I can't ell you if it would have any effect on the fish population, but i seeded crown vetch on the disrupted soil areas (from construction). Don't know the geographic distibution of it, but here it is used extensively as a bank stabilizer on highways.
It is very expensive seed in wight, but coverage are is very large per unit. I seed in combo with alfalfa seed and it established itself quickly. If you are cheap, it tends to creep uphill, so you can seed low and let it spread.
Essentially no maintenence and lick 18" or so ground cover. My two "fancy" mehods of seeding both involve broadcasting the seed with a cyclone and either draggng a harrow over it or I used my cat and drove up and down with the idea to use the tracks to plant the seed and form lots of smal troughs from the cleats to help hold the seed from runoff. Both worked well.
