Aquatic and Marine Biology

Composite fish culture system is a technology developed in India.

Pisciculture is fish farming which is a type of aquaculture. Mariculture is also a type of aquaculture done in ocean.

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 Refer to question 16.

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Fish polyculture means cultivating various species of fish together by fully using all water level food available in the pond and increasing fish production in the highest stage. The fish species which don’t contest with each other for food and habitat are suitable for polyculture.

Aquatic habitat refers to the water bodies. Cactus is a xerophytes i.e. desert plant, reindeer lives in the regions with lower temperature, pines on the mountain region. So it is the sea horse, water lilies and whales which all live in the water bodies and are thus belonging to aquatic animals.

There are some aquatic animals like squids, octopus etc. which do not have streamlined body. They stay deeper in the sea and catch any prey coming towards them. However they make their bodies shape streamlined when required.

Snail is an animal which is having outer skeleton called shell or the lid. It has a foot made of strong muscles. It is a very slow moving animal with a wavy motion.

Birds are the living organisms which can fly in the air and walk on the ground. Pigeon, vulture and sparrow are not at all adapted to swim in water but birds like swans and ducks are adapted for the same.

Different organisms have different mode of movement from one place to another. E.g. fish swims in water, human beings walk, monkey jump and snake slithers to move from one place to another. Slithering is the zig-zag movement of the whole body of snake. Also earthworm moves by crawling and cockroach by climbing. So, it is snakes: walking which is a mismatched pair.

Streamlined body is found in organisms which are adapted for flying or swimming. It helps them to cut through air and water currents. Snake is a terrestrial animal which does not have a streamlined body.

Fish swim in water as they have a streamlined body. They also need to maintain balance so that they may not sink down. For this purpose, they have fins which act as balancer organ for them.

Snakes slither to move from one place to another. Slithering is the zigzag movement of the whole body of snake.

Habitat of animals and plants in different regions depends upon their body structure and their adaptability. For example, animals like Yak, lions and ants live on ground and are known as terrestrial animals. Animals like fish, whales, sharks live in water and are known as aquatic animals. Crab is an animal which is generally found on the sea shores or beaches as it is neither completely terrestrial nor aquatic.