Native American fishing practices kept oyster beds healthy and steadily replenished — an elegantly sustainable model that researchers say we should emulate today.

By Kastalia Medrano

An employee of the Hollywood Oyster company sorts and counts fresh oysters at the company farm in the waters of Chesapeake Bay near Hollywood, Maryland, on March 20, 2014. (Photo: Mladen Antonov/AFP/Getty Images)

This week, Pacific Standard looks at the global seafood industry — how it’s responding to class, consumer trends, and a new climate.

Estuary systems are in decline around the world. Polluted waters, overfishing, and sea levels rising as a result of climate change have left many marine ecosystems a mess. And the Chesapeake Bay, after a century of overfishing and deteriorating water quality, is in trouble.

In the ongoing search for ways to restore the Chesapeake, an interdisciplinary team of scientists from the Smithsonian Institution — including biologists, resource managers, archaeologists, anthropologists, even a paleontologist — may have found the key in one of the watershed’s most vital and iconic symbols: the oyster.

Oyster health is a good barometer for the general health of a marine ecosystem. If the oysters are unhealthy, so is the bay. Not only do oysters reflect the health of their respective ecosystems — they actually improve it by filtering and cleaning the water in their surrounding bays. The Smithsonian team, which published its findings in the Proceedings of the National Academy of Sciences, contextualized the current state of the Chesapeake oyster by surveying four historical time periods: modern (2000–14); historic (from roughly 1600 up to 50 years ago); the prehistoric Native American epoch; and, as a sort of baseline control group, the Pleistocene (780,000 years ago up to 13,000 years ago), which represents the “resting” population, before oysters were ever harvested by humans.

The Smithsonian team believes we can learn from the Native American model, and that adapting it to our fishing practices could be the key to restoring the Chesapeake — and its oysters.

The researchers found that prehistoric Native American fishing practices were by far the most sustainable: At each of the data points studied within that time period, Native Americans fishing in the Chesapeake managed to keep the oyster population healthy and steadily replenishing, all despite a changing climate, a rising sea level, and their own tribes’ increasing populations. They maintained their system for thousands of years, to apparently no ill effect on the oysters or the bay. The Smithsonian team believes we can learn from that model, and that adapting it to our fishing practices could be the key to restoring the Chesapeake — and its oysters.

In an eco-dilemma of this sort, the first element of a sustainable model is triage and recovery. With the oyster population so depleted, getting those numbers up has to be the top priority. That means more sanctuaries, more areas that will allow large, preserved oyster populations to return to their natural pattern of re-generation. Once the population is more stable, we need to complement those sanctuaries with areas of dedicated harvest, with strictly enforced rotation between the two. While the researchers are advocating for some no-take zones, they’re not saying people shouldn’t harvest and eat oysters; quite the opposite.

“Humans are deeply connected to oyster fishing going back thousands of years,” says Torben Rick, an anthropologist with the Smithsonian National Museum of Natural History and lead author of the PNAS study. “We need to find a way to have our cake and eat it too. Often when people talk about oysters, whether in the Chesapeake or other places, we think of oysters as ecosystem engineers that help filter phytoplankton and create reefs and do all these great ecological services, but another thing is the deep connections they have to people.”

Oysters, of course, are valuable not just because of the health they bring to a marine ecosystem but as a food resource that’s very much in demand. The researchers want to find a way to allow the oyster population to re-generate that doesn’t put commercial fishermen out of a job. An optimist, Rick believes that just as Native Americans found the right balance, we can adapt their methods to do the same.

Native Americans during this period were collecting their oysters by hand, or possibly with simple tools: “Unfortunately, that’s just not stuff people wrote down,” Rick says. “But there was certainly no dredging like we do now.” Dredging is the practice of dragging a heavy metal net behind a fishing boat along the ocean floor to collect any number of bottom-dwelling specimens. It can be incredibly damaging to the reef structure, and it’s how we get a lot of our oysters from the Chesapeake today.

Native oystermen also harvested primarily in shallow water, water that could be easily accessed at low tide. They don’t seem to have fished deeper-water oysters on any kind of regular basis. This meant that a substantial portion of the oyster population was mostly left alone, able to re-generate and produce unhunted spat, which is sort of the teenage phase of the oyster, where it grows from free-swimming larva into a hard-shelled adult. Complementing the natives’ recourse to fringing reefs rather than deep-water reefs was a focus on seasonal hunting: Tribes would vary their resources, spending certain parts of the year alternately on agriculture, or gathering wild plants, or deer-hunting. This kind of organic rotation pattern reduced pressure on any one resource, just as how farmers today rotate their crops and pastureland. That kind of diverse subsistence strategy, with oysters functioning as just one seasonal component of many, is key to the sustainable model Rick and his colleagues think we can mimic.

By initially scaling back the harvest, then introducing a system of shallow-reef fishing and rotating sanctuaries, we should be able to set the Chesapeake and its oysters back on the right path.

But basing a sustainable model for oyster fishing off historical Native American practices — no matter how efficient or successful — raises a lot of immediate questions. Chesapeake oysters are at just 1 percent of what their numbers were a century ago, and of course our own population and accompanying demand on food resources is many times what it was during the epoch of Native American harvesting practices. We’ve also become accustomed to industrial fishing on a massive scale, and to whatever food we want whenever we want it, regardless of the season. Man-made climate change has accelerated sea-level rise. And oysters today are even smaller than their historical counterparts.

How do we reconcile such an antiquated and unindustrialized practice with the demands of the modern world? In the early stages, at least, maybe we can’t.

“Given how the state of oysters is so diminished right now, there’s gotta be painful decisions in the beginning,” Rick says. “There’s gotta be some form of reduction at first.”

Oyster fishing in the Chesapeake might be in for some growing pains. And it doesn’t seem unreasonable to guess that this would affect the price of oysters in addition to their availability. But Rick and his colleagues believe the long-term payoff is worth it; after all, restoring the Chesapeake is what everyone wants. Healthy oysters, healthy bay.

Indeed, hand-fishing can actually help offset the shrinking size of the oysters: During the approximately 3,000-year period that the Smithsonian studied, Native Americans were apparently able to fish oysters in the Chesapeake without ever causing a decrease in their average size. By initially scaling back the harvest, then introducing a system of shallow-reef fishing and rotating sanctuaries, we should be able to set the Chesapeake and its oysters back on the right path.

And this sustainable approach to oyster fishing should be replicable in estuaries beyond the Chesapeake.

“Maybe not all the specifics,” Rick says, “but if you paint with a broad brush you can certainly apply this to other ecosystems with oysters or lobsters or just a big shellfish population. Combining paleontology, archaeology, history — you can apply that to any kind of ecosystem.”

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