What do you call an abrupt, abstract ending to a sentence?

While reading the poem Pike by Ted Hughes, I came across this line:

The gills kneading quietly, and the pectorals.

As you can see, the line ends quite abruptly. How would one term this literary device?

Lines ending abruptly may well be (though they are not necessarily) examples of aposiopesis. Wikipedia provides the following definition: "Aposiopesis ... is a figure of speech wherein a sentence is deliberately broken off and left unfinished, the ending to be supplied by the imagination..."

This is an example of a compound subject (gills and pectorals) split by the verb phrase (kneading quietly).