Family overview: Freshwater
eels are the only catadromous fishes in North America. “Catadromous” means
that they spawn in salt water and live as adults in fresh water.
Anadromous fishes, like salmon and American shad, spawn in fresh
water but live as adults in the ocean. On this continent, eels
are represented by a single species, the American eel (Anguilla
rostrata). Although the eel looks snakelike, it is a fish.
The American eel is found widely along the Atlantic and Gulf coasts,
where the young eels move far upstream into small tributaries. The
Delaware River in Pennsylvania has the most abundant population of
eels of all the state's streams, because there are no dam obstructions
to prevent the eel's upriver migration. Eels are rarely found in the
Susquehanna River system. Passageways and lifts to move fish past all
the Susquehanna's dams should soon return eels, shad and other ocean-migrating
fish to that watershed. Eels are also occasionally seen in the Potomac
River watershed. They have even been reported from some headwater sections
of the Ohio River watershed in Pennsylvania. While in fresh water,
eels live in a variety of stream habitats, especially where they can
hide under logs, rocks and undercut banks.
Until the early 1900s, eels supported an intense commercial fishery
in the Susquehanna and Delaware River systems. Adult eels on their
downstream migration toward the sea were trapped by low, in-river
V-shaped wing dams, which were barricades made of rocks. The eels entered
these eel racks from the wide upstream side and swam through the small
funnel opening downstream, into holding baskets. The remains of old “eel weirs” can
still be seen in some Delaware and Susquehanna River watershed streams.
Even in a “poor” eel year, the take was staggering: In 1912, called
an “off year,” 50,000 eels weighing more than 44,000 pounds were
caught in Pennsylvania. Today, eels are caught mostly by anglers
looking for food and sport (eels are good eating, especially smoked).
The genus name “Anguilla” is Latin for “eel.” The species name “rostrata” means “long
Identification: The American eel's body
is long and slender, and seems scaleless. Actually, it has smooth,
tiny scales that are embedded in the skin. A long, low dorsal fin
extends over at least two-thirds of the back. It blends with the
caudal fin and the anal fin, which is also long and low, on the underside.
There are no pelvic fins, but the pectoral fins are well-developed.
The presence of pectoral fins can be used to distinguish an eel from
a lamprey, which has no paired fins. The head has a smallish eye.
The head is long, and tapers to a small mouth. The lower jaw sticks
out a little farther than the upper jaw. Eels are yellowish brown
to dark-olive, and lighter underneath. In Pennsylvania, the maximum
size is two to three feet, although four feet or more is possible.
Females grow larger than males.
Life history: The mysterious life history of freshwater
eels was revealed only in this century, and even today, eels are not completely
understood. The principal puzzle for many years was where eels spawned. Their
spawning grounds have finally been identified as the Sargasso Sea, in the
northern Caribbean-Bermuda region of the Atlantic Ocean. The eels that arrive
there to spawn come from two directions, the American eel from the west and
the European eel from the east. But how young eels of each species know which
continent to go to has not yet been explained.
After the adult eels spawn, they die. The larval eels, called “leptocephali,” are
ribbonlike and transparent. These “glass eels” drift with other tiny
organisms in the northward-flowing ocean currents. The transforming
young eels, called elvers, enter river estuaries when they reach the
continent. The females don't stop. They continue swimming many miles
upstream, mainly at night, even to the river system's headwaters. The
trip from the spawning grounds in the ocean to the eel's freshwater
upstream home takes about a year. The male eels, which remain smaller
than the females, stay in the lower reaches of the coastal river and
in the brackish tidewater just off the river's mouth. After remaining
in fresh water for 10 to 20 years, the adult females, now called “silver
eels” because of their silvery appearance, migrate downstream in
the fall on their long way back to the Sargasso Sea. Sexually mature
female eels may contain two million or more eggs.
Eels are predators. They eat a wide variety of aquatic insects, crayfish
and other crustaceans, frogs, fishes and worms. They feed mostly at
Live striper baits
Pennsylvania Game and Fish
All Stripers All The Time!!