Reproductive biology of male common dolphins ( Delphinus delphis ) in New Zealand waters.

Autor: Palmer EI; Cetacean Ecology Research Group, School of Natural Sciences, Massey University, 0745 Auckland, New Zealand., Betty EL; Cetacean Ecology Research Group, School of Natural Sciences, Massey University, 0745 Auckland, New Zealand., Murphy S; Marine and Freshwater Research Centre, Department of Natural Resources & the Environment, School of Science and Computing, Atlantic Technological University, ATU Galway City, Old Dublin Road, Galway, H91 T8NW Ireland., Perrott MR; School of Veterinary Sciences, Massey University, Palmerston North, New Zealand., Smith ANH; School of Mathematical and Computational Sciences, Massey University, 0745 Auckland, New Zealand., Stockin KA; Cetacean Ecology Research Group, School of Natural Sciences, Massey University, 0745 Auckland, New Zealand.
Jazyk: angličtina
Zdroj: Marine biology [Mar Biol] 2023; Vol. 170 (12), pp. 153. Date of Electronic Publication: 2023 Oct 06.
DOI: 10.1007/s00227-023-04266-5
Abstrakt: Reproductive parameters were assessed in 64 male common dolphins ( Delphinus delphis ) examined post-mortem from strandings and bycatch in New Zealand between 1999 and 2020. The stages of male sexual maturation were assessed using morphological measurements and histological examination of testicular tissue. Age was determined via growth layer groups (GLGs) in teeth. The average age (ASM) and length (LSM) at attainment of sexual maturity were estimated to be 8.8 years and 198.3 cm, respectively. Individual variation in ASM (7.5-10 years) and LSM (190-220 cm) was observed in New Zealand common dolphins. However, on average, sexual maturity was attained at a similar length but at a marginally younger age (< 1 year) in New Zealand compared to populations in the Northern Hemisphere. All testicular variables proved better predictors of sexual maturity compared to demographic variables (age and total body length), with combined testes weight the best outright predictor of sexual maturity. Reproductive seasonality was observed in male common dolphins, with a significant increase in combined testes weight in austral summer. This aligns with most other studied populations, where seasonality in reproduction is typically observed. Given the known anthropogenic impacts on New Zealand common dolphins, we recommend that these findings be used as a baseline from which to monitor population-level changes as part of conservation management efforts.
Supplementary Information: The online version contains supplementary material available at 10.1007/s00227-023-04266-5.
Competing Interests: Conflict of interestThe authors declare that there is no conflict of interest.
(© The Author(s) 2023.)
Databáze: MEDLINE
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