Senegal: Off to the Desert!

Since my arrival in Dakar I've been enjoying time with my fiance, Senegalese turtle and manatee researcher Tomas Diagne, and planning logistics for future manatee work here. After 2 weeks of planning we are now ready to go into the field!

It seems funny to say we're going to the desert to track manatees! But it's true... In late August the last of the manatees we tagged in the Senegal River this past January moved into a tributary near the town of Wendou Kanel, in easternmost Senegal at the border with Mauritania. Aside from the river itself, this is a very dry, sandy landscape with few trees at the edge of the Sahel. We've received reports that the tagged manatee is part of a big group regularly being seen in the tributary, and that mating activity has been observed (manatee mating is a group activity with many males pursuing a female... usually tails and backs can be seen flailing at the surface of the water as they all clamber to reach the object of their desire!). This is a good opportunity to see manatee behavior and document the number of animals using this tributary, as well as a chance to discuss the situation with the local people.

The rainy season is still in full swing here so there's plenty of water in the tributaries, but as the rain ends next month and the water starts falling, we want to ensure these manatees won't be stuck in this area as they have been before. Like other tributaries, this one has a dam whose gates will be closed as the water falls, in order to hold back water for crops. Unfortunately manatees get stuck behind these dams and are at risk of dying before the next rainy season due to the water drying up and/or lack of food. When the dams were built no one knew the manatees used these tributaries during the rainy season (they are usually very secretive and difficult to see in the muddy water), but it has now become an ongoing problem in this region and manatees have to be moved out of the tributaries back to the main river every year (see my postings from January 2009).

So I'm interested to see this area during the rainy season and to try to get an idea of the numbers of manatees using this system. I'll post photos and a report in a week when I return to the internet!

Building and Packing

Some people have the nice but misguided belief that manatee research is all just swimming in beautiful clear, blue water watching the manatees eat and play, and occasionally scratching them. Ummm.... no. I wear many hats in this job, most of which I had no idea about when I started many years ago. Plumber, electrician, cartographer, politician, boat mechanic, grant writer, and occasionally... biologist. I almost never see blue water (think chocolate milk filled with crocs and hippos). But I will say I'm never bored. Lately my job has been 100% logistics.

For the past several weeks I've been preparing for the next field season in Africa. Planning travel to various field sites, building manatee telemetry equipment, refreshing my memory about GPS tags (since I haven't worked with them since 2004), buying supplies... everything I'll need for 6 months of training workshops, surveys, captures, health assessments, tagging and tracking. The amount of cables, datasheets, sample vials, bug spray, and other little things needed is daunting. Bob, I can't find my frisbee! (For the rest of you, it's not used for play...)

Manatee tagging equipment is all built by hand. We tag manatees by putting a belt around the tail, which has a nylon tether attaching to a buoy tag that floats behind the manatee. After 4 days of measuring, foam injection, more measuring, gooey marine sealant, pounding, cutting, butane torching, attaching bolts and buckles, heat-shrinking and realizing I glued my flip flop to the floor, the manatee belts are finished and ready to go! They have several nice features: sonic tags that emit a signal underwater so I can hear the manatee with a hydrophone even if it loses the GPS tag, bolts that corrode so the belt will fall off even if we can't relocate the manatee, and best of all- snazzy new programmable release mechanisms that will (hopefully) pop the belt off the manatee at the end of the study. Thanks Margie and FWC for letting me use your telemetry lab to build these!
Now that I've bought and piled up equipment and supplies for weeks, the trick is to get it all in 2 trunks and 2 duffles that each weigh 50 lbs. or less...

On Wednesday I leave the USA for 6 months. I'm headed first to Senegal for 5 weeks, then to Ghana for just over 2 weeks, and then hopefully Gabon for 4 months. I say "hopefully" because there has been a bit of unrest there recently after presidential elections, so I'm hoping it will subside before early November. The plan is to capture several manatees in central Gabon and deploy the first ever GPS tracking tags for the species. Now the fun part begins!

Senegal: A couple more surprises....

Our last tagged manatee in Senegal (the female in the Senegal River on the far eastern side of the country, at the border with Mauritania) made another big move northward again in late July. But this time she left the main Senegal River and entered a tributary in early August. This is not the tributary we rescued her from last January, and as far as we know, manatees have not been recorded in this one before. It looks like she's swimming on dry land in the Google Earth image below, but that's just because the satellite image was taken during the dry season, when the tributaries dry up completely. So it's both interesting but worrisome, because the rainy season will end in a month and we don't want her trapped again. So hopefully someone will get out there to look at the location soon.

The other surprise for us is that the tag is still transmitting at all. The batteries for the GPS are supposed to last about 6 months, but it has now been transmitting for over 8 months! It's great for us to get as much information as possible... and also to know she may have just entered another area where she could become trapped as the water falls. So we're learning alot.

I'm returning to Senegal in a few days, so I hope to have new information about this tagged manatee soon.