A fish biologists weren't even expecting to find turned out to be an even stranger discovery: a burbot glowing an unnatural yellow-orange, pulled from Oswego Harbor during a routine survey last month, and looking sickly enough to warrant a trip to the lab. The catch wasn't just visually odd. It was the first time a burbot had ever been documented during a fisheries survey in that harbor at all.
A Genetic Quirk Behind the Unusual Color
Biologists captured the burbot while conducting an aquatic invasive species survey in Oswego Harbor, according to WRGB. The station reports the fish was found in Oswego Harbor during a routine survey last month, per the U.S. Fish and Wildlife Service, and that wildlife officials attributed its striking coloration to xanthochromism, a rare genetic condition that gives fish an unusual yellow-orange appearance. Officials described the condition as being caused by a genetic mutation that suppresses normal pigmentation, and the outlet notes that xanthochromism is considerably less common in wild fish than albinism or melanism.
What made the discovery more concerning than curious was the fish's condition. U.S. Geological Survey biologists observed that the burbot was severely underweight and appeared to be in poor health, the station's report states. That assessment prompted researchers to send the fish to Cornell University's College of Veterinary Medicine for further health analysis, with hopes that the examination will provide additional insight into burbot population health throughout the Great Lakes basin.
Burbot Are Native, But Rarely Seen Here
Burbot are native to the region, per the same report, though the species isn't commonly associated with a harbor environment like Oswego's. New York officially lists burbot as a Species of Special Concern, according to the New York Natural Heritage Program. The group's guide notes the fish can't tolerate water temperatures above 70°F (21°C) and spawns in winter, when water temperatures fall between 33°F (0.6°C) and 35°F (1.7°C) — conditions far removed from a harbor more associated with warm-season boat traffic than cold-water spawning grounds.
The Natural Heritage Program's data paints a broader picture of a species under pressure. Lake Ontario burbot populations are expected to remain low, the program says, citing predation by Alewife and Sea Lamprey as contributing factors. While the species' range across New York hasn't significantly changed, the program notes it is assumed that populations are declining statewide at varying rates.
Why Routine Monitoring Matters
The discovery happened only because surveyors were out looking for something else entirely: invasive species. Per the WRGB report, routine monitoring could identify invasive species before they become widespread, which is the entire point behind programs like the one that led biologists into Oswego Harbor that day. The U.S. Fish & Wildlife Service notes that one method used for monitoring in the Great Lakes is eDNA sampling, a tool that can detect the genetic presence of specific species in the environment without needing to physically catch them.
Oddly colored fish and sea creatures tend to generate attention well beyond the water they're pulled from. In 2024, sports fishers off the east coast of Costa Rica discovered a bright-orange nurse shark roughly 6.6 feet long, swimming about 120 feet below the surface, as reported by Live Science. Researchers there concluded from photographs that the shark was likely both albino and xanthic, a combination known as albino-xanthochromism, and noted that while such pigmentation is typically genetic, environmental stress, elevated temperatures, and hormonal imbalances may also play a role.
For now, the Oswego Harbor burbot's fate rests with Cornell's veterinary analysis. The station's report offers no timeline for results, leaving researchers — and curious locals — waiting to find out what, exactly, left this rare fish both colorless in the usual sense and undernourished in a harbor it wasn't expected to be found in at all.
