VPP 322: Aquatic Animal Diseases, Health Care and Management (1+1)

AQUATIC ANIMAL ECOLOGY

• Ecology is defined as the study of the relation of living organisms with each other and their surroundings.
• Ecosytems are defined as the community or net work of individuals, feed back between the living (biotic) and nonliving (abiotic) components of an environment.
• An aquatic ecosystem is an ecosystem located in a body of water.
• Major types of aquatic ecosystem are
  • Marine ecosystem
  • Freshwater ecosystem

Marine ecosytem

• Characterised by the saline water environment which covers approximately 71% of the Earth's surface .
• They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts in the water. Approximately 85% of the dissolved materials in seawater are sodium and chloride.
• Seawater has an average salinity of 35 parts per thousand (ppt) of water. Actual salinity varies among different marine ecosystems

Zonation of marine ecosystems

• Oceanic zone which is the open part of the ocean where animals such as whales, sharks, and tuna live
• Profundal zone which is the bottom or deep water
• Benthic zone which include the bottom substrates
• Intertidal zone which is the area between high and low tides
• Estuaries which form a transition zone between river environment and ocean environment
• Salt marshes which is the upper coastal intertidal zone between land and brackishwater (Saltwater)
• Coral reefs which are underwater structures made from calcium carbonates secreted by corals (colonies of tiny living animals found in marine environment)
• Hydrothermal vents are environments where chemosynthetic sulfur bacteria form the food base
• Organisms that are found in the marine environment include algae, dinoflagellates, corals, fin fishes, cephalopods, echinoderms etc.,

Freshwater Ecosystem

• Characterised by the freshwater environment (with no salinity or salt concentration)
• Freshwater ecosystems cover 0.80% of the Earth's surface and inhabit 0.009% of its total water.
• Freshwater ecosystems contain 41% of the world's known fish species

Types of freshwater ecosystems

• Lentic ecosystem is characterised by slow-moving water, including pools, ponds and lakes
• Lotic ecosystem is characterised by rapidly-moving water as in streams and rivers

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