Selective Breeding: Louisiana Pearlshell

Dear Boss,

I am providing you with my report on the Margaritifera hembeli as a prospective selective breeding candidate. The full classification of this mollusk is as follows:

• Kingdom Animalia
• Phylum Mollusca
• Class Bivalvia
• Order Unionoida
• Family Margaritiferidae
• Genus Margaritifera

This mussel has adapted well to its creek/river environment. Three examples of these adaptations are:

• The Louisiana Pearlshell’s, dark brown to black shell, is rather hard and dense. It is used to protect the mussel’s soft body from predators and also acts to camouflage it amongst the gravel and dirt it lays in.
• The mussel also has the ability to filter its food source from the water it resides in without leaving its shell. Its food consists of phytoplankton, zooplankton, diatoms, and detritus.
• A third example of this mussel’s adaptations is its ability to latch onto a fish during its juvenile life cycle, during which it is called a glochidia. It then acts almost like a parasite as it feeds off the fish excrement.

The trait that I have chosen for the selective breeding process is the shell of the Louisiana Pearlshell. The mussel’s shell is very hard and dense, which would be excellent for decorative purposes or for jewelry. The dark brown or black shell also has some sheen to it which is a plus for aesthetic purposes. The only drawback is that the shell does not grow to be very large, only about 10cm in length. In order to make our selective breeding program effective, I propose that we attempt to make the shells larger in size and also vary in the color spectrum.

The Louisiana Pearlshell’s habitat is limited to a very small area. In order to acquire a sample we would need to travel to Louisiana or the southwest portion of Arkansas. We would also need to ask permission from the authorities to acquire the sample because they are on the list of threatened species for extinction. We will then need to study their habitat extensively before removing them from it, so that we can understand what conditions they thrive in. Once we get the specimens back to our lab, we will allow them to mate at random first. After the initial offspring is produced and has grown to maturity, we will then find which ones are the largest and have the best color variation. We will keep those offspring and return the rest of them back into their natural habitat. Finally, we will continue the process until the majority of the offspring produced, have the desired traits.

While I was considering this plan for selective breeding, it dawned on me that we may create a new species of mussel. With our idea to introduce new color variation, the mussels we introduce may not be as camouflaged in their environment as they need to be, in order to stay hidden from predators. Also the increase in shell size may reduce its density, causing it to be more vulnerable to its enemies. Finally, we do not know the breeding preferences of the Louisiana Pearlshell, and if this new population will even mate with the original population.

I can see the opportunity to make money with this experiment through the sale of beautiful Louisiana Pearlshell jewelry and decorative objects. However, at this time I do not think it is ethical to begin this experiment, especially since the mussel in on the list of Threatened Species. I think we should pursue other opportunities.

Sources:
http://www.natureserve.org/explorer/index.htm

Louisiana Pearlshell

Welcome! I am Marc Rauschuber and this ESL (Endangered Species Live). On today's program, it is the story you have all been waiting for, Clam Calamity! The infamous Louisiana Pearlshell, known by scientists as Margaritifera hembeli, will be the topic of our discussion. We will venture deep into its habitat to examine this creature up close and personal.

The Margaritifera hembeli, comes from the kingdom Animalia and the domain Eukarya. It is a mollusk, which means it is an invertebrate animal that is grouped with other organisms such as snails, oysters and squids.

This animal is a freshwater mussel that gets to be about 100 milimeters in length. It has a dark brown shell despite the deceiving name. This creature prefers to live in shallow water down in the sand or gravel. It is mainly found in small creeks and streams with flowing water. The majority of them live in middle Louisiana, although there are some traces of them in Arkansas as well.

This mussel's diet is relatively simple. They have been found to consume detritus, phytoplankton, diatoms, and zooplankton. They do this by filtering food particles in the water they habitat in. When the Louisiana Pearshell is a juvenile (glochidia) its diet consists of water and fish body fluids.

Bioprosepectors, or people who look for new uses for organisms, have not investigated the Louisiana Pearlshell as of yet. There has been speculation that the oil present on the mussel may contain healing properties far beyond the reaches of traditional medicine. They are saying that this oil may be able to fight some forms of cancer.

This mussel first emerged on the endangered species list back in 1988. However, in 1993 it was

reclassified as threatened after new populations were discovered in Louisiana. The main threats to this organism's habitat, and therefore it's existense come from sedimentation, pollution, and collection. Global warming may present a new threat to the Louisiana Pearshell. Altering the temperature of their habitat and increasing the water level could prove to be devastating to them. Although, not much research has been done concerning this, it is a very likely possibility.

Well that is all for us today, here at ESL. I'm glad you have taken the time to learn about this little known organism. It should be our duty to try and preserve their habitat and existense. Hopefully we can do something about their dwindling populations. Once again, I am Marc Rauschuber. Thank you and goodnight.