摘要：

A total of 1,268 harbour porpoises were obtained from fishing nets in Icelandic coastal waters from September to June in the years 1991 to 1997. Foetal sex ratio was 1.2:1 (male:female). The <span style="font-size: 10px;">bias towards males increased further among older animals in the present collection. The modal <\\\\/span><span style="font-size: 10px;">year classes were 0 and 1 years but the oldest porpoise was a female estimated at 20 years of age. <\\\\/span><span style="font-size: 10px;">Length at birth was estimated as approximately 75 cm, and females grew faster and attained larger <\\\\/span><span style="font-size: 10px;">sizes than males. Asymptotic length was 149.6 cm for males and 160.1 cm for females. Estimated <\\\\/span><span style="font-size: 10px;">age and length at sexual maturity was 1.9 to 2.9 years and 135 cm for males and 2.1 to 4.4 years <\\\\/span><span style="font-size: 10px;">and 138 to 147 cm for females. Immature individuals were significantly shorter than pubertal and <\\\\/span><span style="font-size: 10px;">mature animals in both sexes in age classes 1 to 3. Testes weight increased only slightly with body <\\\\/span><span style="font-size: 10px;">size in immature males but increased rapidly around maturity. Pronounced seasonality was also<\\\\/span><\\\\/div>observed in testes weight, indicating a peak in testes activity in summer. Lack of data from the <span style="font-size: 10px;">summer makes the exact timing of parturition and mating unknown. Births do, however, most <\\\\/span><span style="font-size: 10px;">likely peak in June and July and lactation lasts at least 7 to 8 months. Ovulation and pregnancy <\\\\/span><span style="font-size: 10px;">rates were 0.98.<\\\\/span><\\\\/div>

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