Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark: The 13th Danish Marine Mammal Symposium

Sussie Pagh, Mariann Chriél, Abdi Hedayat, Thorkild Alnor Nielsen, Mette Sif Hansen

Research output: Contribution to conference without publisher/journalPosterResearch

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Abstract

Age determination of sperm whales (Physeter macrocephalus) by counting growth layer groups (GLG´s) in the teeth is to some extent considered to be subjective and only relative, due to: 1) Limited validation of GLG counts to “known age” of the individual; 2) Variation in methods for preparation of teeth e.g. acid (pH) and duration of etching; 3) Difference in interpretations of GLG´s between readers1,2. Bearing in mind these challenges, the age of three sperm whales stranded in Denmark in 2012 and 2014 were determined by counts of GLG´s in the erupted teeth from the lower jaw and comparing these with the number of GLG´s obtained from rudimentary teeth in the upper jaw.

Teeth were obtained from 3 adult male sperm whales; MCE 1642, stranded at Nr. Lyngby Strand, Denmark in 2012; and MCE 1644 and MCE 1645, who stranded at Henne Strand, Denmark in 2014. From each whale one non-erupted tooth from the maxilla and one erupted mandibular tooth was cut longitudinally in two half´s with a diamond blade saw and grained with sandpaper gain 800. One half of each tooth was etched in 10% acetic acid for 7 hours and the other half was etched in 15% acetic acid for 3.5 hours. The GLG´s were counted several times by two readers.
Based on counting of GLG´s the average estimated ages of the three sperm whales were between 29 and 39 years. However, some deviation due to intra- and inter reader differences was observed. The number of GLG´s in the rudimentary teeth did not differ significantly from the GLG´s of the mandibular teeth. Pulp stones were seen in both erupted and non-erupted teeth from all three whales.

Further studies are needed to develop the current preparation techniques to make clear and more easily readable GLG´s to obtain more accurate age determination of sperm whales.
Original languageEnglish
Publication date2016
Number of pages1
Publication statusPublished - 2016
Externally publishedYes
EventThe 13th Danish Marine Mammal Symposium - , Denmark
Duration: 4 Mar 20165 Mar 2016
Conference number: 13th

Conference

ConferenceThe 13th Danish Marine Mammal Symposium
Number13th
CountryDenmark
Period04/03/201605/03/2016

Cite this

Pagh, S., Chriél, M., Hedayat, A., Nielsen, T. A., & Hansen, M. S. (2016). Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark: The 13th Danish Marine Mammal Symposium. Poster presented at The 13th Danish Marine Mammal Symposium, Denmark.
Pagh, Sussie ; Chriél, Mariann ; Hedayat, Abdi ; Nielsen, Thorkild Alnor ; Hansen, Mette Sif. / Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark : The 13th Danish Marine Mammal Symposium. Poster presented at The 13th Danish Marine Mammal Symposium, Denmark.1 p.
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title = "Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark: The 13th Danish Marine Mammal Symposium",
abstract = "Age determination of sperm whales (Physeter macrocephalus) by counting growth layer groups (GLG´s) in the teeth is to some extent considered to be subjective and only relative, due to: 1) Limited validation of GLG counts to “known age” of the individual; 2) Variation in methods for preparation of teeth e.g. acid (pH) and duration of etching; 3) Difference in interpretations of GLG´s between readers1,2. Bearing in mind these challenges, the age of three sperm whales stranded in Denmark in 2012 and 2014 were determined by counts of GLG´s in the erupted teeth from the lower jaw and comparing these with the number of GLG´s obtained from rudimentary teeth in the upper jaw.Teeth were obtained from 3 adult male sperm whales; MCE 1642, stranded at Nr. Lyngby Strand, Denmark in 2012; and MCE 1644 and MCE 1645, who stranded at Henne Strand, Denmark in 2014. From each whale one non-erupted tooth from the maxilla and one erupted mandibular tooth was cut longitudinally in two half´s with a diamond blade saw and grained with sandpaper gain 800. One half of each tooth was etched in 10{\%} acetic acid for 7 hours and the other half was etched in 15{\%} acetic acid for 3.5 hours. The GLG´s were counted several times by two readers.Based on counting of GLG´s the average estimated ages of the three sperm whales were between 29 and 39 years. However, some deviation due to intra- and inter reader differences was observed. The number of GLG´s in the rudimentary teeth did not differ significantly from the GLG´s of the mandibular teeth. Pulp stones were seen in both erupted and non-erupted teeth from all three whales. Further studies are needed to develop the current preparation techniques to make clear and more easily readable GLG´s to obtain more accurate age determination of sperm whales.",
author = "Sussie Pagh and Mariann Chri{\'e}l and Abdi Hedayat and Nielsen, {Thorkild Alnor} and Hansen, {Mette Sif}",
year = "2016",
language = "English",
note = "The 13th Danish Marine Mammal Symposium ; Conference date: 04-03-2016 Through 05-03-2016",

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Pagh, S, Chriél, M, Hedayat, A, Nielsen, TA & Hansen, MS 2016, 'Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark: The 13th Danish Marine Mammal Symposium' The 13th Danish Marine Mammal Symposium, Denmark, 04/03/2016 - 05/03/2016, .

Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark : The 13th Danish Marine Mammal Symposium. / Pagh, Sussie; Chriél, Mariann; Hedayat, Abdi; Nielsen, Thorkild Alnor; Hansen, Mette Sif.

2016. Poster presented at The 13th Danish Marine Mammal Symposium, Denmark.

Research output: Contribution to conference without publisher/journalPosterResearch

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T1 - Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark

T2 - The 13th Danish Marine Mammal Symposium

AU - Pagh, Sussie

AU - Chriél, Mariann

AU - Hedayat, Abdi

AU - Nielsen, Thorkild Alnor

AU - Hansen, Mette Sif

PY - 2016

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N2 - Age determination of sperm whales (Physeter macrocephalus) by counting growth layer groups (GLG´s) in the teeth is to some extent considered to be subjective and only relative, due to: 1) Limited validation of GLG counts to “known age” of the individual; 2) Variation in methods for preparation of teeth e.g. acid (pH) and duration of etching; 3) Difference in interpretations of GLG´s between readers1,2. Bearing in mind these challenges, the age of three sperm whales stranded in Denmark in 2012 and 2014 were determined by counts of GLG´s in the erupted teeth from the lower jaw and comparing these with the number of GLG´s obtained from rudimentary teeth in the upper jaw.Teeth were obtained from 3 adult male sperm whales; MCE 1642, stranded at Nr. Lyngby Strand, Denmark in 2012; and MCE 1644 and MCE 1645, who stranded at Henne Strand, Denmark in 2014. From each whale one non-erupted tooth from the maxilla and one erupted mandibular tooth was cut longitudinally in two half´s with a diamond blade saw and grained with sandpaper gain 800. One half of each tooth was etched in 10% acetic acid for 7 hours and the other half was etched in 15% acetic acid for 3.5 hours. The GLG´s were counted several times by two readers.Based on counting of GLG´s the average estimated ages of the three sperm whales were between 29 and 39 years. However, some deviation due to intra- and inter reader differences was observed. The number of GLG´s in the rudimentary teeth did not differ significantly from the GLG´s of the mandibular teeth. Pulp stones were seen in both erupted and non-erupted teeth from all three whales. Further studies are needed to develop the current preparation techniques to make clear and more easily readable GLG´s to obtain more accurate age determination of sperm whales.

AB - Age determination of sperm whales (Physeter macrocephalus) by counting growth layer groups (GLG´s) in the teeth is to some extent considered to be subjective and only relative, due to: 1) Limited validation of GLG counts to “known age” of the individual; 2) Variation in methods for preparation of teeth e.g. acid (pH) and duration of etching; 3) Difference in interpretations of GLG´s between readers1,2. Bearing in mind these challenges, the age of three sperm whales stranded in Denmark in 2012 and 2014 were determined by counts of GLG´s in the erupted teeth from the lower jaw and comparing these with the number of GLG´s obtained from rudimentary teeth in the upper jaw.Teeth were obtained from 3 adult male sperm whales; MCE 1642, stranded at Nr. Lyngby Strand, Denmark in 2012; and MCE 1644 and MCE 1645, who stranded at Henne Strand, Denmark in 2014. From each whale one non-erupted tooth from the maxilla and one erupted mandibular tooth was cut longitudinally in two half´s with a diamond blade saw and grained with sandpaper gain 800. One half of each tooth was etched in 10% acetic acid for 7 hours and the other half was etched in 15% acetic acid for 3.5 hours. The GLG´s were counted several times by two readers.Based on counting of GLG´s the average estimated ages of the three sperm whales were between 29 and 39 years. However, some deviation due to intra- and inter reader differences was observed. The number of GLG´s in the rudimentary teeth did not differ significantly from the GLG´s of the mandibular teeth. Pulp stones were seen in both erupted and non-erupted teeth from all three whales. Further studies are needed to develop the current preparation techniques to make clear and more easily readable GLG´s to obtain more accurate age determination of sperm whales.

M3 - Poster

ER -

Pagh S, Chriél M, Hedayat A, Nielsen TA, Hansen MS. Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark: The 13th Danish Marine Mammal Symposium. 2016. Poster presented at The 13th Danish Marine Mammal Symposium, Denmark.