Anchovies – a key food source for local marine ecosystem – might be in a state of collapse.

National Geographic posted the photo to their Instagram account Oct. 26, and it immediately set off a social media frenzy, garnering over 350,000 “likes” and thousands of shares across a host of media platforms.

The image, taken on Monterey Bay in mid-October by Nat Geo photographer Paul Nicklen, shows what appears to be thousands of dead anchovies floating on the water’s surface, dumped by a fishing boat that caught more fish than it could haul to shore.

Near the end of the text attached to the post, which raises alarm about a potential collapse of anchovies and their critical importance to the food chain, it reads, “Why are you fine and passionate people of the Monterey Bay allowing this to happen?”

The post then directs people to voice their concerns to the Pacific Fishery Management Council, which is reviewing the status of the anchovy at its meeting in mid-November.

Public comment on PFMC’s website about the potential anchovy collapse stretches more than 450 pages, most of which are 36,000-plus signatures collected by marine conservation nonprofit Oceana. In its letter, Oceana calls for an immediate assessment of anchovy populations, and for fishing quotas to be adjusted accordingly.

At the heart of the controversy is a lack of information: The National Oceanic and Atmospheric Administration hasn’t assessed the anchovy stock since 1995. Their current population off the West Coast is unknown – and subject to much speculation.

Among the public comments submitted to PFMC is a paper – one still under peer review – authored by scientists from the Farallon Institute and retired NOAA Fisheries scientist Alec MacCall. Its assertions, based on egg and larval samples up to 2011 (the most recent year data is available), are shocking: From Mexico to Point Conception, and possibly further north, anchovies are in a state of collapse, one brought on by environmental factors, not fishing.

It proposes that the current anchovy catch quota of 25,000 metric tons off California – long viewed as a conservatively low number – may be dangerously high, and adds, “The decline in anchovy abundance coincides with recent die-offs and reproductive failures of anchovy-dependent predators in the ecosystem (e.g., sea lions and pelicans).”

The paper adds that what’s left of the anchovies is gathered near the shore, “making them unusually visible to the public and giving a mistaken impression of abundance.”

Diane Pleschner-Steele, executive director of California Wetfish Producers Association in Moss Landing, emphasizes the paper is still under peer review, and because it only uses data up to 2011, says its conclusions are flawed. She also says that nonprofits like Oceana are “impugning” fishermen by suggesting they are “taking the last anchovy.”

Over 14,000 metric tons of anchovies have been landed in California this year – the most in more than a decade – and nearly all of them were landed in Monterey Bay. Pleschner-Steele attributes the higher number to the closure of the sardine fishery this year, and that warmer waters have led to a below-average squid season.

“Fishermen are just trying to keep their families fed and boat payments up,” she says, and adds that fishermen have a keen sense for boom or bust. “[They] see what’s out in the ocean.”

David Crabbe, a retired Pacific Grove fisherman and a sitting council member on the PFMC, says he doesn’t think the amount of anchovies being landed right now is cause for concern.

“It hasn’t been a resource that’s been fished very hard,” he says. “It’s really the third or fourth choice for the seine fleet.” (Seine is a type of large drag net.)

Crabbe recalls times when he’d be fishing near Moss Landing and his sonar would pick up anchovy schools that stretched more than 1,000 feet.

“It was just this phenomenal amount,” he says. “I was calling it 100,000 tons just in Moss Landing Channel.”

But Crabbe says that because anchovy numbers fluctuate greatly from year to year, the flat number NOAA uses as a quota is “not the necessarily the right way to manage forage fish.” And both he and Pleschner-Steele agree that a population assessment is needed.

“There’s never enough knowledge,” says Pleschner-Steele.

That is perhaps one of the few points in which they agree with Geoff Shester, Oceana’s California campaign director, who says the current system for managing anchovies – which relies on 20-year-old data – makes it impossible to for fishery officials to respond to changing realities.

“That aspect of managing these fish makes a difference as to whether it’s sustainable and responsible, or if it’s Cannery Row all over again,” he says.

Shester, while not attacking fishermen, who are fishing legally and trying to make a living, also questions the economic wisdom of taking anchovies out of the sea for a mere 5 cents per pound.

Anchovies left in the sea, he posits, are worth a lot more, which is a point raised by Kate Spencer, a captain at Fast Raft Ocean Safaris on Monterey Bay.

In an Oct. 16 letter to PFMC, Spencer writes that a humpback whale eats about a ton of anchovies per day, and calculates that one humpback brings in about $1,000-$3,000 in revenue to whale watching companies per day.

If caught and sold, she adds, anchovies only bring fishermen about $100 per ton.

“The socio-economic value of anchovy left in the water… is huge,” she writes.

Advocates for other animals that feed on anchovies are also concerned.

The U.S. Fish and Wildlife Service sent a letter to PFMC in May, calling for an immediate anchovy stock assessment and suggesting that recent die-offs of seabirds that include California brown pelicans – which were taken off the endangered species list in 2009 and have declined ever since – might be linked to a decline in anchovies.

There has also been a troubling spike in marine mammal die-offs.

Claire Simeone, a conservation medicine veterinarian at The Marine Mammal Center in Sausalito, says she can’t link the die-offs to a potential anchovy decline, as it’s not her area of expertise. But she says the agency has rescued nearly 1,700 animals this year, the most in its 40-year history.

Among them were more than 1,000 starving sea lion pups, which she says were abandoned because their mothers couldn’t find enough food.