PORT LINCOLN, Australia — It has been called Australia’s answer to the Galápagos: a stretch of rich, pristine ocean facing the Antarctic that is home to calving whales and teeming fisheries that have turned local boat captains into tuna barons.

But now the waters, known here as the Great Australian Bight, or just the Bight for short, have drawn a different sort of resource industry: The Norwegian oil giant Statoil plans to start drilling by the end of 2019 to tap what experts call one of the world’s great remaining natural gas reserves.

Here in a country built on resource extraction, where the fossil fuel industry has a long history of political connections that often give it priority over the environment, people fear that this haven for some of the most unusual marine life in the world will be damaged and put at even greater risk from a spill.

“Our fishing industry, our tourism industry, our lifestyle, our local food and our wildlife all depend on a pristine coastline,” said a marine adventure company employee, Elise Lavers, while swimming with endangered Australian sea lions. She called the Bight one of the world’s best-kept environmental secrets.

“We have too much at stake to allow oil drilling in the Great Australian Bight to occur,” Ms. Lavers said.

The pressure to seek an oil and gas bonanza is especially intense because of local politics: Much of the Bight extends along the state of South Australia, a struggling postindustrial area where talk of jobs and economic growth dominated a recent local election.

Whether to open the Bight to drilling was a crucial issue in the election this past week to select lawmakers for the state Parliament. Leading politicians at the national level have chimed in over the years, with pro-growth candidates arguing that the oil and gas industry would create jobs and wealth in South Australia and beyond for decades to come.

“Statoil’s decision to undertake exploration is good news for the South Australian economy,” said Matt Canavan, a conservative senator from the state of Queensland. Even though pro-drilling candidates won in hard-fought races, plans to extract natural gas here still have to be approved by Australia’s offshore oil and gas drilling regulator. Statoil insists that exploration will be safe.

Australia has reached its 27th consecutive year without a recession by supplying energy and raw materials like iron ore to the manufacturing economies of Asia, and particularly China. Opening the Bight to drilling would help Australia stay on track to eclipse Qatar as the world’s largest exporter of natural gas by 2020.

But opposition to the drilling plan highlights the limitations of relying so heavily on the exploitation of natural resources and their export. The plan has met surprisingly strong resistance, despite the need for jobs in a region where manufacturing used to employ one in five workers. Six town councils have raised objections to the drilling.

Communities on Australia’s southern coast are questioning whether the government can justify putting at risk a unique marine wilderness area that supports the country’s most valuable fisheries and a tourism industry worth more than $1 billion.

The Bight gets its name from its appearance: From space, it looks as if a giant bit into the southern coast of Australia. The crescent-shaped bay runs for more than 700 miles, lined by the longest stretch of sea cliffs in the world.

Port Lincoln, a small seaside town of around 16,000 people where sealing and whaling reaches back to the 1820s, is the main jumping-off point for access to the Bight. Today, the enormous wealth that it continues to bring is evident in the mansions that dot its coast — homes of the tuna barons who have made millions from selling to Japan, where sushi chefs pay top dollar for Australian tuna.

“There’s potential for an oil spill that would be catastrophic for the industry and other industries along the coast,” said Robbie Staunton, marine operations manager at Stehr Group, one of Australia’s leading seafood companies.

Computer modeling by the British oil company BP, which withdrew in 2016 from its plan to drill in the Bight, projected that an accident similar to the Deepwater Horizon blowout in 2010 could cause environmental damage along a wide stretch of the southern Australian coastline. This raised local concerns, particularly because the Bight’s waters are deeper, rougher and more remote than those of the Gulf of Mexico.

The projection also raised another problem: whether Australia was even equipped to deal with an accident at an offshore drilling platform. The equipment needed to contain a blowout by capping the flow of oil is thousands of miles away in Singapore, and would take up to 35 days to put in place.

“History shows that the risks are often substantial,” said Kirsten Rough, a researcher for the tuna industry for more than two decades.

There are also environmental risks in the techniques used to locate the oil and gas before drilling begins. Seismic surveys to find the undersea deposits rely on loud explosions that, according to researchers, could drive fish away — especially the tuna that matter most to the area.

Fishermen say they have already noticed disruptions in the movements of tuna since the surveys began.

Others in the fishing industry, though, are more resigned to sharing the waters with drilling rigs. Though initially opposed to the drilling, Hagen Stehr said the focus now should shift to making sure that its impact is limited. This would include ensuring that seismic surveys are not conducted during the times of year when the hauls of fish are the largest.

“You can’t stop the development in the Bight,” said Mr. Stehr, one of the town’s best-known tuna barons, in his Port Lincoln office, surrounded by photographs of himself with former prime ministers.

“What right have we got to have exclusive rights?” asked Mr. Stehr, a native of Germany who started fishing tuna by hand after jumping ship in Port Lincoln in 1960. “South Australia is on its knees.”

Others worry that drilling will push a fragile environment past its limit.

“The Great Australian Bight is Australia’s Galápagos,” said Jeff Hansen, who led a ship from the environmental activist group Sea Shepherd, which docked in the state this month to persuade politicians to protect the Bight.

“Risking it in a push to expand the fossil fuel industry is the height of irresponsibility,” he said.

Many locals harbor deep suspicions about the drilling. They describe a lack of transparency about deals between politicians and big business that has led to a mood of distrust, and a sense of defeat.

“You know you’ll be told this is safe as can be,” said Brendan Guidera, an owner of Pristine Oysters in Coffin Bay, a sleepy coastal town near Port Lincoln.

“When there’s so much money behind something like this, you don’t necessarily trust everything you’re told,” he said.

Oyster growers worry that a spill would be devastating for their industry as well. Coffin Bay oysters are favored by top restaurants across Australia.

Rob Kerin, head of the association that represents the state’s oyster industry, said, “You’ve got to look at the worst-case scenario, and the worst-case scenario doesn’t look good for us.”