Ghost shrimp were originally thought to feed exclusively on organic detritus that they sift from the sand using hairs on their legs, though now they have been seen consuming surface detritus and plankton as well.

 

When the ghost shrimp larvae swim nearshore in the plankton, they are food sources to a variety of fish.  In northern states like Washington and Alaska, those that settle back into to the estuaries are predated by juvenile Dungeness crabs that recruit in the same territory (Feldman).  

 

One of the biggest threats to adult ghost shrimp is mankind, as humans frequently dig them out from their burrows to use as bait for fishing.  Because ghost shrimp disrupt the population growth of harvested oysters, they are often targeted with insecticides.