Reproductive timing in Eurasian otters on the coast of Norway

• Published in: Ecography
• Main Authors: Heggberget, Thrine Moen, Christensen, Hanne
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1994
• Subjects: Northern coast of Norway
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1994.tb00111.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1994.tb00111.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1994.tb00111.x

The seasonal distribution of reproductive phases in female otters and the recruitment of cubs were studied by using information from carcasses collected along the central and northern coast of Norway Relationships between available prey and female body condition were investigated Conception, partuntion and rearing of cubs, at least up to the age of 5–6 months, occurred successfully at all times of the year However, the main birth peak occurred in summer and autumn The frequency of all phases of the breeding cycle, from follicle enlargement to early stages of cub rearing, vaned consistently between seasons Food availability when the cubs were c 2 months old, and energetic demands on the female assumed to be greatest, was probably the main ultimate cause of the seasonal vananon in the recruitment of cubs Intrautenne mortality, possibly due to the seasonal vanation in body condition of females, and loss of litters, may have been important mechanisms in creaung the seasonal recruitment patterns Although the prey biomass on average showed seasonal vanation, the peak season shifted among years and locations It is argued that the availability of suitable prey for otters tend to be unrelated to the seasonal productivity in aquatic environments, due to species–specific growth and behavior of prey and restnctions on the hunting capability of otters Continuous reproduction with seasonal vanation in birth rates may have been maintained by selection for reproductive riskreduction in a nutritionally unpredictable, although generally seasonal, environment