Merlangius merlangus
Encyclopedia
Merlangius merlangus, commonly known as whiting
(or 'English whiting' in the USA) is an important food fish in the eastern North Atlantic, northern Mediterranean, western Baltic
, and Black Sea
. In English
speaking countries outside the whiting's natural range, the name has been applied to various other species of fish, see Whiting (fish) (disambiguation).
Until the later twentieth century, whiting was a cheap fish, regarded as food for the poor or for pet
s, but the general decline in fish stocks means that it is now more highly valued. The other fish that have been given the name whiting are mostly also food fish.
Cod and related species are plagued by parasites. For example the cod worm, Lernaeocera branchialis, starts life as a copepod
, a small free-swimming crustacean larva
. The first host used by cod worm is a flatfish
or lumpsucker
, which they capture with grasping hooks at the front of their body. They penetrate the lumpsucker with a thin filament which they use to suck its blood. The nourished cod worms then mate on the lumpsucker.
The female worm, with her now fertilized eggs, then finds a cod, or a cod-like fish such as a haddock
or whiting. There the worm clings to the gill
s while it metamorphoses into a plump, sinusoidal, wormlike body, with a coiled mass of egg strings at the rear. The front part of the worms body penetrates the body of the cod until it enters the rear bulb of the host's heart
. There, firmly rooted in the cod's circulatory system, the front part of the parasite develops like the branches of a tree, reaching into the main artery
. In this way, the worm extracts nutrients from the cod's blood, remaining safely tucked beneath the cod's gill cover until it releases a new generation of offspring into the water.
Whiting
Whiting is the name of several species of fish:*Merlangius merlangus, the original species to receive the name; a common food fish of the cod family found in the northeastern Atlantic Ocean around Europe and the Mediterranean regions...
(or 'English whiting' in the USA) is an important food fish in the eastern North Atlantic, northern Mediterranean, western Baltic
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
, and Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...
. In English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
speaking countries outside the whiting's natural range, the name has been applied to various other species of fish, see Whiting (fish) (disambiguation).
Until the later twentieth century, whiting was a cheap fish, regarded as food for the poor or for pet
Pet
A pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
s, but the general decline in fish stocks means that it is now more highly valued. The other fish that have been given the name whiting are mostly also food fish.
Parasites
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
, a small free-swimming crustacean larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
. The first host used by cod worm is a flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...
or lumpsucker
Lumpsucker
Lumpsuckers or lumpfish are mostly small scorpaeniform marine fish of the family Cyclopteridae. They are found in the cold waters of the Arctic, North Atlantic, and North Pacific oceans...
, which they capture with grasping hooks at the front of their body. They penetrate the lumpsucker with a thin filament which they use to suck its blood. The nourished cod worms then mate on the lumpsucker.
The female worm, with her now fertilized eggs, then finds a cod, or a cod-like fish such as a haddock
Haddock
The haddock , also known as the offshore hake, is a marine fish distributed on both sides of the North Atlantic. Haddock is a popular food fish and is widely fished commercially....
or whiting. There the worm clings to the gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s while it metamorphoses into a plump, sinusoidal, wormlike body, with a coiled mass of egg strings at the rear. The front part of the worms body penetrates the body of the cod until it enters the rear bulb of the host's heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
. There, firmly rooted in the cod's circulatory system, the front part of the parasite develops like the branches of a tree, reaching into the main artery
Artery
Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
. In this way, the worm extracts nutrients from the cod's blood, remaining safely tucked beneath the cod's gill cover until it releases a new generation of offspring into the water.