Sweeny Todd

Day 31 June 21 – Sweeny Todd

I got a call this morning on the home phone, this is how I discovered we had a home phone. It was Dr. Gamal inviting me to join his international group of students for their week long training program. This is the program my roommate Tim has been working with for the last few days. I said ok and headed out with Tim as he checked the pH and Ammonia levels of the six ponds left to his care. Measuring pH was easy, just stick this thingy into the water and press the pH button, easy. The Ammonia test was slightly more involved. Take two test tubes and fill them with 5ml of water. In one tube place 2 drops of Nesler Reagent which will change the color of the water based on the amount of ammonia in the water. Then place the tubes in the plastic device which has lenses you look though until the colors of the water match. Then record the number the device shows, this is the ammonia measured in ppm.
Next was a demonstration of how to remove the pituitary gland from the brain of a catfish. Been there, done that; let somebody else get covered in catfish slime and blood.
Then there was a very interesting class on tagging fish. Tagging fish is important in a research environment because sometimes it is necessary to be able to differentiate between groups of fish in the same pond. There are a few methods of tagging fish, each with their own benefits and drawbacks.
Fin Clipping – This method is simple and very non-invasive, you simple cut a simple pattern into the dorsal fin. The results of this method do not last long because the cuts simply grow back. Another problem with this method is it can only differentiate between a few groups, it is not useful to separate individual fish. This method would be useful if you need to distinguish between fish that had and had not been given a treatment. But both groups would have to be cut anyway otherwise the operation would influence some fish and not the others.
Brand – Another simple method of marking fish is branding them like cattle. Simply use a modified soldering iron to burn simple marks into the fish’s skin. Because the brand only works directly on skin, only scaleless fish can be used, like catfish. Like fin clipping this method only has a few possible combinations, the more burns the more invasive. Anesthetics are necessary to make the branding process easy and reduce the trauma on the fish.
RFID – This method is very interesting; it uses small radio chips to identify fish. A worker uses a large needle to make an incision and push in a transmitter about the size of a small pill. If the transmitter can fit inside of the fish’s abdominal cavity then the scientists can make it work. This method is great because it is able to differentiate between specific fish, each transmitter has a unique code. This method also requires the use of anesthetics. This method is invasive and has a small mortality rate. It is expensive to buy the transmitters but they can be reused many times.
Flowey – This method uses a needle, string, and numbered tag to identify fish. This is another method that can be used to identify specific fish. The needle is disinfected then poked through the fish between the lateral line and the dorsal fin. Then you pull the string through but leaving enough length for the fish to grow. Before a knot is tied a plastic tab must be put on the string to keep it from being pulled though the fish. While this method is cheap it is also very invasive, unlike RFID, the tags impede to movement of the fish.
After work I was bored and hungry so I decided to head into Abassa, the nearest town. It is about two miles away but when it is so hot I prefer to take a tuk tuk taxi, and it only costs 50 cents. I walked through town buying bags of chips, tam-may-aah, and bread. That is about all the food in town that is worth buying. As I was getting ready to get a tuk tuk back to The World Fish Center I saw a barber shop. I walked in pointed to my hair and the kid walking by who had a short hair cut. It doesn’t look great; there are funny little likes in hair. While I was in the chair I had the random urge to get a shave with the old straight edge razor. After communicating my desire I began to get nervous, I just watched Sweeny Todd. Well my worry was misplaced, he did an excellent job. The best part was the cost, a haircut and shave cost 2$, how cool is that! I took a taxi home and watched Black Hawk Down on TV, awesome.