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What is a "LIT"?

By Andrea Adame 3 years ago
Categories Mahe and Curieuse

One of our Cap Ternay Divemaster Interns, Andy, explains one of our important survey techniques, the “LIT”. This is one of the methodologies we use here on base to assess benthic cover, including coral diversity and abundance.

LIT? What is this? How do you eat it? Is it on the menu tonight?


Let me tell you, this is what I thought the first time I heard the term. LIT stands for Line Intercept Transect.


Now, What exactly is a LIT? A LIT is an amazing adventure that people here at GVI get to have on a pretty regular basis. First things first, to be able to do a LIT, you need to be able to differentiate and identify about 50 different coral genera, and this is no easy feat. When we got here all the coral looked exactly the same, usually just as rocks or boulders where the pretty fish hid. Nowadays I barely see fish, all the coral are so interesting and diverse. I can’t believe that at some point I just thought every coral was the same.


After about 2 months of trial and error, trying and trying and trying some more, getting them wrong so many times (I am talking to you Leptoseris and Pavona) we were cleared to do LITs.


To do a LIT first you start by placing 10m of tape in the reef… It is not as easy at it sounds, sometimes the ocean is being groovy and there is no surge so the tape stays in place NO PROBLEMO. Other times…. The surge is so strong that swimming is a nightmare, never mind placing a tape and making it stay in place. But don’t you worry we have some tricks up our sleeves, usually we carry an extra kilo to place on the tape and weigh it down.


Ok, so we got the tape down and secure, now what? Now we get our nice, big, clean slates and start recording. What do we record? EVERYTHING! Every little thing under the tape, be it coral, algae (fudge you algea), sea urchins, sea cucumbers or anything. We need to record the type of substrate the things are on, so rock, sand, dead coral, silt, rubble or even water. Also we do this cm by cm. So the slate looks a little like this:


10 – 9.98        CA                   RK

9.98 – 9.96     TA                   RK

9.96 – 9.82     ACP     BR       RK

9.82 – 9.80     OT                   DC

9.80 – 9.73     PRT     MV      RK


And so on, and on and on and oonnnnnn. Now what the fudge do those letters mean? Those are the codes for the different things that we record. CA stands for coralline algae, TA is turf algae, ACP is Acropora, OT is other and PRT is Porites. On the second column we record the lifeforms of the coral, so BR is branching and MV is massive, we also have tabulate, digitate, submassive, encrusting and foliose. Finally on the last column we have the substrate. So you get the idea. Now imagine doing that for 10m, our dive slates do not look nice and neat by the end of it, it’s all part of the fun.


The other interesting thing about doing LITs is the swimming technique, an art that we have developed here. I like to call it the Upsidedown Shuffle Swim. To get everything that is under the tape cm by cm you have to be pretty close to the tape, and by pretty close I mean like 5cm away. And the coral does not grow flat on the sand, no no no… This means that boulders of coral and granitic rocks, and sharp Acropora and fire coral and just about everything sharp and pointy is trying to stab you, and the best way to avoid it is the Upsidedown Shuffle Swim.


This means nose down, fins up and kicking away on a very strange sideways shuffle. Now after getting the whole 10m it is time to pack away the tape and head back to the surface.


And that my friends, is how a LIT works.


Hasta la proxima!

Andrea Adame (México, 2016)