AGE AT SEXUAL MATURITY AND PREGNANCY RATES OF HARBOR PORPOISES PHOCOENA-PHOCOENA FROM THE BAY OF FUNDY

Estimates of sexual maturity ranged from 3.15-3.44 yr; few individuals >7 yr of age were present in the sample. Mean age at first pregnancy was 3.76 yr. Pregnancy rate was estimated: 1) considering the entire sample and using the presence of a corpus luteum as indicative of pregnancy, and 2) by considering the sample collected after implantation and using the presence of a foetus as the criterion of pregnancy. Estimated pregnancy rates using these methods were 0.86 and 0.74, respectively. Many young females failed to conceive in their 1st year or two of sexual maturity, but most older females in the sample were pregnant. These high pregnancy rates are indicative of annual reproduction in this population. -from Author