Pelagic fish

Pelagic fish are fish species that inhabit the pelagic zone of ocean or lake waters. They are neither close to the bottom nor near the shore in contrast to demersal fish and reef fish. The term "pelagic" comes from the Ancient Greek πέλαγος (pélagos), meaning 'open sea'. The marine pelagic environment is the largest aquatic habitat on Earth, occupying 1,370 million cubic kilometers (330 million cubic miles), and is the habitat for 11% of known fish species.

Characteristics

Pelagic fish are typically powerful swimmers with streamlined bodies capable of sustained cruising on long-distance migrations. They have a high metabolic rate, a broad diet, and a rapid growth rate. Some species are the fastest-swimming creatures in the sea, often with a crescent-shaped tail and slim body shaped like a spindle tapered at both ends. They have a large amount of myoglobin, a protein that binds oxygen, in their muscles, which allows them to be active predators with high stamina.

Types of Pelagic Fish

Pelagic fish can be categorized into two main types: coastal and oceanic. Coastal pelagic fish inhabit the relatively shallow and sunlit waters above the continental shelf, while oceanic pelagic fish, also known as deep sea or open ocean fish, live in the wide open ocean, often at great depths.

Coastal Pelagic Fish

Coastal pelagic fish are abundant in the cold waters of the Pacific Ocean. They include species such as anchovies, sardines, mackerel, and herring. These species often form large schools, and are an important source of food for larger predators.

Oceanic Pelagic Fish

Oceanic pelagic fish include species like tuna, marlin, and swordfish. These species are capable of long-distance migrations and deep dives. They are also important as top predators in the marine food chain.

Importance to Humans

Pelagic fish are important to humans as food, and are also central to the worldwide commercial and recreational fishing industries. Many species are widely consumed by humans; they are rich in omega-3 fatty acids which are beneficial to human health.

Threats and Conservation

Overfishing and climate change represent significant threats to pelagic fish populations. Many species are currently overfished, and overfishing can have negative effects on pelagic ecosystems. Climate change can alter conditions in pelagic ecosystems through changes in water temperature and ocean acidification.