Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium
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 te...
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ftdtupubl:oai:pure.atira.dk:publications/52b9b397-a3ec-4de0-a59e-cd24c3d195b4 2023-05-15T17:59:23+02:00 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 application/pdf https://orbit.dtu.dk/en/publications/52b9b397-a3ec-4de0-a59e-cd24c3d195b4 https://backend.orbit.dtu.dk/ws/files/127501385/Age_determination.pdf eng eng info:eu-repo/semantics/openAccess 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 ' , 13th Danish Marine Mammal Symposium , Kastrup , Denmark , 04/03/2016 - 05/03/2016 . /dk/atira/pure/sustainabledevelopmentgoals/life_below_water SDG 14 - Life Below Water conferenceObject 2016 ftdtupubl 2022-08-14T08:26:37Z 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. Conference Object Physeter macrocephalus Technical University of Denmark: DTU Orbit |
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collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
topic |
/dk/atira/pure/sustainabledevelopmentgoals/life_below_water SDG 14 - Life Below Water |
spellingShingle |
/dk/atira/pure/sustainabledevelopmentgoals/life_below_water SDG 14 - Life Below Water 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 |
topic_facet |
/dk/atira/pure/sustainabledevelopmentgoals/life_below_water SDG 14 - Life Below Water |
description |
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. |
format |
Conference Object |
author |
Pagh, Sussie Chriél, Mariann Hedayat, Abdi Nielsen, Thorkild Alnor Hansen, Mette Sif |
author_facet |
Pagh, Sussie Chriél, Mariann Hedayat, Abdi Nielsen, Thorkild Alnor Hansen, Mette Sif |
author_sort |
Pagh, Sussie |
title |
Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium |
title_short |
Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium |
title_full |
Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium |
title_fullStr |
Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium |
title_full_unstemmed |
Age determination of sperm whales (Physeter macrocephalus) from the west coast of Jutland, Denmark:The 13th Danish Marine Mammal Symposium |
title_sort |
age determination of sperm whales (physeter macrocephalus) from the west coast of jutland, denmark:the 13th danish marine mammal symposium |
publishDate |
2016 |
url |
https://orbit.dtu.dk/en/publications/52b9b397-a3ec-4de0-a59e-cd24c3d195b4 https://backend.orbit.dtu.dk/ws/files/127501385/Age_determination.pdf |
genre |
Physeter macrocephalus |
genre_facet |
Physeter macrocephalus |
op_source |
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 ' , 13th Danish Marine Mammal Symposium , Kastrup , Denmark , 04/03/2016 - 05/03/2016 . |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766168190828675072 |