Common Sea Fan

Gorgonia ventalina

Taxonomy

Phylum: Cnidaria

Class: Anthazoa

Subclass: Alcyonaria

Order: Gorgonacea

Suborder: Holaxonia

Family: Gorgoniidae

Life History

Gorgonia ventalina is a salt water invertebrate that can be distinguished by its purple tissue and fan shape.  The Common Sea Fan can be found in patches of reefs and outer areas of the reefs typically in water depths up to 30 meters, and they tend to thrive in areas where the water flow is at a constant speed.  The speed of the water is important due to the fact that all sea fans are filter feeders.  Filter feeders are animals (usually invertebrates) that depend on the flow of water to bring important organic materials and nutrients to the animal for the use of growth and respiration.

Geographical Location

Gorgonia ventalina are found in marine environments typically around areas of reefs.  The Common Sea Fan can be found in the southern parts of Florida, around Cuba and the Dominican Republic, off the coast of Belize, and as far south as the northern parts of Colombia and Venezuela.

Ecology

Gorgonia ventalina are part of the phylum Cnidaria which consists of over 10,000 different species of marine invertebrates (Cnidaria, 2012).  The different species found under Cnidaria range from the common jelly fish to “flowering animals” such as coral and, of course, the Common Sea Fan.  The Common Sea Fan is found in a subphylum under the Cnidaria known as the Anthozoa which differs from the Cnidaria in the fact that the medusa is absent.

The sea fans are easily identified for their fan-shape appearance.  The basic shape of a Common Sea Fan is the common slender base that branches out to a single, flat plane layer. Sea fans can either be solitary or colonial.  A flexible, horny substance called gorgonin forms the coral’s central skeleton, which supports all branches of the colony.  This allows living tissues to form a layer over the sea fan skeleton’s surface.  More than a million microscopic alga called zooxanthellae are found in a square centimeter of coral tissue.  The alga makes food for the coral through the process of photosynthesis and it generates the coral’s color.  This is why sea fans appear in shades of purple, red, yellow, or orange (Targett, 2007-08).

Behavior and Reproduction

The Common Sea Fan anchors itself to a rock or other hard substrate and does not move about, therefore, its behavior and interaction with other similar species is very limited.

The reproduction of the sea fan is very interesting.  The Common Sea Fan (like other soft corals) can reproduce asexually as well as sexually and are capable of achieving results in many different ways.   Most sea fans reproduce by releasing large quantities of eggs and sperm into the water.  Because the sperm and eggs are released into the water and are not protected by the mother or father, there is a great possibility that the young can be distributed far from the parents and forming new colonies of sea fans.

Economic/ Ecological Service

Economically, the Common Sea Fan is very important to local communities that are near areas that support sea fan growth.  Sea fans are typically sold in gift shops as souvenirs or home décor pieces.  The revenue earned by sea fan sales is a great way to increase the annual income of the local vendors.  Sea fans are also used is in salt water aquariums to add more of a real-life aspect to the view.

Also, sea fans attract tourists who like to snorkel or scuba dive.  However, in some places such as Bermuda the sea fans are protected by the Coral Reef Preserve Act of 1966 (Wood).  Basically, this law inhibits the removal of any living or dead sea fans from the area; insuring that this animal’s survival is protected without the impact of humans.

Ecologically, sea fans have a symbiotic relationship with zooxanthellae.  This relationship gives the sea fans nutrients and zooxanthellae a place to allow photosynthesis to occur.

Recent Research

One relatively recent research project was conducted over a disease in sea fans.  The research paper was titled “Widespread disease in Caribbean sea fans:  Patterns of infection and tissue loss”.  The focus of this paper was the observation of “large lesions and widespread tissue loss in the sea fans Gorgonia ventalina and G. flabellum L. occurred throughout most of the Caribbean during 1995 and 1996.”  The results indicated that the incidence of the disease was positively correlated with the water depth; the number of diseased sea fans increased with the depth of the water.   The decrease in wave action was determined to cause this direct correlation.   Within the water column, the increase in the water depth means a decrease in wave action.  With the decrease in wave action a decrease in the amount of swaying motion of the sea fans, thus affecting success of pathogen attachment and establishment (Nagelkerken, 1997).

Personal Interests

When presented with this project, I had little knowledge of the different animals that are found in a marine environment.  When looking through a list of the different invertebrate animals, I noticed sea fans were among this group.  At first, I thought it was a mistake because I assumed that a sea fan was a plant due to the nature of its structure.  However, after researching this project, I learned a great deal about the sea fans and I look forward to expanding my education about sea fans even further.

Suggested Sites

Please note that the following suggested sites may have either been removed or relocated by the webpage owners since the time this student report was created.

Marine Species Identification Portal

Oceana

References

Please note that the following references may have either been removed or relocated by the webpage owners since the time this student report was created.

Nagelkerken, I. (1997). Widespread disease in Caribbean sea fans: 11. Patterns of infection and tissue loss.

Targett, D. N. (2007-08). Sea Fans. Retrieved from The College of Earth, Ocean, and Environment: http://www.ceoe.udel.edu/kiosk/seafan.html

Wood, T. A. (n.d.). Common Sea Fan. Retrieved from Marine Invertebrates of Bermuda: http://www.thecephalopodpage.org/MarineInvertebrateZoology/Gorgoniaventalina.html

Marine Bio, image of sea fan; http://marinebio.org/i/corals4.jpg

Oceana, image of sea fan map; http://oceana.org/sites/default/files/explore/creatures/maps/ocean267comsea_002.gif

Cnidaria. (2012). Retrieved from Wikipedia: http://en.wikipedia.org/wiki/Cnidaria