black sea red data book - Department of Biology

Habitat type, Critical habitats, Limiting factors. In coastal waters. Young
specimens are most common near the Cystoseira and Zostera belts. The critical
habitat is the surface microlayer. Main limiting factors are the pollution of the surface
microlayer, and the reduction of the Cystoseira and Zostera biocoenoses.
Biology. A coastal pelagic carnivorous fish feeding mainly on anchovy (Engraulis
encrasicholus ponticus) and silverside (Atherina mochon pontica). Spawning occurs
from May to September. Its filament-bearing eggs, nearly 2 mm in diameter, are
attached to algae (Cystoseira) or sea grasses (Zostera). Newly hatched larvae 9-12
mm long, are intensily coloured in brown and appear like floating fragments of
Cystoseira. Young fish 5-10 cm long are green coloured, resembling floating leaves
of Zostera. Both larvae and young fish occur in the neuston layer 0-5 cm.
Population trends. A sharp decline in population numbers since the early 1980s. A
reduction of at least 50% over the last 10 years.
Threats. Pollution of the surface microlayer of water, considerable reduction of
Cystoseira and Zostera meadows, and decline in anchovy population.
Conservation measures taken. None.
Conservation measures proposed. Include in Black Sea Red Data Book. Reduce
coastal waters pollution.
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