A Puzzle with Missing Pieces: Marine Mammals in the Gulf

While some threats are unique to the Gulf, “some of the threats are the same no matter where you go,” Schwacke said. 

During the Deepwater Horizon oil spill, about 50 percent of Rice’s whale habitat in the Gulf was covered by oil. Before the oil spill, the only information available on the Rice’s whale, which was formerly considered to be a member of Bryde’s whale species, came from historical survey data. After it was designated as an endangered species in 2019 and determined to be a unique species in 2021, genetically distinct from the Bryde’s whale, urgency heightened to understand the ecology of the species. The timing of this new designation aligned with a  $2.3 million research award  Garrison received from the NOAA RESTORE Science Program in 2017 to study the whales and their role in the larger Gulf ecosystem.

“What we found almost immediately was this really large decline in abundance of just about everything." - Tracey Sutton, professor and deep-sea researcher

For the past decade, Sutton and his team have embarked on open-ocean expeditions in the Gulf of Mexico to identify trends in the fish, shrimp, and cephalopods (such as squid and octopus) that live offshore. Researchers drop a net to deep sections of the Gulf, reaching a depth of 1700 meters, and collect specimens to identify. Many of the animals they found have never been discovered before, and with 90 percent of the Gulf’s volume concentrated in the deep ocean, the team has a lot of saltwater to cover. 

Sutton’s crew found declines in abundance consistently from cruise to cruise, indicating that the reproductive abilities of many deep-sea species continue to be impacted more than a decade after the oil spill. They also measured polycyclic aromatic hydrocarbons – a chemical compound of oil that has been found to impact reproduction, development, and immunity – at sublethal levels (which doesn’t kill organisms but harms them) in shrimp and fish eggs as recently as 2018. 

“We are really seeing that our data matter to other people in ways we didn’t envision,” Sutton said. “It was a real challenge for us to figure out how people can use data for a resource that is not actually fished, or that most people don’t even know is out there. How do we now inject that into the bigger picture?”

Because Rice’s whales feed on prey that is sparsely distributed, they may rely on communication from other whales to locate patches of available food. When industrial noise levels crowd the acoustic space in which whales and other marine mammals communicate, their vocalizations travel shorter distances, making it more difficult for them to relay information about food availability. 

With that information, the team can run analyses on the abundance and density of marine mammals and can even identify specific species. The data also help researchers start to understand how animals are moving around different depths and locations. 

Soldevilla has seen the field of passive acoustics progress since she began working with this approach at the Scripps Institution of Oceanography in 2002. Since that time, the technology has gotten more advanced – researchers are now able to collect audio signals at higher frequencies, which requires a faster sampling rate and increased battery power. With increased power comes a greater ability to collect baseline data in new locations for species that were previously unmonitored, all of which is part of the groundwork that Soldevilla believes must be done to figure out the next steps for conservation. 

As the marine mammal branch chief of NOAA Fisheries’ Southeast Regional Office, Laura Engleby has her dream job. Her interests were seeded as a child watching Jacques Cousteau interact with dolphins, and she spent her career moving from dolphin trainer to education director to a NOAA expert on marine mammals, while building a nonprofit organization dedicated to dolphin conservation on the side.

One beacon of hope is the introduction of new technologies that help make it easier to study marine mammals, such as a remote-tagging device being developed at the Woods Hole Oceanographic Institute that could help reduce the stress dolphins experience during health assessments. The project received over  $280,000 from the RESTORE Science Program in 2021  to develop and test this new approach to deploying satellite tags.  

“Tens of milliseconds, and they are out of there,” Moore said. 

“There’s not any super clear overlap in some of this work,” she said. “The individual efforts are not intrinsically linked but they are adjacent; they are touching. So how do we spend the time to think about each of us doing something slightly differently so the pieces line up and we get more out of it? I’m that person who is always like, ‘we can get one more sledding run in before the sun goes down.’ I think even just asking the question is really valuable.” 

Now as a NOAA project manager, Fetherston-Resch and her team are working on a restoration project to aggregate marine mammal data in the Gulf with an online tool where researchers can input their information, combine it with other datasets, and access the findings of other projects. The hope is that people can play with the data and visualize information in new and different ways to help better design restoration, target management actions, and understand data gaps. 

“We are not going anywhere without that synergy, that’s where the insight is,” Fetherston-Resch said. “Without these kinds of partnerships and looking cleverly at how we try to line our work up to accomplish synthesis, we will never achieve insight. You can’t achieve it on accident. Hope is not a strategy.” 

The need to prioritize information gathering for these species is felt by others in the region as well. For Rice’s whales, Garrison hopes to establish a long-term monitoring program that focuses specifically on the species. The RESTORE Science Program’s investment in Garrison’s project was the first research award dedicated to understanding Rice’s whales specifically. Previous data on these animals was gathered during projects that were focused on other research questions and species. 

Research findings from Garrison’s project will feed into recovery plans and critical habitat designations in the future. NOAA Fisheries’ Southeast Regional Office has discussed developing an outreach strategy for the Florida panhandle to raise awareness of the presence of Rice’s whales in the region among boating communities. This strategy includes the opportunity to report vessel strikes to Rice’s whales on the “Whale Help” hotline.  

“We need to be able to keep track of these guys and understand how they are responding to their changing environment,” Garrison said. “No one is built for as rapid an environmental change as we are experiencing and will experience over the next 20 years.”

Climate impacts and other rapid environmental changes undoubtedly complicate the conservation puzzle for marine mammals and cloud pathways to clear solutions, but Engleby and those like her who are dedicated to conserving these animals are determined to do whatever they can to reduce stress on the Gulf’s dolphins and whales. 

“Anything we can do in that regard is beneficial and worth doing,” Engleby said. “We have one of the world’s most endangered whales, the Rice’s whale, in the Gulf of Mexico with an estimated 30 to 50 left. That’s a big deal. That’s going to be difficult. That’s a challenge. But that doesn’t mean we are not determined to do something to try to help these whales and learn everything we can along the way about what’s impacting them that can benefit other types of whales in other places.”