Dolphin Common (lat. Coryphaena hippurus)
The common dolphin is the larger of the two very similar
species in the family Coryphaenidae, both of which are cosmopolitan
in warm seas. This fish is one of the top offshore
gamefish among anglers and is an excellent, hard-fighting
species that puts on an acrobatic show once hooked.
OTHER NAMES:
dolphinfish, common dolphinfish,
mahimahi, mahi
mahi, dorado; Chinese: fei
niau fu, ngau tau yue;
French: coryphéne commune;
Italian: lampuga;
Japanese: shiira, toohyaku;
Portuguese: doirado,
dourado; Spanish: dorado,
dorado com ún, lampuga.
The body is slender and streamlined, tapering
sharply from head to tail. Large males, called bulls, have
high, vertical foreheads, while the female’s forehead is
rounded. The anal fin has 25 to 31 soft rays and is long,
stretching over half of the length of the body. The dorsal fin
has 55 to 66 soft rays. Its caudal fin is deeply forked; there
are no spines in any of the fins; and the mouth has bands of
fine teeth.
Coloring is variable and defies an accurate, simple
description. Generally, when the fish is alive in the water,
the common dolphin is rich iridescent blue or blue-green
dorsally; gold, bluish-gold, or silvery gold on the lower
flanks; and silvery white or yellow on the belly. The sides are
sprinkled with a mixture of dark and light spots, ranging
from black or blue to golden. The dorsal fin is rich blue, and
the anal fin is golden or silvery. The other fins are generally
golden yellow, edged with blue. Dark vertical bands sometimes
appear when the fish is attacking prey. The color
description of the dolphin is difficult because it undergoes
sudden changes in color, which occur in an instant, often
when the fish is excited.
When the fish is removed from the water, however, the
colors fluctuate between blue, green, and yellow; the brilliant
colors that were apparent when in the water fade
quickly. After death, the fish usually turns a uniform yellow
or silvery gray.
The average size is 5 to 15 pounds, although
larger catches up to 50 pounds are not uncommon. The alltackle
world record is an 87-pounder caught in Costa Rica in 1976, and it has been rumored that fish up to 100
pounds have been caught by commercial longliners. The
maximum length is reportedly 82 inches.
Dolphin are fast growing and short lived. Few common
dolphin live longer than 4 years, and most live just 3 years.
Males grow larger than females and are capable of growing
to 60 pounds in just 2 years, although this is exceptional
and the result of consistently favorable warm water temperatures
and abundant food.
The common dolphin is a prolific
spawner and grows rapidly, meaning that it must by nature
be an eating machine. Spawning season begins primarily in
the spring or early summer and lasts several months in
warmer waters. Dolphin reach sexual maturity in their first
year of life and produce a large volume of eggs.
Dolphin are schooling fish and are often congregated in
large numbers, sometimes by the thousands. They are
almost always between the surface and 100-foot depths,
but they are encountered by anglers on or just under the
surface and are probably the most surface-oriented of all
big-game fish. This, plus the fact that they are visually oriented
feeders that primarily forage in daylight, helps endear
them to anglers. Offshore anglers frequently encounter
packs of dolphin and are able to elicit strikes from several
fish in quick order.
These fish are evidently also migratory. It is believed that
dolphin in both hemispheres migrate away from the equator
in the spring and the summer and toward the equator in
the fall and the winter.
Common dolphin are extremely fast swimmers and
feed in pairs, small packs, and schools, extensively consuming
whatever forage fishes are most abundant. Flyingfish
and squid are prominent food in areas where these exist,
and small fish and crustaceans that are around floating sargassum
weed are commonly part of the diet, especially for
smaller dolphin. Dolphin are very aggressive feeders, and
they can move extremely fast to capture a meal.
The common
dolphin is found worldwide
in tropical and subtropical
waters. In the western
Atlantic, it occurs in areas
influenced by the warm
waters of the Gulf Stream
and has been caught as far
north as Prince Edward
Island and as far south as
Río de Janeiro. In the eastern
Pacific, it ranges from Peru
to Oregon.
Common dolphin
are warmwater pelagic fish,
occurring in the open ocean
and usually found close to
the surface, although in
waters of great depth. They
sometimes inhabit coastal
waters and occasionally
areas near piers, but in the
open ocean they often concentrate
around floating objects, especially buoys,
driftwood, and seaweed
lines or clusters. The young
commonly frequent warm
nearshore waters in sargassum
beds or other flotsam.
In developing countries,
commercial fishermen may
place floating bundles of
bamboo reeds, cork planks,
and the like in the water to
concentrate dolphin before
seining or gillnetting
commences.