مرجان (سمك)

تتميز الأسماك التي تعيش في الشعاب المرجانية بالتعدد والتنوع.

سمك المرجان Coral reef fish، هو سمك يعيش بين أو بالقرب من الشعاب المرجانية. وتتمتع الشعاب المرجانية بنظم بيئية متنوعة ومعقدة.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 نظرة عامة

In the foreground is an orange-lined triggerfish displaying spines. Triggerfish have mouths that crush shells. Orange-lined triggerfish are particularly aggressive. The black and white fish are three-stripe damselfish and the unstriped fish are blue-green chromis damselfish. If the triggerfish attacks, the damselfish will hide in the nearby pillar coral. If the triggerfish wants to hide, it will squeeze into a coral crevice and lock itself in place with its spines.

• 

  Most coral reef fish have spines in their fins like this damselfish.

• 

  The usually placid yellow tang can erect spines in its tail and slash at its opponent with rapid sideways movements.

 التنوع والانتشار

انتشار الشعاب المرجانية.

• 

  Among goby species, small coral reef-dwelling fishes, is the world's shortest lived vertebrate, the seven-figure pygmy goby, which lives for less than 60 days.

• 

  The slowest-moving fishes are the sea horses, often found in reefs. The slowest of these, the dwarf seahorse, attains about five feet per hour.

• 

  Toadfish often inhabit reefs. Male toadfish "sing" at up to 100 decibels with their swim bladders to attract mates.

 تكيفات أسماك المرجان

التناقض بين أسماك الشعاب المرجانية والمياه المفتوحة.

Many reef fish, like this queen angelfish, have a body flattened like a pancake, with pectoral and pelvic fins that act with the flattened body to maximize manoeuvrability.

In contrast, open water fish like this Atlantic bluefin tuna, are usually streamlined for straightline speed, with a deeply forked tail and a smooth body shaped like a spindle tapered at both ends. They are countershaded with silvery colours.

 الألوان

The psychedelic mandarinfish is one of only two animal species known to have blue colouring because of cellular pigment.

The well camouflaged striated frogfish, a species of anglerfish, are ambush predators.

Clown triggerfish

• 

  The foureye butterflyfish has false eyes on its back end, confusing predators about which is the front end of the fish.

• 

  The frogfish is an ambush predator disguised to look like an algae-covered stone

• 

  Another ambush predator is the tassled scorpionfish camouflaged to look like part of a coral encrusted sea floor.

• 

  Gobies are very cautious, yet they can fail to see a tassled scorpionfish until it is too late.

 استراتيجيات التغذية

 آكلات اللحوم العامة

Red snapper, are generalized reef feeders with standard jaw and mouth structures that allow them to eat almost anything, though they prefer small fish and crustaceans.

• 

  Adult coral trout hunt a variety of reef fish, particularly damselfish, while their juveniles mostly eat crustaceans such as prawns.

• 

  Bluestripe snapper eat just about anything.

• 

  Yellowfin goatfish change their colouration so they can school with the blue-striped snapper.

• 

  Coral grouper sometimes cooperate with giant morays in hunting.

 آكلات اللحوم المتخصصة

• 

  Many small reef fishes gain advantages by schooling.

• 

  Cardinalfish swim in schools for protection against trevally.

• 

  Bigeye trevally hunt cardinalfish in packs and herd them against the reef. When the cardinalfish panic and break school formation, the trevally pick them off.

• 

  Porcupinefish inflate themselves by swallowing water or air, which restricts potential predators to those with bigger mouths.

صور خارجية
	Giant moray with cleaner wrasses
	Porcupinefish with cleaner wrasses

• 

  The Emperor angelfish feeds on coral sponges.

• 

  The titan triggerfish followed by small orange-lined triggerfish and moorish idol that feed on leftovers.

• 

  Two small cleaner wrasses servicing a larger fish at a cleaning station

• 

  The reef lizardfish secretes a mucus coating which reduces drag when they swim. But some parasites find the mucus good to eat.

 الحيوانات العاشبة

Surgeonfish are among the most common of coral reef herbivores, often feeding in shoals. This may be a mechanism for overwhelming the highly aggressive defence responses of small territorial damselfishes that vigorously guard small patches of algae on coral reefs.

• 

  Relatively defenceless parrotfish feed on algae.

• 

  Ferocious barracuda prey in schools on parrotfish.

• 

  Coral rabbitfish have venomous spines which they erect if threatened.

• 

  Schooling spinefoot rabbitfish are often joined by defenceless parrotfish.

 التكافل

A hawkfish, safely perched on Acropora, surveys its surroundings

صور خارجية
	Perlfish emerging from a sea cucumber
	Clownfish swimming among coral

• 

  The tentacles of sea anemones bristle with tiny toxic harpoons.

• 

  Saddle butterflyfish are resistant to the sea anemone toxin.

• 

  Yellowtail clownfish with sea anemone

• 

  Common clownfish guarding their sea anemone home

A monogenean parasitic on the Blacktip grouper

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 السمية

Head on view of the beautiful but venomous lionfish

• 

  The most venomous known fish is the reef stonefish.

• 

  The spotted trunkfish secretes a ciguatera toxin from glands on its skin.

• 

  Like many other apex reef fish, the giant moray can cause ciguatera poisoning if eaten.

• 

  The stargazer buries itself in sand and can deliver electric shocks as well as venom.

 قروش وشفنين المرجان

The whitetip reef shark almost exclusively inhabits coral reefs.

Whitetip reef sharks spend much of the day lying still on the bottom.

Adult blacktip reef sharks are often found patrolling reef ledges.

Coral reef drop-offs are favoured habitat for grey reef sharks.

A Caribbean reef shark cruises a coral reef in the Bahamas.

• 

  The great hammerhead uses its hammer both to locate electrical signatures of stingrays buried in the sand and to pin them down.

 انظر أيضاً

• Anthiinae
• List of marine aquarium fish species – most of these fish are coral reef fish
• قائمة أسماك المرجان في البحر الأحمر

 المصادر

• Lieske, E and R. Myers. (2001) "Coral Reef Fishes: Indo-Pacific and Caribbean" Princeton University Press. ISBN 0-691-08995-7.

• Moyle, PB and Cech, JJ (2003) Fishes, An Introduction to Ichthyology. 5th Ed, Benjamin Cummings. ISBN 978-0-13-100847-2

• Randall, J. (1997) "Fishes of the Great Barrier Reef and Coral Sea" University of Hawaii Press. ISBN 0-8248-1895-4.

• Sale PF (2006) Coral Reef Fishes: Dynamics and Diversity in a Complex Ecosystem by Peter F. Sale Academic Press. ISBN 0-12-373609-9.

• Sale PF (1982) "The structure and dynamics of coral reef fish communities" in Pauly D and Murphy GI (eds.) Theory and management of tropical fisheries, ICLARM Conference Proceedings (9), ISBN 971-0400-22-3.

 وصلات خارجية

• Featured Creatures in Coral Reefs at the Smithsonian Ocean Portal
• Coral Reef Fishes: Adaptations, Diversity, and Economic Value
• ARC: Centre of Excellence Coral Reef Studies
• Coral Reefs at the Open Directory Project
• WhyReef, an online virtual reef for kids