black sea red data book - Department of Biology

Crimea in autumn, but migratory routes should be studied more thoroughly, including,
in particular, the Turkish strait system - the single possible route for genetic exchange
between Black Sea and Mediterranean Sea populations. The Kerch Strait, Bosphorus,
and contiguous waters are the most critical places for cetacean movements because of
strong antropogenic pressure, caused by a variety of activities. The peculiarities of
bottlenose dolphin reproduction mentioned below seem to be the main natural factor
limiting population growth.
Biology. The biggest (up to 3.3 m long) Black Sea cetacean, with a long life span
(about 25-30 years) and low fertility. Females become mature earlier (after 5-6,
maximum 12 years) than males (8-12 years). Sexual behaviour during the whole
year, with a peak in spring-early summer. The 12-months gestation periods take turns
with barren intervals from 2-3 to six years. Usually one calf. Lactation varies from
four months to 1.5 year. Most benthic and pelagic fish species, both small and big,
are suitable prey, including Black Sea scad, herring, anchovy, whiting, turbot, grey
and striped mullet, red mullet, bonito, etc. In recent years the acclimatized Far East
mullet (Mugil so-iuy) has become its preferred prey during migrations off the Crimea.
Each dolphin consumes 6-32 kg of fish per day.
Population trends. The bottlenose population was always estimated as smaller than
that of the other Black Sea cetacean. In the 20th century, up to the early 1980s, it was
reduced by mass kills by the dolphin-processing industry which was highly developed
in the USSR and Turkey. Currently, there are no strict scientific data on population
abundance.
Threats. Incidental catching in fishing nets; disturbance caused by extensive
cabotage traffic; habitat limitation as a result of chronic pollution and artificial
freshening of former feeding areas, e.g. Karkinit Bay in Ukraine. Since the 1960s
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