Life History Traits of Sperm Whales Physeter macrocephalus Linnaeus, 1758 Stranded along Italian Coasts (Cetartiodactyla: Physeteridae)

• Published in: Animals
• Main Authors: Maio, Nicola, Fioravanti, Tatiana, Latini, Lucrezia, Petraccioli, Agnese, Mezzasalma, Marcello, Cozzi, Bruno, Mazzariol, Sandro, Podestà, Michela, Insacco, Gianni, Pollaro, Francesco, Lucifora, Giuseppe, Ferrandino, Ida, Zizzo, Nicola, Spadola, Filippo, Garibaldi, Fulvio, Guarino, Fabio Maria, Splendiani, Andrea, Caputo Barucchi, Vincenzo
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Italian sea; age at sexual maturity; age estimation; cetacea; geographic origin; odontocetes; Physeter macrocephalus; Sperm whale
• Online Access: https://hdl.handle.net/11566/315894; https://doi.org/10.3390/ani13010079

Simple Summary Several life-history traits of Mediterranean sperm whales are little explored. We present new original data on the relationships between age and body length and age at maturity of individuals stranded along the Italian coast. We found that Mediterranean male sperm whales attain sexual maturity at 10 years and for the same body length class are older than Atlantic ones. Our finding of a Mediterranean pregnant female of only 6.5 m of body length and an assessed age of 24-26 years is particularly noteworthy, as the females of this species reach sexual maturity at about 9 meters total length and 9 years of age in other marine areas. Two different hypotheses can be advanced to explain this difference in size, based on either ecological or genetic factors. The first is based on a lesser energy intake of Mediterranean individuals compared to Atlantic ones, mostly due to a smaller prey size and less trophic conditions. The second hypothesis concerns a low genetic diversity and mating among closely related individuals. Considering its low genetic diversity, the Mediterranean sperm whale population should be the target of focused conservation efforts as it might be relatively less responsive to environmental changes. We investigated the relationship between age and body length, and age at sexual maturity of Physeter macrocephalus individuals stranded along the Italian coast. Our molecular analysis shows that all our samples belong to the C.001.002 haplotype, shared between Atlantic and Mediterranean populations. We show that males attain sexual maturity at 10 years, similar to those from other marine areas. However, considering the same body length class, Mediterranean males are older than Atlantic ones. Our finding of a Mediterranean pregnant female of only 6.5 m in length and an assessed age of 24-26 years is particularly noteworthy, considering that females reach sexual maturity at about 9 years and 9 m of total length in other regions. Comparing our results with the literature data, we highlight the ...