Fish go through various life stages between fertilization and adulthood. The life of fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac which provides stored nutrition. Before the yolk sac completely disappears, the young fish must mature enough to be able to forage independently. When they have developed to the point where they are capable of feeding by themselves, the fish are called fry. When, in addition, they have developed scales and working fins, the transition to a juvenile fish is complete and it is called a fingerling, so called as they are typically about the size of human fingers. The juvenile stage lasts until the fish is fully grown, sexually mature and interacting with other adult fish.
Ichthyoplankton (planktonic or drifting fish) are the eggs and larvae of fish. They are usually found in the sunlit zone of the water column, less than 200 metres deep, sometimes called the epipelagic or photic zone. Ichthyoplankton are planktonic, meaning they cannot swim effectively under their own power, but must drift with ocean currents. Fish eggs cannot swim at all, and are unambiguously planktonic. Early stage larvae swim poorly, but later stage larvae swim better and cease to be planktonic as they grow into juveniles. Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply. Both eggs and larvae are themselves eaten by larger animals. [1] [2]
According to Kendall et al. 1984 [2] [3] there are three main developmental stages of fish:
This article is about the larval and juvenile stage.
Fry and fingerling are generic terms that can be applied to the juveniles of most fish species, but some groups of fishes have juvenile development stages particular to the group. This section details the stages and the particular names used for juvenile salmon.
Juvenile fish need protection from predators. Juvenile species, as with small species in general, can achieve some safety in numbers by schooling together. [10] Juvenile coastal fish are drawn to turbid shallow waters and to mangrove structures, where they have better protection from predators. [11] [12] As the fish grow, their foraging ability increases and their vulnerability to predators decreases, and they tend to shift from mangroves to mudflats. [13] In the open sea juvenile species often aggregate around floating objects such as jellyfish and Sargassum seaweed. This can significantly increase their survival rates. [14] [15]
Juvenile fish are marketed as food.
Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, jellyfish, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals can be divided into species that undergo complete metamorphosis ("holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis ("ametaboly").
Plankton are the diverse collection of organisms that drift in water but are unable to actively propel themselves against currents. The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales.
A leptocephalus is the flat and transparent larva of the eel, marine eels, and other members of the superorder Elopomorpha. This is one of the most diverse groups of teleosts, containing 801 species in 4 orders, 24 families, and 156 genera. This group is thought to have arisen in the Cretaceous period over 140 million years ago.
The European eel is a species of eel. They are critically endangered due to hydroelectric dams, overfishing by fisheries on coasts for human consumption, and parasites.
The American eel is a facultative catadromous fish found on the eastern coast of North America. Freshwater eels are fish belonging to the elopomorph superorder, a group of phylogenetically ancient teleosts. The American eel has a slender, supple, snake-like body that is covered with a mucus layer, which makes the eel appear to be naked and slimy despite the presence of minute scales. A long dorsal fin runs from the middle of the back and is continuous with a similar ventral fin. Pelvic fins are absent, and relatively small pectoral fins can be found near the midline, followed by the head and gill covers. Variations exist in coloration, from olive green, brown shading to greenish-yellow and light gray or white on the belly. Eels from clear water are often lighter than those from dark, tannic acid streams.
The Atlantic mackerel, also known as Boston mackerel, Norwegian mackerel, Scottish mackerel or just mackerel, is a species of mackerel found in the temperate waters of the Mediterranean Sea, the Black Sea, and the northern Atlantic Ocean, where it is extremely common and occurs in huge shoals in the epipelagic zone down to about 200 m (660 ft). It spends the warmer months close to shore and near the ocean surface, appearing along the coast in spring and departing with the arrival of colder weather in the fall and winter months. During the fall and winter, it migrates out into deeper and more southern water, seeking warmer temperatures.
A salmon run is an annual fish migration event where many salmonid species, which are typically hatched in fresh water and live most of the adult life downstream in the ocean, swim back against the stream to the upper reaches of rivers to spawn on the gravel beds of small creeks. After spawning, all species of Pacific salmon and most Atlantic salmon die, and the salmon life cycle starts over again with the new generation of hatchlings.
The Atlantic salmon is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlantic salmon are found in the northern Atlantic Ocean and in rivers that flow into it. Most populations are anadromous, hatching in streams and rivers but moving out to sea as they grow where they mature, after which the adults seasonally move upstream again to spawn.
The coho salmon is a species of anadromous fish in the salmon family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon and is often sold as medium red salmon. The scientific species name is based on the Russian common name kizhuch (кижуч).
Doryteuthis opalescens, the opalescent inshore squid or market squid, is a small species of squid in the family Loliginidae. It is a myopsid squid, a near shore group with corneas over their eyes. The species is found in the eastern Pacific Ocean from Baja California, Mexico to Alaska, United States, and as an inshore squid can be found within a range of 200 miles (320 km) off the coast.
The New Zealand sand flounder is a righteye flounder of the genus Rhombosolea, found around New Zealand in shallow waters down to depths of 100 m.
King-of-the-salmon, is a species of ribbonfish in the family Trachipteridae. Its common name comes from the legends of the Makah people west of the Strait of Juan de Fuca, which hold that this fish leads the salmon annually to their spawning grounds. Catching or eating king-of-the-salmon was forbidden, as it was feared killing one would stop the salmon run. This myth is reflected by a former specific epithet used for this fish, rex-salmonorum, rex being Latin for "king". The king-of-the-salmon is found in the eastern Pacific Ocean from Alaska to Chile. It is usually found in the open ocean to a depth of 900 meters, though adults sometimes feed on the sea bottom.
Holacanthus bermudensis, also known as the blue angelfish or Bermuda blue angelfish, is a species of ray-finned fish, a marine angelfish belonging to the family Pomacanthidae. It occurs in the western Atlantic Ocean.
The green sturgeon is a species of sturgeon native to the northern Pacific Ocean, from China and Russia to Canada and the United States.
The leopard coral grouper, also known as the common coral trout, leopard coral trout, blue-dotted coral grouper or spotted coral grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It is found in the Western Pacific Ocean.
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of freely releasing eggs and sperm into a body of water ; the physical act is known as spawning. The vast majority of aquatic and amphibious animals reproduce through spawning. These include the following groups:
Whitebait is a collective term for the immature fry of fish, typically between 25 and 50 millimetres long. Such young fish often travel together in schools along coasts, and move into estuaries and sometimes up rivers where they can be easily caught using fine-meshed fishing nets. Whitebaiting is the activity of catching whitebait.
The Indian oil sardine is a species of ray-finned fish in the genus Sardinella. It is one of the two most important commercial fishes in India. The Indian oil sardine is one of the more regionally limited species of Sardinella and can be found in the northern regions of the Indian Ocean. These fish feed on phytoplankton (diatoms) and zooplankton (copepods).
Ichthyoplankton are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the epipelagic or photic zone. Ichthyoplankton are planktonic, meaning they cannot swim effectively under their own power, but must drift with the ocean currents. Fish eggs cannot swim at all, and are unambiguously planktonic. Early stage larvae swim poorly, but later stage larvae swim better and cease to be planktonic as they grow into juveniles. Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply. Both eggs and larvae are themselves eaten by larger animals.
The Pacific sandfish is a species of sandfish native to the Pacific coast of North America, from San Francisco Bay to Unimak Island in the Aleutian Islands. Like its cousin the sailfin or Japanese sandfish, the Pacific sandfish is a small, deepwater fish distributed over sandy and muddy depths. It is not valued for sushi like its Japanese cousin, but is occasionally caught from piers by recreational anglers.