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School of Blue Tang


School of Blue Tang
Photo Information
Copyright: Alfredo Wang (alfhwa) Silver Star Critiquer/Silver Note Writer [C: 10 W: 0 N: 19] (93)
Genre: Animals
Medium: Color
Date Taken: 2007-10-25
Categories: Fish
Camera: Olympus Stylus 770SW
Exposure: f/3.5, 1/320 seconds
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2007-11-06 6:52
Viewed: 5556
Points: 4
[Note Guidelines] Photographer's Note
Shot taken at Trunk Bay, in St. John, near the underwater snorkeling trail.

Order - Perciformes
Family - Acanthuridae
Genus - Acanthurus
Species - coeruleus

The blue tang is one of 75 species in the surgeonfish family, Acanthuridae. This family of fishes are referred to as surgeonfish due to the very sharp, moveable spines on either side of the tail that resemble surgeons' scapels.

Tangs are found in coral reefs and inshore grassy or rocky areas at depths of 6-131 feet (2-40 m).

In coral reefs, blue tangs live in holes and crevices where they are sheltered from predators while they sleep at night. The blue tang lives singly, in pairs, or in small groups of up to 10 or 12 individuals, although occasionally it forms large aggregations that forage about the shallow reefs, grazing on algae. These aggregations sometimes include doctorfish (Acanthurus chirurgus) and other surgeonfish. The juvenile blue tang is rarely seen on the reef due to its small size and need for constant cover from predators. The intermediate phase with the blue body and yellow tail is often observed on reefs while young adults are abundant everywhere on the reef.

The blue tang reaches approximately 12 inches (30.5 cm) in length. The largest specimen, caught off the coast of South America, measured 14.4 inches (37 cm). It reaches sexual maturity at 9-12 months of age and lengths of 4-5 inches (11-13 cm).

This fish feeds entirely on algae. It grazes algae from rocky areas and browses filamentous algae, thereby avoiding large quantities of calcareous materials. Other surgeonfishes have heavier-walled, gizzard-like stomachs, and are capable of handling ingested sand and other calcareous materials. Blue tangs are important in keeping algae populations under control, preventing algae from overgrowing and suffocating corals.

Tuna, bar jack, tiger grouper, and other large carnivorous fishes are known predators of the blue tang.

Source: Florida Museum of Natural History
http://www.flmnh.ufl.edu/fish/)

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Critiques [Translate]

Hello Alfredo! Beautiful composition. Very nice colors. Original shot. Regards!

Olá Alfredo.
Registro espetacular! Belíssimo cardume!
Ótimas cores e contraste.
Excelente POV superior, proporcionando a distinção das espécies diferentes.
Parabéns!
Abraços,
José Roberto

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