The body is elongated, tapering to the caudal stem, covered with small cycloid scales . The lower jaw is shorter than the upper. There are no teeth on the palate. The chin antenna is short. The eyes are relatively small, their diameter is 16-20% of the length of the head. On the first branchial arch there are 16-21 branchial stamens . Three dorsal and two anal fins, clearly separated from each other. The second rays of the ventral fins are filiform, elongated; their endings reach the middle of the first anal fin. The lateral line is light, goes straight from the head to the beginning of the second dorsal fin, and then bends downward and continues until the beginning of the caudal fin. There are no lateral line pores on the head. The endings of the parapophyses are not expanded. The caudal fin is rounded. Coloring of upper body from olive-brown to green or yellow, light belly. Dark spots are scattered on the sides of the body and fins [2] .
The maximum body length is 38.1 cm [3] .
Benthic fish live in coastal areas to a depth of 70 m. In spring, when warming coastal waters, they move to deeper waters with a low temperature, and in autumn they return closer to the coast. They can spawn both in estuaries and in fresh water. Pure freshwater populations in several lakes are known. Caviar is euryhaline, can develop normally both in fresh water and water with salinity up to half of full-salt sea water [2] [3] .
They feed on small crustaceans ( shrimp , amphipods ), and the diet also includes polychaetes , small mollusks , squids and small fish [2] .
Distributed in the northwestern Atlantic Ocean from the south of Labrador and Newfoundland to Virginia [2] .
Irregular fishing is carried out by Canada and the USA . Caught by nets, traps and tiers . In the 1950s and 1960s, catches reached 1,600 tons. In the 2000-2010s, they caught no more than 170 tons. A popular sport fishing facility [3] .
Between 1947 and 1976, General Electric dumped nearly 590 tons of polychlorinated biphenyls into the Hudson River . During this time, Atlantic tomcodes due to mutations have developed resistance to these toxicants [4]
