Striped Bass (morone saxatilis)
The silvery striped bass gets its name from the 7
or 8 dark, continuous lines along the side of its body. Most striped bass
weighing more than 30 pounds are females. The fish can weigh up to 100
pounds and reach nearly 5 feet in length!
Striped bass spawn in fresh water but spend most of their
adult lives in the ocean. On the Atlantic coast they range from the St.
Lawrence River in Canada to Florida's St. Johns River, although they are
most prevalent from Maine to North Carolina.
After about 3 years, at the juvenile stage, the females
begin to migrate to the ocean where they mature. The males tend to remain
in the estuary longer than the females. After 5 to 7 years, females return
to spawn for the first time. It takes several years for spawning females
to reach full productivity. An average 6 year old female produces half
a million eggs while a 15 year old can produce three million.
When water temperature begins to rise in the spring,
mature fish begin their spawning runs. Most Atlantic Coast striped bass
spawn in freshwater rivers and streams of Chesapeake Bay. Other important
areas include the Hudson River, Delaware River and rivers along the North
Once the female deposits her eggs, they are fertilized
by milt (sperm) ejected from the males. Because they are only semi-buoyant,
the eggs require enough water flow to stay suspended for 2 or 3 days until
Larval striped bass obtain nutrients from the yolk sac
for about 5 days after hatching. The larvae are particularly vulnerable
to pollution, starvation and predators during this stage.
Cause for Concern
The decline of Atlantic striped bass was so alarming
that Congress enacted an Emergency Striped Bass Act in 1979. Under the
Act, a study was initiated to assess the size of the migratory stock,
investigate the causes of the decline, calculate its economic importance
and recommend measures for restoration.
From this research, scientists from the U.S. Fish and
Wildlife Service,state agencies and universities discovered new information
about striped bass to assist them in restoration. Careful assessment of
the stock showed that, because of overfishing, the striped bass population
was much more susceptible to natural stresses and pollution. They also
discovered that fluctuation of water temperature at spawning grounds is
the most significant natural stress the fish face.
Research conducted in the Chesapeake's Nanticoke and
Choptank rivers indicated that highly acidic rain reacts with aluminum
in the soil, causing it to dissolve in the water. The combination of high
acidity and aluminum is lethal to newly hatched stripers. Larval striped
bass are also very susceptible to toxic pollutants like arsenic, copper,
cadmium, aluminum and malathion, a commonly used pesticide. Studies showed
that chlorination of effluent from sewage plants and electric power stations
adversely affects zooplankton, leading to starvation of newly hatched
striped bass that feed on it.
The study team also concluded that reducing fishing pressure
would have an immediate positive effect by enabling females with eggs
to spawn. An Atlantic States Marine Fishery Commission management plan,
based partly on recommendations of this study, set size and pound limits
to reduce the catch.
In 1985, Maryland imposed a total moratorium on striped
bass. Virginia followed by banning striped bass fishing in spawning areas.
Fours years later, Virginia also imposed a total ban on striped bass fishing.
However, fishery managers knew that harvest restrictions alone would not
permanently restore striped bass to the Bay.
Bringing the Striper Back
Under the Emergency Striped Bass Restoration Act,
Congress designated the Fish and Wildlife Service as the lead federal
agency to determine the cause of the fishery's decline. Striped bass restoration
began in 1980. Water quality problems on spawning grounds were evaluated.
By 1985, a coast-wide striped bass tagging and hatchery program was initiated
to determine the rates of exploitation and natural mortality, and determine
if hatchery-reared fish could supplement wild stocks in severely depleted
Fishery managers and biologists from the Fish and Wildlife
Foundation, National Marine Fisheries Service, state agencies from Massachusetts
to North Carolina and universities continue to participate in the striped
bass tagging program. A central database, designed and managed by the
Service, stores stocking information, migratory data from tag returns
and other information upon which management decisions are based.
Since 1985, more than 190,000 hatchery-reared and wild
striped bass have been tagged with external anchor or “spaghetti” tags.
Anglers returned more than 30,000 of these tags by 1993. In addition,
all hatchery-raised striped bass, more than 9 million fish in all, are
tagged with tiny micro-encoded pieces of wire that anglers cannot see
but researchers can read with specialized equipment. These hatchery-reared
striped bass provide managers with information about population dynamics,
growth and migratory patterns. In 1988, hatchery fish comprised nearly
50 percent of Maryland juvenile striped bass in some rivers like the Patuxent.
Today, as hoped, wild fish far outnumber hatchery fish. Evaluations continue
on the potential contribution of hatchery fish to depleted stocks.
During the years of the moratorium in Maryland, fishery
managers continued to monitor striped bass populations in Chesapeake Bay.
In particular, the juvenile index survey was closely watched. Conducted
annually since 1954, this survey of the young-of-the-year reflects the
success of spawning. The striped bass management plan set a goal for loosening
restrictions based on this index. The juvenile indices averaged from 1987
to 1989 met the management plan goal. In 1989, both Virginia and Maryland
lifted their moratoriums on striped bass. Limited commercial and recreational
striped bass fishing resumed.
The Future of the Fishery
Striped bass stocks continue
to gradually increase. The 1993 juvenile index was the highest since the
survey first began. Besides the young-of-the-year index, managers have
noted an increase in adult striped bass and in the proportion of spawning
females, age 8 or older. This information is critical to establishing
fishing seasons, minimum fish lengths, daily catch limits and harvest
Since Chesapeake Bay is the primary spawning and nursery
area for 70-90 percent of the Atlantic stocks of striped bass, restoration
depends on protecting and improving habitat and water quality. We have
much to gain from restoring striped bass and Chesapeake Bay; we have much
more to lose if we decline the challenge. Through harvest restrictions,
pollution control, stocking and commitment we can restore the striped
bass to Chesapeake Bay.