7143

• UCREFRP Catalog Number: 7143
• Author: Inskip, P. D.
• Title: Habitat Suitability Index Models
• USFW Year: 1982.
• USFW - Doc Type: Northern Pike.
• Copyright Material: NO

Consumption rate varies seasonally. Maximum rates usually occur in
spring or early summer (Johnson 1966a; Weithman and Anderson 1977; Diana
1979), following the spawning period. Weithman and Anderson (1977) observed
peak feeding at temperatures between 15 and 18° C for yearling northern pike
held under experimental conditions; there was a summer reduction in consump-
tion rate between May and September highs.
Reproduction
Northern pike spawn in spring, shortly after ice-out, when the water has
warmed to 8 to 12° C (Embody 1918; McNamara 1936; Clark 1950; Fabricius and
Gustafson 1958; Franklin and Smith 1963; June 1971; Priegel and Krohn 1975).
Movement to spawning grounds often begins before all ice has melted. Upstream
spawning migrations out of lakes in Michigan (Carbine 1942) and Minnesota
(Franklin and Smith 1963) occurred as soon as there was sufficient clearance
between inshore ice-and the bottom to permit passage. Robertson (1969)
observed that upstream movement of northern pike was interrupted when the
water temperature dropped below 5.5° C. Isolated spawning may occur at tem-
peratures less than 8° C (McNamara 1936; Clark .1950; Schryer et al. 1971).
Most females have completed spawning by the time temperatures exceed 13° C
(Schryer et al. 1971).
Spawning occurs over vegetation in areas of calm, shallow water
(Williamson 1942; Clark 1950; Fabricius 1950). There is a strong tendency to
migrate up tributaries to flooded marshes, wetlands, or shallow pools among
both lake (Carbine and Applegate 1948; Schultz 1955; Robertson 1969; Koshinsky
1979) and river (Harrison and Hadley 1978) populations. Flooded terrestrial
vegetation (McCarraher and Thomas 1972) and shallow, weedy bays or backwaters
may also be used (Jarvenpa 1962a; Frost and Kipling 1967). The absence of
inundated vegetation can inhibit or delay spawning (Fabricius 1950; Fabricius
and Gustafson 1958). The timing of spawning has been linked to water level
changes (Fabricius 1950; June 1970, 1971, 1977).
Spawning groups, consisting of a female plus one, or more typically,
several, males move continually. Only a few eggs, 5 to 60 according to
Svardson (1949), are released at any one spot (Svardso~ 1949; Clark 1950;
Fabricius and Gustafson 1958). Gametes are broadcast (Fabricius and Gustafson
1958), and no parental care is provided (Eddy and Underhill 1974). Eggs
adhere to vegetation (Fabricius and Gustafson 1958; Frost ,and Kipling 1967).
Both .laboratory (Fabricius and Gustafson 1958) and field (Koshinsky 1979)
observations indicate that spawning occurs in distinct series of mating acts,
between which the fish are stationary, presumably to rest.- Spawning groups
may cover considerable distances before all eggs are released (Koshinsky
1979). Distances between egg releases are likely to be greater when the
distribution of spawning habitat is patchy (Fabricius and Gustafson 1958).
Northern pike do not spawn at night (Clark 1950; Fabricius and Gustafson
1958). Spawning may be interrupted by cold weather, water ]evel drawdowns
(Clark 1950; Fabricius and Gustafson 1958; June 1970), strong wind, or rain
(Koshinsky 1979). Prolonged interruptions may result in resorption of eggs
(June 1970).
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