We are in the final stages of our analysis, so we thought we would highlight a CARMMHA consortium researcher who has been leading our statistical analysis and population modeling. Please read on to learn more about Len Thomas of the University of St. Andrews, Scotland, in his own words…

What is your role in the CARMMHA consortium?

My role is to bring together findings from all the other projects within the Consortium to predict how populations of dolphins and whales will recover from the effects of the Deepwater Horizon oil spill.

Can you describe the specific primary objectives of your research?

Prior to CARMMHA, as part of the original Deepwater Horizon natural resources damage assessment, we made population models for each marine mammal stock of interest. These models track how population numbers change over time. They take as inputs information such as survival and breeding rates. To estimate the effect of the oil spill, we compared model runs made using baseline values with runs using survival and breeding rates measured after the oil spill. Most of our information came from just one stock, of bottlenose dolphins in Barataria Bay.

The CARMMHA project is providing us with updated data on whether and how that stock is recovering, new data on other dolphin stocks, and an opportunity to gather more information from the literature and from marine mammal experts on how our data on dolphins might apply to other species. Lastly, we’re further refining the population models, for example to explore how natural variation in environmental conditions might affect the outcomes. With all this updated information, we will re-run the population models, leading to a more accurate estimate of the effect of the oil spill and how long it will take each population to recover.

What have been your most important findings so far?

Early indications from the teams assessing the health of the Barataria Bay population indicate that the cohort of animals that experienced the oil spill do not appear to show an overall increase in health. This means that the population will take longer to recover than we originally forecast. On the other hand, at a recent meeting we convened of marine mammal experts, the consensus was that populations in general rebound quicker from reductions than our original models assumed. It remains to be seen whether these two effects balance one another out, and also what further information the other projects in CARMMHA come up with.

Why do you think it is important to be a part of this consortium?

Determining what’s happening to our whales and dolphins after the oil spill, figuring out why, and predicting what might happen in the future requires a lot of different skills. I’m responsible for leading the statistical and modelling aspects, but what I’m doing would not be possible without input from veterinarians, physiologists, immunologists, cardiologists, population ecologists, etc. CARMMHA has a fantastic inter-disciplinary team and we’re all working very closely with one another to give us the best chance of succeeding. Stand by for some exciting results as be bring everything together!