Dataset Information

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

ABSTRACT: Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics. The most frequently utilized methods to age bottlenose dolphins (Tursiops truncatus) include tooth extraction; counting dental growth layer groups and dental radiography. These methods are inaccurate in dolphins > 13 years old, due to overlapping of the growth layer groups in dolphins and worn teeth. Establishing a non-invasive method of accurately aging bottlenose dolphins across the entire age range is important to long term conservation efforts to understand health status, lifespan, reproduction and survivability. A database of 126 radiographs from 94 dolphins of known chronological age was utilized to establish the stages of skeletal ossification over time. A numerical score from -1 to 8 was assigned to 16 anatomic locations on the pectoral radiograph, to create a formula to estimate age. The most informative areas to evaluate morphologically were the metaphyseal regions of the radius and ulna, and the proximal and distal epiphysis of metacarpals II and III. Third order polynomial regression calculated separate age predictor formulas for male and female dolphins, with females reaching sexual maturity earlier than males. Completion of epiphyseal closure of the long bones correlated with average sexual maturity. Managed care dolphin ages could be properly estimated with decreasing precision from within 3 months in animals < 5 years old, to within 5 years in animals > 30 years old. This diagnostic tool could also be applied to diagnose atypical ossification patterns consistent with nutritional, developmental or growth abnormalities, and identifying subclinical health issues. In conclusion, knowledge of the lifespan and the onset of sexual maturity for each species will allow this model to be applied to other cetaceans, facilitating age estimation via pectoral radiography in future research.

SUBMITTER: Barratclough A

PROVIDER: S-EPMC6762177 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

Barratclough Ashley A Sanz-Requena Roberto R Marti-Bonmati Luis L Schmitt Todd L TL Jensen Eric E García-Párraga Daniel D

PloS one 20190926 9

Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics. The most frequently utilized methods to age bottlenose dolphins (Tursiops truncatus) include tooth extraction; counting dental growth layer groups and dental radiography. These methods are inaccurate in dolphins > 13 years old, due to overlapping of the growth layer groups in dolphins and worn teeth. Esta ...[more]

PMID: 31557197

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Project description:In recent decades, animal welfare science has evolved to utilize a multidisciplinary approach to assess the welfare of animals in accredited zoos and aquariums. Science-based animal welfare assessments have become an essential component of management programs and widespread application is expected by animal care professionals. Management practices for bottlenose dolphins in accredited facilities incorporate several programs that potentially impact animal welfare including environmental enrichment and animal training. Additionally, habitat characteristics, such as the dimensions of the habitat, have been proposed to affect welfare. While accredited facilities are required to meet high standards of care, habitat characteristics and management practices are not standardized across locations. Knowledge and subsequent application of these practices and habitat characteristics can enhance our understanding of factors associated with positive welfare. As part of a larger study of dolphin welfare titled "Towards understanding the welfare of cetaceans in zoos and aquariums" (colloquially called the Cetacean Welfare Study), survey data were collected from 86 bottlenose dolphins in 40 habitats at 38 facilities in seven countries. The major aims of this paper are to provide general descriptive information regarding dolphin management in accredited zoos and aquariums and to provide supplemental context to the other research published from the Cetacean Welfare Study data set. This paper provides a review of current habitat characteristics and management practices at those 38 accredited zoos and aquariums. These data enabled the identification and quantification of how cetacean management practices differed between participating facilities accredited by the Alliance for Marine Mammal Parks and Aquariums and the Association of Zoos & Aquariums. Variables were selected based on their potential association with welfare including the physical habitat, environmental enrichment, and training programs. The variables were also used for subsequent research in this collection of related papers to investigate important connections between potential indicators of welfare and habitat characteristics, environmental enrichment, and training programs.

Project description:As apex predators, cetaceans are recognized as sentinels for the health of marine ecosystems. The ability to identify the impacts of anthropogenic contamination on the health of a species requires long term monitoring to establish baseline health parameters. This makes health measurements that can be sampled from free ranging animals highly desirable. In the current study, we investigate the utility of skin gene expression profiling to monitor the physiological, health, and contaminant exposure status in bottlenose dolphins. Remote integument biopsies were obtained from bottlenose dolphins at three locations in the northern Gulf of Mexico prior to oil exposure (May 2010) and during summer and winter of the two years (2010-2011) following their exposure to oil from the Deepwater Horizon oil spill. A bottlenose dolphin-specific oligonucleotide microarray was used to characterize the skin transcriptomes of 94 individuals from three genetically distinguishable populations in Barataria Bay, Louisiana, Chandeleur Sound, Louisiana, and Mississippi Sound, Mississippi. Location did not significantly affect the transcriptome patterns of the dolphins included in the study. In contrast, season had a profound effect on gene expression, with nearly one-third of all genes on the array differing significantly in expression between winter and the warmer seasons (p<0.01, fold-change >1.5). Gene ontology enrichment analysis revealed that processes related to cell proliferation, motility and differentiation dominated the seasonal differences in expression, which likely reflects the differences in ambient temperature to which the skin is exposed, and possibly changes in blood flow. More subtle differences were seen between spring and summer transcriptomes (1.5% differentially expressed), with two presumed oil-exposed animals presenting gene expression profiles more similar to the summer (exposed) animals than the other spring animals. Xenobiotic pathway components also showed some seasonal trends, which may reflect crosstalk between xenobiotic pathways and those regulating corticoids, hormones, and cytokines. Seasonal effects have not previously been considered in studies assessing gene expression in cetaceans, but clearly must be taken into account when applying transcriptomic analyses to investigate their exposure or health status.

Dataset Information

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

Publications

Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age.

Similar Datasets

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