January 12, 2023
Featured image: Galápagos horn shark © Avi Klapfer
By Courtney Mattison
Before humans ever made landfall in the Galápagos Archipelago in 1535, only 300 years before Darwin’s fateful voyage, whale sharks migrated through the northern islands among oceanic manta rays and schools of hammerheads while green sea turtles munched on algae growing between barnacles the size of tennis balls on the rocks below. Sea lions and fur seals sunbathed on shore, reclining among marine iguanas, crimson Sally Lightfoot crabs, frigates and blue-footed boobies. Despite the challenges of tourism, commercial fishing and climate change, the Galápagos of today looks surprisingly similar. It’s tempting to assume that these islands and surrounding waters are relatively pristine given their remote location and UNESCO World Heritage status, and in some ways they are. But beneath the surface, the story is more nuanced and there may be more of an ecological decline occurring here than appears at first glance. As Mission Blue founder and National Geographic Society Explorer-at-Large Dr. Sylvia Earle says:
Essentially nothing has been totally lost here… On the land, most of the species that were here when [Darwin] was here are still here. There are a few losses, but generally, mostly intact. In the ocean, we don’t really know what’s been lost.
Cryptic species – those that are difficult to document – and species that are considered less interesting to tourists are often overlooked, and so too may be changes to their populations. Long before humans began exploring and extracting from the Galápagos, some less-visible critters were also thriving here. Slipper lobsters crept between rocks on the seafloor among clumps of sea cucumbers as Pacific seahorses clung to nearby fronds of algae. Endemic horned sharks laid their spiral egg cases in the sand and red-lipped batfish pouted in the depths. Each of these species still exists in the Galápagos, but some of them seem increasingly difficult to find. In July 2022, researchers conducting surveys on the Mission Blue expedition to the Galápagos Islands Hope Spot encountered far fewer slipper lobsters and sea cucumbers than expected, and no seahorses.
Hope Spot Champion and lead investigator, Professor Alex Hearn, set out on this Mission Blue expedition onboard the MV Argo with the objective of measuring the success of the Galápagos Marine Reserve nearly 25 years after its establishment while developing strategies that could improve it in the future. Better understanding the status of and threats to its overlooked species is vital to improving the Park’s already-successful efforts. Alongside Dr. Sylvia Earle, Dr. Hearn and their international team of researchers used past data to estimate trends in population abundance while developing new baselines and monitoring plans where no prior data existed.
The team was well equipped with a wide variety of techniques and tools at their disposal. Divers conducted transect surveys to measure populations of bullhead horn shark (Heterodontus quoyi), Pacific seahorse (Hippocampus ingens), red-lipped batfish (Ogcocephalus darwini), and sea cucumber (Isostichopus fuscus), and obtained permits to measure and release individual slipper lobsters (Scyllarides astori) and compare their population to baseline survey data from 2002-04. To detect other more cryptic species that aren’t possible to count in a visual survey, Dr. Diana Pazmiño of Universidad San Francisco de Quito took water samples to identify species’ environmental DNA (“eDNA”), the genetic material shed by animals as they move through the water. Dr. Hearn and Daniel Armijos of the Galápagos Science Center deployed baited remote underwater video devices (“BRUVs”) to attract and record fish diversity, abundance and behavior. National Geographic Explorer Salomé Buglass, a PhD candidate at the University of British Columbia and Charles Darwin Foundation, searched for rare kelp forests via SCUBA and using the MV Argo’s DeepSee submersible. And in a new pilot study, multimedia artist and expedition film team member Taylor Griffith created hydrophone recordings of underwater soundscapes at different sites around the archipelago. According to Dr. Hearn, Taylor’s recordings could reveal changes in the fish community as well as the “sound community,” and researchers could “use that [information] as a baseline to compare, for example, sites that are heavily used by marine traffic or divers.”
Samples and measurements from the expedition are still being analyzed, but initial data suggest possible population shifts. Compared to 2002-04 baseline data, slipper lobster populations may now be ten times lower. Dr. Hearn hopes to organize a follow-up expedition focusing specifically on slipper lobsters to further measure this concerning decline. Conversely, while no Pacific seahorses were encountered on this expedition, ongoing qualitative analysis of interviews with local dive guides may indicate that the pause in tourism from the COVID pandemic helped this species recover when given a break from diver harassment. Seahorse and sea cucumber populations have historically been subject to overharvesting. “It was a gold rush,” says Dr. Hearn of the collection of millions of sea cucumbers for Eastern medicine in the 1990’s, which led to a harvesting ban that was relaxed again in 2021.
As the expedition researchers’ findings are published in the coming months and years, they will give a voice to the cryptic and forgotten species of the Galápagos Archipelago. With more information on how these species’ communities and populations are shifting, the Park can be better informed about management strategies to protect them. Despite concerns about possible declines in the meantime, Professor Hearn is hopeful:
“Galápagos is like a microcosm of Earth. We only have one planet and as humanity we’re learning — not doing such a great job, but still learning — how to live in harmony with biodiversity… If we can get it right here, then maybe there’s hope for the rest of the world too.”
Special thanks to Rolex and National Geographic for sponsoring this expedition, to SCUBAPRO for outfitting the Mission Blue Galápagos research team, and to Deep Sea Productions for generous in-kind filmmaking support. This expedition was planned in collaboration with Oceanic Society with additional expert content creation from Proudfoot, Taylor Griffith and Tui de Roy.