"The Functional role of the caudal fin in the feeding ecology of the common thresher shark Alopias velpinus"

Summary:
     This study was about the use of the tail fin of the thresher shark. It is known that sharks use their unique tails to give them lift as they move through the water. However, this species of shark has an unusually long tail. There has been evidence suggesting that the tail is also used as a feeding mechanism but it has not been observed or scientifically proven. This study was done to prove whether or not this hypothesis is correct.
     The evidence in the past of these sharks using their tails as a feeding mechanism has been thresher sharks have been caught on long lines by their tails. This suggests that instead of biting their prey initially, the sharks use their tail before eating their prey. Using this evidence to create a hypothesis, scientists expected sharks to use their tails on their prey.
     In order to test this hypothesis, scientists set out long lines with bait attached. Then they places a camera underwater in order to monitor how the sharks react to the bait. Mature and juvenile sharks were taped and both male and female. The sharks used their tails to strike before biting the bait. There were two different approaches the sharks used. The first approach was the shark undulated and their tails made a sinusoidal motion that hit the fish. This was observed in 59% of the strikes and resulted in a 47% success rate. The second most common motion was the lateral strike of the tail. This was observed 12 times and had a 92& success rate. These results confirmed the hypothesis.

Evaluation: 
      The article was accurate in describing the experiment and gave a detailed description of how they were able to preform the experiment. The article was clear and easy to follow. It stayed on the subject and didn't jump around. It gave support to the findings and used enough details to allow the reader to understand the experiment and the reason behind it. The article for the most part was concise. It did go into a lot of detail about the programs used and how they edited the film of the sharks. Overall, the authors didn't stray from the main points and their sentences weren't wordy. The experiment was ethical. No sharks were harmed because they didn't use hooks on the long lines. No fish were harmed either because they didn't use live bait. The readability was not difficult. Some words a lay audience would not understand but I was able to understand them as a freshman marine science major. The sentences weren't complex and it didn't take long to read. Overall, as a reader I'm satisfied with the article. It wasn't too difficult to read and all the information was presented.
     The purpose of this article was to inform the scientific community that it is proven that thresher sharks do use their tails in prey. The audience would be marine scientist and shark biologist. The audience is not lay, it would probably be a low to high tech audience. The document was not organized very well. There were no headings and the figures were not introduced in the text.

Reference:
Aalbers, S. A., Bernal, D. D., & Sepulveda, C. A. (2010). The functional role of the caudal fin in the feeding ecology of   the common thresher shark Alopias vulpinus. Journal Of Fish Biology, 76(7), 1863-1868. doi:10.1111/j.1095-8649.2010.02616.x