Description: Muskellunge, Esox masquinongy, are long slender fish that can grow up to 152 cm (60 in) and 27.2kg (60lbs). These fish have a very similar body shape to their close relative, the northern pike (Esox lucius), but have few characteristics that set them apart. One main difference is that and Muskellunge typically have light bodies with dark markings and Muskellunge typically have light bodies with dark markings. These dark markings can be divided into two groups in Minnesota: “spotted” and “blonde.” “Blondes” (Esox masquinongy immaculatus) are Muskellunge with little to no dark markings giving them a silver appearance, these Muskellunge are native to inland lakes in Minnesota. “Spotted” (Esox masquinongy masquinongy) Muskellunge are native to the Great Lakes and their tributaries and are named for their small, broken up, dark spots. Another key characteristic of Muskellunge is the rusty red-brown tint and pointed appearance of the fins and tail. Muskellunge also have twelve to eighteen sensory pores under their lower jaw and scales only on the top half of the opercles (Fuller et al., 2019). Identification is typically done using a combination of coloration, fin shape, and sensory pores.Systematics: Muskellunge can be divided into three subspecies Esox masquinongy; masquinongy, immaculatus, and ohioensis. These subspecies are not recognized by all people because they have little differentiation besides the coloration (Fuller et al., 2019). Muskellunge are a member of the Esociformes order which also includes, pickerel and mudminnows. Within the Esociformes, muskellunge are most closely related to the pikes (Esox lucius and Esox reichertii). The pikes and Muskellunge then make up the sister taxon with the pickerels (Esox americanus and Esox niger). This group forms the sister group to the Umbrids which make up the rest of the Esociformes. The Esociformes makes up the sister taxa to the Salmonidae (Lopez et al., 2004).
Habitat & Range:
Muskellunge are native to the Great Lakes, St. Lawrence River, Hudson Bay, and the Red and Mississippi River basins (U.S Fish & Wildlife Service, 2019). However, the modern range has been expanded by stocking efforts in many states and provinces. In Minnesota, there are 107 lakes and 6 river systems that are classified as muskellunge waters; of these bodies, 44 lakes and all 6 of the rivers are considered to be native populations; the rest of these lakes were populated through stocking efforts (Minnesota Department of Natural Resources).
Muskellunge require a very diverse set of requirements throughout their different stages of development. During spawning, muskellunge require depths less than 1.5 meters with high levels of dissolved oxygen. Anoxic conditions would result in the embryos dying before being able to hatch. Once the embryos hatch and become fingerlings, they move into floating and emergent vegetation, most commonly a Chara or Potamogeton species. Once these fish reach the juvenile stage, they begin to move away from their natal area and establish small home ranges in vegetated areas or other types of well-developed structure (Cook & Solomon, 1987).
Food: Muskellunge have been known to feed on prey greater than 41% of their body lengths but some claim that they may be able to handle prey upwards of 50% (Bozek et al., 1999).This is an important ability when growing upwards of 22.7 kg (50 pounds) because eating larger meals less often requires less energy than chasing around smaller, quicker fish. A study done in northern Wisconsin showed that the Muskellunge’s main two food sources were yellow perch (Perca flavescens) and members of the Catostomidae family. Yellow perch were the most important to their diet throughout the year making up the largest percentage of Muskellunge diets by number, and the second most by mass. The second most important food source were members of the Catostomidae family. While they made up a significantly lower percentage by number, they made up a higher percentage by mass due to larger sized fish. Other important fishes were the Cyprinids, Lepomis spp., and Pomoxis spp.; these species are important due to their high quantity and play a larger role in the diet of smaller fish that are unable to eat large Catostomids (Bozek et al., 1999). Reproduction: The muskellunge spawning cycle typically begins when temperatures on the spawning grounds reach 8-10 degrees Celsius when the fish move toward shallower water. Once the temperature reaches 14 degrees Celsius when female fish pair off with one or two males smaller them and swim over the weeds throughout the day. They then will roll anus to anus and simultaneously release eggs and sperm while lashing their tails to spreading the eggs over the vegetation and sediment; no nest is formed during this process (Cook & Solomon., 1987). The eggs are non-adhesive unlike other esocids (Bezek et al., 1999). This means that the eggs must lay on the bottom whereas other esocids can attach their eggs to vegetation or debris in the water. This makes muskellunge much more susceptible to anoxic conditions than others because the eggs laying on the bottom could be covered by sediment. Throughout this process females will deposit between 6,000 and 265,000 2.5-3.5mm eggs. After the spawning process is completed the eggs are on their own with no support from either parent. Once the eggs hatch the larvae live off the egg sack for about 10 days. After the egg sack is consumed, the larvae begin to consume zooplankton and invertebrates (Cook & Solomon, 1987). Other Interesting Facts: With the nickname “the fish of 10,000 casts”, these elusive predatorshold one of the most sought after records within the fishing community; however, this record comes with a controversial history. Many different organizations recognize different fish for this sought-after title. Some people acknowledge the 69 pound 11 ounce fish caught by Louie Spray in October of 1949 (Wisconsin Department of Natural Resources, 2018); however, others recognize Cal Johnson’s 67 pound 8 ounce fish that he caught three months earlier in July of 1949 (International Game Fish Association, 2016), and others disregard both of these fish all together. The controversy behind these two fish is that they were caught in such a close period of time many people believe that its suspicious that there have been no fish close to that large caught since, but Louie and Cal caught two in one year. Also, once Louie claimed the record, his previously failing bar filled with people hoping to see the record fish and hear the stories. People also believe this record is suspicious due to the way Louie’s fish was mounted; when an analysis was done on the mount it appeared that length had been added to the fish by making a cut between the pelvic and pectoral fins by adding a piece from another fish. The people who disregard both records adhere to the modern record program started in 2006 to give anglers a chance at the record. The modern record is a fish caught by Joe Seeberger in Michigan that was 58 inches long and 58 pounds (Newman, 2012). Many anglers are against the modern record because for a fish to count for the record it must be kept and killed to be officially weighed and killing these fish is a taboo to many anglers.
Conservation & Economic Importance: The image around the muskellunge has changed substantially throughout the years. In the late 1800’s and early 1900’s there was a commercial fishery in place that harvested Muskellunge as a food source (U.S Fish & Wildlife Service, 2019). This harvesting caused a decline in populations which have now recovered and are considered least concern according to the IUCN Red List in 2003 (NatureServe, 2013). As the sport fishery grew, regulations became stricter, and people moved away from the consumption of these fish. In Wisconsin, length limits were originally set at 32 or 34 inches depending on the body of water throughout the state (AveLallemant & Margenau, 2000). These limits were put in place to allow fish to reach maturity before they were harvested by anglers. The limits changed throughout the years moving more toward creating trophy fisheries with limits set at a statewide 40” minimum with a few lakes at 50” and Lake Michigan and Superior at a 54” minimum. These changes have been made with support from the recreational angling community to try to promote more opportunities at catching larger fish. This trophy fishery is extremely important to Wisconsin’s economy bringing in roughly 425 million dollars in 2006 off Muskellunge anglers alone (Simonson, 2010). There are many communities built with money brought in by fishermen who come to fish the many lakes in northern Wisconsin. Without these anglers, many communities would suffer economic hardships.
Resources:
AveLallemant, S.P. Margenau, T.L. 2000.North American Journal of Fisheries Management. Effects of a 40-Inch Minimum Length on Muskellunge in Wisconsin. Volume 20, 2000: 1
Bezek, M.A. Burri, T.M. Frie, R.V. 1999. North American Journal of Fisheries
Management. Diets of Muskellunge in Northern Wisconsin Lakes. 19:258– 270.
Cook, M.F. Solomon, R.C. 1987 U.S Department of the Interior. Habitat Suitability
Index Models: Muskellunge. Biological Report 82(10.148): 1-8
Fuller, P. Neilson, M. and Hopper, K. 2019, Esox masquinongy Mitchill, 1824: U.S.