punctuation - AE/Scientific language: When to use a comma before "which"

I'm struggling with the question whether to put a comma before "which" in many instances. While the general rule is "if the content after which is necessary to understand the rest of the sentence, put no comma" and "if the content is merely unimportant/additional information, put a comma", I often fail at applying this rule to my sentences.

Here are a few examples:

Shoaling behavior also holds a crucial role in the life of juvenile animals[X] which form shoals throughout the juvenile phase

(mechanoreception[X] which occurs through highly sensitive inner ears or neuromasts)

This greatly over- or underestimates the degree of phenotypic plasticity[X] which may lead to incorrect conclusions regarding the evolutionary consequences of phenotypic plasticity

Juveniles have great developmental freedom[X] which reduces the costs of being plastic

An example for the latter category are sexual ornaments[X] which are costly

Signal interpretation is modified by both past environments and the environment the signal is perceived in[X] which includes not only the external but also the internal environment

Animals actively searching for a partner are more conspicuous to predators[X] which makes mate choice a costly process.

Thanks for your help!