I've have never pumped fish eggs with a mechanical pump. I have used siphon hoses to transfer aquarium fry from the breeding tanks to the fry tanks with very good success.

That said, your best type of pump would be a vacuum pump (think septic tank sucker truck without the high water volume and speed). A pump that pulls a vacuum on a tank so that the intake hose valve is opened the vacuum pulls the water in without it going though any mechanical device and then the water can be discharged by gravity or the vacuum pump reversed to pressurize the tank which pushes the water back out the intake hose. The sizing with respect to water flow velocities would need to be on the low side, but I can not say as to what the safe range of speed/turbulence the eggs could handle.

Is a siphon hose a possibility? A 2 inch hose would suck a fair amount of eggs and water if thrown over a dam. The eggs could be collected in a tub/tank and transported to the new BOW.

Fish on!,
Noel