To the Save the Smalltooth Sawfish Foundation:

The smalltooth sawfish is one of many members of a group called elasmobranches. This group is very powerful and very influential in the ocean. Elasmobranches represent creatures from all over the ocean food chain. Perhaps most impressive is that elasmobranches are actually the top of the ocean food chain. They are not only rays and scates, but they are sharks as well. The smalltooth sawfish is in fact a shark itself. Like I said, sharks are the top of the ocean food chain and play a very important role in our ecosystem. They are the clean up crew of the ocean. They clean dead, decaying materials from ocean reefs, make dinner out of rotting carcasses and basically nothing goes to waste with the sharks around. They are also the most feared creatures of the ocean with their bad reputations of thrashing and murdering innocent passer bys, but what exactly would our oceans be like if these creatures became extinct? With the disappearance of the sharks make the oceans an easier place to live or do we actually need a top to the food chain?

A food web is composed of four layers. The producers are the autotrophs located at the bottom levels. The primary consumer is the next level, followed by the secondary consumer and the third and final level being the tertiary consumer. These are the levels of our ecosystems. Each level is affected by the next. The smalltooth sawfish is a shark, but it is a small shark so it is located at the secondary consumer level. If the extinction of this species occurred it would not only affect the population of the primary consumers, but the tertiary consumers as well. Sharks make up the majority of these two top levels of the ocean food chain. If these elasmobranches became extinct it could cause overpopulation in fish. “Without them, numbers of mid-sized and smaller fish can quickly boom and then crash when their own food supply runs out” (Shark Finning). I propose an experiment to test the population of fish in waters where sharks are less abundant compared to where many sharks reside. I suspect that the number of fish in the waters where there are less sharks present will be greatly larger than those of waters that have high numbers of shark populations.

In order to test my hypothesis I have come up with an experiment. First we will look at some coasts that have a higher number of shark populations. I suggest we start with several waters of the coast of Australia. According to the website Shark Bay: Sea Week 2005, out of the 370 shark species present today, almost half of them mainly reside in Australian waters. By scuba diving with experts we can take an observation of the population of sharks. We can then observe the amount of fish. Are there many schools of fish? Are there a lot of solitary fish? What does the dispersment of fish look like? Next, we can travel to the Gulf of Mexico where there is also a larger shark population and observe the same data. Next, we will focus on areas where the shark populations have been observed as declining. Through the use of shark tagging, scientists have been able to figure out this type of data because it lets them know the most popular areas for sharks as well as when the sharks start to leave certain areas (Shark Bay). In Hawaiian waters the population of sharks has been observed to decrease in the last decade (Ichthyology). We will observe the same data for these fish and sharks as we did for the more populated areas. We can also look at areas near the Florida panhandle. This is an area that often has differences in the populations of sharks every year (Ichthyology). After observing this data we will look at our numbers and see if my hypothesis was correct.

I think that this experiment could not only teach us a little bit more about the importance of elasmobranches to the ocean’s eco system, but it could also show how every part of an ecosystem is important. One affects the other and so on. I think research like this could teach us just how important every piece to the ecosystem puzzle is.


Sources

Shark Bay: Seaweek 2005. ND. 5 May 2007.
www.mesa.edu.au/seaweek2005/

Knight, Peter. Shark Finning. Defenders Magazine. December 2002. 6 May 2007

Luer, Carl A. Sharks and Cancer. Florida Program for Shark Research. ND. 6 May
2007. http://flmnh.ufl.edu/fish/sharks/nsrc/sharksandcancer.html

Dear Boss,

Here is the information you requested on some potential ideas for the selective breeding process we are going to begin work on for the Small tooth Sawfish. I hope my ideas and information on the adaptations of the Small tooth Sawfish prove helpful in jump starting our selective breeding project. I have started with a complete classification of our subject the Small tooth Sawfish.

Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Pristiformes
Family: Pristidae
Genus: Pristis
Species: pectinata

Even though there has not been extensive research on the changes in habitat of the Small tooth Sawfish as it ages, scientists have still been able to observe some of the adaptations of the Sawfish. Here are some of their adaptations:

The rostrum or the saw of the Small tooth Sawfish not only provides for a frightening defense to ward off predators and other enemies, but it is also used as a tool to catch food. Since the teeth that protrude from the sides of the rostrum can be rather sharp, the Sawfish can thrash back and forth through a school of fish and literally chop up a tasty meal. Also, they can use the saw to dig in the sand on the ocean floor to uncover a nice dinner.
Small tooth Sawfish have internal fertilization. The eggs form and hatch inside of the mother. She acts as an incubator for her young and they are released from her body when the gestation period is over. This can take up to five months.
Small tooth Sawfish are elasmobranches. Elasmobranches are skeletons made of cartilage. Other species included are rays and sharks. This is helpful these oceanic species because the cartilage allows for more maneuverability while swimming through the ocean.


I have chosen to focus on the rostrum to work with selective breeding. The rostrum makes up about a quarter of the body of the Small tooth Sawfish. It is completely made of cartilage except for the teeth that line the sides of the saw. My intentions on looking into using the rostrum for the selective breeding process are to focus on the cartilage for medical needs. I think the cartilage would be useful in helping with surgeries that focus on the need for new cartilage in areas of the body where cartilage has been destroyed. Plastic surgery would even be an area that cartilage is needed for facelifts, nose jobs, chin implants, etc. Since the Small tooth Sawfish reach up to 6 meters in length, I think that this would be a perfect amount of cartilage to use, but I am not so sure about how a human’s body would adapt to the cartilage. I also know that the cartilage located in the snout of the Saw fish may not be as sturdy as the cartilage contained in a humans body is. If we use selective breeding, we can weed out the species that has a more delicate snout and focus on breeding Saw fish with the stronger snouts and tougher cartilage to be used for medical reasons in a human’s body.

First, we will locate different specimens of Saw fish from different locations to see if there is a difference in the toughness of the snout. Once we find the Saw fish that we prefer, we will take specimens and keep them in our lab and hopefully have them breed. Of course in order to take proper care in making sure we have the right conditions for these animals, we must do some research on their habitats. Once they begin to breed we will test the toughness of the cartilage by taking small samples. We will do this by a means that will not harm the Saw fish. We will then allow them to keep breeding until we believe the cartilage produced is tough enough to be used in a human. We will then release the Saw fish that do not need to be used.

As I was coming up with this proposal it came to me that we may actually produce a newer, tougher breed of the Small tooth Saw fish that would help in its survival. Since the Saw fish tend to have a hard time up against larger predator like sharks and whales, this process of selective breeding could produce a potentially tougher breed that would have an easier time protecting it self against predators. I think with a sturdier rostrum this fish could have more luck in defending itself. While we are selectively breeding for tougher Saw fish, we could also be helping the species survive.

I do think that this proposal to selectively breed the Small tooth Sawfish for cartilage to be used in human surgeries is a good idea. I think it is a way to help in human surgeries as well as a way to help make the Small tooth Saw fish better suited for today’s oceans.


Sources:

(1) Florida Fish and Wildlife Conservation Commission. Fish and Wildlife
Research Institute: Small tooth Sawfish. 20 April 2007.
http://research.myfwc.com/features/view_article.asp?id=26160

(2) NOAA Fisheries Office of Protected Resources: Small tooth Sawfish
(pristis pectinata). 20 April 2007.
http://www.nmfs.noaa.gov/pr/species/fish/smalltoothsawfish.htm

(3) FloridaSawFish.com 20 April 2007
www.floridasawfish.com

To the Society for the Conservation of the Small tooth Sawfish:

I appreciate your interest in the Small tooth Sawfish (Pristis pectinata). Unfortunately, the numbers of Sawfish that are left are rapidly diminishing due to loss of habitat. With most Small tooth Sawfish mainly residing off the coast of Florida, there has been a significant increase in the development of waterfront. There have been many efforts to preserve the habitat of this special fish as well as notify the public of these problems (1). Of course another problem that has contributed to the decline in population are fisherman nets. The Sawfish become entangled in these nets by their rostrum.

(http://www.flmnh.ufl.edu/fish/gallery/descript/STSawfish/sawfish.JPG)

Even though these fish are more common in shallow water and estuaries, they are also known to exist in cooler, deeper waters. I think it would be interesting to use DN Fingerprinting to look at the difference between the shallow water Small tooth Sawfish and the Sawfish that reside in deeper waters. Also, we could look at the differences in the fresh water and salt water Sawfish as well. It might be interesting to see if one is healthier than the other and if there was a way to get these creatures to breed in other areas that would provide a better habitat. One way to observe the effects of this idea is the Pacu project located at http://www.ology.amnh.org/genetics/aroundtheworld/pages/pacu.html. With the Pacu project, scientists were able to take pieces of the Pacu’s fins from different bodies of water and examine their distinct differences. This would tell them which areas were better suited for the fish to breed in. By doing this the scientist would possibly be able to save the Pacu from extinction.

To the Society for Genetic Modification of the Small tooth Sawfish:

I am pleased to hear about your interest in the genetic engineering of the Small tooth Sawfish.

As you have learned from my documentary, Small tooth Sawfish have a snout or rostrum that makes up at least a quarter of their body. All around this snout are teeth that protrude from the sides. Even though the species uses their teeth for hunting and protection purposes, they are also the main reason these fish are often caught in the nets of shallow fishermen. I propose that we work with genetic engineering to find a way to shorten the snout of the Small tooth Sawfish.

In humans scientists were able to discover that the pituitary gland is responsible for growth. Sometimes there is a problem with the pituitary gland and it can cause a person to be shorter or taller than the average human. Even though I am not sure if it is possible, I think that scientists could look at possible glands or genes that could be responsible for the growth of the snout in a Small tooth Sawfish. Once the gene is identified we could begin research on how to decrease the size of the snout. I think this would be very helpful to the Sawfish because the snout would be more maneuverable and there would be less of a chance for them to get caught in fisherman nets.

Even though a smaller snout could be helpful to the Sawfish it could also be harmful as well. With a smaller snout this could be more dangerous for the fish when it comes to protection. A big reason that the rostrum is so good for protection is because it looks scary (2). With a smaller snout predators may be less intimidated or afraid and more likely to attack.

Little steps like locating a gene responsible for the growth of the snout could be stepping stones in the repopulation of the Small tooth Sawfish.

Sources:

(1) NOAA Fisheries, Office of Protected Resources. Small tooth Sawfish. 1 Apr. 2003. 31 March 2007.

http://www.nmfs.noaa.gov/pr/species/fish/smalltoothsawfish.htm

(2) Passarelli, Nancy. Curtis, Tobey. Florida Museum of Natural History. Small tooth Sawfish. 2 Jun. 2006. 25 Feb. 2007.

http://www.flmnh.ufl.edu/fish/Gallery/Descript/STSawfish/STSawfish.html

(3) Oology. The Gene Scene: How to Avoid a Pacu Snafu. 31 March 2007.

http://www.ology.amnh.org/genetics/aroundtheworld/pages/pacu.html

The Creature Behind the Saw

Hello and welcome back to Shark’s Corner. I am your host Tammy Tiburon. I am very excited about our next presentation, The Creature Behind the Saw. Not only is the small tooth sawfish one of the many endangered species in the sea, but as this documentary will show you, they are also one of the most unique.

[Image source: http://www.elasmodiver.com/images/sawfish-ripleys-01.jpg]

According to Aldrovandi, “A practical fish employs a saw in the manner of a sawfish.” The smalltooth sawfish (Pristis pectinata) is one of the seas greatest mysteries. The sawfish has a shark-like body in shades of gray or brown and an elongated saw-like snout with several sets of teeth protruding from the sides. In fact, the snout or saw of the sawfish makes up over an estimated one fourth of the fishes body. Classified in the kingdom Animalia and the domain Eukarya, these fish are often found in salt waters and estuaries of rivers along the eastern and southeastern waters of the United States (1).

So how does this odd looking creature find its food? Well, I am guessing you thought it would have something to do with that saw and you are right. The smalltooth sawfish mainly eats other small fish and crustaceans. The rostrum, which is the correct term for the saw of the sawfish, has electro-sensitive pores located on it. Now, these pores come in handy because they can detect movement underneath the ocean floor. Once the sawfish detects something underneath the sand it uses its rostrum like a shovel and uncovers its next yummy meal (2).

So far, there have been no documented efforts by bioprospectors to discover any kinds of new uses pertaining to the smalltooth sawfish, but perhaps there will be efforts to do research on the electro-sensitive pores contained in the rostrum of the smalltooth sawfish.

Fisherman, pollution and even global warming are just a few of the things that are endangering the smalltooth sawfish. Global warming contributes with the melting of the ice caps and the increasing amounts of water released into the ocean. Even though the smalltooth sawfish is able to survive in not only salt water, but freshwater as well, their habitats and food supplies are being altered due to global warming. According to scientists, the change in the oceans temperature by just one degree can affect the entire sea (1).

The smalltooth sawfish is just one of many of the seas little wonders. If we learn to pitch in and take care of our Earth, perhaps we will begin to see an increase in the numbers of these magnificent creatures.


Sources:

(1) NOAA Fisheries, Office of Protected Resources. Smalltooth Sawfish. 1 Apr. 2003. 25 Feb. 2007.
http://www.nmfs.noaa.gov/pr/species/fish/smalltoothsawfish.htm

(2) Wikipedia. Sawfish. 20 Feb. 2007. 25 Feb. 2007
http://en.wikipedia.org/wiki/Sawfish_(fish)

(3) Passarelli, Nancy. Curtis, Tobey. Florida Museum of Natural History. Smalltooth Sawfish. 2 Jun. 2006. 25 Feb. 2007.
http://www.flmnh.ufl.edu/fish/Gallery/Descript/STSawfish/STSawfish.html

(4) Smithsonian Marine Station at Fort Pierce. Smalltooth Sawfish. ND. 25 Feb.
2007.
http://www.sms.si.edu/irlfieldguide/images/Smalltooth%20sawfish%2004.jpg