Halibut

The Halibut fish is a large and flat-bodied fish that is found in the flounder family. Like all other flounders, it consists of both of their eyes on the top side of its flattened body. The common name given for three flatfish is halibut, which belongs to the genus Hippoglossus from the family of right-eye flounders. The word is derived from holy and butte or flatfish for its popularity on Catholic holy days. Halibut fishes are demersal fish, and these are highly considered as a food fish as well as a sport fish. Halibut’s meaning is as follows: it is a marine flatfish that belongs to the genus Hippoglossus used widely as food.

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Halibut Fish Description

Physical description: The Atlantic halibut fish is considered the world's largest flatfish. In July 2014, a 219-kilogram Pacific halibut was caught in Glacier Bay, Alaska. Halibut fishes are dark brown in colour along the top side, which has an off-white underbelly and have very small scales. These small scales are invisible to our naked eyes as they are found embedded in their skin. Halibuts are symmetrical in nature at birth which have one eye on each side of the head. Then six months later, during the larval stage of metamorphosis, one of the eyes migrates to the other side of the head. Halibut eyes are set permanently once the skull is found to be ossified fully. At the same time, the stationary-eyed side of the fish darkens in order to match the top side, whereas the other side remains white. This colour scheme helps the halibut to disguise from above and from below, which is known as countershading.

Habitat: This fish utilises demersal habitat or habitats along the seafloor. It primarily lives along the shelf of the continent, which is the region that is slightly offshore but before the deep sea. During some seasons, they utilise shallower waters, and during others, they swim into deeper regions. Their preferred ranges of habitat in temperature are between approximately 37 and 47 degrees Fahrenheit.

Distribution: The two primary species of halibut fishes live in the regions of the Atlantic and Pacific Oceans. The fish of the Pacific ocean lives near the coastline that is present along the northern Pacific Ocean, from the regions of the western coasts in North America up to Alaska and across eastern Russia and Asia. The Atlantic species ranges along both the eastern and western coasts of the Atlantic Ocean.

Diet: These fishes are carnivorous animals, which means that they depend on other animals for feeding. Because they can grow to such large sizes, the adults can primarily feed on other fish species. Some common prey includes capelin, cod, herring, haddock, and more. They also prey on crustaceans, squid, and virtually anything that they can swallow.

Behaviour: This fish hunts for prey using an ambush. By blending in with the bottom, it waits for the prey to stray too close. They can migrate seasonally in order to congregate in larger numbers to undergo spawning. The fish can move from the regions of shallow waters to deeper regions during the winter season to reproduce.

Reproduction: These fishes can undergo breeding through the process of spawning, where the female fishes release eggs into the water, and the male fishes fertilise them outside of their body. A single female fish can produce several million eggs in a season. It takes around two weeks for these eggs to hatch. In the larval stage, the young ones receive no parental care, and simply they can float in the water for some time. Once they reach their juvenile phase, their eyes get migrated to the right side of their bodies, and they start their life on the bottom. For the female halibut fishes, it will take at least eight years to reach the stage of sexual maturity.

Health Benefits of Halibut Fish

Halibut is considered an excellent source for the mineral selenium, a trace of the mineral with many of the health benefits that a human body requires in small amounts. A fully cooked half-filet of the halibut fish is the recommended serving size, it can provide over 100% of the daily dietary needs. Selenium acts as a powerful antioxidant that helps the body to repair the damaged cells and can decrease inflammation. It can also play an important role in maintaining thyroid health.

In addition to this, the halibut fish is a good source of several types of other micronutrients that involves contributing to good health, including:

• Niacin: Niacin plays an important role in heart health, and it even helps to prevent certain kinds of heart diseases. It also involves the protection of skin from sun damage. A half-filet of halibut fish can provide 57% of the essential dietary needs.

• Phosphorus: Phosphorus is the second most abundant mineral that is found in the human body, phosphorus helps in building bones, regulates the process of metabolism, helps to maintain a regular heartbeat and more.

• Magnesium: Magnesium is necessary for taking more than 600 reactions in the human body; this includes the formation of proteins, movements of muscles and energy creation.

• Vitamin B12: Vitamin B12 acts as an essential micronutrient in the formation of red blood cells and is involved in the proper functioning of the human nervous system. It is naturally found in animal foods.

• Vitamin B6: Vitamin B6 is also known as pyridoxine. It is involved in undertaking hundreds of reactions in the human body. It is beneficial to boost brain function and the proper functioning of the central nervous system.

Halibut Fish Possible Concerns

With any of the food, there will be certain potential concerns that have to be considered before eating the halibut fish.

Mercury Levels: Mercury is considered a heavy toxic metal that is found naturally in water, air, and soil. Fishes are prone to get exposed to lower concentrations of mercury that is present in the water due to water pollution. Over some time, the metal can get built up in the body of the fish. Thus the larger fishes and those fishes which have longer life spans often contain more amounts of mercury. Some of the fishes like shark, King mackerel, tilefish, orange roughy, swordfish, and ahi tuna are known to carry the highest risk of mercury contamination. In most people, the mercury levels that are consumed by having the fish and shellfish in recommended amounts is not a major concern. The benefits of consuming moderate amounts of fish that are rich in omega-3 fatty acids, such as halibut, may outweigh the risk. Whereas pregnant and nursing mothers should completely avoid consuming high-mercury fish. Omega-3 fatty acids help in the brain development of both fetuses and babies. Halibut fishes are considered to have low to moderate levels of mercury content and are considered to be safe to eat in moderate amounts.

Purine Content: Purines are found to be produced naturally in the body and are found in certain foods. These get broken down to form uric acid, which can result in gout and the development of kidney stones in some people. Those who are at risk of these conditions should limit the intake of purine content from certain foods. Even though the halibut fishes contain purines, their levels can vary from low to moderate. Therefore, these are considered to be safe for those who are healthy and not at risk of certain kidney diseases.

Sustainability: Sustainability is a major concern with the increased demand for fish that are wild-caught. One of the ways to sustain the populations of wild fish is to increase the availability of the farmed fish. It’s the fastest-growing food production in the world. According to the Seafood Watch, wild Atlantic halibut fish are on the avoid list due to their low population. It has been found to be overfished and is not expected to repopulate until 2056. Pacific halibut species are thought to be safe in order to consume due to their sustainable fishing practices that are enforced in the Pacific Ocean.

Interesting Facts about Halibut Fish

The halibut fishes have a number of interesting traits and adaptations. Let us learn more about these fishes and what makes them unique.

• Eye: Like all of the fishes from the flounder’s families, the eyes of the halibut fish do not start life with both of the eyes present on one side of their heads. When they are hatched, they have only one eye on either side of the head like most fishes. As they get older, one of these eyes migrates to the other side.

• Larval Lifestyle: The larva of these fishes that are newly hatched not only have normal eyes but along with that, they also live more like the typical fishes. They have a pelagic lifestyle and can swim in open waters. Once they reach their juvenile stage, they begin their demersal life living on the seafloor.

• Overfishing: People target these fishes for both the purposes of sport and commercial fishing. They eat the meat, and sport fishermen target the largest fishes for their strength and powerful swimming during capture.

• Slow-Growing: Unfortunately, the people have fished these creatures heavily, their numbers have suffered a lot. Because these fishes can live for a long time, they are also slow to reach their maturity and replenish their populations.

Other Species of the Hippoglossus Genus

Atlantic halibut, Hippoglossus hippoglossus: The Atlantic halibut is a flatfish of the family Pleuronectidae. These are the demersal fishes that are found living on or nearby sand, gravel, or clay bottoms at a depth of between 50 and 2,000 m. The halibut fish is one of the largest teleost fishes that are found in the world, and it is considered an endangered species due to its slow rate of growth and overfishing. Halibut fishes are strong swimmers, and they are capable of migrating to long distances. The size of halibut fishes is not age-specific, but rather they tend to follow a cycle that is related to halibut abundance.

The native habitat of these Atlantic halibut fishes is the temperate and arctic waters present in the northern Atlantic, from the regions of Labrador and Greenland to Iceland. It is considered the largest flatfish that is found in the world, reaching lengths of up to 4.7 m and weights of 320 kg. Its lifespan can reach 50 years.

Pacific Halibut, Hippoglossus Stenolepis: The Pacific halibut fish is a species of fish of righteye flounder. This is a very large species of flatfishes that are native to the regions of the North Pacific, and these are fished by certain sport fishers, commercial fisheries, and subsistence fishers. The Pacific halibut is found to be present on the regions of the continental shelf of the North Pacific Ocean and the Bering Sea. Fishing for the Pacific halibut is mostly concentrated in the regions of the Gulf of Alaska, the Bering Sea, and off the west coast of Canada. Small halibut fish catches are reported in the regions of Oregon, coastal Washington, and California.

Greenland Halibut, Reinhardtius Hippoglossoides: The Greenland turbot or Greenland halibut fishes belongs to the family Pleuronectidae, and it is considered as the only species present in the genus Reinhardtius. It is considered a predatory fish that ranges mostly at the depths of between 500 and 1,000 m, and it is also found in the regions of Northern Pacific, cold Northern Atlantic, and Arctic Oceans. It has several other names, including blue halibut fish, black halibut fish, Newfoundland turbot, and lesser halibut. While both Newfoundland turbot and Greenland turbot names are commonly used in North America.

The Greenland halibut fish supports the important fisheries, and it is caught in large quantities. An argument over the rights of fishing for the species of Greenland halibut in the regions of the Atlantic Ocean off Canada is caused due to the Turbot War in the mid-1990s. The Greenland halibut fish is a flatfish, and during the development of the fish, the left eye gets migrated so that it is found present on the right side of the head. The Greenland halibut fish can swim in a vertical position, and both of the sides of the body is a speckled brown in colour, whereas the left side of the fish is rather paler than the right.