Located in southeast Africa -- more than 9,000 miles from the Baylor campus -- Lake Malawi contains between 500 and 1,500 species of a single type of fish known as the cichlid. To put that in perspective, there are more different species of cichlid in this one lake than there are different species of all fish in North America.
Dr. Pat Danley, an assistant professor of biology in Baylor's College of Arts and Sciences, has been studying the fish in Lake Malawi since 1995. Last summer, he led a team of Baylor graduate students there to study why there are so many different species of cichlid in one lake and what allows them to coexist.
In the following pages, Danley shares with Baylor Magazine what his research is all about -- and what it's like to do field work half a world away from his usual lab.
I thought about this, and I told my wife, "I don't think the settings were that primitive." She just looked at me and shook her head. I guess I have been going to Malawi too long to see how it might be considered primitive at first glance.
The field station we work out of is generously provided for our use by the Malawian parks system (the Lake Malawi National Park in particular) and the University of Malawi. I think it's a great place to work, but I can see how it has some limitations. There is no hot water at the field station. The electricity may go out for a couple hours a week, and if it does, we have to haul our own water for the toilet. There is no TV or Internet at the station, though I don't miss either much. When I do, I can walk into the nearby village and connect through a wireless Internet connection.
Things are a bit more uncomfortable when we travel on the boat around the lake. This year we had, between my group and the crew, 12 people living on something like a 25-foot boat. We all ate, slept, dove and analyzed data from the boat. It got to be a little tight after the 10th day on the boat.
The other real concern is safety in the field. The research station is located about six hours from a "Western" hospital. We have to be particularly careful when a good hospital is that far away. However, there is a really great health clinic in the village operated by an Irish non-profit group. They take good care of us if we have any minor health problems.
Overall, though, I'm really comfortable working where we do. The staff is great, and the equipment is great. I just wish there was a hot shower.
The most challenging part of working at the lake is the absence of American shopping centers. When I do field work in the U.S., I never have to worry about a piece of equipment breaking. I can always go out and replace a piece of equipment through a trip to the hardware store or dive shop. In Malawi, there are no Home Depots, and the closest hardware store is a 90-minute drive away. I always try to pack a backup of everything whenever I go to Malawi.
In my lab, we maintain two species of Lake Malawi cichlid. These two species are fairly similar, and their similarities make them very useful for my lab work. However, it's hard to convey the extraordinary diversity of the fish in Lake Malawi to my graduate students when all they have seen are these two species. Going into the field impresses upon them the remarkable biological diversity found in the lake. Most of the people I have gone to Lake Malawi with over the years usually need a couple of days to get over the shock of seeing so many types of fish all at once.
Three things make Lake Malawi an ideal system to conduct the research that my lab does: the number of fish in the lake, the common origin of the fish, and the relatively young age of the lake.
Lake Malawi contains somewhere between 500 and 1,500 species of cichlid fish. The exact number of fish has yet to be identified, and more species are discovered in the lake every year.
Furthermore, all of these fish are descended from a common ancestor since the formation of the lake 2 million years ago. So in the past 2 million years, as many as 1,500 species of fish have diverged from a single fish species that entered the lake. This makes Lake Malawi's cichlid fish one of the most recent, rapid and extensive speciation events ever identified.
We were interested in exploring two topics: why there are so many species in the lake, and what allows these species to co-exist. To address the first topic, we travelled around the lake and collected genetic and morphological information from a number of different species at a number of different locations. We are interested in finding out how much populations within a species differ from each other relative to how much they differ between species. To address the second topic, we collected ecological information concerning the number of species and their abundance at a number of different locations across the lake. We also collected information concerning the habitat at each of these locations, such as the size of the rocks, water temperature, depth, etc. By examining the habitat data and the abundance data, we hope to identify what factors have allowed as many as 50 different species to coexist at a single location in the lake.
I'm interested in how species are formed and what allows them to coexist. Given the diversity of fish found in Lake Malawi, it really is an ideal place to study these questions.
One of the great mysteries in the field of biology is how species are formed. Over the past 50 years or so, a large number of experiments have been performed and observations have been made that address this question. My hope would be that my research contributes to this larger body of work concerning the speciation process. In doing so, my work will help explain not only the diversity of cichlids in Lake Malawi, but also the diversity of all species on the planet.
Graduate students are integral to my work. While I have a couple of my own research projects, I see myself largely as a project manager for the work being done by my graduate students. Working with my graduate students, we develop research projects and I oversee the collection, analysis and presentation of the data. I love the mentorship aspect of my job.
We returned from Malawi with nearly 1,500 DNA samples, tissue samples and photographs in addition to a lot of ecological information. The ecological data has been analyzed, and we are preparing to submit our findings to an ecology journal.
The tissues and photographs are being organized and curated. We've begun our analysis of the tissue and photographs, but I expect that it will take about a year to do a proper analysis.
In addition, my lab is conducting a number of experiments with Lake Malawi cichlid fish that we've bred in the lab. I'm very excited about some of the work we are doing with our captive population.
I feel truly blessed to be able to go work in Lake Malawi for my job. The people are warm, generous and kind, and the diving is spectacular. Lake Malawi is one of the clearest lakes on the planet, and the diversity and beauty of its fish would rival those found on any coral reef.