Grouper

Grouper

Groupers are one of the apex predators in the oceans. They are eaten by others like sharks but they are very important for the marine food chain.

General information

Diet: Small fish, Squid, Octopus and other animals like snails, crabs etc.

Predators: Sharks and Big fishes
Habitat: coral reefs

Special Power: Gulping other fish in fraction of a second
Colour: Colours differ from red, pink, orange but most groupers have dark colours like grey.
Length: 1-5 meters depending on the species


Information about the fish

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A brief study on coral reefs

Coral reefs

• Describe coral reefs: 

• Coral reefs are large colonies of coral polyps bonded together.

coral polyp                    Group of coral polyps

• Where they are located 
• Coral reefs are located in warm, temperate and shallow waters in oceans. 
• How they are built and what they are made of?
• They are made of calcium carbonate, coral reefs begin to form when free swimming coral larvae attach to submerged rocks or other hard surfaces along the edges of island or continent.
• why they are important as an ecosystem and as a resource?
• 
  
• Coral reefs are some of the most diverse and valuable ecosystems on Earth. Coral reefs support more species per unit area than any other marine environment, including about 4,000 species of fish, 800 species of hard corals and hundreds of other species. Scientists estimate that there may be another 1 to 8 million undiscovered species of organisms living in and around reefs (Reaka-Kudla, 1997).

1. In what parts of the world are coral reefs located?

Coral reefs are located in these tropical parts of the world.The largest coral reef is located near Australia and it called the great barrier reef.

2. Are there any coral reefs in the Arctic Ocean ?

No, Coral reef are not located in those cold areas. they are only found in 30n and 30s latitude

3. What is coral? (what kind of organism)

Corals are not living organisms coral polyp is the living organism that forms a coral reef

5. What are cnidae and nematocysts?

Cnidae and Nematocyst: minute, elongated, or spherical capsule produced by exclusively by members of the phylum Cnidaria, (E.G., jellyfish, corals sea anemones). Several such capsules occur on the body surface. Each is produced by a special cell called a Cnidoblast and contains a coiled, hallow, usually barbed thread, which quickly turns outward (i.e.. is reverted) from the capsule upon proper stimulation. The purpose of the thread , which often contains poison, is to ward off enemies or to capture prey. 

6. How does coral get food? What does it eat?

A coral polyp is a filter feeding animal which means it eats plankton. It catches plankton by its tentacles.

7. What are zooxanthellae and why are they important? 

These are unicellular organisms closely related to algae they grow in the body of animals such as corals and other benethic organisms. These tiny organisms provide nutrients they make from photosynthesis and give some of it to the host so the host gives it a place to live, this is very important for the growth of animals such as corals, jellyfish, anemones and etc. 
 

8. How does coral grow and reproduce? How do reefs form?

Corals form when free swimming coral polyps attach to submerged rocks.
Coral reefs can reproduce sexually and asexually, in asexual reproduction, new clonal polyps bud off parent polyps to begin new colonies.
 

9. How much does a coral reef usually grow in a year?

A coral reef only grows nearly a few millimetres a year
 

10. Why are coral reefs so important? Give at least two reasons?

Coral reefs are so important because it provides nursery areas and breeding places for animals but the main thing is it provides places for thousands of animals.

Cuttlefish

Scientific name: Sepiida

Habitat: Near coral reefs

Diet: Small Fish, Crabs and lobsters

Predators: Sharks and big Fish

Rank in food chain: Consumer

Type of water it lives in: Saltwater

Size: 1-5 feet

Class: Mollusks

Relatives: Octopus and Squid

 

Fact: Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda, which also includes squid, octopuses, and nautiluses. 'Cuttle' is a reference to their unique internal shell, the cuttlebone. Despite their name, cuttlefish are true molluscs.
Cuttlefish have large, W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 to 25 cm (5.9 to 9.8 in), with the largest species, Sepia apama, reaching 50 cm (20 in) in mantle length and over 10.5 kg (23 lb.) in weight.
Cuttlefish eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefish. Their predators include dolphins, sharks, fish, seals, seabirds, and other cuttlefish. Their life expectancy is about one to two years. Recent studies indicate cuttlefish are among the most intelligent invertebrates.Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates.^[2]
The 'cuttle' in 'cuttlefish' comes from the Old English word cudele, meaning 'cuttlefish', which may be cognate with the Old Norse koddi ('cushion') and the Middle Low German küdel ('pouch').The Greco-Roman world valued the cephalopod as a source of the unique brown pigment the creature releases from its siphon when it is alarmed. The word for it in both Greek and Latin, sepia, is now used to refer to a brown pigment in English.

Ocean animals-2 Octopus

Octopus

Scientific name: Octopoda

Habitat: All over the world



Diet: Crabs, Squids, Plankton and small Fish

Predators: Sharks, Whales, bigger Octopuses and bigger Fish

Special Abilities: Some octopuses squirt ink like the squid and all the octopuses can change color very fast

Rank in the food chain: Secondary consumers  

Type of water it lives in: saltwater

Biggest type of Octopus: Enteroctopus

Smallest type of octopus: Wolfi

Size: 1/2 feet-7mtrs

Did you know: Octopuses are thought to be the most intelligent animals without a back bone, or invertebrates. They can recognize various shapes and said to be have a good memory. They can even plan and open the lid of a jar.   



Relatives: Cuttlefish and squid
Class: Mollusks

An octopus is a sea animal with eight arms. There are more than 150 species, or types, of octopus. They belong to the group of animals called Mollusks, which also includes squid, clams, and oysters. Octopuses live in seas throughout the world.

An octopus has a soft, baglike body and large eyes. Its long, slender arms reach out in all directions. Each arm has two rows of cuplike suckers with great holding power.

Octopuses vary greatly in size. The smallest are only about 2 inches (5 centimeters) long. The largest may be 18 feet (5.5 meters) long and have a 30-foot (9-meter) arm span.

An octopus can change color quickly depending on its surroundings or its mood. It can be gray, brown, pink, blue, green, or even an angry red if it is suddenly frightened.

An octopus usually crawls along the ocean bottom on its arms searching for food. It eats mainly crabs and lobsters. Skillful hunters, octopuses also attack large prey such as sharks. If an octopus is in danger, it shoots a jet of water out of its body. This moves the octopus backward very quickly. An octopus also may release an inky fluid to darken the water and confuse an enemy.

A female octopus lays her eggs under rocks or in holes. She guards the eggs for four to eight weeks. Upon hatching, the young drift for several weeks before going to the ocean bottom

This video has been taken by me @ CineAqua, Paris, France.