The staggering importance of a little fish you probably haven’t heard of

If you look at the base of the B.C. marine ecosystem, you’ll find a funny little fish with a lot of names – eulachon, oulachon, oolichan, hooligan, ooligan, candlefish.  This species is critically important to the viability of numerous other species in our coastal waters, but has been quietly plummeting, with stocks down by ~98%. While economical, effective, and simple solutions to environmental crises may be few and far between, scientists in Oregon seem to have found an answer to the plight of the eulachon. The results are preliminary, but promising and word is spreading quickly through the fishing industry. To understand why this innovative research is so exciting and encouraging, we start near the bottom of the marine food chain with an examination of a fish of staggering importance.

Eulachon, a species of smelt that spawn in a limited number of rivers on the West Coast, spend most of their three-year life cycle in the marine environment where, much like herring, they play a pivotal role in sustaining the coastal food chain. As a forage fish, eulachon are a foundational species that feed hundreds of different types of animals. From salmon to marine birds, lingcod to killer whales, sea lions to eagles, nearly every marine animal in BC relies on forage fish as principal aspect of their diet.

Eulachon returning to spawn in the Columbia River. Photo by Sam Beebe, @sbeebe, CC-BY-2.0

Eulachon are vitally important to First Nations’ culture too; harvests are used for food, social, and ceremonial purposes. Eulachon’s high oil content has made them an incredibly valuable source of nutrients for coastal communities – it also means they’ll burn like a candle if lit on fire, which, logically enough, has earned them the name “candle fish.” For thousands of years, Coastal First Nations rendered eulachons into a grease, the health benefits and longevity of which made it a staple aspect of their diet. It was a coveted commodity traded between communities and carried in cedar boxes across well-trodden “grease trails” – the most famous of which stretches from Bella Coola to Quesnel.

Audry Duncan from the Haisla Nation setting up eulachon in a smoker. Photo by Sam Beebe, @sbeebe, CC-BY-2.0

Although there are still a few rivers, such as the Klinaklini and Kingcome that have strong runs, the eulachon population coast-wide in British Columbia is estimated to have declined by 98 per cent.

As a result, the Committee on the Status of Endangered Wildlife in Canada has listed the Fraser River eulachon population as endangered, the Central Pacific Coast population as endangered, and the Nass/Skeena Rivers population as a species of special concern.

Despite their ecological and cultural importance, there are significant knowledge gaps about eulachon’s basic biology, migration routes, and historical spawning patterns. Unlike salmon, which are studied extensively, eulachon have little direct commercial market value (none currently as the fishery is now closed – though at one point there were active eulachon fisheries on the Fraser, Nass, Skeena, Klinaklini, and Kingcome Rivers). Intrinsically and indirectly, of course, they are invaluable and feed countless other market species. Given the constrained level of scientific attention given to eulachon, the Department of Fisheries and Oceans Canada (DFO) says it is difficult to conclusively pin-point the cause of their population crash. Instead, their decline has been linked to a variety of activities, such as the marine transportation of oil, natural gas, and toxic chemicals, estuary alteration, shoreline development, industrial runoff, agricultural pollution, trawl fisheries, and forestry activity.

According to recent egg and larval surveys in the Fraser River, DFO reports eulachon abundance as being at an all-time low. Considering the diversity between localized pressures, however, DFO notes that it is “unlikely that such threats would explain the nearly synchronous coast-wide decline of eulachon that has occurred.” 

Though certain threats, it is worth noting, have been more pervasive and persistent. Many believe that the shrimp trawl fishery, for example, is responsible for much of the eulachon collapse. 

Eulachon are prone to getting caught in mid-water and bottom nets trawling for other species, like the ones used to harvest shrimp. Virtually every eulachon that hits the deck of a fishing vessel will die, according to DFO’s report, and another 60-70% of the fish who escape through the net will be killed as “collateral damage”. 

Monitoring indicates that in‐season eulachon bycatch estimates have decreased over time, dropping from 22,406 pounds in 2001 to 8,818 pounds in 2005, and less than 2,205 pounds since 2006. It is hard not to speculate, however, that the reason fewer eulachon are being caught in shrimp nets is because there are fewer of them around to begin with, as indicated by this DFO graph from 2007.

 Fraser eulachon spawning stock biomass from 1995 to 2007 estimated by egg and larval survey at Fraser sampling locations.  

A population dynamics model conducted by DFO for the Fraser river eulachon run indicated that even a small removal or increased mortality rate (5t of the weakest cycle line) would significantly impair any potential for recovery. “Given the large uncertainty regarding magnitude of threats to the Eulachon,” the report continued, “minimal allowable harm should be permitted at this time, and be reduced below current levels as much as possible.” 

DFO also says that “climate change effects may impact both the marine and freshwater habitats.” The exceptionally large and warm expanse of water currently stretching across the North Pacific Ocean is, unfortunately, making this look quite likely.  “Right now it’s super warm all the way across the Pacific to Japan,” said Bill Peterson, an oceanographer with NOAA’s Northwest Fisheries Science Center in Newport, Ore. Not since records began has the region of the North Pacific Ocean been so warm for so long, the Northwest Fisheries Science Center reported. “The warm expanse has been characterized by sea surface temperatures as much as three degrees C (about 5.4 degrees F) higher than average, lasting for months, and appears on large- scale temperature maps as a red-orange mass of warm water many hundreds of miles across.” 

Image from Northwest Fisheries Science Center illustrating the expanse of warm water stretching across the Gulf of Alaska and Bering Sea.

The mistreatment of eulachon stocks in B.C. is an environmental and cultural tragedy, to say the least. Forage fish like herring and eulachon form a pillar that holds up the entire coastal ecosystem, yet for decades they have been hastily killed as bycatch and chucked overboard by the tonne, with little consideration for the consequences.

Yet all is not lost. Scientists in Oregon seem to have hit upon an effective and low-cost solution – they are lighting up the shrimp nets. Funded by a grant from the National Oceanic and Atmospheric Administration, researchers attached 10 green Lindgren-Pitman lights to the fishing line of each net. After 42 tows, the researchers found that the illuminated net caught 90% fewer eulachon than the regular trawl gear, but roughly the same amount of shrimp.

Image from NOAA, Left: A pink shrimp haul without the use of LED lights shows Eulachon bycatch. Right: The results of LED lights hung on the trawl lines. LEDs have significantly reduced bycatch of threatened Eulachon as well as other fish by showing where the fish can escape the net.

Specific light placement is key, though, as some variations actually increased bycatch levels. “The new technique was shown to be effective when the lights were placed four feet apart across the center third of the footrope, an area near the bottom of the trawl that keeps the net open as it moves through the water. Researchers caution shrimpers to not place the lights around the rigid-grate bycatch reduction device, or BRD, as it actually decreased the effectiveness of the BRD for eulachon,” the NOAA report reads.

Results were so dramatic, the researchers immediately encouraged all shrimpers to start testing the technique. Within two months nearly every vessel across the border was using the illuminated net method, reporting very large reduction in bycatch of  small demersal fish, but eulachon in particular.

When contacted to ask if the B.C. shrimping industry was planning on adopting a similar bycatch reduction strategy, DFO said they are waiting to see the published results from the Oregon studies but they have had “initial discussions with the B.C. trawl industry and they have expressed an interest in testing this technique. Further discussion is expected.”

Eulachon are of vital importance to the marine ecosystem on the West Coast, and to First Nations. Urgent action needs to be taken to help these stocks recover. And a good start might be as simple as switching on some underwater lights.

Banner Image: Eulachon habitat at Kitamaat Village beach. Photo by Sam Beebe, @sbeebe, CC-BY-2.0