Lingcod
The lingcod or ling cod 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.
Distribution and 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. However, lingcod are the most abundant near British Columbia, Canada, and Washington, USA. The lingcod 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 or kelp beds near the shore. More specifically, year 1 lingcod are found in homogeneous soft sediment to avoid predation from adult lingcod as well as wave relief areas. Meanwhile, year 2 lingcod are found usually near alternating sizes of rock substrates with varying combinations of moderate and low relief but still in generally shallow waters. As lingcod approach adulthood, they move to more rocky habitats or into seaweed, kelp, and eelgrass beds. The benefit of this habitat is food abundance. Year 3+ lingcod are positively associated with a hard substrate such as rocky reefs and generally deeper waters as well. Such a shift in habitat based on the life stages portrays lingcod's ontogenetic shift.
Typically, female lingcod will migrate seasonally to spawn but male lingcod prefer to stay near the familiar habitat in which they were born. However, in certain cases, there have been cases of immature lingcod migrating more than. Females mainly go to more shallow waters to lay eggs. Lingcod have a narrow home range and show territorial behaviors. This behavior aids lingcod in returning to the same reef for spawning.
Description
Lingcod 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 grow relatively quickly, up to 5 feet and, but has been reported to weigh.Polymorphism
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 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 than their 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.
Diet
Adult lingcod are aggressive predators. They consume other bottom-dwelling fish, including other lingcod, squid, octopus, and crab. They are "known to prey on almost anything they can get in their mouths."Larval lingcod feed on zooplankton, krill, and larval crustaceans, while juvenile lingcod feed on small fish.
Lingcod are most vulnerable to predators as eggs and larvae. Adult males therefore guard the egg nests. But this makes them vulnerable to predation by seals, sea lions, and anglers.
Lifecycle and reproduction
Lingcod can also live more than 20 years but typically only live up to 14 years for males and 20 years for females.Starting in November, male lingcod migrate to nearshore spawning grounds and establish territories. Such interannual nest fidelity coupled with great precision of the site is one of the first recorded examples of such behaviors in temperate marine fish. This behavior also provides evidence that male Lingcod's selection for nesting sites are a component of prespawning mate attraction behavior.
Spawning likely occurs at night and occurs annually between January and March. A female lingcod may lay up to 500,000 eggs in a nest, which she will place under rocks or rocky crevices within a male's territory. The female lingcod will leave the nest site immediately after depositing eggs. However, the male lingcod will come to fertilize the eggs by spawning. After the eggs are fertilized, the male will actively defend the nest from predators for 6 weeks until the eggs hatch between January and June.Male lingcod typically will only defend one nest, however, it has been observed for male lingcods to defend up to three nests if the nests are within their territory and close enough to each other. Two types of guarding behavior can be observed in male Lingcod. The first type of behavior includes a male lying directly on or next to the nest and remaining motionless unless disturbed. The second type of behavior includes a male in a sentry post and providing active defense when any other fish would swim close. This reproductive method is oviparous which reflects the males guarding the eggs in a nest until the eggs hatch. Oviparous parental care provides offspring care by one, both, or neither parent by maximizing both sexes' fitness through a wide range of mating behaviors such as monogamy to polygamy. Usually, like in the case of Lingcod, males are the primary caregivers but Lingcod typically follows a polygamy mating structure which contributes to the effective population size of Lingcod.The larvae are pelagic until late May or early June, when they settle to the bottom as juveniles. Initially they inhabit eelgrass beds, then move to flat, sandy areas that are not the typical habitat of older lingcod. They eventually settle in habitats of similar relief and substrate as older lingcod but remain at shallower depths for several years.
Females reach sexual maturity when they are 3 years old and 30 inches long. Males reach sexual maturity when they are 2 years old and about 20 inches long. An adult male can be distinguished externally from a female by the presence of a small, conical papilla behind the anal vent. Up to age two, males and females grow at similar rates, with both reaching an average length of. After age two, females grow faster than males, with the growth of males tapering off at about age eight, and females continuing to grow until about age 12 to 14.