Lingcod 4

The lingcod or ling cod (''Ophiodon elongatus'') is a fish of the greenling family Hexagrammidae. Despite its name, the lingcod is neither a cod nor a ling. It is also known as the buffalo cod, cultus cod, or Buckethead. It is the only extant member of the genus Ophiodon. A slightly larger, extinct species, '' Ophiodon ozymandias'', is known from fossils from the Late Miocene of Southern California.

''Ophiodon elongatus'' is native to the North American west coast from Shumagin Islands in the Gulf of Alaska to Baja California, Mexico. It has been observed up to a size of and a confirmed weight of , with unconfirmed reports of fish weighing more than .
It is spotted in various shades of gray. The lingcod is a popular eating fish and is thus prized by anglers. Though not closely related to either ling or cod, the name "lingcod" originated because it somewhat resembles those fish. Around 20% of lingcods have blue green to turquoise flesh.^p. 298 The color, which is no longer present after cooking, may be due to biliverdin, but this has not been established beyond doubt.

Description

Lingcods have several variations in their appearance, including dark gray, blue, brown, or green coloring on the back, sometimes accompanying mottling or spotting on the upper back that is copper colored. The belly is typically lighter than the body. Lingcod typically has a large head and mouth where the upper jaw extends posteriorly past the eyes. They have 18 large and sharp teeth that are canine-like. This body of a lingcod resembles a fusiform body plan, indicating their primary mode of movement is quick, short, bursts. The head of a lingcod is unscaled and has a cirrus above the eye. Lingcod's lateral line is prominent and white while the body is covered in cycloid scales. The dorsal fin is composed of spines and rays, separated by a notch. The anal fin also contains 3 spines. Lingcod do not have a swim bladder. Lingcod grows relatively quickly and up to 5 feet (60 inches or 152 centimeters) or but has been reported to weigh .

Polymorphism of Lingcod

About 20% of the lingcod population in the Pacific Ocean on the west coast of North America presents a blue coloration, while the other 80% presents with the brown coloration morphology. Blue lingcods have blue coloration in both the external and internal tissue. In general, the effect of blue polymorphism observed in other fish species, such as other members of the family Hexagrammidae and family Cottidae, can be from the bile pigment biliverdin. Biliverdin is a product of heme catabolism which circulates the lymph and suffuses tissues. However, this hypothesis has not been tested in lingcod. Dysfunction of the liver or gallbladder may also result in biliverdin permeating tissues and biliverdin is also linked to starvation. Anecdotally, blue coloration in lingcod has been thought to be caused by dietary preferences through the individual preference of the consumption of prey items that have increased levels of biliverdin in their tissue or prey items that trigger biliverdin release. Another species which also experiences blue coloration and lives in the same range of the Lingcod is the Cabezon (''Scorpaenichthys marmoratus'') from the which may support the theory that the coloration depends on the fish's diet and environment.

A study examining the relationship between parasites and lingcods from the coast of Alaska, Washington, and California, USA found that blue male lingcods carried 1.89 times more parasites brown counterparts. However, the study found that there was no difference in blue and brown female lingcod regarding parasite burden despite blue coloration being more common in females. The discrepancy in the burden of parasites between male and female lingcod may be because male vertebrates' immune systems are typically less effective than females since male sex hormones have immunocompromising properties.

The same study found that blue Lingcod individuals of both sexes have a lower hepatosomatic index value, which may indicate blueness is also an indication of poor body condition. The exact mechanism behind the production of blueness is not yet determined. One explanation includes that parasites may cause physiological damage to the fish, producing blueness as a result. Another possible explanation is that starvation may be the driving factor for blue coloration and parasite burden, but this factor is unmeasurable. Moreover, the study's findings suggest that the immune system may play a role in blue coloration, but when coupled with parasitism expresses a role in the population dynamics of lingcod. Future studies are required for further determination of the cause of polymorphism of Lingcod.

Range & Habitat

Ophiodon elongatus is native to the North American west coast from the Shumagin Islands in the Gulf of Alaska to Baja California, Mexico. They are found on the bottom, with most individuals occupying rocky areas at depths of , however, Lingcod has been found at depths of . Tagging studies have shown lingcod is a largely nonmigratory species, with colonization and recruitment occurring in localized areas only.DFO, 2001, Lingcod, DFO Science Stock Report A6-18
However, Lingcod are the most abundant near British Columbia, Canada, and Washington, USA. The Lingcods within this range are composed of two stocks, whose status is maintained by NOAA Fisheries: The Northern Pacific stock and the Southern Pacific stock.

When lingcod are in their larvae life stage, they typically live near the surface of the ocean. At the juvenile life stage, lingcod live on sandy ocean bottoms with eelgrass