The lake whitefish derives its scientific name from the Greek term "Coregonus," meaning "angle eye," and the Latin word "clupeaformis," which translates to "herring-shaped." This nomenclature hints at the fish's physical characteristics, showcasing its intriguing features.
Lake whitefish are part of the Coregoninae subfamily of the salmon family Salmonidae. They possess an adipose fin, a distinguishing trait shared among all salmonids. One notable feature of the lake whitefish is its "humpback" appearance, with a relatively small head compared to the length of its body. This unique attribute gives rise to its colloquial name, the "humpback" fish.
In terms of physical structure, the lake whitefish has a snout that overhangs its short lower jaw, allowing it to feed on the bottom of lake beds or capture food particles from the water's surface. Its snout differentiates it from the northern cisco, another whitefish species, which has a shorter snout with a lower jaw extending beyond it. Moreover, the lake whitefish is easily distinguishable from the mooneye due to the presence of two small flaps in each nostril.
The coloration of lake whitefish typically ranges from silver to white, with hints of olive, pale green, or brown on the dorsal side. The ventral fins are white, and the tail displays a dark posterior edge. Notably, the lake whitefish possesses a severely forked tail fin, enabling it to swim swiftly through the water.
Lake whitefish exhibit a wide range of sizes, depending on their habitat. Inland lake populations can reach impressive weights of up to 5 pounds (2,300 g), with exceptional individuals occasionally exceeding this limit. The record for the largest lake whitefish caught on rod and reel stands at an impressive 15 pounds 6 oz, hauled from Clear Lake in Ontario, Canada, on May 21, 1983, by angler Chris T. D. Webster.
On average, lake whitefish weigh around 4 pounds, with lengths of up to 31 inches (79 cm) achievable. A typical lake whitefish measures approximately 20 inches (51 cm), showcasing the species' substantial growth potential.
Habitat
Lake whitefish primarily inhabit cool waters and can be found in a multitude of inland lakes. They have also been observed venturing into brackish waters. Their distribution spans from Alaska and western Canada to the Atlantic coastal drainage of Maine, with populations reaching as far as New Brunswick and Labrador.
Reproduction
Lake whitefish engage in spawning activities from September to January, predominantly during the night. In autumn, mature whitefish migrate to shallower waters, depositing their eggs on rubble and gravel shoals. Unlike some fish species, lake whitefish do not exhibit parental care, leaving the young to hatch and fend for themselves come spring.
In northwestern Canada, an extensive spawning migration takes place, with whitefish traveling upstream in the Athabasca River. The longest recorded movement of a tagged whitefish spans an impressive 388 km (241 mi), stretching from Fort McMurray to the north shore of Lake Athabasca in Alberta, Canada.
Diet
The diet of lake whitefish undergoes a transition as they progress through different life stages. Larval and postlarval fish primarily feed on plankton. Once they reach a size of approximately 3 to 4 inches (76-102 mm), they shift their focus to bottom-dwelling organisms such as snails, insect larvae, zebra mussels, and fingernail clams. This diet persists throughout their adult lives.
During late June and July, some inland lake populations of ciscoes and lake whitefish embark on feeding frenzies, targeting emerging mayflies and midges. Natural predators of the lake whitefish include burbot, lake trout, and northern pike.
Commercial Fishing
Lake whitefish hold significant economic value and are among the most important species targeted by commercial inland fisheries in North America. The annual catch of lake whitefish in 1999 was reported at 8,328 tons in Canada and 5,353 tons in the United States, according to the FAO.
The upper Great Lakes fishery particularly relies on lake whitefish, given its delicate flavor and high local consumer acceptance. Throughout the years, the annual harvest of lake whitefish from the Great Lakes has averaged around 11 million pounds. While recent harvest figures have slightly declined, resulting in reduced prices, the demand for this delectable fish remains steadfast.
Sports Fishing
Amateur anglers also relish the opportunity to engage with lake whitefish during the months of June, July, and early August. With a simple line and jig system, anglers can successfully hook lake whitefish as they feast on mayflies and midges. In winter, ice fishing for whitefish becomes increasingly popular, particularly in northern Wisconsin, where specialized fishing guides cater to enthusiasts. Effective ice fishing techniques often involve using a jigging spoon with additional "slider hooks" and baited with wax worms. The popularity of lake whitefish has allowed for its expansion into various markets, including restaurants and grocery stores.
Lake whitefish face a significant threat from the sea lamprey, an invasive parasite species. Alongside lake trout and lake herring, the lake whitefish is aggressively targeted by sea lampreys, posing a considerable challenge to its population. The introduction of sea lampreys into the Great Lakes region dates back to the 1930s and 1940s when they began devastating indigenous fish populations. It is believed that their entry was facilitated by the opening of the Erie Canal in 1825 and further spread through improvements to the Welland Canal in 1919, connecting Lake Ontario to Lake Erie, Lake Michigan, Lake Huron, and Lake Superior.
Since the last glaciation period approximately 12,000 years ago, whitefish species have recolonized numerous North American lakes from different directions, stemming from genetically diverged stocks or races. After these recolonizations, whitefish populations have diversified locally, resulting in the recognition of two primary ecotypes within the lake whitefish species: the normal ecotype and the dwarf ecotype. These ecotypes differ based on their occupation of the benthic and pelagic zones, respectively. Notably, normal whitefish exhibit more significant growth rates and lifespans compared to their dwarf counterparts.
The coexistence of multiple whitefish populations in sympatry, combined with their reproductive isolation, provides an excellent opportunity for studying the evolutionary forces driving their ecological divergence and reproductive patterns. Understanding these mechanisms can shed light on the fascinating evolution of lake whitefish and their adaptation to diverse aquatic habitats.