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Golden Hammerhead
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Golden Hammerhead Description |
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The Golden
Hammerhead Shark inhabits the northeastern coast of
South America, from Venezuela to Uruguay. It is found
in coastal waters at depths of 30 to 130 feet (9 to
40 metres) over muddy bottoms. The Golden Hammerhead
is a small species which attains a maximum size of about
4 feet and 20 pounds (1.22 metres and 9 kilograms).
The most distinctive characteristic of this species
is its striking bright orange or yellow color. Juveniles
less than 2.5 feet (80 centimetres) long are bright
yellow or orange; adults are pale yellow. The color
is apparently due to pigments present in this species'
diet; juveniles feed primarily on penaeid shrimp (especially
Xiphopenaeus kroyeri), while adults feed on marine catfishes
(family Ariidae) and their eggs. Two pigments have been
isolated and, at the time of Castro's 1989 report, their
biochemical characterization was being ascertained (one
of these pigments is almost certainly a form of carotene,
a class of unsaturated hydrocarbons which gives ariid
catfish eggs their rich golden/orange color). Male Golden
Hammerheads mature at a length of about 2.5 feet (80
centimetres); females of this species at a length of
about 3.2 feet (98 centimetres). Off Trinidad, female
Golden Hammerheads ovulate and mate during the month
of August. Developing pups of this species - like those
most other members of the family Carcharhinidae (the
one exception is the Tiger Shark, Galeocerdo cuvier,
which relies on yolk reserves throughout its 13- to
16-month gestation period) - are nourished at late stages
of gestation via a yolk-sac placenta. Gestation of the
Golden Hammerhead appears to last about 10 months; off
Trinidad, birth occurs in shallow waters from late May
to June. Broods of this species consist of 5 to 12 pups,
which at birth measure about 1 foot (30 centimetres)
long. In female Golden Hammerheads, the ovarian cycle
runs concurrently with the gestation cycle, so it seems
likely that females of this species are fertilized shortly
after giving birth and that the species reproduces every
year (rather than having a two-year reproductive cycle
as in many larger carcharhinids, in which females take
a year off after giving birth, recovering and building
up energy stores for a year before mating again). |
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