Biologists running a routine fish survey in Oswego Harbor, on the New York shore of Lake Ontario, pulled up something they had never logged there before: a native burbot glowing an almost fluorescent yellow-orange, "bright enough to make even the brightest fall foliage look pale in comparison," according to the U.S. Fish and Wildlife Service.
The fish was caught by the Aquatic Invasive Species survey crew from the agency's Lower Great Lakes Fish and Wildlife Conservation Office, which works the harbor and nearby waters mainly to monitor invasive species, not oddly colored natives. Burbot — a bottom-dwelling, eel-shaped relative of cod sometimes called "lawyer fish" for their slippery reputation — usually keep to deep, cold water well offshore. This is the first one the office's fisheries survey has ever documented in the harbor itself, though a handful of anglers have reported catching them there over the years.
A rarer condition than albinism
The vivid coloring is a case of xanthochromism, officials said — a pigment disorder that suppresses the dark, melanin-based cells called melanophores while leaving yellow and orange pigment cells intact. It is, the agency noted, "considerably less common in wild fish than albinism or melanism," the better-known conditions that wash fish out entirely or turn them nearly black. Xanthochromism has turned up occasionally in bass, catfish, trout and even lobsters, but a documented case in a Great Lakes burbot was unusual enough that biologists flagged it immediately.
Lake Ontario's burbot population is already thin. Decades of lamprey predation and a shifting food web hit the species hard in the mid-20th century, and wildlife managers still consider numbers in the lake "extremely low," per the Fish and Wildlife Service. A single oddly pigmented specimen will not move that needle, but it does give biologists one more confirmed detection in a stretch of water where the species is rarely recorded at all.
The fish was measured, photographed and released back into the harbor as part of the survey's normal catch-and-release protocol. Agency staff said they plan to keep an eye out for repeat sightings, though xanthochromic individuals are not known to be more or less likely to survive than normally pigmented fish — they are simply easier to spot.