Abstract:

The most frequently used 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, or worn teeth. A non-invasive accurate method of aging free ranging dolphins would improve interpretation of biological health data. A database of 126 radiographs from 93 dolphins, in managed care, of known chronological age, was utilized to establish the stages of skeletal maturation 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. Ages could be estimated to within 3 months in animals < 5 years old, within 2 years between 5 and 30 years, and within 5 years in animals > 30 years old. This method can be applied to free ranging dolphins during health assessments to accurately estimate their age. This dataset supports the publication: Barratclough, A., Sanz-Requena, R., Marti-Bonmati, L., Schmitt, T. L., Jensen, E., & García-Párraga, D. (2019). Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age. PLOS ONE, 14(9), e0222722. doi:10.1371/journal.pone.0222722

Suggested Citation:

Barratclough, Ashley, Roberto Sanz-Requena, Luis Marti-Bonmati, Todd L. Schmitt, Eric Jensen and Daniel García-Párraga. 2019. Radiographic assessment of pectoral fin bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/B35TPMPA

Publications:

Barratclough, A., Sanz-Requena, R., Marti-Bonmati, L., Schmitt, T. L., Jensen, E., & García-Párraga, D. (2019). Radiographic assessment of pectoral flipper bone maturation in bottlenose dolphins (Tursiops truncatus), as a novel technique to accurately estimate chronological age. PLOS ONE, 14(9), e0222722. doi:10.1371/journal.pone.0222722

Purpose:

Accurate age estimation in wildlife conservation is an important diagnostic tool in the interpretation of biological data, necropsy examination, reproductive status and population demographics. Establishing a non-invasive method of accurately ageing bottlenose dolphins across the entire age range is important to long-term conservation efforts to understand health status, lifespan, reproduction and survivability. This diagnostic tool could also be applied to diagnose atypical ossification patterns consistent with nutritional disorders or growth abnormalities, identifying subclinical health issues. Knowledge of the lifespan of the cetacean and the onset of sexual maturity may allow this model to be applied to other cetacean species, to facilitate age estimation via pectoral radiography in future research.

Data Parameters and Units:

Radiograph Identification Number Male or Female Age in Years. Negative ages indicate aborted cases. In some older animals, estimates are provided. Age in Months. Negative ages indicate aborted cases. In some older animals, age in months is not calculated. Bone density score for the radius (-1-8) Bone density score for the ulna (-1-8) Bone density score for the proximal second metacarpal (-1-8) Bone density score for the distal second metacarpal (-1-8) Bone density score for the proximal first phalanx of the second metacarpal (-1-8) Bone density score for the distal first phalanx of the second metacarpal (-1-8) Bone density score for the second phalanx of the second metacarpal (-1-8) Bone density score for the proximal third metacarpal (-1-8) Bone density score for the distal third metacarpal (-1-8) Bone density score for the proximal first phalanx of the third metacarpal (-1-8) Bone density score for the distal first phalanx of the third metacarpal (-1-8) Bone density score for the second phalanx of the third metacarpal (-1-8) Bone density score for the proximal fourth metacarpal (-1-8) Bone density score for the distal fourth metacarpal (-1-8) Bone density score for the first phalanx of the fourth metacarpal (-1-8) Bone density score for the fifth metacarpal (-1-8)

Methods:

A database of 126 radiographs from 93 dolphins, in managed care, of known chronological age, was utilized to establish the stages of skeletal maturation 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 definitions for the scoring system are provided in the worksheet and an example radiograph is provided.

Provenance and Historical References:

This dataset was initially published on 2019-09-11 and was revised again on 2020-04-05. The dataset now includes both the original (Pectoral.bone.density_version1-published_20190911xlsx) file as well as the revised version (Pectoral.bone.density_20200405) including the image (Scoring Locations.pdf) showing 16 anatomic locations on the pectoral radiograph.

Individual Files: