I use a version of the raking method shown below. These are recreational methods. Pro's drag a 3'wide sled through the water that scoops them up, and use big pumps to flush the much out of the sled.
http://www.lehsd.k12.nj.us/seaport/Vaughn/methods_of_clamming.htm
Huh huh huh...You said shinicock. /Beavis