Fascinating Fact
Salmon are famous for migrating between the sea and rivers, feeding at sea before returning to freshwater to spawn.
Sea fish live in habitats ranging from shallow rock pools to deep, dark waters. Different species have evolved body shapes, colours, and behaviours that suit where they feed and hide, whether that is in open water, among reefs, or on the seabed. Learning a few key features, like mouth position, fin shape, and body patterning, can make identification much easier.
Key Terms
- Pelagic: Living in the open sea, away from the shore and the seabed.
- Demersal: Living on or near the seabed, often feeding along the bottom.
- Gills: Breathing organs that take oxygen from water as it flows over them.
Frequently Asked Questions (Click to see answers)
What is the difference between pelagic and demersal fish?
Pelagic fish live and feed in open water, while demersal fish stay on or near the seabed. Their body shapes often match their habitat, with many demersal fish adapted for bottom-living.
How do sea fish breathe underwater?
Sea fish breathe using gills. Water passes over the gill surfaces, and oxygen moves into the blood while carbon dioxide moves out, so the fish can breathe without coming to the surface.
Why do some fish swim in shoals?
Shoaling can reduce the risk of predators by making it harder to target one fish. It can also help fish find food and stay together while travelling through the sea.
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