Flatfish, flounder, halibut, mud flounder, plie, southern fluke; Spanish: lenguado de Floride.
The body is very high. Scales are absent. The mouth is large. There are sharp bony spines with swollen bases in the skin. Lateral line with 85-86 apertures. D - 60-70, A - 45-52, P - 10-13. Coloration of blind side of body is light. The ocular side of both adults and juveniles may be sandy-yellow with white or dark brown spots of irregular shape.
Widespread in the Black Sea and the Sea of Azov, noted in the Bosphorus, the eastern part of the Mediterranean Sea and in the Adriatic Sea
Sea bottom fish that burrows into the ground. Adult fish live on shell, sand, mud and sandy soils at depths of up to 100 meters. Juveniles stay on sandbanks at depths of up to 10 meters.
Spawning lasts from late March to the second half of June. It takes place in the evening at a depth of 20-60 meters at a water temperature of 10-10.5 degrees Celsius. Mass spawning takes place in April-May. The fecundity ranges from 1.2 to 24.9 million eggs. The average fecundity is 6 million eggs. Spawning is portion. One batch has an average of 600-700 thousand eggs.
The eggs are pelagic and spherical in shape. Embryonic development occurs at a temperature of 15.6 - 16.6 degrees Celsius and lasts 3.5 - 4 days. The larvae are about 3 millimeters long, and the body is transparent and symmetrical. Larvae are kept in the upper layers of water. When they are 25-30 millimeters long, they acquire the shape of an adult and switch to a benthic way of life. At the age of 4-5 days, larvae develop a mouth, but they still have poor eyesight and move very slowly. During this period, which is called critical, 20-25 out of 500 larvae survive. The rest die from predators and starvation.
Fifteen to twenty days after hatching from the eggs, the larvae turn into fry and settle to the bottom. By autumn, 5-6 young kalcans survive, with a body length of 6-7 cm.
The most rapid growth is noted in the first three years of life. The maximum growth is at the age of sexual maturity. Males become sexually mature at the age of 4-6 years, females - 6-8 years. Length up to 85 centimeters, weight 8.6 kg, the maximum age - 16 years. Males are smaller than females.
For the first two months of life, the larvae live a pelagic life in the open sea. When fry reach a length of 5-6 centimeters, they emerge in August in shallow coastal areas of the sea at depths of 2-10 meters. They live as such for two to three months. Yearlings and two-yearlings are found at a depth of 15-25 meters. Adult skuas form isolated local herds. When the temperature rises to 5-8 degrees Celsius in the spring, they approach the shore. In summer, after spawning, retreats to deeper waters. Overwinters at depths of 15-100 meters.
Kalkan is caught by fixed nets and longlines. The commercial catches are dominated by individuals 5-10 years old.
|Conservation status||Least Concern|
|Life span, years||50|
|Maximum body weight, kg||7|
|Maximum length, cm||100|
|Sailing speed, m/s||0,003|
|Threat to people||Edible|
|Way of eating||Predator|