Validation of a blubber-based endocrine pregnancy test for humpback whales

Pallin, Logan; Robbins, Jooke; Kellar, Nicholas M.; Bérubé, Martine; Friedlaender, Ari S.

doi:10.1093/conphys/coy031

Cited by 41 publications

(63 citation statements)

References 43 publications

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“… Logistic model used to assign the probability of pregnancy in humpback whales sampled along the WAP. Model was previously described in Pallin et al [ 51 ]. …”

Section: Resultsmentioning

confidence: 99%

“…Pregnancy was assigned using the methods developed by Pallin et al [ 51 ]. Briefly, we used the progesterone concentrations from a collection of female humpback whales of known pregnancy status, based on annual calving observations, to develop a predictive model.…”

Section: Methodsmentioning

confidence: 99%

“…We interpreted the pregnancy state of females sampled along the WAP based on the relationship of their progesterone concentration with the reference levels from known pregnant animals. The model returned the probability that each female was pregnant [ 51 ]. If the probability of being pregnant was greater than 99.9%, that female was assumed to be pregnant.…”

Section: Methodsmentioning

confidence: 99%

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High pregnancy rates in humpback whales (Megaptera novaeangliae) around the Western Antarctic Peninsula, evidence of a rapidly growing population

et al. 2018

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Antarctic humpback whales are recovering from near extirpation from commercial whaling. To understand the dynamics of this recovery and establish a baseline to monitor impacts of a rapidly changing environment, we investigated sex ratios and pregnancy rates of females within the Western Antarctic Peninsula (WAP) feeding population. DNA profiling of 577 tissue samples (2010–2016) identified 239 males and 268 females. Blubber progesterone levels indicated 63.5% of the females biopsied were pregnant. This proportion varied significantly across years, from 36% in 2010 to 86% in 2014. A comparison of samples collected in summer versus fall showed significant increases in the proportion of females present (50% to 59%) and pregnant (59% to 72%), consistent with demographic variation in migratory timing. We also found evidence of annual reproduction among females; 54.5% of females accompanied by a calf were pregnant. These high pregnancy rates are consistent with a population recovering from past exploitation, but appear inconsistent with recent estimates of WAP humpback population growth. Thus, our results will help to better understand population growth potential and set a current baseline from which to determine the impact of climate change and variability on fecundity and reproductive rates.

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“… Logistic model used to assign the probability of pregnancy in humpback whales sampled along the WAP. Model was previously described in Pallin et al [ 51 ]. …”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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High pregnancy rates in humpback whales (Megaptera novaeangliae) around the Western Antarctic Peninsula, evidence of a rapidly growing population

et al. 2018

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“…Blubber has become a widely used sample matrix for reproductive and stress assessments of both odontocete (for examples see: Kellar et al , 2006 , Kellar et al ., 2009 , Trego et al , 2013 , Kellar et al , 2015 , Trana et al , 2016 , Champagne et al , 2018 ), and mysticete whales (e.g. Mansour et al , 2002 , Kellar et al , 2013 , Vu et al , 2015 , Mello et al , 2017 , Pallin et al , 2018 , Carone et al , 2019 , Atkinson et al , 2020 ). For instance, pregnant females can be readily identified using blubber progesterone concentrations in several whale species ( Mansour et al , 2002 , Kellar et al , 2013 , Pallin et al , 2018 , Inoue et al ., 2019 , Atkinson et al , 2020 ), and blubber cortisol measurements have shown promise for assessing human impacts ( Kellar et al , 2015 ) and environmental stressors ( Trana et al , 2016 ) on cetaceans.…”

Section: Introductionmentioning

confidence: 99%

Stress and reproductive events detected in North Atlantic right whale blubber using a simplified hormone extraction protocol

Graham

Burgess

Rolland

2021

Conservation Physiology

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As studies quantifying steroid hormones in marine mammal blubber progress, methodological refinements may improve the utility and consistency of blubber hormone measurements. This study advances blubber extraction methodologies by testing a simplified extraction protocol that reduces time and complexity compared to a protocol widely used in cetacean blubber studies. Using blubber samples archived from remote biopsy (n = 21 live whales) and necropsy collection (n = 7 dead whales) of North Atlantic right whales (NARW; Eubalaena glacialis) of known life history states, we performed analytical and biological validations to assess the feasibility of measuring reproductive (testosterone, progesterone) and glucocorticoid (cortisol) hormones in blubber via enzyme immunoassay following the simplified extraction. Analytical validations (parallelism, accuracy, extraction efficiency, repeatability) showed the simplified extraction produced similar results to the extended protocol, offering a more efficient and consistent technique. In live, apparently healthy whales, blubber testosterone concentrations (mean ± SE) were significantly higher in males (2.02 ± 0.36 ng/g) compared to females (0.81 ± 0.15 ng/g). Blubber progesterone was highest in a confirmed pregnant female (60.3 ng/g), which was 12-fold greater than the mean concentration of non-pregnant females (4.56 ± 0.88 ng/g). Blubber cortisol concentrations in whales that died from anthropogenic causes averaged 5.31 ± 2.28 ng/g, whereas most live, healthy whales had cortisol values below 1 ng/g. Among living whales, a whale actively entangled in fishing gear had the highest blubber cortisol measurement (3.51 ng/g), exhibiting levels similar to whales that died from acute entanglement (2.88 ± 0.42 ng/g). Overall, the highest blubber cortisol concentration (18.0 ng/g) was measured in a dead whale with a severe chronic entanglement, approximately 30-fold greater than mean blubber cortisol of apparently healthy whales (0.58 ± 0.11 ng/g). The methodological approach presented here provides a reference for researchers interested in an alternative, streamlined technique for hormone extraction of cetacean blubber and contributes to the diverse tool set for stress and reproductive assessments of endangered NARWs.

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“…Blubber samples from whales can be obtained by biopsy sampling and therefore measuring the level of progesterone in blubber has the potential to investigate the reproductive status in free-ranging cetacean species. For example, Pallin et al (2018) used blubber biopsy samples for assigning pregnancy in humpback whales Megaptera novaeangliae. It is expected that the application and development of such non-lethal methods will increase in the future.…”

Section: Introductionmentioning

confidence: 99%

Comparison of progesterone concentrations in blubber and plasma among female Antarctic minke whales of known reproductive status

Inoue¹,

Yasunaga²,

Pastene³

2019

Fish Sci

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The utility of progesterone concentration in blubber as a means of determining reproductive status in the Antarctic minke whale Balaenoptera bonaerensis was assessed through a comparative analysis of progesterone concentration in blubber and plasma among 230 female whales of known reproductive status (immature, resting, ovulating or pregnant). Whales were sampled during the austral summer in the Antarctic Ocean. The general pattern of progesterone concentration by reproductive category was well correlated between blubber and plasma samples, validating in principle the use of progesterone concentrations in blubber to determine the reproductive status of females. However, some differences were found for resting and ovulating females, which require further consideration. For blubber, overlap of progesterone concentrations was observed between reproductive categories with the exception of immature/ovulating and immature/pregnant. This result suggests that the method of using progesterone concentration in blubber cannot distinguish between pregnant and non-pregnant mature females. However, it can be used to distinguish between immature and mature females. Although a low overlap ratio in concentration was found between immature and resting females, the method is still useful for determining sexual maturity, because resting females of the Antarctic minke whale are seldom found in the Antarctic Ocean.

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Validation of a blubber-based endocrine pregnancy test for humpback whales

Cited by 41 publications

References 43 publications

High pregnancy rates in humpback whales (Megaptera novaeangliae) around the Western Antarctic Peninsula, evidence of a rapidly growing population

High pregnancy rates in humpback whales (Megaptera novaeangliae) around the Western Antarctic Peninsula, evidence of a rapidly growing population

Stress and reproductive events detected in North Atlantic right whale blubber using a simplified hormone extraction protocol

Comparison of progesterone concentrations in blubber and plasma among female Antarctic minke whales of known reproductive status

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