The rockfish, better known in the Chesapeake Bay as the "striped bass," or simply "striper," can swim from the St. Lawrence River in Canada to the St. Johns River in Florida, from the Suwannee River in western Florida to Lake Pontchartrain, Louisiana, and the open waters of the Atlantic. A rockfish tagged in the Chesapeake was recaptured in Canadian waters, over 1,000 miles away.

Striped bass are named for the distinctive seven or eight continuous dark stripes along their silvery sides from the gills to the tail. The back of the rockfish varies in color between light green, olive, steel blue, brown, and black. Their undersides are usually white or silver, with a brassy iridescence. Mature stripers are known for their great size; they can reach over 100 pounds and nearly five feet in length.

Rockfish spawn in estuaries, or the edges of tidal freshwater, such as a river. The migratory behavior of the rockfish is more complex than that of most other anadromous (a-NAD-ro-mus) fish, or fish that migrate from seas up into rivers to spawn. Most anadromous fish spend their adult lives in the ocean, only moving into freshwater rivers and streams to spawn. However, rockfish migrate depending on age, sex, sexual maturity, and even the river in which they were born. In late winter and spring, mature rockfish move from the Atlantic into tidal freshwater, such as the Chesapeake Bay, to spawn. The fish spawn when they reach the bay because at certain times the bay waters are warmer than the ocean. In the Chesapeake Bay, this temperature increase generally occurs in April, May, and early June. Females reach sexual maturity between 4 and 8 years of age while most males reach sexual maturity at age 2 or 3.

After spawning, mature rockfish return to the Atlantic, spending the summer and early fall in waters off New England and then migrating south in late fall and early winter off the North Carolina and Virginia capes. Immature rockfish spend the first three to five years of their lives in the bay before migrating into the Atlantic. Many rockfish live for 20 years or more. The oldest ever recorded was 31 years. Estuaries such as the Chesapeake Bay are critical to the life cycle of rockfish, which need them for spawning grounds and nurseries.

The rockfish is considered by many to be the premier sport fish on the Chesapeake Bay. The flaky white meat is a delicacy. The rockfish was named the official fish of the State of Maryland in 1965. The current Maryland record for a rockfish, set in 1995, was a fish that weighed 67 pounds, 8 ounces.

Commercial fishing of rockfish in the Chesapeake generally increased from the early 1930s, with a record commercial catch in 1973 of 14.7 million pounds. Rockfish harvests then declined steadily to 1.7 million pounds by 1983. In response to this dramatic downturn, Congress passed the Atlantic Striped Bass Conservation Act in 1984. Maryland and Delaware imposed fishing moratoria from 1985 to 1989, and Virginia imposed a one-year moratorium in 1989. The rockfish fishery reopened in 1990 following three successful spawning years but remains tightly restricted.

The rockfish harvest declined for many reasons. Overfishing, when so many fish are caught that only a few are left, caused the population to become more susceptible to natural stresses and pollution. Changes in water temperature in spawning grounds can also cause significant natural stress. Other factors include low levels of dissolved oxygen in the deeper waters of the bay, which has eliminated much of the summer habitat of adult and juvenile rockfish. Acidity and contaminants in spawning habitats, as well as water factors such as salinity (the level of salt in the water), turbidity (how clear or dirty the water is), light, temperature and pH level (level of acidity) also affect the survival of rockfish. Larval rockfish are especially susceptible to toxic pollutants in the waters.

Despite these threats, rockfish stocks continue to gradually increase in the bay. Because the bay serves as the main spawning and nursery area for between 70 and 90 percent of the Atlantic stock, restoration efforts remain critically important to the future of the rockfish.