Brendan Talwar

A crowdfunded ecology project byBrendan Talwar

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Monmouth University and the University of Exeter

Lab Note #14
Feb 15, 2015

Hey everyone,

The past month has been super productive and a lot of fun out on the water. On January 5th, I arrived back on Eleuthera along with Monmouth University students taking a Tropical Island Ecology course. They stayed with us for two weeks and focused on mangrove ecosystems for the first half of their trip and then our deep sea shark research for the second. Without their help, we would be weeks behind as the new group of interns only arrived a few days ago, leaving Alp, who stayed on this semester in an expanded role, and I to run the project on our own. Typically we need around 5 people or more to safely conduct our work, so these guys were vital to our data collection. On top of that they helped us with our educational/scientific jaw collection.

Check out the photos (below, courtesy of Rachel Fry) of the jaws that were cleaned with the help of Monmouth students and TAs. Be sure to notice the various types of teeth- all evolved for different feeding strategies- and notice the multiple rows. As teeth fall out, they get replaced by the ones behind them in a continuous cycle much like a conveyor belt. They are able to do this as the individual teeth are attached to the skin covering the jaw, not the jaw itself. Shark teeth are incredibly important as tools for understanding prehistoric sharks as they are often the only body parts that remain in the fossil record given that sharks, rays, skates, and chimaeras (known collectively as the Class Chondrichthyes) are cartilaginous .

Notice the rows of teeth on this nurse shark jaw- unfortunately we found the animal on a beach nearby, likely caught by a fisherman and left behind. We collected all of the information we could upon finding it.


A gulper shark jaw. This is from the only individual of this species that we've caught so far.

A Cuban dogfish jaw. Typically when an animal doesn't survive in the cage, deep sea isopods scavenge most of the tissue and the jaw is often already clean when it comes up.


A dusky smooth-hound jaw. As you can see from the upper rows, these guys have tiny teeth with few serrations.

For comparison, here is a lemon shark jaw. Notice how the teeth are incredibly sharp and pointed, a helpful trait when catching small fishes like yellowfin mojarra in mangrove creeks.

We take these jaws and prep them in order to maximize the use out of every animal sacrificed in the study. On top of contributing to our research, and providing numerous samples for researchers in Florida and the UK, jaws are cleaned for educational presentations and displays here at CEI and around Eleuthera. Being able to show a student jaw morphology and dentition from various species engages them in our work and complements our hands-on approach to teaching.

The University of Exeter also came out with us in early January. A goal of the trip was to create daily video blogs to share their experiences with folks back home, and one of the students made one for a day on the boat with us. It offers a great look at a typical day with a visiting program... big thanks to those who made it!


Let me know if you have any questions and thank you as always for your interest in our work.

Best,

Brendan

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