A few minutes before lunch, Lee Hrenchuk is down by the beach, scraping mucous off a northern pike.

This is not some bleeding-edge culinary practice, as much as some chefs in Toronto probably wish it were.

The Experimental Lakes Area, a sprawling outdoor laboratory where entire lakes are manipulated over the course of years, was slated for closure in 2012. No longer under federal management, it's back in fishy business. 2:01 Hrenchuk, a biologist at northwestern Ontario's Experimental Lakes Area, hopes chemical markers in the slime covering the species, affectionately known as "snot rockets" to local anglers, will yield a means of determining the health of fish.

Every year, tens of thousands of fish are killed in Canada solely for tissue samples that allow biologists to monitor the effects of industrial pollutants on aquatic life. On the smallest and most remote lakes and rivers, this is not a sustainable practice, even though the environmental monitoring is intended to protect fish.

That led Vince Palace, an aquatic toxicologist at the institution officially known as ELA-IISD, to try to devise a non-lethal means of determining the health of freshwater fish. (The IISD stands for International Institute for Sustainable Development, the non-profit organization that runs the area.)

So on a glorious August day, his colleague Hrenchuk has anaesthetized a northern pike, laid it out on a picnic table and is gathering up a glob of mucous in the hopes this goo contains enough biochemical markers to allow scientists to determine whether fish are suffering from stress.

Lee Hrenchuk collects mucous from a northern pike. (CBC) "We know they produce these [chemicals] in their blood and they produce them in their body, and we want to see if we can use this simple method of taking mucous off their body as a way to see what those markers are without having to harm the fish," Hrenchuk says at her outdoor workstation by the beach at Boundary Lake.

"We have small lakes and small fish populations, so we're big proponents of non-lethal sampling methods."

This attempt to devise a non-lethal means of monitoring fish health is one of 11 large research projects underway this year at the ELA, a sprawling outdoor laboratory where entire lakes are manipulated over the course of years or even decades for the sake of freshwater science.

Founded in 1968 by the federal government, the ELA encompasses hundreds of small lakes scattered about a sprawling rectangle of Crown land about 75 kilometres east of Kenora.

Although ELA scientists have permission to conduct experiments on 58 of these lakes, they typically manipulate only three to five in any given year. Other bodies of water serve as control lakes or are recovering from previous experiments.

Eagle Lake First Nation student Devin Pitchenese holds a northern pike caught as part of an experimental effort to figure out a non-lethal way to test fish for evidence of environmental stress. (Bartley Kives/CBC) But as recently as three years ago, there was next to no science taking place at the ELA.

In 2012, the former Conservative government announced plans to shut down the field station and the research area, which was administered at the time by Fisheries and Oceans Canada.

While the closure would have shaved about $2 million off the Fisheries and Oceans budget, it also would have triggered a cleanup job estimated at about $50 million. When the feds established the ELA, their initial deal with Ontario called for all the lakes within the area to be returned to their natural state.

ELA researchers deploy a seine net to collect fish and crustaceans at Rawson Lake, also known as Lake 239. (Bartley Kives/CBC) The cleanup tab, however, didn't spark as much outrage in the scientific community as the proposed closure of the ELA itself. There's no other place on earth where scientists have permission to conduct whole-ecosystem research on lakes, and few other places where pristine fresh water is accessible to scientists but far from human impacts.

But they were even angrier because the five-decade track record at the ELA saw scientists quietly conduct a series of groundbreaking research projects into the effects of industrial and household pollutants on fresh water.

Scientists lobby to keep Experimental Lakes Area station ​In the 1970s, their early work with algae blooms led to a near-global ban on laundry detergents containing phosphorus. Phosphorus is the chief culprit in the nutrient loading that's changed the ecological makeup of lakes around the world, including Lake Winnipeg's northern basin, where blooms of blue-green algae periodically clog fishing nets and then create low-oxygen "dead zones" when they die and decompose.

The Experimental Lakes Area, a sprawling outdoor laboratory where entire lakes are manipulated over the course of years, was slated for closure in 2012. No longer under federal management, it's back in fishy business. 3:54 In the 1980s, they proved the U.S. energy industry wrong by demonstrating the harmful effects of acid rain on underwater food chains, eventually leading to new emission standards for airborne pollutants.

In the 2000s, they confirmed birth-control drugs can interfere with fish reproduction, which has implications for waste-water treatment. They also demonstrated how quickly methylated mercury from the atmosphere winds up in lakes and the organisms that live within them.

The latter experiment, which saw ELA scientists add tiny but measurable amounts of mercury to one lake, was intended to establish the need for new emission controls for coal-fired power plants, a major source of atmospheric mercury.

The 2012 closure announcement halted all the science at the ELA except for basic measurements of the likes of water flows, chemistry and temperature, although even this data collection was reduced to once a month from twice a week, said Mike Paterson, the chief research scientist at ELA-IISD.

A planned experiment to test the environmental effects of nanosilver, the anti-microbial particles added to washing machines and underwear, was put off. Some senior research scientists retired, while others left for jobs with other facilities. Collaborating academics from universities around the world chose to conduct their own research elsewhere.

Mike Paterson is the chief research scientist at ELA-IISD. (Bartley Kives/CBC) I strongly believe ELA provides some of the most important scientific research that's done anywhere on lakes and water quality. The idea of the loss of it, I couldn't believe it. "It was devastating," Paterson recalls. "

"So we were desperately trying to find a way to save it, to keep it alive and encourage the government to maintain the dataset so it would be unbroken for hopefully the many years ahead."

All of the research proposals in the pipe had to stop because other people's money was on the table, Paterson explains.

"We couldn't assure any granting agencies that we would be around, there would be personnel to do the work. We didn't know what scientists we would have in the future if we managed to survive at all. So all of that stopped," he says.

While the pending closure was stressful, the publicized backlash made it worse. Paterson said in 2013, he needed permission from the deputy minister of Fisheries and Oceans Canada just to visit the ELA field station.

"It was surreal," he says. "We were just this small group of scientists, doing work in the wilderness of northwest Ontario. All of a sudden we're on the front pages of the newspaper. All of a sudden DFO was paying attention to us in a way they [had] never done previously.

"Every move, every action, everything we did was being scrutinized. This was not something I anticipated when I got into this career."

Paterson says he was never given an explanation for the proposed closure, though he says he doesn't believe the plan originated in the upper echelons of the former Conservative government, which reconsidered the idea.

Kelli-Nicole Croucher works in the laboratory at the Experimental Lakes Area field station. After a year of talks, Ottawa transferred the ELA in 2014 to Ontario, which in turn transferred the research area to the Winnipeg-based International Institute for Sustainable Development, a non-profit think tank.

The transfer was in effect a merger, as ELA-IISD now combines the practical research conducted at the ELA with the policy and communications work conducted by the IISD. The new management also conducts outreach and education programs, something Paterson says would have been impossible when ELA was a federal facility.

As part of the transfer deal, Kathleen Wynne's Liberal government in Ontario now covers $2 million of the ELA's $2.7-million annual budget. Fisheries and Oceans continues to provide $250,000 worth of funding, while private sources cover the remaining $450,000 tab, said Kathy Clark, publishing manager at ELA-IISD.

Funding issues aside, Paterson describes the transfer to IISD as a breath of fresh air. The ELA now has a full-time staff of 12, up from three people in 2013. When you include graduate students and visiting researchers, there are anywhere from 20 to 60 people at the field station on any given day during the summer, which is close to historic levels.

As a result, ELA research projects that were forced to go on hiatus, such as the nanosilver experiment, have proceeded, while new experiments are in the works.

Paterson says ELA scientists have more freedom to conduct research now, under IISD management, than they did when Fisheries and Oceans was in control. The federal department was primarily interested in fish, he says.

"If you look historically at the research that has had the greatest impact here, a lot of it is related to issues around water quality and not necessarily including fish," he says. "We're no longer restricted by those Fisheries and Oceans mandates, so we can really do whatever research that can best help improve water quality in Canada and around the world."

A vintage light-intensity measurement device — a magnifying glass that burns into paper — is part of the meteorological station at the Experimental Lakes Area. (Bartley Kives) As a result, the ELA expects to play a greater role in climate-change research, as the data collected from its lakes as well as at an Environment Canada weather station perched on a hill above the field station represents one of the world's large collections of baseline environmental data.

"This is one of the few places in the world to have that very detailed data set for such an extensive period of time," says ELA-IISD research scientist Scott Higgins.

The ELA's continuous record of atmospheric, water flow and water chemistry measurements dates back to 1969 — along with a parallel record of changes to organisms living within its lakes. That may prove useful to researchers around the world, Higgins said.

But much of the research at the facility still involves fish.

On Lake 626 — all the lakes are given numbers, rather than names — there's a project underway to see how increasing water clarity affects trout, which typically thrive better in murkier water where the light and heat does not penetrate as deeply.

The ELA blasted a channel through Canadian Shield rock to deprive Lake 626 of its primary water source. Without new water, lakes become clearer and warmer because dissolved organic materials in the lake bleach in the sun.

There's also Hrenchuk and Palace's work with northern pike mucous. If they can successfully measure chemical markers in the slime, biologists could be able to determine whether fish are getting stressed out by pollutants well before those pollutants cause more noticeable physiological changes.

In other words, they hope the slime can serve as a biochemical canary in a coal mine.

"In any situation where you have an experiment or a stress on the environment, you don't necessarily start to see populations dying or fish getting really small. It's the subtle things that begin to show up first," Hrenchuk says.

The mucous-collection procedure has several steps. First, a student volunteer catches the pike, using a conventional rod and reel. The fish then gets a bath in a cooler filled with water and anaesthetic.

ELA-IISD biologist Lee Hrenchuk returns a northern pike to Boundary Lake after collecting mucous off it. The pike is weighed, measured and implanted with a chip that allows it to be identified if it's ever caught again. Hrenchuk then collects the mucous, first by scraping it into a glob and then sucking it up with a plastic syringe.

"I like to think it's not that uncomfortable. They produce copious amounts of mucous. If you've ever caught one, you know there's slime dripping everywhere."

The chip-implanted pike then gets a recovery bath in a second cooler before Hrenchuk sets it loose off the beach at Boundary Lake.

"There's a school of perch out there. Maybe it will have a snack," she says.

She then heads for a lunch of her own, entirely free of mucous.