Types of Extinct Fish

Freshwater

• Freshwater fish live in freshwater lakes, rivers and seas around the globe. Some of the fish that have gone extinct died as a result of the destruction of their habitat, such as the Acanthobrama hulensis, which lived in the Hula lake of Israel before it was largely drained for irrigation. Other fish, such as the deepwater cisco of Lake Huron and Lake Michigan, died as a result of overfishing combined with natural predation.

Saltwater

• Saltwater fish live in oceans and in salty seas such as the Mediterranean Sea and Black Sea. The IUCN currently lists one saltwater fish that has gone extinct, the New Zealand grayling. The New Zealand grayling lived in saltwater but used freshwater areas as a breeding ground. It appears that the grayling died out partially as a result of unnatural competition of alien species such as trout introduced into their freshwater breeding grounds, as well as the destruction of their habitat caused by irrigation and drainage.

Prehistoric

• Many species of fish died out in prehistoric times, unrelated to human activity. The dunkleosteus lived 400 million years ago; it was an armored fish with sharp, piercing teeth. It grew to at least 20 feet long and resembled modern sharks, the ancestors of which the dunkleosteus may have eaten for food. It died during the Devonian mass extinction event around 365 million years ago. Another massive fish was the megalodon, the largest shark species to exist, which lived approximately 2 million years ago. While the exact cause of the megaladon's extinction is unknown, paleontologists speculate that its source of food died during the Ice Age.

Lampreys

• Lampreys are a type of jawless fish that resemble eels. The IUCN records one modern lamprey species as extinct, the Ukranian migratory lamprey. This lamprey appears to have died out in the late 19th century, although the exact causes remain unknown. According to the IUCN, some researchers speculate that the lamprey died as a result of targeted overfishing.