In this author spotlight, Sara Maxwell, a Postdoctoral Fellow with Marine Conservation Institute and the University of California, Santa Cruz, answers questions about her background, her research and her PLoS ONE manuscript, Using Satellite Tracking to Optimize Protection of Long-Lived Marine Species: Olive Ridley Sea Turtle Conservation in Central Africa.

First, a bit of background – how did you become interested in studying migratory patterns of large pelagic animals?

My interests have always centered around conservation primarily.  In my mid-20s as I was considering going back to graduate school, I knew I wanted to study a system that would interest me over the course of an entire career – and a system where my science could make a difference.  The migratory patterns of marine mammals fit the bill well, and turtles in particular have always been particularly special to me. During my undergraduate career, I spent a summer working with sea turtles at Duke University’s Marine Laboratory and it was ultimately the turtles that drew me into marine biology and conservation.  When the opportunity to work with turtles in Gabon arose, I didn’t think twice!

In the manuscript, it mentions that sea turtles are “excellent candidates and models for protecting vulnerable, discrete breeding areas.” Why is this so?

Sea turtles are a highly migratory and dispersed species throughout most of their lives, but during the breeding and nesting season, they come together in large concentrations – and for fairly long stretches of time.  Breeding and nesting areas are relatively close together. Olive ridley sea turtles, for example, nest every year to three years.  Female turtles stay in the breeding-nesting grounds for several months while they mate and lay up to three clutches of eggs, and breeding males are found in the same areas.  Breeding and mating areas, however, are close to shore – so closer to humans, fishing and other threats – but because they are in a small area for a specific period of the year and during an important life history stage, it makes protecting them easier and more politically and socio-economically feasible.

Mayumba National Park is a marine protected area just north of the border of the Republic of Congo. The area is home to leatherback and olive ridley sea turtles but of the two turtles, olive ridleys make up 59 to 95 percent of the dead turtles that wash up on shore.  Is there a reason for this and how does tracking via satellite help to minimize the number of stranded olive ridley sea turtles?

We understand the situation in Mayumba a lot better than we did before this study but it is still a bit of a thousands of leatherbacks sea turtles nesting in Mayumba every year but only a few hundred olive ridleys – yet the olive ridleys are dying in much greater numbers.  We used satellite tracking to determine where the turtles were going in relation to the park that was created to protect them. We found that they are spending a lot of time outside the park boundaries where they are exposed to fishing nets and drowning.  Leatherback movement patterns are somewhat similar; however we don’t see the same number of dead animals washing ashore.  This could be because leatherbacks are heavier and their bodies sink instead of washing ashore or they don’t encounter fishing nets as frequently because they are in deeper waters or have different diving behavior.  There are lots of things we still don’t know, but what we do know is that creating a larger park – one that is in both Gabon and the Republic of Congo – will protect both species better more from fishing nets.  Satellite tracking has been the key tool that brought us to that conclusion, through this study and another great study by Matthew Witt and colleagues published in Oryx in 2008.

One of the three elements you mention, as being necessary to provide protection to breeding females, is the level of confidence in tracks given the limitations of satellite telemetry. How accurate is satellite telemetry and what was done to eliminate location error of internesting movements?

Satellite tracking is an incredibly powerful technology – but it can be tricky too!  We were focused on a fairly small area of the world in this study (approximately 1500 km2), and like all measurements, satellite telemetry locations have error associated with them.  In the case of telemetry, however, this error can be tens of kilometers which could have a significant impact on the conclusions we were making about where turtles are found in relation to park boundaries.  To help counter this, we used a technique called state-space modeling that has been fairly recently applied to animal movement.  State-space models allowed us to assign the Bayesian equivalent of confidence intervals to every track location.  By doing this, we could calculate error estimates for how animals are using park boundaries – and recommend changes in the park boundaries that take this uncertainty into account.

You have included a few figures in the manuscript. Of them, which one is the most important and why?

This is a difficult question!  I think Figure 3, (above figure) which shows the key areas that the olive ridleys are using along with the outer bounds for our error estimation, is critical in showing what we learned from the study – and what we are still uncertain about due to satellite telemetry error. Figure 4 is important as well because it shows the olive ridley and leatherback sea turtle distributions together.  Though the analytical techniques were different, this figure shows that the proposed park boundaries (which extend into both Gabon and Congo as well as further offshore) are really on target to protect BOTH of these species – this was a really exciting finding, and one in which is already helping to guide management in the area.

Did you find anything surprising or unexpected while conducting your research for this paper?

One of the most critical things that we learned from conducting this research is not in this paper – and is critical to protecting the olive ridley population.  There is a substantial nest monitoring effort that goes on in Gabon and in Mayumba National Park but most of the monitoring has focused on leatherback sea turtles.  Olive ridleys, however, nest earlier in the year, and in the most remote part of the park.  We were on this remote part of the beach earlier in the year, both to deploy our satellite transmitters and to monitor the nests.  As a result we discovered that almost 100% of the nests being laid by olive ridleys were being predated upon by natural predators such as crabs and mongooses. Olive ridley nests are not as deep in the sand as leatherbacks, so predators could reach the eggs and none of the eggs being laid were hatching.  This obviously will have a huge impact on the population. As a result of what we learned, however, over the last three years, with support from the US Marine Turtle Conservation Fund, Mayumba National Park has started a hatchery where they incubate the eggs in a protected area of the beach to ensure that the eggs are safe and hatchlings are born.

What’s next?  Where do you hope to go from here?

The directions are endless!  But there are several directions we are actively working towards.  We are working to combine not just the satellite tracks from olive ridley and leatherback sea turtle data but also humpback whales.  The goal is to have a comprehensive understanding of how key species in the region are moving in relation to both park boundaries and also other human activities such as fishing and oil and gas development.  We have begun modeling the at-sea habitat olive ridleys use during the nesting season in relation to the physical and oceanographic environment.  The goal is predicting where ridleys are likely to be found in relation to other nesting beaches where we weren’t able to deploy satellite tags.  Finally, we are also collaborating with scientists from Pendoley Environmental who have tracked olive ridleys from another nesting beach in Angola.  We are finding that the turtles have similar migratory patterns and are focusing on the same foraging grounds and oceanographic features. All of these efforts are focused on how can we better understand and protect the turtles.

To read more about Sara’s experience in the field, please see her posts on Turtling in Africa in the On TOPP of the World Blog and to view the satellite tracks online, visit the SEATURTLE.ORG tracking page. The paper Using Satellite Tracking to Optimize Protection of Long-Lived Marine Species: Olive Ridley Sea Turtle Conservation in Central Africa is freely available to rate, comment on, and share.

I work in the production group at PLoS ONE, and as this milestone represents the output of our group, we thought it would be appropriate for me to interview the authors of the 10,000th article, “Immunoproteomics Analysis of the Murine Antibody Response to Vaccination with an Improved Francisella tularensis Live Vaccine Strain (LVS)”, by Twine et. al.

This is an article which focuses on the pathogen tularemia and the possible development of a human vaccine, and so we asked Dr. Sue Twine of the National Research Council Canada to share her expertise, and experiences with PLoS, in order to help us celebrate. When asked how she felt about being published as our 10,000th article, Dr. Twine responded, “I’m honoured – congratulations PLoS ONE!”

AvG: Please tell us a bit about your scientific background – have you always tested vaccines and/or studied the tularemia disease?

ST: My interest in tularemia developed through a somewhat convoluted path. I’ve always been fascinated by proteins, so I spent my PhD studying protein-ligand interactions. I then moved from the UK to Canada to pursue postdoctoral studies, using biophysical approaches to study protein-protein interactions. I joined the National Research Council Canada in 2002 as part of the proteomics group – I wanted to study proteins on a much larger scale. It was through one of my mentors here, Dr Wayne Conlan, that I developed an interest in tularemia and vaccine development. His enthusiasm for this little known organism is infectious, and I quickly became fascinated by how little was known about the pathogen.

AvG: Why do you think it is important to develop a tularemia vaccine?

ST: Bioterrorism is perceived to be a realistic threat with the potential to cause mass casualty events. Because of its extreme virulence, ease of aerosol dissemination, and capacity to cause severe disease in humans, F. tularensis is considered a potential biological weapon and is classified as a Category A select agent by the CDC. Among the bacterial diseases, anthrax, plague, and tularemia are considered the most serious biothreats. Anthrax vaccines already exist and are being stockpiled, and a new plague vaccine will soon go into production. LVS could serve as a stockpile vaccine for tularemia if it can meet the necessary regulatory requirements.

AvG: What do you find most exciting about your findings?

ST: A major factor impeding the licensing of a tularemia vaccine is the absence of a well defined immune correlate of protection that can be used to predict whether or not a vaccine recipient has elicited a protective immune response. From a clinical perspective, an antibody response that correlates with protection is ideal for this purpose since blood samples are easy to obtain and analyze. In human experiments conducted by the US Army in the 1960s, everyone given LVS generated an antibody response against whole bacteria, but all were not protected from exposure to virulent Francisella tularensis. Thus, mere seroconversion cannot serve as a correlate of protection for this vaccine.  BALB/c mice are protected by vaccination with LVS, whereas C57BL/6 mice are not. Comparing the antibody repertoires generated in each mouse strain revealed several differences. Thus, our work indicates that examining the pattern of antibody responses to a diversity of Francisella antigens can reveal a correlate of protection that is not obvious by using reactivity to crude bulk antigen.

AvG: What do you see as a next step with your results?

ST: The next step is to apply the immunoproteomics approach to sera from humans vaccinated with LVS, to determine whether a similar repertoire of antibodies are generated

AvG: What made you decide to submit to PLoS ONE?

ST: Our manuscript describes work funded by a contract from NIAID as part of the efforts of the tularemia vaccine development team.  One of the main goals of the contract is to provide new useful and accessible tools to the larger tularemia research community.  Publishing in an open access journal like PLoS ONE means that our article potentially will reach a wider audience of researchers. This is therefore in line with this specific contract goal of the tularemia vaccine development team.

AvG: Since this was your first PLoS ONE paper, how did you find the submission experience?

ST: From start to finish it was by far the most straightforward and rapid submission experience I have ever had. I was surprised how quickly the article went through the peer review process. I was able to address reviewers’ concerns quickly, and my article was sent to production within two weeks of submission!

AvG: How did you find the production experience?

ST: The PLoS ONE production staff was great to work with. Again, I was surprised how efficiently the article went through the production process.

AvG: Would you be interested in publishing with PLoS ONE again?

ST: Absolutely yes!

Congratulations to Dr Twine and her co-authors, Mireille D. Petit, Kelly M. Fulton, Robert V. House, and J. Wayne Conlan. We are proud to have reached this milestone, and we look forward to publishing more great research in future years!

BZ: I’d like to start with a bit more detail on your scientific background – what brought you into the research on viruses?

PS: I studied Biology at the Saarland University, Germany, and also obtained my PhD there, working on gamma-herpesviruses. This allowed me to gain first insights into the ‘world of viruses’ and I got quite interested in the biological diversity in this research area. I then moved on to Institut Pasteur, Paris, and joined Simon Wain-Hobson as a post-doc. I switched my focus to retroviruses (e.g. HIV/SIV) and had the chance to study certain aspects of HIV/SIV pathogenesis in vitro and in an animal model. During this time I started to fully appreciate the complexity implicated in the research on viruses. Currently I am focused on HIV drug discovery and host factors involved in viral replication, but I am still fascinated by various aspects related to viral infections spanning quite different areas such as evolution, population dynamics, cellular and molecular biology, immunology, physiology and so on.

BZ: What was it that attracted you to PLoS ONE in the first place?

PS: This is rather a question of the ‘who’ than the ‘what’. When I joined Institut Pasteur Korea in 2006, Phil Bernstein, who was involved in the launch of PLoS Biology, was the Head of Scientific Affairs and International Relations at the institute. Phil told me about PLoS ONE and that the journal was looking for academic editors. Since I liked the idea of Open Access and to publish papers with a novel, scientifically sound message irrespective of the potential impact, I felt this is a good chance to support these concepts as well as to learn more about scientific publishing in general and I joined the Academic Board early in 2007.

BZ: How many hours a week would you say you devote to PLoS ONE and when do you fit that into your busy schedule?

PS: That is about one hour per day. In particular, I try to proceed with the assignments of reviewers or academic editors as quickly as possible.

BZ: How does the peer-review process on PLoS ONE work? What is the standard of peer-review on PLoS ONE?

PS: In general, the process is very similar to other journals in that manuscripts are usually sent out for review by 2-3 outside experts and decisions are made taking their opinions into account. There are additional options, for instance AEs can decide directly or can start a ‘consultation session’ with other members of the Academic Board. The standard of peer-review is high and the criteria for acceptance are strict, but do not consider the potential impact of a manuscript, which should be rather judged by the scientific community.

BZ: How quickly does this process move?

PS: In my experience, the process moves rather quickly. Usually it takes about 4 weeks from initial submission to a decision to reject, accept with modifications or accept as is. This is also due to the excellent work of the many external experts, who usually provide their comments in short time.

BZ: What’s the general quality of submissions like?

PS: In my opinion, the quality is very good. Of course, since we do not judge the potential impact of a manuscript, there are some papers with rather limited focus, which may nevertheless be important for people working in that specific area. On the other hand, the majority of manuscripts deal with hypothesis-driven research, reporting on novel findings and the general quality of the manuscripts in my field is high.

BZ: What would you say is the ‘best’ paper you have handled and why?

PS: I do not see ‘the best paper’. There are several good papers I handled and there are certainly different reasons, why I personally consider a paper important or not. I think there are too many variables in this question.

BZ: What do you feel makes PLoS ONE relevant to scientists?

PS: For me, there are two main aspects. First, I think it is important to publish scientifically sound research irrespective of a potential impact. There are so many studies done each day around the world and not everything will be a ‘block buster’. Yet, many of these studies will contribute a useful piece of information for people working in the same field and thus deserve publication because they contribute to an overall progress. The second very important aspect is Open Access, which ensures that everybody has access to this information.

BZ: Thank you very much for your time. It was great fun talking to you.