Hematologic and serum biochemical reference intervals for free-ranging common bottlenose dolphins (Tursiops truncatus) and variation in the distributions of clinicopathologic values related to geographic sampling site

Schwacke, Lori H.; Hall, Ailsa J.; Townsend, Forrest I.; Wells, Randall S.; Hansen, Larry J.; Hohn, Aleta A.; Bossart, Gregory D.; Fair, Patricia A.; Rowles, Teresa K.

doi:10.2460/ajvr.70.8.973

Cited by 64 publications

(106 citation statements)

References 41 publications

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“…However, the leukocyte counts associated with all animals found in this study (i.e. both those with reproductive success and failures) were within the range (95 th percentiles) previously reported for wild dolphins found in the reference non-oiled areas, where reproductive success rates were much higher (Schwacke et al 2009). This suggests that factor(s) other than the high-normal leukocyte counts, or in addition to the leukocyte counts, may be responsible for the abnormally high reproductive failures seen in the oiled dolphin stocks.…”

Section: Discussionsupporting

confidence: 84%

“…During the CRHAs, measurements and samples were collected for a wide spectrum of diagnostic analyses including sonographic images of the lungs, measurements of mass and length, and blood samples for chemical, cell composition and endocrine analysis (Schwacke et al 2009, 2010, Hart et al 2013. Important for this study, blubber wedge biopsies were also collected from the vast majority of these animals using previously published techniques (Wells et al 2004(Wells et al , 2005.…”

Section: Ultrasound Pregnancy Evaluations and Capture-release Health mentioning

confidence: 99%

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Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015)

Kellar¹,

Speakman²,

Smith³

et al. 2017

Endang. Species. Res.

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Following the Deepwater Horizon (DWH) oil spill, reproductive success rates in 2 northern Gulf of Mexico (GoM) bottlenose dolphin stocks exposed to oil were evaluated for 4 yr during and after the spill (2010 to 2015) in efforts to assess population-level reproductive health. Pregnancy was determined from either (1) ultrasound examinations of the reproductive tract during capture-release health assessments, or (2) endocrine evaluations of blubber tissue collected from dart biopsies of free-ranging dolphins. Follow-up photo-identification was then used to track the status of pregnant females and any associated neonatal calves for a minimum of 1 yr after the initial pregnancy detection (IPD). For all pregnant females observed following IPD, individuals seen with a calf (reproductive success) and without one (reproductive failure) were recorded. The resulting estimated reproductive success rates for both GoM stocks (19.4%; 7/36) were less than a third of those previously reported in other areas not impacted by the spill (i.e. Sarasota Bay, FL; Indian River Lagoon, FL; and Charleston Harbor, SC) using similar techniques (64.7%; 22/34). We also evaluated the relationships between reproductive success and 13 potential covariates, including stock, ordinal date, progesterone, cortisol, thyroid hormone concentrations, leukocyte count, lung health score, and total body length. Among these, the results only provide strong evidence (Bayes factor > 20) of a relationship between reproductive failure and the total leukocyte count covariate. The high reproductive failure rates measured in both GoM stocks following the DWH oil spill are consistent with mammalian literature that shows a link between petroleum exposure and reproductive abnormalities and failures.

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Section: Discussionsupporting

confidence: 84%

Section: Ultrasound Pregnancy Evaluations and Capture-release Health mentioning

confidence: 99%

Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015)

Kellar¹,

Speakman²,

Smith³

et al. 2017

Endang. Species. Res.

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“…Abnormal haematological and serum biochemical conditions observed in dolphins sampled near Sapelo Island and Brunswick, GA, USA. (Parameter values were compared with reference intervals for appropriate age-and sex-class as described by Schwacke et al [22]. Prevalence calculation based on n ¼ 27 samples for haematology (haemoglobin) and n ¼ 29 for serum chemistry (all other parameters).…”

Section: Resultsmentioning

confidence: 99%

“…Haematological and serum biochemical values were compared with reference intervals for the appropriate age class established from previously sampled wild dolphin populations [22]. Appropriate reference thresholds were not available for endocrine parameters.…”

Section: (I) Comparison With Baseline Valuesmentioning

confidence: 99%

Anaemia, hypothyroidism and immune suppression associated with polychlorinated biphenyl exposure in bottlenose dolphins ( Tursiops truncatus )

et al. 2011

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Polychlorinated biphenyls (PCBs), persistent chemicals widely used for industrial purposes, have been banned in most parts of the world for decades. Owing to their bioaccumulative nature, PCBs are still found in high concentrations in marine mammals, particularly those that occupy upper trophic positions. While PCB-related health effects have been well-documented in some mammals, studies among dolphins and whales are limited. We conducted health evaluations of bottlenose dolphins (Tursiops truncatus) near a site on the Georgia, United States coast heavily contaminated by Aroclor 1268, an uncommon PCB mixture primarily comprised of octa-through deca-chlorobiphenyl congeners. A high proportion (26%) of sampled dolphins suffered anaemia, a finding previously reported from primate laboratory studies using high doses of a more common PCB mixture, Aroclor 1254. In addition, the dolphins showed reduced thyroid hormone levels and total thyroxine, free thyroxine and triiodothyronine negatively correlated with PCB concentration measured in blubber (p ¼ 0.039, , 0.001, 0.009, respectively). Similarly, T-lymphocyte proliferation and indices of innate immunity decreased with blubber PCB concentration, suggesting an increased susceptibility to infectious disease. Other persistent contaminants such as DDT which could potentially confound results were similar in the Georgia dolphins when compared with previously sampled reference sites, and therefore probably did not contribute to the observed correlations. Our results clearly demonstrate that dolphins are vulnerable to PCB-related toxic effects, at least partially mediated through the endocrine system. The severity of the effects suggests that the PCB mixture to which the Georgia dolphins were exposed has substantial toxic potential and further studies are warranted to elucidate mechanisms and potential impacts on other top-level predators, including humans, who regularly consume fish from the same marine waters.

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“…The GLMM results will determine potential stratifications for development of reference intervals, but the GLMM tests for differences in means rather than differences in the tails (95 th percentiles) of the distributions. While this may suggest a need for stratification, the final decision to stratify/partition data will be based on the bootstrap approach used by Schwacke et al (2009) for hematologic and serum biochemical reference intervals. …”

Section: Resultsmentioning

confidence: 99%

The Bottlenose Dolphin (Tursiops truncatus) as a Model to Understand Variation in Stress and Reproductive Hormone Measures in Relation to Sampling Matrix, Demographics, and Environmental Factors

Wells¹

2012

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Award Number: N0001412IP20053 / N0001411IP20085 http://coastalhealth.noaa.gov/default.aspx LONG-TERM GOALSOur overarching goal is to develop indicators and methods to quantify chronic stress in bottlenose dolphins. Much research has focused on the stimuli which induce stress in marine mammals, as well as the hormonal mediators of the stress response. Stress may be induced by a variety factors, including noise, pollutant or toxin exposure, presence of predators, loss of prey, and/or habitat changes. The stress response is complex and difficult to study experimentally in marine mammals due to ethical and logistical considerations, but has been well characterized in other laboratory mammal species. In mammals as well as other vertebrates, the stress response has two modes of operation: The fast mode involves the rapid release of fast-acting agents, such catecholamines, by the medulla which drive the fight-or-flight response, enhancing vigilance, alertness, arousal, and attention. The catecholamines in turn play a major role in excitation of the hypothalamic-pituitary-adrenal (HPA) axis, initiating a hormonal cascade which culminates in stimulation of the adrenal cortex to secrete glucocorticoids (GCs). The delayed but more sustained response driven by GCs coordinates brain and body functions to cope with stress and facilitate recovery, adaptation, and re-establishment of homeostasis. These functions include mobilization of substrates for energy metabolism, suppression of immune and inflammatory reactions, and inhibition of bone and muscle growth. Studies of both captive and freeranging individuals support the existence of these same stress response pathways in marine mammals.While the HPA axis and physiological processes driven by the GCs are essential for an individual's ability to respond and adapt to stress, prolonged stimulation can overly burden the body's regulatory systems and induce deleterious effects. Prolonged elevation of GC hormones can lead to chronic immune suppression and inhibition of other energy expending hormonal systems, including disruption of reproductive function along the hypothalamo-pituitary-gonadal axis, all of which may cumulatively lead to decreased survival and/or inability to reproduce. For this reason, developing indicators and methods to quantify chronic stress in marine mammals is essential for understanding risks and longterm consequences for populations.

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Hematologic and serum biochemical reference intervals for free-ranging common bottlenose dolphins (Tursiops truncatus) and variation in the distributions of clinicopathologic values related to geographic sampling site

Cited by 64 publications

References 41 publications

Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015)

Low reproductive success rates of common bottlenose dolphins Tursiops truncatus in the northern Gulf of Mexico following the Deepwater Horizon disaster (2010-2015)

Anaemia, hypothyroidism and immune suppression associated with polychlorinated biphenyl exposure in bottlenose dolphins ( Tursiops truncatus )

The Bottlenose Dolphin (Tursiops truncatus) as a Model to Understand Variation in Stress and Reproductive Hormone Measures in Relation to Sampling Matrix, Demographics, and Environmental Factors

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