Reproductive seasonality and maturity of male Neophocaena phocaenoides asiaeorientalis in captivity: A case study based on the hormone evidence

Authors: Daoquan, Chen¹; Yujiang, Hao²; Qingzhong, Zhao¹; Ding, Wang¹

Source: Marine and Freshwater Behaviour and Physiology, Volume 39, Number 2, June 2006 , pp. 163-173(11)

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Abstract:

To provide hormone evidence on reproductive seasonality and maturity of the Yangtze finless porpoise, the authors monitored the monthly variations of serum reproductive hormones of a male Yangtze finless porpoise in captivity via radioimmunoassay from 1997 to 2003. It was demonstrated that the immature animal had a serum T level of 28–101ngdL −1 (65±52ngdL −1 ), reached puberty with the serum T concentration ranging between 250 and 590ngdL −1 (390±130ngdL −1 ), and attained reproductive maturity when the serum T level went beyond 1120±180ngdL −1 in the breeding season. The body length growth of the animal showed a pattern similar to the serum T variations during its adolescent period from the age of 4 to 6 years. Moreover, the serum T concentration of the male porpoise exhibited significant seasonal variations, indicating that its breeding season may start as early as March and end as late as September.

Keywords: Yangtze finless porpoise; Neophocaena phocaenoides asiaeorientalis; testosterone; maturity; seasonality

Document Type: Research article

DOI: http://dx.doi.org/10.1080/10236240600563396

Affiliations: 1: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China 2: Graduate School of Chinese Academy of Sciences, Beijing 100039, China

Publication date: 2006-06-01