Pelagic larvae of Black Sea polychaeta

Pelagic larvae of 22 species of Polychata representing 21 genera and 14 families were identified from about 800 meroplanktonic samples collected in the coastal zone and open part of the Black Sea throughout 1984-1994. Five ecological groups were distinguished: (I) warm-water, short-distance, neritic epipelagic species (Lysidice ninetta); (2) cold-water, longdistance neritic epipelagic species (Harmothoe imbricata); (3) eurythermic, long-distance, neritic epipelagic species (Polydora ciliata); (4) warm-water, long-distance, neritic epipelagic species (Neanthes succinea) and (5) cold-water, teleplanic bathypelagic species (Victorniella zaikai). H. imbricata larvae extended from the coastal waters of Crimea to the strait of the Bosphorus. Their nectochaetes were found in the coastal water and also in the open sea at a distance 144 km from a coast. N. succinea larvae occurred very frequently in the northwestern part with the highest density 135 ind·m-3 . V.zaikai larvae was widely distributed in the Black Sea inhabiting the deeper layers of water (50-250 m). They are able to exist close to the anaerobic zone at a hydrogen sulfide concentration of 0.25 mHiter-1 and an oxygen minimum of 0.06 ml·liter1