Journal entry 4

Last Saturday (October 8th) it was raining like crazy in the morning, which is something I've started getting used to by now. But it meant I was expecting a slow day. The morning was fairly typical in that we processed all the data from our whale shark encounters the day before. Then in the afternoon... WE GOT TO TAG BABY LEMON SHARKS! There is a conservation volunteer group called Global Vision International (GVI) that has a base camp on the south of Mahe (the island I'm on). MCSS and GVI have a functional relationship; as a matter of fact, three of the MCSS interns completed a phase with GIV previously. So someone from GVI sent word to MCSS that there were 5 baby lemon sharks in the mangroves by the GVI camp. One of our MCSS staff is trained to tag sharks, so all of us whale shark interns were able to go attend and participate in the process. The first order of shark tagging business was to spot and catch them. We had two advantages 1. The GVI volunteers knew where the sharks were and 2. It was low tide. We tromped through the mangroves and spread out a net starting at the mangrove and extending it to the open ocean, then slowly brought the net closer together.

I was on the pivot end of the net so I didn't move; I just stood there in the water with the fishing net. We were so lucky in that, one after one, the baby lemon sharks just started swimming straight into the net! Two of them got tangled in the net and had to be maneuvered out. We were able to catch three of the five sharks spotted. They were put in coolers and brought to the beach to be tagged. The shark was flipped upside down so it went into a state of tonic immobility and therefore not aware of the rest of the tagging process. Then an incision was made, an acoustic tag was placed inside, and then the shark was sutured, all while still being upside down.

The spaghetti tags were too big for little sharks, so that is why the acoustic tags were used. There are acoustic receivers set up along certain bays and coastlines of Mahe, so when tagged sharks, rays, or other fish pass by, the receiver picks up on the acoustic tag. This helps MCSS and other scientists understand where these animals travel, if they come in certain bays, and if they ever return once they leave the area. Only two of the lemon sharks were tagged because the third shark seemed too stressed but all three sharks were successfully returned to the water as soon as we were finished with them. These little baby sharks were incredible! All of them were only about a foot and a half long. Later we found out these were sharptooth lemon sharks which are considered more vulnerable than other lemon sharks. It was an overall great day.

Yesterday we went back to try and tag the other baby lemon sharks, but after a lot of waiting, wading, baiting, and rain, we had to call it a day. Also, since the tide was coming in during our attempt, the current was flowing the wrong way to entice the sharks to the net and the deeper water just seemed to make everything much more difficult. However, one of the bait fish did have a perfect little bite mark taken from it that could have very well been from a sneaky lemon shark hiding in the mangrove.

Today since there were still no whale sharks seen in the area we went to go retrieve the acoustical receivers (Vemco VR2Ws) at the mouth of Baie Ternay. We had a GPS location for each receiver and they were placed shallow enough to snorkel to. We were only able to find one of the three acoustical receivers this afternoon because the visibility was awful. The receiver was replaced with another one and the data from the retrieved receiver will be downloaded here at MCSS. So even though we haven't been able to be on as many whale shark encounters as hoped, it's still always busy at MCSS and there are plenty of projects to get involved with.