Lingcod

Lingcod
Ophiodon elongatus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Osteichthyes
Class: Actinopterygii
Subclass: Neopterygii
Order: Scorpaeniformes[1]
Family: Hexagrammidae
Genus: Ophiodon
Girard, 1854
Species: O. elongatus
Binomial name
Ophiodon elongatus
Girard, 1854
Range of the lingcod.

The lingcod or ling cod (Ophiodon elongatus), also known as the buffalo cod or cultus cod, is a fish of the greenling family Hexagrammidae. It is the only extant member of the genus Ophiodon.[2] A slightly larger, extinct species, Ophiodon ozymandias, is known from fossils from the Late Miocene of Southern California.[3]

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 152 cm (60 in) and a weight of 59 kg (130 lbs).[4] It is spotted in various shades of grey. 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.[5]p.298 The colour is destroyed by cooking.[6] The colour may be due to biliverdin, but this has not been established beyond doubt.[7]

Distribution and lifecycle

Lingcod are endemic to the west coast of North America, with the center of abundance off the coast of British Columbia. They are found on the bottom, with most individuals occupying rocky areas at depths of 10 to 100 m (32 to 328 ft). Tagging studies have shown lingcod are a largely nonmigratory species, with colonization and recruitment occurring in localized areas only.[8]

Starting in October, lingcod migrate to nearshore spawning grounds. The males migrate first, and establish nest sites in strong current areas in rock crevices or on ledges. Spawning takes place between December and March, and females leave the nest site immediately after depositing eggs. Males actively defend the nest from predators until the eggs hatch in early March through late April.

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.

Skeleton of a lingcod

Females and males mature at age three to five years (61–75 cm) and two years of age (45 cm), respectively. 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 45 cm. 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. Lingcod live a maximum of about 14 years for males and 20 years for females, reaching a maximum size around 90 cm and 120 cm, respectively. Off the coast of Alaska, many reach 70 lb (32 kg).

Lingcod are voracious predators, feeding on nearly anything they can fit in their mouths, including invertebrates and many species of fish, such as herring (Clupea pallasii), salmon, and Pacific hake (Merluccius productus). One of their favorite foods is smaller octopuses, and they also readily devour large rockfish. Lingcod that survive the larval stages have few predators themselves, and are vulnerable mainly to marine mammals, such as sea lions and harbor seals.

Age determination

In 1977, Dr. Dick Beamish and Doris Chilton of the Pacific Biological Station published an article showing that cross sections of the fourth to eighth fin rays from the second dorsal fin provided a method for estimating the age of lingcod.[9][10] This method has since been validated by a mark-recapture study in which lingcod received an injection of oxytetracycline. Other methods of aging, such as those using scales and otoliths, were found to underestimate ages for older fish.

Ages are determined from fins in much the same manner as for other aging structures: sections of varying thickness are examined under a microscope, and the annuli, or rings, that are formed for each year of growth are counted and used to estimate the age. The cross sections must be made at right angles to the length of the fin ray, and it is therefore important that fins be dried flat, with the cut surface at right angles to the fin rays. In addition, the distance the section is cut from the fin ray base is important, so all fins should be collected with the bases intact.[11][12]

One problem associated with using fin rays to age older fish is the center may be resorbed, resulting in the loss of the first two annuli. It is therefore necessary to determine an average width for the first two annuli by examining the fins from juvenile fish. This measurement can then be used to estimate the position of the third annulus on older fish.

Gallery

References

  1. ↑ "Scorpaeniformes". Paleobiology Database. Retrieved November 15, 2012.
  2. ↑ "World Register of Marine Species Ophiodon Girard, 1854".
  3. ↑ Jordan, D.S. & J.Z. Gilbert, 1920. Fossil fishes of diatom beds of Lompoc, Stanford University. http://www.biodiversitylibrary.org/item/68104
  4. ↑ Froese, Rainer and Pauly, Daniel, eds. (2010). "Ophiodon elongatus" in FishBase. October 2010 version.
  5. ↑ Love, Milton S. (2011). Certainly more than you want to know about the fishes of the Pacific Coast : a postmodern experience (PDF). Santa Barbara, Calif.: Really Big Press. ISBN 978-0962872563. Retrieved 18 October 2014.
  6. ↑ "EDF Seafood Selector: Lingcod".
  7. ↑ Bland, Alastair. "Red Fish, Blue Fish: Where The Fish Flesh Rainbow Comes From". the salt. NPR. Retrieved 18 October 2014.
  8. ↑ DFO, 2001, Lingcod, DFO Science Stock Report A6-18
  9. ↑ Beamish, R.J. and D. Chilton. 1977. Age determination of lingcod (Ophiodon elongatus) using dorsal fin rays and scales. J. Fish. Res. Board Can. 27:1305-1313.
  10. ↑ Chilton, D.E. and R.J. Beamish. 1982. Age determination methods for fishes studied by the Groundfish Program at the Pacific Biological Station. Can. Spec. Publ. Fish. Aquat. Sci. 60: 102 p.
  11. ↑ Cass, A.J., and R.J. Beamish. 1983. First evidence of validity of the fin-ray method of age determination for marine fishes. N. Am. J. Fish. Man. 3: 182-188.
  12. ↑ McFarlane, G.A., and J.R. King. The validity of the fin-ray method of age determination for lingcod (Ophiodon elongatus). Fish. Bull. 99: 459-464.

This article incorporates material from Fisheries and Oceans Canada. This reproduction was not done in affiliation with or with the endorsement of Fisheries and Oceans Canada.

External links

This article is issued from Wikipedia - version of the Wednesday, November 11, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.