These parasites live in freshwater habitats. The salinity of the water affects how well the copepod reproduces. "Sweet water" is the only possible environment for the reproduction to be possible. This parasite was found in ponds with 0.071-1.6965% NaCl. All of the copepods were found in fresh-water and flood lakes only, never in saltier neighboring lakes.
Since the host specificity is so low in this parasite, there is a large range of host species. In Russia, there are reports of mass infection of the crucian carp (Carcassius carassius). The mosquito fish that were released in Central Asia for the control of malarial mosquitoes are parasitized greatly. The copepod is also found in North America. Local American fish such as Lepomis spp. and Ictalurus spp. possess the parasite in small numbers. These parasites have been found on hosts other than fish. Sexually mature females have been found on a Pelophylax ridibundus tadpole as well as on a Diemyctelus pyrrhogaster salamander. (Baur, 1962; Hoffman, 1967)
- Aquatic Biomes
- lakes and ponds
- rivers and streams
- temporary pools
copepod gains, loses, or modifies the structures on its body. The nauplius stage that hatches from the egg looks very different from the adult. Not only do the young vary in morphology from the mature adults, but sexual dimorphism marked as well. The male is dwarfed and attached to the much larger female.goes through many metamorphoses throughout its lifetime. With each stage, the
The mature female is about 9 mm in length on average. Her cephalothorax has four horns, which vary slightly in length. The horns are conical and soft. The anterior ventral pair is simple, while the dorsal pair is T-shaped. The head of the copepod is a small bump that projects between the horns. The female has a slim, cylindrical neck that gradually enlarges into a larger trunk. Its abdomen is short and rounded at the end and has three segments. The mouth-tube is absent in the adult female. The structure of the mouthparts themselves is not understood very well. A small projection, believed to be the upper lip, covers part of the mouth. A large, completely separated, lower lip closes the oral space behind the maxillae. The mandibles are very small. They are partially covered by upper lip as well as by maxillule. These simple curved stylets, with an enlarged base, can only be seen with difficulty. The Maxillipeds are located behind the mouth. They are distinctly segmented. Segment one has an inner papilla that contains a small seta, while segment two has five strong claws. The first maxilla is nodular and is tipped with a small chitinous projection. The second maxilla terminates into two stout claws.
The first four legs ofare very small. They are biramous and each branch has three segments. Its first leg is located just behind the arms and the second through fourth legs are widely spaced along the body. The egg sacs that the adult female produces are long and slender. The eggs are multiseriate and the shape varies, depending on the age of the eggs. They can vary from elongated and conical to oval shaped.
The free-swimming, juvenile female is much smaller than the adult. It has an average length of .7 mm. In the nauplius stages thehas a transparent or light green color. In its copepodid stages it has the normal body form as other copepods. Its abdomen has four or five somites. The first and second somites are completely separated. The female's cephalothorax contains a transverse chitinous bar that divides it into anterior and posterior regions. Its furcal rami have dorsal and lateral setae as well as three apical setae. The distal half of the middle setae is long and feathered. The appendages and mouthparts of the free-swimming female are the same as in the mature form, except the antennule has a 5th segment separated.
The male differs greatly from the adult female, but shares similar morphology to that of the free-swimming female. It is not obviously apparent, but the antennule is segmented into six segments. Its first leg has a larger claw and a smaller inner spine. The antenna of the male is shorter than in the female, it has a larger claw as well. (Calman, 1911; Gurney, 1933; Yamaguti, 1963)
- Sexual Dimorphism
- female larger
- Development - Life Cycle
In the fourth copepodid stage, both sexes become sexually mature. In this free-swimming stage the female becomes fertilized and the male dies without developing further. The females seek their second host. This is where the females form their egg sacs.
- Key Reproductive Features
- gonochoric/gonochoristic/dioecious (sexes separate)
- Parental Investment
These parasites attach to the gills of fish, using their frontal cement gland. The copepod usually lives on the surface of the body. After eating away the scale of the fish, it enters the internal tissues. This causes the fish to undergo significant changes in its structure and tissues. The fish reacts by trying to isolate the parasite and form a compact sheath. This sheath is made up of a thick layer of epithelial and connective tissues. The formation of this sheath causes the tissues of the fish to swell. These swollen tissues often become stained red with the increased activity of the parasite. In mosquito fish, the copepod destroys the host's fins. This is especially disastrous to the host when infection of the male's sexual fin causes paralysis and thus sterility. Although the parasites are found on the fish any time of the year, high infestation intensity which leads to death of the fish occurs only in the summer. The differences between the sexes are apparent when the female is observed fixed immovably to her host, while the much smaller male lives on the female's body. The male uses its prehensile second antennae to hold on as well as crawl around the body of the female. (Baur, 1962; Yamaguti, 1963)
Communication and Perception
Many kinds of fish are the intermediate and definitive hosts. Mainly these hosts are from the family Cyprinidae. Fish such as Carissus auratus, Anguilla japonica, Carassius carassius, Gobio cynocephalus and Cypinus carpio all are parasitized by . Many fish serve as intermediate as well as definitive hosts during heavy infestation. The parasite feeds on the internal tissues of the fish. It attaches to the gill chambers of the fish and parasitizes it externally. This parasite is a big threat because it lacks host specificity to such an extent that it can infect all freshwater fish and even frog tadpoles and salamanders. (Baur, 1962; Hoffman, 1967)
- Primary Diet
- eats body fluids
- Animal Foods
- body fluids
These species are probably preyed on indirectly. Several of the larval stages die due to not reaching a suitable host.
Many kinds of fish are the intermediate and definitive hosts. Mainly these hosts are from the family Cyprinidae. Fish such as Carissus auratus, Anguilla japonica, Carassius carassius, Gobio cynocephalus and Cypinus carpio all are parasitized by . Many fish serve as intermediate as well as definitive hosts during heavy infestation. This parasite lacks host specificity to an extent that it can infect all freshwater fish and even frog tadpoles and salamanders. (Baur, 1962; Hoffman, 1967)
- Ecosystem Impact
Economic Importance for Humans: Negative
- Negative Impacts
- causes or carries domestic animal disease
One method for destroying parasite is treatment with a solution of bleaching powder containing .0001% chlorine. A concentration of .0005% is much higher. This concentration kills fish, but not the adult parasite, so that effective attack can only be made on larvae during spring. By this method, some control has been established (Gurney 1933).
Renee Sherman Mulcrone (editor).
Henna Tirmizi (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.
- Pacific Ocean
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
- 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.
an animal that mainly eats meat
- causes or carries domestic animal disease
either directly causes, or indirectly transmits, a disease to a domestic animal
uses smells or other chemicals to communicate
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
mainly lives in water that is not salty.
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.
- internal fertilization
fertilization takes place within the female's body
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.
having the capacity to move from one place to another.
- native range
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
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).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
Baur, O. 1962. Parasites of Freshwater Fish and the Biological Basis for thier Control. Bulletin of the State Scientific Research Institute of Lake and River Fisheries, XLIX: 108-112.
Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..
Calman, W. 1911. The Life of Crustacea. London: Methuen & Co. Ltd..
Gurney, R. 1933. British Fresh-Water Copepoda Vol.III. London: Dulau & Co. Ltd..
Hoffman, G. 1967. Parasites of North American Freshwater Fishes. Berkeley and Los Angeles: University of California Press.
Waterman, T. 1961. Sense Organs, Integraton, and Behavior. The Physiology of Crustacea, Vol II: 59-73.
Yamaguti, S. 1963. Parasitic Copepoda and Branchiura of Fishes. New York, London, and Sydney: Interscience Publishers.