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.

TributeThe manatee community was stunned and saddened today to learn of the death of our colleague Akoi Kouadio of Cote D'Ivoire. Akoi worked tirelessly with West African manatees for many years after being trained by Buddy Powell in the mid-1980's. He did his PhD work on the manatees of Fresco Lagoon in Cote D'Ivoire and also did surveys in the Congo and several other African countries. He had the longest running manatee research program in Africa and was an advisor to many. I first met Akoi in 2000 when we both participated in Buddy's manatee captures in Belize. More recently we worked together on the CMS West African Manatee Action Plan, and celebrated when it was completed and signed by 15 countries last October. Akoi was a shy man, and probably would've been embarrassed at any kind of public tribute, but his dedication was absolute and we all will miss him greatly.

Senegal Tagged Manatee Update

As some of you will recall, last January I satellite tagged three manatees in eastern Senegal as part of a multi-agency group that rescued them from tributaries where they were trapped behind dams (See posting from 1/31/09). We released the manatees back into the Senegal River and they have been tracked since then by my colleagues at CBD-Habitat (the Spanish NGO that bought the tags) and Oceanium Dakar (Senegalese NGO).

In early April both the red and blue tagged manatees were in the Senegal River within several kilometers of each other. They were staying in the same area, likely feeding. Then, very suddenly, the red tag gave an accurate location in the village of Bababe, several kilometers inland from the river. The blue tag stopped transmitting it's location a day or two later. Oceanium Dakar sent two biologists to Bababe (a 10 hour bus trip) to recover the red tag, and when they arrived they found fishermen in the village had not only it, but the belt that goes around the manatee's tail as well. The fishermen said the manatee's tag had gotten entangled in their nets, the manatee had broken free and left the tagging gear. Infact, this is exactly what the tagging gear is designed to do- break off the manatee if it becomes entangled- because obviously we don't want the gear to cause the manatee any injury or to drown. The tag had fishing net wrapped tightly around the antenna (in the center of the photo below, courtesy of Kader Diagne).

After finding the red tag, the biologists used a radio tracking receiver to try to locate the blue tag on the river. It was later found in another village near Bababe and also had gotten caught in fishing nets. (Photo courtesy of Kader Diagne)
A fisherman shows where a manatee ripped a hole in his net. (Photo courtesy of Kader Diagne)

So while it's a disappointing that the tags came off, it's encouraging to know the safety mechanisms worked, and the travel data gained during the 3 months they were tagging is very valuable. This is the first time this technology has ever been used for West African manatees, so we're learning alot, both about the manatees and how the tags function in this part of the world.
Meanwhile, the yellow tagged manatee (the female) is still out there! She has made multiple movements up and down the Senegal River (shown in the map below by different colored tracks, courtesy of CBD-Habitat), and twice has come within 17 miles of crossing into Mali.
Now that 6 months have passed, the battery in the GPS unit in her tag is dying, but the tag can still be located by the VHF signal. So hopefully she can be relocated and the tag recovered. Even if we don't find her, the equipment is designed with bolts that corrode, so it will fall off. There is alot of data to be analyzed (tags also tell us things like water temperature and how much the manatee moves between each satellite fix, so we can tell if they are resting or traveling). I'm looking forward to continued collaboration with folks in Senegal to learn about their manatees!

Thanks Angola folks!!

It's been great working with both the WCS folks (Tim, Sal, Howard, Angela, Betania & Antonio) and the Angola LNG Team. Thanks to them we were able to do the first manatee surveys in the lower Congo River. So thanks to Sheryl, Geoff, Bert, Mary and....

Stuart, who made sure all the logistics happened, made us feel welcome on base and tells great jokes (or maybe it's just his Scottish accent that makes me laugh)
Joao, translator extraordinaire!
Warren (with a little bush snake), always ready to come upriver or slice manatee bone for DNA samples
Mike (who really doesn't want to pet the snake) helped get me to the hunter's village when I needed to last summer and Tim, who helped with DNA samples and survey trips.

The boat crew... they came a long way in their boating skills in the last year and even got to see their first manatee. Perreira (left) and Eduardo (right). Junior, the new environmental technician, is in the middle.
Wilson, community liason officer who translated for me

It's been a good experience and I hope we will publish some good new information from it all.

Harpoons

Last August when I came to Soyo I learned that the only manatee hunter for the area, Mr. Domingos, had died a week before I arrived. I visited his village on that trip and found four manatee harpoons there. Since then I’ve been working to try to find a way to get them “off the street” so that no one else in this area will take up manatee hunting. Angola LNG generously agreed to trade supplies to the Domingos family for the harpoons and a specialized net Mr. Domingos used for catching manatees. On Wednesday Joao and I met with Mr. Domingos’ widow and youngest son Lando to discuss the terms of the exchange. In return for the manatee harpoons and net, Angola LNG has offered them 6 bags of cement, 4 fishing nets, line and floats for the nets, 8 boxes of hooks and a large cooler. This is all very valuable, especially since the son is a fisherman. They presented us with 2 very old, rusted harpoon tips and the son agreed to go upriver with us the following day to collect the rest at a village. Mrs. Domingos said a third harpoon was locked in a neighbor’s house, but they could give it to us later.

Joao, Mrs. Domingos, me and Lando Domingos meeting at their village near Soyo

On Thursday we dropped Lando off at the village of Pendi to gather the rest of the harpoons and the net while we did our river surveys. When we returned to Pendi I had hoped to see him waiting on shore with lots of equipment, and was sadly surprised to find him standing there with one more very old rusted harpoon tip and nothing else. When we asked him where the rest was, he said his cousin had deployed the manatee net in the river to try to catch a manatee, and it had disappeared. He claimed a manatee or “big fish” had probably swum off with it. He didn’t volunteer anything about additional harpoons and when we asked him, he only referenced the one his mother had mentioned. Joao explained to Lando that the deal for the trade is that he turn over all the equipment, so we cannot give him anything until he does. It was pretty obvious he had hoped to give us a few old, unusable harpoons and then we would just turn over all the goods to him, but he began to realize on the trip home that we meant to give him nothing until he turned over the rest. He says he’ll try to get the net back.

What Lando doesn’t realize yet is that I photographed all the harpoons last summer just after Mr. Domingos died. Each tip has a unique design since they were all hand made, and the ones I photographed are in much better condition. So it’s very easy to tell whether or not we’re being given the ones that are still usable. So far I believe Lando has turned over one of the four I photographed. Even though I had to leave Angola, Joao and Mary (the socio-economic advisor and Joao’s boss) will continue to work with the Domingos family to recover all the gear. I was a bit disappointed that it didn’t happen while I was there, since I’ve been working to broker this deal for a year, but in the end I hope it will still mean the end of manatee hunting in this area. And we definitely made some progress! I just have to remind myself that nothing happens quickly in Africa.

These are the three harpoon tips we have received so far. Their hunting days are over, and hopefully we'll find a place in Angola to display them as part of a cultural heritage exhibit.

The newest Angola LNG boat was named the Manatee! So maybe I've managed to raise some awareness on the base :-)