What is the biggest fish in the sea?

Picture taken at Georgia Aquarium, pictured is...

Image via Wikipedia

The whale shark is the biggest fish on the planet. The largest whale shark measures about 66 feet long and 74,957 pounds.

Not to be confused with the blue whale, a mammal, which is the largest animal on the planet. The largest blue whale measured about 110 feet and up to 400,000 pounds!

The whale shark got its name because the shark’s mouth is shaped just like baleen whales. Baleen whales and whale sharks both munch on krill. For being the largest fish in the sea the whale shark is surprisingly affable to divers and known as a relaxed fish.

How are ‘whale sharks’ and ‘whales’ different?

Whales are mammals, just like people, and must breathe air. Dolphins, seals, porpoises, otters (and some people say, polar bears) are mammals that live in the ocean (ie., marine mammals).

Another difference is that mammals raise their young. Whale sharks give live birth like mammals, but, move on right after and don’t raise them. Most other fish do lay eggs.

Fish also have gills to breathe underwater, unlike mammals that must come up to the surface of the ocean and breathe air.

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Can you tell how old a fish is by looking at it?

fishscaleagerings1There is one possible way to tell how old a fish is while it’s still alive. And, at that, – it’s pretty invasive. You need to take some of its scales (see image).

The scales are similar to the rings of a tree. Depending on how many dark rings you may see (if you were to hold the scale up to a light source) it will determine the age of the fish. However, since scales can regenerate often, the rings could be cloudy and difficult to decipher.  You can get a more accurate age of a fish by other methods which require the fish to be dead. These include reading the rings on the cross-section of a fish ear bone (otolith) or fin ray.

Knowing the age of a fish is very important for understanding how to maintain populations and stocks for fisheries management.

Image (c) eralabs.com.

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