I am not a shrimper or a commercial fisherman, but clearly some factor makes nets appropriate for one or the other. These are not large tides, less than a meter

I am not a shrimper or a commercial fisherman, but clearly some factor makes nets appropriate for one or the other. These are not large tides, less than a meter between high and low. Any creatures caught will miss a meal (or possibly become one), but considering that the net is quite literally dipped into the waterway they live in and pulled up later, they should live. Any fish will be thrown in after a minute or two in the net. These are not commercial harvests, just private ones that might garner 5 kg total catch.