Thursday, April 16, 2015

Senegal: Quick trip to Delta Saloum

Earlier this week I spent two days in the Delta Saloum region of central Senegal to meet with the director and staff of Bamboung National Park. Two years ago they found a dead manatee (the cause of its death was not due to humans as far as they could tell) and Tomas was able to collect samples from it, which I analyzed in Florida. Now it was time to go back, meet the guys who work there, share the results of my analyses, see their site, and talk about future manatee work. As you can see by their logo above, the manatee is the emblem of their park, and everyone I met was super enthusiastic about manatees, and excited to hear the results that came from a few carcass samples. The results included the manatee's age (29 years old), diet (seagrass and clams), and genetics information (the manatee turned out to be a new mitochondrial DNA haplotype for the species which I also identified from a manatee from Joal, a town in northern Delta Saloum)

Here's the team I met (I later also met the director in his office). The guy in the brown shirt was absolutely thrilled to hear I had proved (using stable isotope analyses) that the manatee from their park had eaten mollusks in addition to plants. His grandfather was a manatee hunter, and he remembers as a child his grandfather telling him about the manatees eating clams, but when he tells tourists that story, they tell him he's mistaken. He was so happy that there is now scientific proof! During our meeting we decided we'd make a manatee information plaque for the park. Two years ago they buried the dead manatee to clean the skeleton, so we'll dig it up and set up the bones for a manatee educational display.   

At the edge of the camp area the staff showed me a freshwater spring (it's not visible here but is just in front of the small beach in this photo). There are hundreds of freshwater springs in Delta Saloum, which allow manatees to live in a saltwater environment but drink the freshwater they need to survive.
I also noticed lots of oysters growing on mangrove roots, another possible source of food for manatees. I'll sample those next trip because I didn't have preservative with me this time.
On our boat trip back from Bamboung to the mainland I collected samples from three species of mangroves, which I'll add to my stable isotope analyses to determine if manatees in this area are eating them. In all likelihood they are, but stable isotope work will allow us to see whether or not the mangrove's signature is found in the manatee samples.
I should also mention that I met with Karim Sall, a longtime manager of the marine protected area at the north end of Delta Saloum. He has seen manatees several times in the reserve's extensive seagrass beds, so I'm planning to go sampling there next summer. It's great to reconnect with folks in Senegal and get manatee fieldwork started again! Lots more to come.....

Friday, April 03, 2015

Manatee Hunter Arrested in Togo

Photo courtesy of Gabriel Segniagbeto

A well-known manatee hunter has been arrested in Togo and over 20 skulls and 17 other bones confiscated, thanks to the great work of a Togolese organization called Alliance Nationale des Consumateurs et de l'Environment (ANCE). Click here to see the story and photos. I heard about this hunter as far back as 2008 when I was in Togo to attend the Convention of Migratory Species meetings where we wrote an MOU and Action Plan for the African manatee. But at that time the Togolese people I met felt there was no way to have the guy arrested. Here's hoping this will greatly help conservation of Togo's remaining manatees, which appear to be in extreme danger of being hunted out. I'm in contact with ANCE and hoping to help them get manatee research and educational programs started there.

Detecting African Manatee Populations

A new genetics study just completed as part of my dissertation research has defined African manatee populations across their large range (21 countries) for the first time. Over eight years I collected 78 manatee tissue samples from eight countries and successfully isolated DNA from 63 of them in order to determine where distinct populations of the species occur. Collecting the samples was actually the hardest part of the study, because manatees in Africa live in very remote places, and even when samples were collected (from carcasses, live manatees rescued or captured for studies, and from manatee bushmeat in markets) it sometimes took over a year to get the proper export permits to send them to my lab in the USA for analysis. Most of the samples came from Senegal and Gabon, because those are the studies where I have long-term study sites. Other samples were collected during trips to other countries or provided by collaborators working in those countries. I studied two mitochondrial genes which are commonly used for population genetics because they can inform us about deeper evolutionary levels, and populations rather than individuals. I identified different haplotypes, which are a unique combination of forms of a gene found on same chromosome. That sounds complicated, but think of haplotypes being ice cream, and the different combinations are like different flavors. For example, mocha chip and mint chocolate chip are more similar to each other than to strawberry ice cream because they both have chocolate chips. In the same way, some haplotypes are mostly closely related to each other and are from the same population, whereas others are more distantly related and are from different populations.

My research identified 25 new haplotypes for the African manatee, which is exciting since only five had been identified prior to this study. The study identified four populations: one in West Africa (coastal Senegal, Guinea, and Guinea-Bissau), a separate population in the Senegal River, an inland Niger River population that included samples from Mali, Niger, Chad and Cameroon, and a large population in West and Central Africa (Ivory Coast, Ghana, Benin, Cameroon, and Gabon). This study is a first step and once it is published, we will continue collecting and analyzing samples in order to continuing defining more fine-scale population structure.  

Here's a map of DNA (control region) haplotypes identified in 63 African manatee samples. Sixteen new (solid colors) and five previously published haplotypes (patterns; Vianna et al. 2006) are shown in pie charts. Circle size corresponds to the total number of samples per country, and slices are proportional to haplotypes found (see inset table). Asterisks (*) indicate previously published haplotypes identified by this study at four new locations.

By defining manatee populations across Africa, this work aids conservation efforts for the species by informing wildlife managers in many countries about where unique populations exist, where they can focus trans-boundary conservation and management efforts (when populations occur across borders), and where efforts need to be targeted to specific locations where manatee populations are isolated. My co-authors and I are very excited to publish this work in the scientific literature soon!

Friday, March 13, 2015

African Manatees Are Omnivores!

     There’s a good reason manatees are also known as Sea Cows. They’re often seen feeding in seagrass beds or along the banks of rivers, much as cows graze meadows on land. The Florida manatee, the most studied species, is believed to be a strict herbivore (although there have been occasional observations of them eating marine invertebrates, and recently fish). But during my ten years of work with African manatees, in almost every country I’ve visited, I’ve repeatedly heard stories from local people that manatees steal fish from nets, and that they eat clams and mollusks, both freshwater and marine varieties. At first I was surprised, because I thought African manatees would be just like their Florida cousins, but I heard these reports so often from people in countries thousands of miles apart, that I decided I had to investigate.

Fishermen in eastern Senegal show catfish heads left in nets after manatees ate the rest of the fish.
      African manatees are very hard to observe in the wild due to their shy nature and the murky water habitats they live in, so I decided to research their diet using a technique known as stable isotope analysis. The name sounds intimidating, but the concept of stable isotopes is really quite simple: every plant and animal has a unique carbon and nitrogen signature, which differs for lots of reasons including the attributes of environment they live in (rainfall, water quality, soil quality, pollution, etc.) and many other factors. By collecting samples of everything we think an organism eats from each habitat they live in, these signatures can be used to determine what makes up an animal’s diet.
       In my case, I collected plant, fish, and mollusk samples throughout manatee habitats in Senegal and Gabon, as well as bone samples from manatees from the same areas, to determine their average lifetime diets in the different habitats in which they lived. I was also able to sample manatee bones collected 70 years ago from a museum collection, so that I could compare manatee diet in the past to samples collected recently. Then I took all the samples to the laboratory, processed them to get their stable isotope values, input those values into an analysis program, and got some exciting results.

This is a manatee ear bone, sectioned to sample average lifetime diet.
        African manatees sampled from both Gabon and Senegal, and both freshwater and marine systems, regularly ate mollusks and fish as part of their diets. For Gabon manatees living in lagoons and rivers in the Central African rainforest, the model estimated their diet was 90% plants and 10% invertebrates (fish were not sampled from Gabon). In the Senegal River, for manatees living in a desert environment at the edge of the Sahara, plants composed 46 - 57% of diet. The remaining diet proportions were composed of mollusks (19 - 24%) and fish (24 - 27%). Manatees living along Senegal’s coast indicated a diet of 48% clams and 51% seagrass. So for manatees in Senegal, approximately 50% of their diets were not plants! For a species considered an herbivore, this is pretty big news. There was no significant difference between historical and recent manatee samples for either the Senegal River or the coast, and although sample sizes were small, this indicates that sampled manatees had similar diets throughout life, and that diet proportions have not changed significantly over the past 70 years.
      So why is this important? The results of this study give us accurate information about the food resources manatees utilize over time in the different habitats they live in. This can help resource managers prioritize specific places where food resources are abundant for conservation purposes. This new information also increases the list of species we need to monitor as important food sources for manatees. For example, now that we know manatees in Senegal depend upon mollusks and fish, we need to try to resolve conflicts with fishermen and help to conserve not just the plants, but all the species manatees depend upon. This is the first dietary analysis study for the African manatee and I look forward to publishing the results in the scientific literature soon, and continuing my studies of manatee diet in other countries.

Friday, March 06, 2015

Back to Africa At Last!!

At the end of January I finished packing up and left Florida, which definitely was the end of an era for me. I moved there in May 1998 to begin a job with the Florida Fish and Wildlife Commission running a manatee research field station in southwest Florida. After 6 years I left that job to pursue international manatee work and began working in Africa in 2006. Although I've spent a lot of time in Africa since then, I returned to FL for my PhD in 2009, and my home base has been there until now. I'll miss my friends and colleagues there a lot, but it's time to get back to fieldwork and conservation on the ground in Africa.

After leaving Florida in early February, my husband Tomas and I drove north on our "Friends, Family and Funders" tour of the northeast. We spent 2 weeks in Washington DC and I gave presentations about my dissertation results and ongoing projects in Africa to the U.S. Marine Mammal Commission and the Fish and Wildlife Service. We also donated an African manatee skull to the Smithsonian Museum and were treated to an amazing behind the scenes tour of their marine mammal storage facility in Maryland by longtime curator Charley Potter and Dr. Daryl Domning.

Me, Tomas, and Dr. Domning with the skull we donated
Side by side comparison of West Indian (Florida), African, and Amazonian manatee skulls.
Ok, so it's not a manatee, but the blue whale skull at the Smithsonian facility was amazing!
On March 1 we flew back to Senegal, and we're currently setting up our home and office. I look forward to sharing more African manatee news and stories soon!

Tuesday, December 30, 2014

Happy New Year!!

I have no idea where the time went this past Fall! I apologize for my silence the past few months. I'm now wrapping up my work and life in Gainesville, FL and preparing for the big move back to Africa in March. I'll be based in Senegal and am very excited to get back to African manatee fieldwork.

Big things are coming for the African manatee project in 2015!  These include:
- continuing development of long-term study sites and partnerships in Senegal
- in collaboration with the USFWS, I'll begin a new two year training program for manatee graduate students from Central Africa, called MENTOR Manatee 
- continuation of support for our projects in Cameroon, Gabon, Nigeria, and Mali
- work on 7 manatee scientific manuscripts...hopefully several will be published in 2015!
- continuing African manatee population genetics in collaboration with colleagues at the USGS Sirenia Project
- and much more!

Wishing everyone a successful and happy 2015!

Friday, October 24, 2014

Senegal: Tocc Tocc Reserve update

It's been a busy summer and autumn for the EcoGuards and Community leaders at Tocc Tocc Reserve in northern Senegal. The EcoGuards are now patrolling the reserve full time, and we're fortunate to have raised enough funds for a second boat for the reserve, which allows more wildlife monitoring and patrols.
The EcoGuards confiscated and destroyed the first illegal fish traps in the reserve (after giving the owners warnings to remove them, which they did not). The installation of buoys marking the reserve boundaries now guarantee people are aware of the protected area, which aids in enforcement of the regulations. However, because the local community supports and oversees the reserve, there have been few instances of broken rules, and most of those cases came from seasonal fishermen from outside the community. Ten fishermen have been arrested and fined for violating no fishing rules within refuge. Funds collected from fines were used by the community conservation committee towards refuge costs. So we believe the reserve is now protecting all the wildlife that uses it.
Additionally, since educational programs began last year, we have received five reports of manatees entangled in fishing nets from villages outside the reserve. In four cases, the EcoGuards were able to safely release the manatees back to the wild, and in the fifth case the manatee had unfortunately drowned, but genetics samples were collected that are helping us further understand the Lac de Guiers manatee population. We believe the increase in the number of reported entangled manatees (none were reported before this project began) is a direct result of our educational outreach and awareness programs in the area. Now that all the abandoned nets have been removed, manatee sightings within the reserve have also greatly increased. Between April-June 2014, manatees were sighted almost every day, which is a very large increase over the previous year, when they were sighted only every few weeks.
Photo courtesy of Modou Diop Boh

In September, the first observation tower was completed, and eleven members of Senegal's parliament visited the refuge to see a good example of community-based conservation that can be used as a model for other sites in Senegal. It was a grand occasion with lots of speeches by the politicians and tours of the new tower.  
photos courtesy of Tomas Diagne
Next, we begin raising funds to build an education center at the reserve for the public and tourists.