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If the Basques were the first to commercialize whaling in the 11th century, it was the Americans who took it global. From the 18th to the 20th century, thousands of whaling ships—the majority flying the US flag—scoured the world’s oceans in search of cetaceans. The Americans’ large ships allowed them to process the whales at sea, harvesting the valuable oil, baleen, and ambergris without having to return to port first. Since they were paid by the whale, the American whalers set themselves ambitious targets. Reaching them, however, wasn’t always easy.
Early industrial whaling was incredibly inefficient. Harpoons were prone to breakage or loss. Whales would fight back, and use their tails to flood the whalers’ small pursuit boats. Other whales would swim around rocks when harpooned, eventually prising the weapon out, “and all the labour would be lost, which hath often happened,” lamented Frederic Marten, a 17th century British whaler. Some wounded whales would drag the whalers’ small boats away from the main ship, or run the line in a way that risked them capsizing, leaving the whalers with no choice but to cut the whales free.
Some of these wounded whales would go on to live another day. But some would die and sink quickly when the lines were cut, only surfacing days later, after the ships had moved on.
Most of our understanding of the scale of industrial whaling stems from accounts of whales that were successfully caught—tallies that rely on reports of oil or baleen sold at port. But Morgana Vighi and her team at the University of Barcelona in Spain wanted to pin down the number of whales that whalers killed but did not catch.
To do so, they visited archives in the United States and Europe, looking for whalers’ logbooks preserved in physical form or on microfilm. They focused on whalers who targeted southern right whales and sperm whales in the southwest Atlantic Ocean, off Argentina and Brazil—a heavily exploited region. In total, Vighi and her colleagues read 255 logbooks covering nearly 150 years of whaling from the late 18th to the early 20th century.
In the logbooks, captains wrote of quarrels and mutinies, and of missing their wives. They also left detailed itineraries of boat launches, whale sightings, and vivid descriptions of successful and failed catches. Some captains recorded their catches with hand-carved stamps. Vighi’s team turned the diaries into data that could be analyzed to establish the loss rates for these two species of whales.
The painstaking work was made more difficult by the effects of time and tricky language. “Most of the whalers were not so literate,” Vighi says.
The research showed that no journey went by without losses. But in the early phases of industrial whaling, between 1775 and 1850, those losses were significant. The scientists calculated that, for sperm whales, the loss rate reached 1.1, meaning for every 10 whales caught, one was lost at sea. For southern right whales, the rate was 1.5—for every 10 killed and captured, five were lost.
After 1850, southern right whales started disappearing from the logbooks in favor of sperm whales. The researchers suggest this could be a grim reflection of their population being driven to near extinction—a likely possibility given whalers often targeted right whale mothers and their calves. Over time, the loss rates for both species steadily decreased, reflecting improvements in whaling techniques and weaponry, such as explosive harpoons or harpoons with toggle heads.
“Technology was a lot less advanced compared to modern whaling, nonetheless this did significant damage to a lot of populations,” says Phil Clapham, a cetacean ecologist and senior scientist at Seastar Scientific who was not involved in the study. “Particularly the slower whales because they were the ones they could catch.”
“These reconstructions are fundamental to guide current recovery efforts by telling us how far or how close the current populations are from their natural state,” says Ana Rodrigues, an ecologist at the Center for Functional and Evolutionary Ecology in France who wasn’t involved in the research. “Ignoring these [lost] whales leads to underestimates of the historical population sizes, and translates into less ambitious conservation targets.”