I'd rake it. You can choose how much you want to get out at one time. The big landscaping hard tine rakes work great. My big concern with a seine is how do you get the fa out of it? This is the number one call in my business, especially this time of year. And unless that mesh is extremely fine, it will get all stuck in that net, and will probably be more work getting it out of net than the pond. Second is you might overload the net with weight, and that won't take much. Stuff is solid water, like a full sponge. My third concern would be you just ruin the net. Have not seen a photo so can't say for sure, but I have to voice my concerns here.
