Age Determination of Harbour Porpoise (Phocoena phocoena relicta) from the Bulgarian BlackSeaCoast

. The following research presents the results of a pilot for Bulgaria age determination of one of the three cetacean species in the Black Sea, the harbour porpoise (Phocoena phocoena relicta), based on analysis of growth layers groups (GLGs). Knowledge of age structure andlongevity (maximum age) are essential for modeling of marine mammal population dynamics. For small cetaceans, growth layers groups deposited in the teeth are most useful measure, because they indicate chronological age. Teeth were taken from 42 harbour porpoises (Ph. ph. relicta). The samples were collected from dead, stranded individuals from the Bulgarian Black Sea coast. The maximum duration of life found in this study is 10 years. The age structure shows dominance of individuals of two age groups - up to one year old and 5 years old. In the present study, no significant differences here found in the age structure in the different areas where the samples were taken, which leads to the conclusion that the age distribution of the stranded individuals Ph. ph. relicta in researched area is even.