black sea red data book - Department of Biology

important breeding, calving and feeding areas for the Black Sea population, isolated
from the nearest one in the North-East Atlantic. On the other hand, the Azov and
Marmara Seas and their straits are critical habitats because of heavy boat traffic,
extensive fisheries and water pollution there. Severe, but infrequent natural
phenomena limiting the Black Sea population are: (a) mass mortality due to lung
worm infection (nematodes, Halocercus taurica and H. ponticus); and (b) kills as a
result of sudden ice formation in the Sea of Azov before animals can migrate back to
the Black Sea.
Biology. A relatively short-lived marine mammal with a high individual fecundity
relative to other Black Sea cetaceans. Both males and females attain sexual maturity
after 3-4 years. Mating mainly in summer; females become pregnant almost annually,
with a gestation period of 9-11 months and usually the birth of one calf between May
and early August. After lactation (4-6 months) the young adopt a basic diet of small
benthic (various goby species) and mass pelagic (anchovy, atherine) fish. The daily
ration of an adult animal is 3-5 kg. The life-span of Black Sea P. phocoena is not
clear, and is perhaps similar to that of their relatives in the North Atlantic -c. 7-8,
maximum 15 years. P. phocoena is the smallest cetacean of the Black Sea: its
average body length is 1.3 to 1.5 m, maximum 1.8 m; average weight approximates
30 kg. Females are slightly larger than males.
Population trends. Between 1930 and 1980, the population was strongly affected by
mass commercial killing. Subsequent estimates of abundances made by Soviet and
Turkish scientists (1967-1989) were declared unreliable by the TWC Scientific
Committee because of a faulty methodology for observation and extrapolation. At
present both the animal numbers and population trends are unknown. According to
recent sightings off the Bulgarian, Georgian, Romanian, and Ukrainian (Crimea)
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