Isostichopus badionotus

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Geographic Range

Populations of Isostichopus badionotus are primarily seen along the northern Pacific coast of South America and around the Galapagos Islands. Another region highly populated with this species is along the northeastern shores of Venezuela. (Jenkins and Mulliken, January 1999)

Habitat

Isostichopus badionotus, like most echinoderms, prefer shallow water. The most suitable environments for these "bottom-feeding" animals are substrates set in the calm waters of channels and coves, shielded by high cover. (Gosner, 1978; Guzman and Guevara, 2002)

Physical Description

Isostichopus badionotus is shaped like a cucumber. It is radially symmetrical and lacks spines (typical of Echinodermata). The three-rowed sea cucumber also lacks any true appendages other than its tube feet. The animal is mostly solid in color, however, the side of its body that it uses to move along the sea floor is slightly lighter in pigment. Calcareous deposits are embedded in the epidermal layer of this animal. Having definite anterior and posterior ends, the sea cucumber has a large mouth surrounded by bushy tentacles with thick bases that divide into numerous tiny branches. A dark pigmented peristomial membrane surrounds a circular lip. (Bullough, 1950)

  • Range length
    .02 to 2 m
    0.07 to 6.56 ft
  • Average length
    .10 - .30 m
    ft

Development

The three-rowed sea cucumber is a tubular organism, formed in specialized pelagic larval stages. In reproduction, sperm and eggs are released into the water & developing young undergo a complex metamorphisis. Organs and tissues are almost completely regenerative. (Bullough, 1950; Gosner, 1978)

Reproduction

Isostichopus badionotus have separate sexes and possess a reproductive system consisting of a single gonad and either an oviduct or a vas deferens. In temperate climates, eggs are laid in late winter and early spring. Sperm reach the eggs by way of the water. The fertilized eggs develop into free-swimming pelagic larvae.

A unique reproductive mechanism of Isostichopus badionotus is the ability to divide itself into two. (Conde, 1996)

  • Breeding season
    Late Winter/Early Spring

There is no parental investment beyond spawning.

  • Parental Investment
  • pre-fertilization
    • provisioning

Behavior

There is little known about the relationships between Isostichopus badionotus and other members of its phylum. They are essentially lone creatures that spend the majority of their lives feeding. The three-rowed sea cucumber seems to interact with other animals only in efforts to protect itself. (Gosner, 1978)

Communication and Perception

Echinoderms in general have a decentralized nervous system. Holothurians can right themselves when turned over, suggesting they have tactile and light receptors. In addition, some evidence suggest the buccal tentacles may be chemically sensitive. (Brusca and Brusca, 1990)

Food Habits

Three-rowed sea cucumbers are deposit-feeders, literally eating deposited material or sediments off of the ocean floor. Using its tentacles, the animal pushes large scoops of sediments into its mouth (Bullough, 1950).

Because sediments are typically low in concentration of nutrients, the sea cucumbers ingest enormous amounts of sediment per day to ensure proper nourishment. It is estimated that each Isostichopus badionotus ingests between 1 and 2.3 tons of sediment per year. Isostichopus badionotus is a selective feeder, especially in the presence of a competing species such as fish, or when a particular blend of sediment is high in organic material. Isostichopus badionotus prefers and is better adapted to the finest grain of sediment; however, the size and amount of sediments processed depends on the size of the individual (Conde, 1996). (Bullough, 1950; Conde, 1996)

Predation

Members of the class Holothuria will defend themselves by casting out most or part of their viscera through the cloacal opening, and in two to three weeks, regenerate the lost organs. (Gosner, 1978)

Ecosystem Roles

Three-rowed sea cucumbers ingesting and process food particles and discharge newly fixed and enriched matter that has a nutrient content greater than its surrounding environment. Once ingested, sediment particles stay inside the animal about 3 hours to ensure complete nitrogen-fixation.

This highly active process of filtering and enriching sediments is extremely important to marine conditions. Reworking modifies the physical and chemical stability of the marine environment by continually producing "new" ground and causing pulses in biodiversity. Through destroying both stratification of sediment layers and ridding its community of infestations, the Isostichopus badionotus plays a key role in structuring the micocommunities that exist. (Conde, 1996)

Economic Importance for Humans: Positive

Harvested sea cucumbers are regarded as both a tonic and celebratory food in many East Asian cultures. (Jenkins and Mulliken, January 1999)

  • Positive Impacts
  • food

Conservation Status

This species and the ecosystems in which it thrives are threatened both by contaminated substrates, where boats leave behind high concentration of metals, and by illegal fishing and export of the animals for eating purposes. Conservation strategies and limits on fishing are being considered. (Bruckner, et al., 2003)

Contributors

Renee Sherman Mulcrone (editor).

Celia Rangel (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

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.

World Map

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.

biodegradation

helps break down and decompose dead plants and/or animals

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

food

A substance that provides both nutrients and energy to a living thing.

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.

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.

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.

motile

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.

radial symmetry

a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Bruckner, A., K. Johnson, J. Field. 2003. Conservation strategies for sea cucumbers: Can a CITES Appendix II listing promote sustainable international trade?. SPC Beche-de-mer information bulletin, 18: 24-33. Accessed December 22, 2004 at http://www.spc.int/coastfish/News/BDM/18/Bruckner.pdf.

Brusca, R., G. Brusca. 1990. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..

Bullough, W. 1950. Practical Invertebrate Anatomy. London: MacMillan.

Conde, J. 1996. Holoturios o Pepinos de Mar. Ciencia Hoje, 20, 117: 36-42.

Gosner, K. 1978. A Field Guide to the Atlantic Seashore. Boston: Houghton Mifflin.

Guzman, H., C. Guevara. 2002. Population Structure, Distribution and Abundance of Three commercial species of sea cucumber (Echinodermata) in Panama. Caribbean Journal of Science, 38: 230-238. Accessed December 14, 2004 at http://caribjsci.org/dec02/38_230-238.pdf.

Jenkins, M., T. Mulliken. January 1999. Evolution of Exploitation in the Galapagos Islands. Traffic Bulletin, 17, no. 3.