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!