We know that most fishes lay eggs. These eggs are fertilized outside the body. Fishes that emit eggs are described as oviparous. But some fishes give birth to living young. These are described as viviparous.
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Among the viviparous fishes are guppies, platies, swordtails and mollies. The eggs are fertilized inside the body of the female and grow into baby fish there. At the appropriate time, they are born. In platies it is 21 days after fertilization.
The number of eggs that are laid and fertilized vary a great deal from one kind of fish to another. some fishes expel their eggs and then abandon them, showing no more interest in them. These kind of fishes lay great numbers of eggs. Those fishes that watch over their developing young lay far fewer eggs.
Fishes also lay two types of eggs. One type floats and the other sinks. Eggs that float are called pelagic eggs. They are usually tiny and transparent and do not have much yolk. Eggs that sink are called demersal eggs. They are usually heavier and yolky.
As an example, herring lay demersal eggs and show no care for these eggs. They may deposit 20,000 to 40,000 eggs. Cod, on the other hand, lay pelagic eggs. An average-sized cod can lay one hundred million eggs!
Mackerel lay 400,000 to 500,000 eggs in a season, but they never lay more than 50,000 at a time. Large halibut can lay over two million eggs!
Eggs vary in size, too. Herring eggs are one millimetre in diameter. Cod eggs are about 1.5 millimetres. Halibut eggs are 3 millimetres. eggs that are guarded until the young are larger have greater chance for survival. But millions and millions of fish eggs are eaten by other creatures.
Image Source: www.diverosa.com
The number of eggs that are laid and fertilized vary a great deal from one kind of fish to another. some fishes expel their eggs and then abandon them, showing no more interest in them. These kind of fishes lay great numbers of eggs. Those fishes that watch over their developing young lay far fewer eggs.
Fishes also lay two types of eggs. One type floats and the other sinks. Eggs that float are called pelagic eggs. They are usually tiny and transparent and do not have much yolk. Eggs that sink are called demersal eggs. They are usually heavier and yolky.
As an example, herring lay demersal eggs and show no care for these eggs. They may deposit 20,000 to 40,000 eggs. Cod, on the other hand, lay pelagic eggs. An average-sized cod can lay one hundred million eggs!
Mackerel lay 400,000 to 500,000 eggs in a season, but they never lay more than 50,000 at a time. Large halibut can lay over two million eggs!
Eggs vary in size, too. Herring eggs are one millimetre in diameter. Cod eggs are about 1.5 millimetres. Halibut eggs are 3 millimetres. eggs that are guarded until the young are larger have greater chance for survival. But millions and millions of fish eggs are eaten by other creatures.
Awesome share! Thank you very much :)
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