Project Overview

Summary:

In January 2018, Dr. Lori Schwacke at the National Marine Mammal Foundation was awarded an RFP-VI grant totaling $4,736,265 to lead the GoMRI project entitled “Consortium for Advanced Research on Marine Mammal Health Assessment (CARMMHA). The consortium brought together nine institutions and approximately 47 research team members (including students). Through a combination of thematic projects, field assessments, and integrative modeling, CARMMHA planned to provide a comprehensive understanding and synthesis of the health impacts of oil-associated chemicals from the Deepwater Horizon Oil Spill on cetaceans, and a suite of models that would integrate available information collected prior to, immediately following and over eight years after the spill, to demonstrate where population-level impacts have occurred and to reassess the current recovery trajectories for Gulf of Mexico (GOM) cetaceans. Our primary objectives were to:

• Conduct innovative veterinary/laboratory studies to address priority questions related to health effects of oil exposure in dolphins that have emerged from prior studies;
• Integrate data from lower taxa to understand the potential indirect effects on dolphins from ecosystem changes that occurred before, during, and after the DWH spill in GOM bays, sounds, and estuaries;
• Fill a critical information gap related to the current health status of dolphins outside of the previously studied bays, sounds, and estuaries following the DWH oil spill;
• Apply state-of-the-art modeling approaches to synthesize all available data and information from prior and on-going studies, including from the above objectives, to develop new population recovery trajectories for multiple cetacean stocks.

Outreach Highlights

As of June 30, 2020, CARMMHA members have participated in more than 30 outreach related activities including school presentations, blog posts, workshops, news articles, film screenings, and more. Some of our key outreach products and activities include:

• Working closely with groups such as the Girl Scouts and the Fleet Science Center to host two-hour interactive workshops on how pollutants can affect the health of marine mammals, and how we can study those effects;
• Producing 33 blog posts over the past two years covering a range of topics from our field work to publications and outreach events;
• Participating in several community outreach events such as a Sea Grant oil spill response workshop, university lecture series, the AMMPA educators meeting, and community engagement events such as Dauphin Island Sea Lab Discovery Days;
• Publishing interviews and articles with GoMRI publications and the Univ. of Illinois;
• Hosting seven film screenings of Dispatches from the Gulf 2 and speaker panels.

Research Highlights

As of June 30, 2020, the consortium’s research has resulted in 5 peer-reviewed publications, 34 scientific presentations, and 24 datasets being submitted to the GoMRI Information and Data Cooperative (GRIIDC), which are/will be made available to the public. An additional 23 peer-review publications are either submitted, in co-author review, or in final stages of preparation. Two PhD candidates worked on CARMMHA research. Significant outcomes of this project’s research objectives are highlighted below.

1. 1.     Conduct innovative veterinary/laboratory studies to address priority questions related to health effects of oil exposure in dolphins that have emerged from prior studies.

• One lingering scientific question that CARMMHA aimed to address was whether or not dolphins exposed to DWH oiling had evidence of cardiotoxic effects as had been identified through GoMRI research on other marine species. We developed a suite of cardiac assessment techniques, never before applied in wild dolphins, that includes auscultation, echocardiography, and electrocardiography. Using these new methods, we identified abnormal heart morphometrics and cases of pulmonary arterial hypertension in Barataria Bay dolphins, potentially linking our previous observations of lung disease with the cardiotoxicity of DWH oil seen in other species. In stranded dolphins, we identified myocardial fibrosis as a cardiac lesion with a higher prevalence in dolphins exposed to DWH oil. Taken together these findings suggest that there may be cardiac effects of oil exposure in dolphins either via direct effects to the heart leading to morphometric abnormalities/lesions or via damage to the lung and secondary heart effects.
• Our team created a framework for how to evaluate pregnant dolphins in the field that includes ultrasound and bloodwork diagnostic indicators. The framework helps to identify risk factors for predicting failures. We found that in both managed care dolphins and in a wild population, maternal illness was the most prevalent underlying cause for pregnancy failure. The reproductive impairment was first observed as part of the DWH NRDA research, but from our CARMMHA field efforts we documented that there are still ongoing reproductive issues in some dolphins even nine years after the spill.
• We developed a suite of new techniques to understand pathways for the immunotoxic effects that had been previously observed in dolphins exposed to the DWH oil. We demonstrated a variety of dysregulated immune system components, including with the proportions and function of regulatory T cells, cytokine patterns, and inflammation markers. We also enhanced the weight of evidence with experimental exposure of mice to DWH oil, and laboratory in vitro exposures of dolphin cells to DWH oil.

1. 2.     Integrate data from lower taxa to understand the potential indirect effects on dolphins from ecosystem changes that occurred before, during, and after the DWH spill.

• We examined stable isotopes and fatty acid patterns in dolphin tissues and prey species in relation to environmental parameters across the northern GOM. While we did not find direct evidence of temporal prey shifts following the spill, we did show that stable isotope patterns, which are indicative of dolphin habitat use, can help to predict exposure to morbillivirus, a major disease of dolphins and whales. We further found that stable isotopes and movement trends can predict a dolphin’s relative resistance to environmental changes.

1. 3.     Fill a critical information gap related to the current health status of dolphins outside of the previously studied bays, sounds, and estuaries following the DWH oil spill.

• We used genetic methods of DNA sequencing and microsatellite genotyping to

establish a more detailed understanding of dolphin population structure in the northern GOM. While previous genetic data indicated that dolphins in Barataria Bay are genetically differentiated from those inhabiting adjacent coastal waters outside of the bay, for Mississippi Sound, the genetic data do not support such differentiation between dolphins within the Sound and those in adjacent coastal waters. Furthermore, the health data that we collected from dolphins near Dauphin Island, AL, showed lung disease and low cortisol levels consistent with the adverse health conditions previously observed during NRDA studies of Mississippi Sound dolphins.

1. 4.     Apply state-of-the-art modeling approaches to synthesize all available data and information to develop new population recovery trajectories for GOM cetacean stocks.

• Our field studies demonstrated that the adverse health effects seen in dolphins directly after the DWH spill have not significantly improved, and in some cases may have worsened.
• We used formal expert elicitation to synthesize the new information generated, together with already-existing information to produce distributions on quantities of greatest importance for modeling population recovery. Two panels of experts, 12 in total, met over two days each. The first panel, on population biology, concluded that density dependent fecundity may drive more rapid recovery than previously thought. The second panel, on cetacean health, concluded that only approximately one fifth of affected individual dolphins and whales may recover in their lifetime, and gave updated distributions on the reduction of survival and reproduction for affected individuals from offshore populations.
• Updated analyses of photo-identification studies in Barataria Bay have produced more robust estimates of changes in survival over time, which mirror the changes observed in the health data. Updated estimates of spatial distribution of the population were also produced.
• Updated population models, using the above information, produce generally more optimistic trajectories compared to previous estimates, but still predict that recovery will require multiple decades for many GOM populations.

 Proposal Abstract - RFP-VI PI Lori Schwacke