Marine Life

This hall at the Natural History Museum of Venice demonstrates some of the characteristics that fish and other living things use to survive in and move through ocean waters.

The largest ocean predators, the sharks and sea mammals, are themselves prey for other large predators, especially human beings. Overfishing by modern commercial fishing operations has reduced the populations of both large predators and the smaller fish and other organisms on which they feed.

Earth’s oceans are home to millions of species, from microscopic plankton to sharks and large mammals. Sharks like these are near the top of the ocean food web. Sharks feed on smaller sharks, fish, and krill.

Some fish species are relatively tall and flat; others are long and thin. The shape of each species is an adaptation that gives it a survival advantage in its own habitat. Fin shapes and tail shapes also help species propel themselves, attain speed, and achieve balance.

Cetaceans are marine mammals and among the largest animals in the ocean. The order Cetacea includes dolphins, porpoises, and whales. Pinnipeds (seals, sea lions, and walruses) are also marine mammals. These species are all carnivorous, with diets that include fish, squid, and krill.

Maldives is a small island nation in the Indian Ocean. The islands were formed by coral, which built reefs and atolls on the foundations of an ancient underwater volcano. About 200 of the over 1,200 islands are inhabited.

The colorful coral reefs attract divers and other tourists from around the world, but the influx of visitors is changing the ecological balance of this unique environment. To protect the reefs and the fishing industry on which the islanders depend, the nation stringently regulates tourism. 

The species Plectorhinchus vittatus gets its popular name from its lips, which are larger and more fleshed out those of most fish species. Adults have tall, thin, streamlined bodies striped in black and white, with bright yellow faces, tails, and fins. They swim alone or in groups.

The species Heniochus acuminatus has several popular names, including pennant coralfish and reef bannerfish. These fish live in relatively protected environments, such as deep channels and lagoons. Their major food source is plankton. They swim alone or in pairs and small groups.

Coral bleaching, or whitening, is a sign that a coral reef is deteriorated or dying. As a coral reef declines, so do the species of living things that depend on it. Bleaching has several causes, including changes in ocean water temperature and salinity, and chemical pollution. 

Climate Change and Coral Bleaching - Before and After document the effects of coral bleaching at Airport Reef, American Samoa. These reefs are bleaching at an alarming rate. Scientists are concerned about coral bleaching because coral reefs are feeding and spawning grounds for millions of species.

In 2014, the branching stems in this vast bed of coral were covered with microscopic reddish brown plants, with light lavender tips. Light green mosses and colonies of algae also grew among the coral. Small, bright blue and turquoise fish darted above the reef bed.