Geographic Range
Lernaeocera branchialis
is an ectoparasitic crustacean of cod and haddock found mainly in the North Atlantic.
- Biogeographic Regions
- atlantic ocean
Habitat
Lernaeocera branchialis
is strictly aquatic, being pelagic and in the upper 200 m of open ocean.
- Habitat Regions
- temperate
- saltwater or marine
- Aquatic Biomes
- pelagic
Physical Description
Lernaeocera branchialis
is among the largest of
copepods
. It ranges in size from 2-3 mm as a chalimus (a specialized copepodid larva) to
more than 40 mm as an adult.
Lernaeocera branchialis
is highly evolved as an adult, having lost all semblance of crustacean heritage,
and is therefore identified by its larval stages. As an adult, it appears S-shaped
with 2 pairs of antennae on its head. This ectoparasite also has 2 pairs of maxillae
used for piercing gill flesh, 1 pair of mandibles, and reduced antennules. Although
the division between its head and trunk is not clearly defined, its posterior body
segmentation in its larval stages is distinguishably crustacean. As a female adult,
it appears as a mass of egg strings with a large egg sac. On a host, these parts of
L. branchialis
are seen external to the fish's body, and its egg sac is connected to other parts
that lie internal to the fish host. These parts consist of a complex of antlers used
for piercing, sucking, and maintaining feeding position. Respiration in
L. branchialis
is achieved through gills, and sometimes through its body surface.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
Development
The development of L. branchialis consists of several stages, begining when the animal hatches from an egg as a non-parasitic, free-swimming nauplius (the early larval stage of crustaceans). Three pairs of appendages (antennules, antennae, and mandibles) are used mainly for locomotion. Lernaeocera branchialis develops into a copepodid, which attaches to an intermediate host, such as a lumpfish (e.g. Cyclopterus lumpus ), sculpin ( Cottidae ), or flounder ( Pleuronectidae ). After development into a chalimus, it copulates with another chalimus of the opposite sex and detaches. Lernaeocera branchialis is only 2 to 3 mm long at this point and is still resembles a copepod . It then undergoes a pelagic stage and searches for a definitive host. Once attached to the gill area of a cod or haddock, it undergoes profound metamorphosis and develops an egg sac and antlers. Any recognizable external segmentation is lost, and it grows more than 40 mm, excluding egg strings. In its final stages, L. branchialis appears reddish and worm-like, with its head (connected by a neck to a soft body) buried in gills. As a feeding adult, it is reduced to body parts needed for reproduction, feeding, and holding its position within the cod or haddock.
In comparison to other pennelids, its larval stage is almost indistinguishable from
the larva of its free-living adult relatives. Although the biological role of
L. branchialis
larvae is unchanged, its adult form has adopted parasitism.
- Development - Life Cycle
- metamorphosis
Reproduction
Lernaeocera branchialis
develops into a copepodid, which attaches to an intermediate host, such as a lumpfish
(e.g.
Cyclopterus lumpus
), sculpin (
Cottidae
), or flounder (
Pleuronectidae
). After development into a chalimus, it copulates with another chalimus of the opposite
sex and detaches.
Lernaeocera branchialis
is only 2 to 3 mm long at this point and is still resembles a
copepod
. It then undergoes a pelagic stage and searches for a definitive host. Once attached
to the gill area of a cod or haddock, it undergoes profound metamorphosis and develops
an egg sac and antlers. Any recognizable external segmentation is lost, and it grows
more than 40 mm, excluding egg strings.
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- Parental Investment
-
pre-fertilization
- provisioning
Behavior
This species is a parasite which is motile or sessile, depending on its life stage.
Communication and Perception
Crustaceans
have various sensory resceptors, mainly setae over the body. Photoreceptors are
also generally present.
Food Habits
Lernaeocera branchialis
parasitizes
cod and haddock
. It feeds on blood though root-like attachment organs, which invade throughout host
tissue. Like other species of the
Pennellidae
family, it has a characteristic anterior site of growth and feeding.
Lernaeocera branchialis
attaches to the host fish in the branchial area. The parasite's cephalothorax grows
into and through the ventral aorta, which is accomplished with its grotesque antler
complex. The parasite inserts its antlers into the host's fleshy gill cavity by 3
branched processes, aided by strong antennae and maxillae for piercing into the wall
of the bulbus arteriosus.
- Primary Diet
-
carnivore
- eats body fluids
- Animal Foods
- body fluids
Predation
Larval mortality is high as few individuals make it to the suitable host. This species may be preyed on by fish.
Ecosystem Roles
Lernaeocera branchialis parasitizes cod and haddock.
- Ecosystem Impact
- parasite
- cod and haddock, Gadidae
Economic Importance for Humans: Negative
Lernaeocera branchialis
causes severe damage by invasively feeding on blood. Death of the fish may occur
from open lesions, too much blood loss, or possible formations of clots and occlusions
of the aorta or blood vessels.
Lernaeocera branchialis
also causes a 20-30% loss of weight and liver fat in fish from the effects of growth
retardation. It also has profound effects on reproduction by delaying gonad development
and sexual maturity, and its presence influences fish behavior and reduces its resistance
to other stresses.
Lernaeocera branchialis
is also known to be one of the most serious agents of trypanosomal parasites in
Gadus mordua
(cod). Overall, the parasite's changes on fish body weight loss and increased mortality
affects commercial fisheries by making it more expensive to market cod, haddock, and
flounder.
Conservation Status
Additional Links
Contributors
Renee Sherman Mulcrone (editor).
Aimee Austria (author), University of Michigan-Ann Arbor, Teresa Friedrich (editor), University of Michigan-Ann Arbor.
- Atlantic Ocean
-
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- saltwater or marine
-
mainly lives in oceans, seas, or other bodies of salt water.
- pelagic
-
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- metamorphosis
-
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- parasite
-
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
- sessile
-
non-motile; permanently attached at the base.
Attached to substratum and moving little or not at all. Synapomorphy of the Anthozoa
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- parasite
-
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
- carnivore
-
an animal that mainly eats meat
References
Brusca, R., G. Brusca. 2003. Invertebrates . Sunderland, Massachusets: Sinauer Associates, Inc..
Croll, N. 1966. Ecology of Parasites . Cambridge: Harvard University Press.
Jones, J. 1998. Distant water sailors: parasitic copepoda of the open ocean. J. Marine Systems , 15: 207-214.
Lapage, G. 1951. Parasitic Animals . Cambridge: University Press.
Matthews, B. 1998. An Introduction to Parasitology . Cambridge: University Press.
Roberts, L., J. Janovy Jr.. 2000. Foundations of Parasitology. 6th Ed. . USA: McGraw-Hill Companies, Inc..
Rohde, K. 1993. Ecology of Marine Parasites: An Introduction to Marine Parasitology. 2nd Ed. . Trowbridge (UK): Redwood Books.
Scholz, T. 2001. Parasites in cultured and feral fish. Veterinary Parasitology , 84: 317-335.
Schram, T., P. Heuch. 2001. The egg string attachment mechanism of selected pennellid copepods. J. Mar. Biol. Ass. U. K. , 81: 23-32.
Van Damme, P. 1995. . Morphological and morphometric study on crustacean parasites with the genus Lernaeocera . International J. for Parasitology , 25: 1401-1411.