zoomer:
That does look like a tiger, other things to look at are whether the tail is rounded or pointed (rounded on the tiger) and on the gill plate there scale pattern that is only on the tiger (On the northern, the cheek is fully scaled, but only the upper half of the opercle, or gill cover, is scaled. Another way to differentiate the fish is to count the pores, tiny sensory openings, along the underside of the jaw. In northerns, there are four or five pores on each side; muskellunge have six to nine pores on a side. Scalation on the cheek is intermediate between the northern pike, with a fully scaled cheek, and the muskellunge, which has scales on the upper half of the cheek. About the upper two-thirds of the tiger musky’s cheek is scaled. The number of pores beneath one side of the lower jaw is six or seven. The musky has no scales on the lower half of its cheek and the lower half of its gill cover, which helps to distinguish it from the northern pike. Also, the musky has six to nine pores, tiny sensory openings, beneath each side of its jaw; the northern pike has five or fewer pores).
Both phases can be available in the same body of water, either by stocking or naturally crossing. The tiger is sterile, so if there is naturally occurring population, both subspecies (northern & musky) would be present in the same body of water.
Mark