Well, its like any change. The fish all need to re-adjust to a different environment. One without much cover. Im ssure it prolly meant some of the big uns with established territories were forced to go and find new homes and clean house on alot of smaller fish on the way. smaller fish that no longer had the benefit of vegetation cover.
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The art of government is to make two-thirds of a nation pay all it possibly can pay for the benefit of the other third.--Voltaire