Coral reefs are some of the most exquisite and
beguiling habitats on Earth. These teaming ecological societies play host to a
myriad of vibrant marine species, from crustaceans and small fish to reef
sharks and turtles. Amidst this hectic and heavenly environment, every creature
has its own, fascinating secrets - and they're just waiting for mankind to
discover them.
With
its lurid yellow scales, the Yellow Tang blends into its alluring and
effervescent environment with ease. They can grow to sizes of 20 centimetres in
diametre, excluding their elongated snout and pectoral fins. Yellow Tangs
possess large dorsal and anal fins which are slightly thinner than their actual
body, which in itself is extremely fine. At the join between the Tang's oval
body and triangular tail, there is a distinctive white spine - known as a
scalpel, on account of the Tang's membership to the Surgeonfish family. This
aptly-named scalpel is the Tang's greatest defence against predation - it can
launch this at a predator in order to inflict it a grave injury. Young Tangs'
spines are also poisoned, making them even more potent than those of older
specimens. Since all Tang, not just Yellows, are territorial fish, these
scalpels are of paramount importance.
Yellow
Tang prefer sub-tropical, coastal waters with temperatures of around 21 degrees
Celsius. They are found in abundance on the coral reefs of Hawaii, Micronesia,
Palau, the Philippines, Japan, Hong Kong and Vietnam at depths of between 2 and
46 metres.
For
reef fish, Yellow Tang are fairly long-lived - able to endure for around 30
years in the wild, although most do not survive past 10 years of age when held
in captivity. These vibrant marine creatures reach sexual maturity at the age
of around 2 or 3.
Yellow
Tang reproduce externally, either in groups or in pairs. Group spawning occurs
frequently, with large groups of females releasing their eggs and males
releasing their sperm over a small area. Occasionally, Yellow Tang will mate
with a partner; a male and female Tang will swim parallel to each other
vertically, simultaneously releasing their eggs and sperm into the water. This
act, unlike group spawning, is preceded by courtship, during which the male
will attempt to attract a passing female by exhibiting his size and vibrance.
Females release up to 40,000 eggs during a single spawning session and will
reproduce once a month over a period from from March to September. Males,
meanwhile, will mate several times and with several different females during a
single spawning session.
Yellow
Tang are of great importance to the coral reef ecosystem, as they feed on
coral-constricting algae - limiting its growth across a wide area. Some Tang
will also graze upon zooplankton, although their forty teeth are better suited
to the consumption of algae and seaweed.
Generally
speaking, people think of reef fish as being virtually immune to the threat of
humanity, since they are hunted neither for sport nor for food. This, however,
is a great misconception. Human encroachment into coral reefs causes great
habitat destruction, as does the use of explosives to harvest game fish. Larger
numbers of Yellow Tang are captured for aquariums and private fish tanks than
any other tropical or subtropical fish, causing a vast decrease in their
natural population. This is also a cause of great devastation to the coral
reefs themselves, since a lack of Yellow Tang and other reef fish gives
constrictive algae more time to grow over the coral - consuming it and
gradually causing the entire environment to deteriorate. This is the extent to
which food chains have an effect on their ecosystems - the removal of one
single, vital link can result in complete and utter destruction.
Bibliography
Daniel Bailey
Sunday 7th of February 2016, 16:24 GMT
England
Dedicated to Beth at London Sea Aquarium - thank you for being a wonderful teacher; I will never forget all you taught me.
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