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Longevity and age-specific fecundity are also related to growth rate. Ten-year old and older northern pike are not uncommon in northern Canadian and Alaskan lakes, where growth is slow, and individuals as old as 24 years have been recorded (Miller and Kennedy 1948; Rawson 1959; Alt 1969). Populations in Wisconsin (Van Engel 1940) and more southern waters (Buss and Miller 1961; Schryer et al. 1971) are composed mostly of 4-year old and younger fish. Fecundity increases exponentially with length and proportionally with weight (Carbine 1944; Frost and Kipling 1967; Priegel and Krohn 1975). Carbine (1944) reported an average fecundity of 32,200 eggs for 30 pike between 40 and 89 cm (total length). Northern pike become piscivorous very early in life. Fry begin to feed approximately 10 days after hatching, on reaching a length of 10 to I2 mm (Hunt and Carbine 1951; Franklin and Smith 1963). The diet initially ccnsists of zooplankton but quickly broadens to include aquatic insect larvae and then fish (Hunt and Carbine 1951; Frost 1954; McCarraher 1957; Fago 1977). By the time the fry reach 50 to 60 mm, typically within 4 to 5 weeks after hatching in the northern Midwest (Franklin and Smith 1963; Fago 1977) and Northeast (Forney 1968), fish comprise most of the diet (Hunt and Carbine 1951; Frost 1954). Fry are cannibalistic at sizes as small as 21 mm (Hunt and Carbine 1951). Fish continue to predominate in the diet throughout the remainder of the life history, but northern pike occasionally prey on leeches, aquatic insects, crayfish, waterfowl, and small- mammals (Frost 1954; Lagler 1956; Seaburg and Moyle 1964; Lawler 1965; Mann 1976). Northern pike feed opportunistically, exploiting seasonally abundant food sources (Frost 1954; Lawler 1965; Wagner 1972). Soft-rayed, cylindrical fishes are apparently mc,re easily swallowed than are spiny and/or laterally compressed species (Frost 1954; Hoogland et al. 1957; Beyerle and Williams 1968; Johnson 1969; Mauck and Coble 1971; Wagner 1972; Weithman and Anderson 1977;. Wolfert and Miller 1978). Gizzard shad (Dorosoma cepedianum) (Wagner 1972), alewife (Alosa pseudoharengus) (Wolfert and Miller 1978), yellow perch (Perca flavescens) (Lawler 1965; Johnson 1969; Diana 1979}, and trout-perch (Percopsis omiscomaycus) (Lawler 1965) have been noted as being especially common in the diet. White suckers (Catostomus commersoni) are commonly eaten by large northern pike (Lawler 1965; Koshinsky 1979). Reports of cannibalism among juvenile and adult northern pike are not unusual, but, in most cases, it accounts for a minor part of the diet (Frost 1954; Lawler 1965; Johnson 1969; Wagner 1972; Mann 1976). Alt (1968) described a Hatable exception; he found that the diet during summer and early fall consisted primarily of northern pike in several Alaskan lakes. Dryden and Jessop (1974) reported a high incidence of cannibalism among northern pike captured during a spawning run in a stream in the Northwest Territories. It appears that cannibalism occurs more frequently in waters with few fish species than in those where the fish community is diverse. Northern pike are visual predators (Polyak 1957; Braekevelt 1975) and are primarily day active (Carlander and Cleary 1949; Diana 1980). Their ambush style of hunting requires cover, usually sought in the form of aquatic plants. Tree stumps and fallen logs may also be used (Grossman, pers. comm.). 2