Spotted
Eagle Ray: (Aetobatus narinari)"Hailepo"
With its eerie shape and flapping dorsal
fins, the eagle ray is among the most elegant and mysterious-looking fish in the ocean.
Its back is covered with a symmetrical dot pattern ranging in color from white and yellow
to green. Its underbelly is white and its long tail, sometimes measuring twice as long as
its body, is black. When an eagle ray is resting on the sandy ocean floor, its
highly-patterned back acts as a camouflage, hiding it from both prey and attackers.
The spotted eagle ray (Aetobatus
narinari), like all rays and sharks, has a skeleton of cartilage.
Its large "wings" are tapered like a bird's and can measure
up to seven and a half feet across. The eagle ray's shovel-shaped
snout, and its duckbilled mouth are extremely sensitive to smells
and electrical currents in the water. This makes the eagle ray an
effective hunter. Feeding on mollusks, crustaceans and small fish,
this beautiful ray can reach weights of up to 500 pounds. The eagle
ray lives mostly among rocky and muddy coral reefs and feeds along
the sandy ocean bottom.
Manta Ray: Manta birostris - (Hahalua)
Once labeled "devil fish" by sailors believing the horn-like
features on their head were a sign of evil, mantas are now known to
be gentle filter feeders and harmless to man. They are a favorite
sight of anyone who enjoys the underwater world. Manta rays can be
quite curious, especially when they are around divers. When threatened,
they will curve one pectoral fin toward the back and the other toward
the belly forming an s-shape cross section, while exposing their back
towards the threat.
Manta
rays are among the largest fish in the ocean. They can grow to
have
wingspans up to 30 feet and weigh up to 3,000 pounds. Despite their
size, they are graceful creatures, soaring through the water like
massive birds in flight.
It appears that mantas do not breed until their winglike pectoral fins reach a length of 13-15 feet.
Many male mantas follow a single female, mirroring her behaviour in a bid to attract her as a mate. When she makes the final selection, she allows the male(s) to bite onto her long fin tip and slide beneath her for belly-to-belly copulation.
Females, which give birth to a single pup after a 12-month gestation, rarely give birth in consecutive years. That extremely slow reproduction could place the fish in danger from overfishing, both for subsistence and for export to be used in traditional Chinese medicines.
The rays sometimes swim across the ocean floor, skimming the reefs with their mouths. More commonly, they feed at the surface on small zooplankton and krill funneling them into their mouths with specialized head fins—cephalic fins—unfurled below into twin scoops.
Sometimes they gather in larger groups to feed on a concentration of krill. Over and over, they summersault in tight loops, their white bellies flashing. Some suggest that the looping is a vortex generator—the hydrodynamic equivalent of a sheep dog herding millions of krill into a concentrated ball to be rammed into the gaping manta mouths on their next pass.
Manta ray populations, sadly, are decreasing rapidly in number. The
number of mantas caught each year has quadrupled with an increase
in Asian demand for dried manta brachial elements ("horns")
for traditional medicines, according to the Manta
Pacific Research Foundation. The foundation has recently placed
manta rays on a watch list of species that scientists consider vulnerable
or threatened with extinction.
Read
about why Manta Ray's need protection now. Although there is no
immediate fishing threat to the mantas in Hawaii, Manta Pacific Research
Foundation is taking a pro-active role in implementing a No Kill,
No Extraction law for the Hawaiian waters. You can help from your
home by signing this petition
to supporting legislation to make it illegal to kill, capture, or
intentionally injure manta rays in Hawaiian waters.
Manta ray's secret life revealed
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