Table 2. Analysis of molecular variance in three different population groupings based on 109 microsatellite markers.

Population Groups Defined	Components	Percentage of Variation
Four groups according to habitat type	Among groups	−1.90
	Among populations within groups	34.14***
	Within populations	67.76***
Seven groups according to geographic proximity	Among groups	7.35***
	Among populations within groups	25.65***
	Within populations	67.00***
Marine vs. freshwater populations	Among groups	−2.05
	Among populations within groups	33.75***
	Within populations	68.30***

^***P < 0.001. The percentage of genetic variation among groups is indicated by bold type.