Not necessarily. My preference is to use “shrimps” when I mean to enumerate a discrete quantity, and shrimp solely as a collective noun, but both “shrimps” and “shrimp” are acceptable plurals.
In this case, I think the author uses “shrimps,” because he is speaking of multiple populations of shrimp, just as one might use “sands.”
Nevertheless, these shrimps are lost in the sands of times./s
:-)