress physiology. Here we report lifetime profiles of cortisol and corticosterone in baleen of a North Atlantic right whale ("NARW" - Eubalaena glacialis) calf that died from a vessel strike, as well as four southern right whale ("SRW" - Eubalaena australis) calves that were found dead with varying severity of chronic wounding from Kelp Gull (Larus dominicanus) attacks. In all five calves, prenatally grown baleen exhibited a distinctive profile of elevated glucocorticoids that declined shortly before birth, similar to GC profiles reported from baleen of pregnant females. After birth, GC profiles in calf baleen corresponded with the degree of wounding. The NARW calf and two SRW calves with no or few gull wounds had relatively low and constant GC content throughout life, while two SRW calves with high numbers of gull wounds had pronounced elevations in baleen GC content in postnatal baleen followed by a precipitous decline shortly before death, a profile suggestive of prolonged chronic stress. Baleen samples may present a promising and valuable tool for defining the baseline physiology of whale calves and may prove useful for addressing conservation-relevant questions such as distinguishing acute from chronic stress and, potentially, determining cause of death.Fil: Ajó, Alejandro A. Fernández. Northern Arizona University; Estados UnidosFil: Hunt, Kathleen E.. Northern Arizona University; Estados UnidosFil: Uhart, Marcela María. University of California at Davis; Estados UnidosFil: Rowntree, Victoria. University of Utah; Estados UnidosFil: Sironi, Mariano. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Instituto de Conservación de Ballenas; ArgentinaFil: Marón, Carina Flavia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Instituto de Conservación de Ballenas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Martino, Matias. Southern Right Whale Health Monitoring Program; ArgentinaFil: Buck, Charles Loren. Northern Arizona University; Estados Unido

Longitudinal progesterone profiles in baleen from female North Atlantic right whales (Eubalaena glacialis) match known calving history

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Conservation Physiology 4 (2016): cow014, doi:10.1093/conphys/cow014.Reproduction of mysticete whales is difficult to monitor, and basic parameters, such as pregnancy rate and inter-calving interval, remain unknown for many populations. We hypothesized that baleen plates (keratinous strips that grow downward from the palate of mysticete whales) might record previous pregnancies, in the form of high-progesterone regions in the sections of baleen that grew while the whale was pregnant. To test this hypothesis, longitudinal baleen progesterone profiles from two adult female North Atlantic right whales (Eubalaena glacialis) that died as a result of ship strike were compared with dates of known pregnancies inferred from calf sightings and post-mortem data. We sampled a full-length baleen plate from each female at 4 cm intervals from base (newest baleen) to tip (oldest baleen), each interval representing ∼60 days of baleen growth, with high-progesterone areas then sampled at 2 or 1 cm intervals. Pulverized baleen powder was assayed for progesterone using enzyme immunoassay. The date of growth of each sampling location on the baleen plate was estimated based on the distance from the base of the plate and baleen growth rates derived from annual cycles of stable isotope ratios. Baleen progesterone profiles from both whales showed dramatic elevations (two orders of magnitude higher than baseline) in areas corresponding to known pregnancies. Baleen hormone analysis shows great potential for estimation of recent reproductive history, inter-calving interval and general reproductive biology in this species and, possibly, in other mysticete whales.This work was supported by the Eppley Foundation for Research, the National Oceanographic and Atmospheric Administration Marine Mammal Health and Stranding Program and the Woods Hole Oceanographic Institution Ocean Life Institute

Multiple steroid and thyroid hormones detected in baleen from eight whale species

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Conservation Physiology 5 (2017): cox061, doi:10.1093/conphys/cox061.Recent studies have demonstrated that some hormones are present in baleen powder from bowhead (Balaena mysticetus) and North Atlantic right (Eubalaena glacialis) whales. To test the potential generalizability of this technique for studies of stress and reproduction in large whales, we sought to determine whether all major classes of steroid and thyroid hormones are detectable in baleen, and whether these hormones are detectable in other mysticetes. Powdered baleen samples were recovered from single specimens of North Atlantic right, bowhead, blue (Balaenoptera [B.]musculus), sei (B. borealis), minke (B. acutorostrata), fin (B. physalus), humpback (Megaptera novaeangliae) and gray (Eschrichtius robustus) whales. Hormones were extracted with a methanol vortex method, after which we tested all species with commercial enzyme immunoassays (EIAs, Arbor Assays) for progesterone, testosterone, 17β-estradiol, cortisol, corticosterone, aldosterone, thyroxine and tri-iodothyronine, representing a wide array of steroid and thyroid hormones of interest for whale physiology research. In total, 64 parallelism tests (8 species × 8 hormones) were evaluated to verify good binding affinity of the assay antibodies to hormones in baleen. We also tested assay accuracy, although available sample volume limited this test to progesterone, testosterone and cortisol. All tested hormones were detectable in baleen powder of all species, and all assays passed parallelism and accuracy tests. Although only single individuals were tested, the consistent detectability of all hormones in all species indicates that baleen hormone analysis is likely applicable to a broad range of mysticetes, and that the EIA kits tested here perform well with baleen extract. Quantification of hormones in baleen may be a suitable technique with which to explore questions that have historically been difficult to address in large whales, including pregnancy and inter-calving interval, age of sexual maturation, timing and duration of seasonal reproductive cycles, adrenal physiology and metabolic rate.This work was supported by (1) the Center for Bioengineering Innovation at Northern Arizona University and (2) the New England Aquarium

Fecal glucocorticoids and anthropogenic injury and mortality in North Atlantic right whales Eubalaena glacialis

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Endangered Species Research 34 (2017): 417-429, doi:10.3354/esr00866.As human impacts on marine ecosystems escalate, there is increasing interest in quantifying sub-lethal physiological and pathological responses of marine mammals. Glucocorticoid hormones are commonly used to assess stress responses to anthropogenic factors in wildlife. While obtaining blood samples to measure circulating hormones is not currently feasible for free-swimming large whales, immunoassay of fecal glucocorticoid metabolites (fGCs) has been validated for North Atlantic right whales Eubalaena glacialis (NARW). Using a general linear model, we compared fGC concentrations in right whales chronically entangled in fishing gear (n = 6) or live-stranded (n = 1), with right whales quickly killed by vessels (n = 5) and healthy right whales (n = 113) to characterize fGC responses to acute vs. chronic stressors. fGCs in entangled whales (mean ± SE: 1856.4 ± 1644.9 ng g-1) and the stranded whale (5740.7 ng g-1) were significantly higher than in whales killed by vessels (46.2 ± 19.2 ng g-1) and healthy whales (51.7 ± 8.7 ng g-1). Paired feces and serum collected from the live-stranded right whale provided comparison of fGCs in 2 matrices in a chronically stressed whale. Serum cortisol and corticosterone in this whale (50.0 and 29.0 ng ml-1, respectively) were much higher than values reported in other cetaceans, in concordance with extremely elevated fGCs. Meaningful patterns in fGC concentration related to acute vs. chronic impacts persisted despite potential for bacterial degradation of hormone metabolites in dead whales. These results provide biological validation for using fGCs as a biomarker of chronic stress in NARWs.This research was funded by the NOAA/NMFS, Office of Naval Research Marine Mammals and Biology Program, Northeast Consortium, Island Foundation, Irving Oil, NEAq Internal Research Fund, Prescott Grant NA08NMF4390590, and NOAA CINAR Cooperative Agreement NA09OAR4320129

Phenology Effects on Productivity and Hatching-Asynchrony of American Kestrels (\u3cem\u3eFalco sparverius\u3c/em\u3e) Across a Continent

Optimal reproductive performance occurs when birds time reproduction to coincide with peak food availability. Deviation from optimal timing, or mismatch, can affect productivity, though birds may mediate some mismatch effects by altering their incubation behavior. We studied the consequences of nesting timing (i.e., clutch initiation relative to an index of spring start) on productivity across the breeding range of American kestrels (Falco sparverius) in the United States and southern Canada, and associations between nesting timing, incubation behavior, and hatching asynchrony. We used observations from long-term nest box monitoring, remote trail cameras, and community-scientist-based programs to obtain data on clutch initiation, productivity, incubation, and hatching synchrony. Kestrels that initiated clutches after the extended spring index (SI-x, start of spring estimate) had higher rates of nest failure and fewer nestlings than earlier nesters, and effects of nesting timing on productivity were strongest in the Northeast. In contrast, kestrels in the Southwest experienced a more gradual decline in productivity across the season. Spatial effects may be the result of regional differences in growing seasons and temporal nesting windows (duration of nesting season). Specifically, resource availability in the Northeast was highly peaked during the breeding season, potentially resulting in shorter nesting windows. Conversely, resource curves were more prolonged in the Southwest, and growing seasons are becoming longer with climate change, potentially resulting in longer nesting windows. We found an inverse relationship between nesting timing and the onset of male incubation. Males from breeding pairs that initiated clutches after SI-x began incubation sooner than males from breeding pairs that initiated clutches before SI-x. Early-onset of male incubation was positively associated with hatching asynchrony, creating increased age variation in developing young. In sum, nesting phenology relative to the SI-x has consequences for American kestrels’ productivity, and these consequences vary across space. The early onset of incubation may act as a potential adaptive behavior to advance the average hatch date and spread out energetic demands. Given the effects of nesting timing on productivity, kestrels are likely to be sensitive to climate-driven advances in growing seasons and vulnerable to phenological mismatch, particularly in the Northeast

Assessment of a non-invasive approach to pregnancy diagnosis in gray whales through drone-based photogrammetry and faecal hormone analysis

This project was supported by the NOAA National Marine Fisheries Service Office of Science and Technology, the Office of Naval Research Marine Mammals and Biology Program (no. N00014-20-1-2760), the Oregon State University Marine Mammal Institute and Oregon Sea Grant.Knowledge of baleen whales’ reproductive physiology is limited and requires long-term individual-based studies and innovative tools. We used 6 years of individual-level data on the Pacific Coast Feeding Group gray whales to evaluate the utility of faecal progesterone immunoassays and drone-based photogrammetry for pregnancy diagnosis. We explored the variability in faecal progesterone metabolites and body morphology relative to observed reproductive status and estimated the pregnancy probability for mature females of unknown reproductive status using normal mixture models. Individual females had higher faecal progesterone concentrations when pregnant than when presumed nonpregnant. Yet, at the population level, high overlap and variability in progesterone metabolite concentrations occurred between pregnant and non-pregnant groups, limiting this metric for accurate pregnancy diagnosis in gray whales. Alternatively, body width at 50% of the total body length (W50) correctly discriminated pregnant from non-pregnant females at individual and population levels, with high accuracy. Application of the model using W50 metric to mature females of unknown pregnancy status identified eight additional pregnancies with high confidence. Our findings highlight the utility of drone-based photogrammetry to non-invasively diagnose pregnancy in this group of gray whales, and the potential for improved data on reproductive rates for population management of baleen whales generally.Publisher PDFPeer reviewe

Overcoming the challenges of studying conservation physiology in large whales : a review of available methods

Large whales are subjected to a variety of conservation pressures that could be better monitored and managed if physiological information could be gathered readily from free-swimming whales. However, traditional approaches to studying physiology have been impractical for large whales, because there is no routine method for capture of the largest species and there is presently no practical method of obtaining blood samples from free-swimming whales. We review the currently available techniques for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices. We focus on methods that should produce information relevant to conservation physiology, e.g. measures relevant to stress physiology, reproductive status, nutritional status, immune response, health, and disease. The following four types of samples are discussed: faecal samples, respiratory samples (‘blow’), skin/blubber samples, and photographs. Faecal samples have historically been used for diet analysis but increasingly are also used for hormonal analyses, as well as for assessment of exposure to toxins, pollutants, and parasites. Blow samples contain many hormones as well as respiratory microbes, a diverse array of metabolites, and a variety of immune-related substances. Biopsy dart samples are widely used for genetic, contaminant, and fatty-acid analyses and are now being used for endocrine studies along with proteomic and transcriptomic approaches. Photographic analyses have benefited from recently developed quantitative techniques allowing assessment of skin condition, ectoparasite load, and nutritional status, along with wounds and scars from ship strikes and fishing gear entanglement. Field application of these techniques has the potential to improve our understanding of the physiology of large whales greatly, better enabling assessment of the relative impacts of many anthropogenic and ecological pressures.Publisher PDFPeer reviewe

Multi-year patterns in testosterone, cortisol and corticosterone in baleen from adult males of three whale species

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Conservation Physiology 6 (2018): coy049, doi:10.1093/conphys/coy049.Male baleen whales have long been suspected to have annual cycles in testosterone, but due to difficulty in collecting endocrine samples, little direct evidence exists to confirm this hypothesis. Potential influences of stress or adrenal stress hormones (cortisol, corticosterone) on male reproduction have also been difficult to study. Baleen has recently been shown to accumulate steroid hormones during growth, such that a single baleen plate contains a continuous, multi-year retrospective record of the whale’s endocrine history. As a preliminary investigation into potential testosterone cyclicity in male whales and influences of stress, we determined patterns in immunoreactive testosterone, two glucocorticoids (cortisol and corticosterone), and stable-isotope (SI) ratios, across the full length of baleen plates from a bowhead whale (Balaena mysticetus), a North Atlantic right whale (Eubalaena glacialis) and a blue whale (Balaenoptera musculus), all adult males. Baleen was subsampled at 2 cm (bowhead, right) or 1 cm (blue) intervals and hormones were extracted from baleen powder with methanol, followed by quantification of all three hormones using enzyme immunoassays validated for baleen extract of these species. Baleen of all three males contained regularly spaced peaks in testosterone content, with number and spacing of testosterone peaks corresponding well to SI data and to species-specific estimates of annual baleen growth rate. Cortisol and corticosterone exhibited some peaks that co-occurred with testosterone peaks, while other glucocorticoid peaks occurred independent of testosterone peaks. The right whale had unusually high glucocorticoids during a period with a known entanglement in fishing gear and a possible disease episode; in the subsequent year, testosterone was unusually low. Further study of baleen testosterone patterns in male whales could help clarify conservation- and management-related questions such as age of sexual maturity, location and season of breeding, and the potential effect of anthropogenic and natural stressors on male testosterone cycles.This work was supported by (1) the Arizona Board of Regents Technology Research Initiative Fund; (2) the Center for Bioengineering Innovation at Northern Arizona University; (3) the Greenland Institute of Natural Resources; (4) the Woods Hole Oceanographic Institution Ocean Life Institute and (5) Fisheries and Ocean Canada’s (DFO) Priorities and Partnership Strategic Initiatives Fund and Oceans Protection Plan

Success stories and emerging themes in conservation physiology

The potential benefits of physiology for conservation are well established and include greater specificity of management techniques, determination of cause–effect relationships, increased sensitivity of health and disturbance monitoring and greater capacity for predicting future change. While descriptions of the specific avenues in which conservation and physiology can be integrated are readily available and important to the continuing expansion of the discipline of ‘conservation physiology’, to date there has been no assessment of how the field has specifically contributed to conservation success. However, the goal of conservation physiology is to foster conservation solutions and it is therefore important to assess whether physiological approaches contribute to downstream conservation outcomes and management decisions. Here, we present eight areas of conservation concern, ranging from chemical contamination to invasive species to ecotourism, where physiological approaches have led to beneficial changes in human behaviour, management or policy. We also discuss the shared characteristics of these successes, identifying emerging themes in the discipline. Specifically, we conclude that conservation physiology: (i) goes beyond documenting change to provide solutions; (ii) offers a diversity of physiological metrics beyond glucocorticoids (stress hormones); (iii) includes approaches that are transferable among species, locations and times; (iv) simultaneously allows for human use and benefits to wildlife; and (v) is characterized by successes that can be difficult to find in the primary literature. Overall, we submit that the field of conservation physiology has a strong foundation of achievements characterized by a diversity of conservation issues, taxa, physiological traits, ecosystem types and spatial scales. We hope that these concrete successes will encourage the continued evolution and use of physiological tools within conservation-based research and management plans."This work was supported by the Society for Integrative and Comparative Biology; the University of Windsor, Ontario, Canada; Dalhousie University, Nova Scotia, Canada; and the Canadian Society of Zoologists. C.L.M. was supported by a Natural Sciences and Engineering Research Council of Canada PGS-D (427552). S.J.C. and O.P.L. are supported by the Canada Research Chairs program. E.J.C. was supported by a grant from the National Science Foundation (BCS-1134687). K.R.H. was supported by grants from the National Science Foundation’s MacroSystems Biology program (award no. 1340856) and the US Department of Agriculture (NRI 2015-67013-23138). J.R.R. was supported by grants from the National Science Foundation (EF-1241889), National Institutes of Health (R01GM109499, R01TW010286), US Department of Agriculture (NRI 2006-01370, 2009-35102-0543) and US Environmental Protection Agency (CAREER 83518801)."https://academic.oup.com/conphys/article/4/1/cov057/295129