The black sea bass is a species of fish that lives in the Western Atlantic Ocean, and the largest number of these fish are concentrated around New Jersey and North Carolina in the United States. Fished both commercially and for sport, the high demand for the black sea bass has lead to the implementation of harvesting and catch quotas in some regions for the purpose of population control. One defining characteristic of the black sea bass is that it is a hermaphrodite, and most are born female and switch to male prior to becoming seven years of age.
Black sea bass are gray, brown, and black in appearance, with dark and white spots. The dorsal fin of the fish is white, while its other fins have dark spots. When mating, the male fish becomes blue in appearance and develops a blue hump on its head. Juvenile fish are green or brown, and have a dark stripe along the ridge of their back. Average length for the fish is around 20 inches (50.8 cm), and they weigh three pounds (1.36 kg), although fish weighing up to eight pounds (3.62 kg) have been caught.
Predators of this fish include summer flounder, monk fish, spiny dogfish, and little skate. Adult black sea bass eat crabs, clams, and other regional invertebrate. The young fish are primarily bottom feeders and eat debris. Juvenile fish mature around two to three years of age, and the fish can live to around 15 years.
Mating season for the black sea bass is February to July, and starts earlier in warmer water. Once laid floating in the water, the eggs hatch in five days post fertilization. During the breeding and summer months, the fish live in shallower, rocky water. In the winter, the bass migrate to deeper water, and the juvenile fish leave first in the early Autumn.
Even though most black sea bass are hermaphrodites, some fish are born male and stay that way. Most are born female, and switch sexes after laying eggs. If the male population of black sea bass is greatly reduced, some females will make an early switch to male to reach a better gender balance.
In some areas, the fish are population controlled by a harvest quota system on commercial fishing. Overfishing seems to occur more in the Southern Atlantic regions then in the Northern waters around New Jersey and Maine in the United States. Overall, the population has been declining in both numbers and average weight size for the last half century.