Me getting in position to photo ID a whale shark

August 27, 2011

MCSS Internship: Week 1, training

Right now I am in the Seychelles Islands participating in a whale shark internship with the Marine Conservation Society Seychelles (MCSS). The nature of the internship is focused on whale shark field research and ecotourism. Whatever knowledge and findings I acquire here I plan to apply to my Integrated Studies capstone project, which is scheduled to be completed in April 2012.

MONDAY 8/22:
We (the interns) were lectured on a broad overview of whale sharks in the Seychelles. The Seychellois whale shark aggregation population has a pretty specific "demographic" consisting of mostly juvenile males about 19 feet in length (5.8 m). Scientists are still trying to learn what "normal" whale shark behavior is. In the lecture Dr. David Rowat explained that in an effort to better understand whale shark behavior he will have a microlight aircraft fly overhead whale sharks and observe their behavior with no humans vs. humans at 15 m vs. humans at 10 m vs. humans at 5 m etcetera.
In addition, this year we will also have the assistance of a Helikite that will be able to take video (among other things) of the surround area from the sky to monitor behavior too. The overall impression I was left with about the lecture was that whale sharks are awesome (obviously) and there is so much more research that can and should be carried out in the future.

In the afternoon the staff and interns went for a snorkel where our water abilities were gauged. Most importantly I learned how to duck dive and worked on equalizing so I can start swimming deeper. Just to brag for a moment, on that snorkel I saw lionfish, parrot fish, trumpet fish, a spotted eagle ray, AND a little hawksbill sea turtle! So incredible.

TUESDAY 8/23:
We were again lectured in the morning by Dr. Rowat, but specifically on whale shark anatomy. It was very through and included explanations of whale shark muscles, reproduction, respiration, feeding, taste & smell, vision, mechano-sensing (hearing), electro-senses, and the brain. To spare you the details of everything I learned, the part of the lecture I found most interesting was talking about whale shark spiracles. Spiracles are a vestigial first gill slit that allows bottom dwelling sharks to pump water over their gills (aka breathe) even when they're not moving. The fact that whale sharks are able to breathe while not moving has interesting implicates as to why they would need this function unless they behave similarly to other bottom dwellers at some point in their lives. Are they possibly bottom dwellers while neonatal or as adults? Do they even use their spiracles in the same way other Orectolobiformes do? Who knows!
In the afternoon we had a lecture and demonstration on laser photogrammetry. It is another fairly new technology that allows people to accurately measure whale sharks for the first time. In essence, you attach 2 lasers a certain distance apart (50 cm for ours) and mount an underwater camera in the middle.
Then when you take a picture of the shark there is a laser "scale" on the actual shark so you can determine the length that way. It has something to do with the amount of pixels inbetween the lasers so no matter the distance the photo was taken, an accurate length measurement can be determined. I'm not quite sure of it entirely, but that's the gist anyways. Then we went out to snorkel and practice our laser photogrammetry and photo ID techniques on a fake 3.8 m "whale shark" tethered underwater. (The whale shark is actually a piece of triangle tarp with spots on it). I still need a lot of practice!

WEDNESDAY 8/23:
Our morning lecture by Dr. Rowat was on aerial surveys. MCSS uses a microlight flexwing aircraft to survey the island of Mahe every morning and again in the afternoon during our whale shark encounter tours (weather permitting). The area around Mahe is divided in 7 zones and the pilot uses a "synoptic survey" technique which means he flies in continuous transect to avoid any double counting of whale sharks (they simply can't swim fast enough). Reasons for survey bias were discussed as well as the optimal survey ratio developed by Marsh & Sinclair. Our microlight pilot flies at a conservative 1500 ft. Dr. Rowat also explained other studies that use aerial surveys and encouraged us to look into how throughly and accurately the aerial data was. "Aerial surveys are only as good as the frequency they're done and the amount of area they cover."
In the afternoon we worked in the MCSS office on the I3S software that uses algorithms to match pictures of the spot patterns on whale sharks with other sharks in the database. It is very tedious work but also very important. When we are on the whale shark encounters it is important we properly photo ID the shark so we can run it through the I3S database to see which whale sharks are returning to the Seychelles and which sharks are new. It is an important piece in understanding the Seychellois whale shark population because it creates a "capture history". However, I started seeing spots and strips by the end of it.

Thursday 8/24:
Dr. Rowat lectured us on the the practice of catch, mark, and recapture (CMR) that helps scientists get a population size. We discussed the Lincoln-Peterson Model for estimating population size and tried it ourselves using coins we "caught", "marked" with a sharpie, and "recaptured" in a bag. The POPAN and/or MARK open population modules are used here.
There was more practice of photo IDing in the afternoon using the I3S software.

Friday 8/25:
Our final discussion of week one training was on satellite tagging whale sharks. Dr. Rowat explained the pros and cons of different satellite tags used on whale sharks and his most current whale shark findings to date. More specifically Dr. Rowat talked about Archival 'Pop Offs' Satellite Tags or PAT tags and Daily Diaries that allow the reconstruction of every move the tagged shark makes within a 24 hour period.
In the afternoon we did office work on aerial surveys. We learned about the GPS program we will be using the analyze the data the microflight pilot collects and how to input other data into the proper spreadsheets.

For more updates and photos, you can visit the MCSS blog at http://seychelles-whale-sharks.blogspot.com/
Tomorrow I will be on a boat to hopefully have my 1st whale shark encounter!!!