Animal Diversity Web

Geographic Range

Livoneca redmanii is distributed along the Atlantic and Gulf coasts of the United States, ranging from Wood Holes, Massachusetts to the Mississippi River. (Sandifer and Kerby, 1983)

• Biogeographic Regions
• atlantic ocean
  • native

Habitat

Livoneca redmanii is found in aquatic environments on marine fish along coastal areas, specifically in the Atlantic coast and Gulf of Mexico. It commonly parasitizes Pomatomus saltatrix (bluefish), Morone saxatilis (striped bass), and Birdiella chrysura (silver perch). (Richardson, 1905; Sandifer and Kerby, 1983)

• Habitat Regions
• saltwater or marine

• Aquatic Biomes
• coastal

• Other Habitat Features
• intertidal or littoral

Physical Description

Livoneca redmanii is generally light brown with black chromatophores throughout life. This parasite has an ovate body, with an average width of 13 mm and an average length of 21 mm. The head is as wide as long, usually 3 mm, and has indistinct eyes situated post-laterally and two pairs of antennae. The first pair of antennae are separated by 1 mm and are composed of six to seven articles, whereas the second pair have eight to nine articles. The thorax contains seven segments. The first five are each about 2 mm and the last two are about 1 1/2 mm. The abdomen is not set in the thorax. It is slightly narrower than the thorax and has six segments, which gradually decrease in width. The uropoda are equal in length. The inner branch is larger than the outer one by about one half. The legs, which are the most pertinent feature for this parasite's lifestyle, have curved dactyli for grasping on to the fish. (Richardson, 1905; Sandifer and Kerby, 1983)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Average length

  21 mm

  0.83 in

Development

As a species in the family Cymothoidae, Livoneca redmanii is likely a protandrous, hermaphroditic gill parasite. Free living planktonic larva can remain free-swimming for a restricted amount of time without a host, about 1-2 weeks. They may alternate between parasitic and free-living stages during the transition to functional male stages. Early in life it is a parasitic male within the gill chamber of the host fish. Later it transforms into a female, which can bear free living young in the marsupium, while still in the gill chamber. The exact stimulus initiating the sex change is not clear. It may be the presence of a new male entering the gill chamber. Due to the varying sizes of females and males, it appears that the male will undergo the sex change molt when a second male attempts to establish on the same host. Nevertheless, studies have shown that sex change does happen under neuroendocrine control. (Brusca, 1981; Sadzikowski and Wallace, 1974; Sandifer and Kerby, 1983)

Reproduction

As a species in the family Cymothoidae, Livoneca redmanii is likely a protandrous, hermaphroditic gill parasite. Free living planktonic larva can remain free-swimming for a restricted amount of time without a host, about 1-2 weeks. They may alternate between parasitic and free-living stages during the transition to functional male stages. Early in life it is a parasitic male within the gill chamber of the host fish. Later it transforms into a female, which can bear free living young in the marsupium, while still in the gill chamber. The number of eggs carried in the marsupium varies directly with body length, ranging from 300-600. The hatching eggs are released via the gill chamber and opercular opening of the host.

The exact stimulus initiating the sex change is not clear. It may be the presence of a new male entering the gill chamber. Due to the varying sizes of females and males, it appears that the male will undergo the sex change molt when a second male attempts to establish on the same host. Nevertheless, studies have shown that sex change does happen under neuroendocrine control. (Brusca, 1981; Sadzikowski and Wallace, 1974; Sandifer and Kerby, 1983)

• Key Reproductive Features
• sequential hermaphrodite
  • protandrous
• sexual

• Parental Investment
• pre-fertilization
  • provisioning

Behavior

Free-living Livoneca redmanii larvae tend to reside near the shore where such hosts as white perch, Morone americana are present. In general, L. redmanii, tend to be parasites of younger fish, although the reason for this is unknown. Studies also show that there is a correlation between the size of the parasite and the length of the fish. The bigger parasite prefers the host with greater length. (Marks, et al., 1996; Sadzikowski and Wallace, 1974)

• Key Behaviors
• parasite
• motile
• sedentary

Communication and Perception

Crustaceans have various sensory resceptors, mainly setae over the body. Photoreceptors are also generally present. (Brusca and Brusca, 2003)

• Communication Channels
• tactile
• chemical

• Perception Channels
• tactile
• chemical

Food Habits

The parasitic isopod is mainly found within the gill chamber between the operculum and the gills, where it feeds on tissue. Although inhabiting the gill chamber and closely associated with the host's blood, Livoneca redmanii does not feed on the blood. (Sadzikowski and Wallace, 1974)

• Primary Diet
• carnivore
  • eats body fluids

• Animal Foods
• body fluids

Predation

This species is probably consumed by fish in its free-living stages. Mortality for early stages are high due to not reaching a suitable host.

Ecosystem Roles

Livoneca redmanii commonly parasitizes Pomatomus saltatrix (bluefish), Morone saxatilis (striped bass), and Birdiella chrysura (silver perch).

• Ecosystem Impact
• parasite

Economic Importance for Humans: Positive

There are no known benefits for humans.

Economic Importance for Humans: Negative

Although Livoneca redmanii parasitizes fish which are economically important to humans, there seems to be no negative impact because the damage to these fish is so little.

Conservation Status

Livoneca redmanii seems to be in no immediate danger because its type of hosts are abundant.

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

Contributors

Renee Sherman Mulcrone (editor).

Janelin Sendow (author), University of Michigan-Ann Arbor, Teresa Friedrich (editor), University of Michigan-Ann Arbor.

References

Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..

Brusca, R. 1981. A monograph on the Isopoda; Cymothoidae(Crustacea) of the eastern Pacific.. Zoological Journal of Linnean Society, 73: 117-199.

Kabata, Z. 1984. Diseases of marine animals. Vol 4. Part 1.. Germany: Biologishe Anstalt Helgoland.

Marks, R., F. Juanes, J. Hare. 1996. Occurence and effect of the parasitic isopod, Lironeca ovalis, on young-of-the-year bluefish, Pomatomus saltatrix . Canadian Journal of Fisheries Aquatic Science, 53: 2052-2057.

Menzies, R., D. Frankenberg. 1966. Handbook on the common marine isopod Crustacea of Georgia. Athens, Georgia: University of Georgia Press.

Richardson, H. 1901. Key to the isopods of the Atlantic coast of North America, with descriptions of new and little known species.. Proceedings of United States National Museum, 23: 439-579.

Richardson, H. 1905. Monograph on the isopods of North America. Bulletin of United States National Museum, 54: 727.

Sadzikowski, M., D. Wallace. 1974. The incidence of Lironeca ovalis (Say) (Crustacea, Isopoda) and its Effects on the Growth of White Perch, Morone americana (Gmelin), in the Delaware River near Artificiaal Island. Chesapeake Science, 15: 163-164.

Sandifer, P., J. Kerby. 1983. Early life History and Biology of the common Fish Parasite, Lironeca ovalis . Estuaries, 6: 420-425.