These are everywhere and often times well disguised. You need to research where you are publishing before sending it in. I, like many young graduates, were tas

These are everywhere and often times well disguised. You need to research where you are publishing before sending it in. I, like many young graduates, were tasked with finding 5-10 "less popular" journals to publish to in order to get some practice in. This was mostly an exercise in learning the industry and so I didn't get much help from my advisor. In my particular sub-field of computer science the major journals were highly exclusionary and so getting published even with your advisor's name on the paper was not likely. I cannot tell you how many times I went back to my advisor only to find out a couple journals I chose were predatory. Some were obvious to remove (and I did), some you could Google and get to the 3rd page to figure out if it was predatory, some you really needed to understand how journals work (scoring, reviewing criteria, rejection rate, etc). A hallmark is always a strangely low rejection rate. Sometimes you can dig deep and figure out by looking at the review process. It is sometimes a lot of work to avoid accidentally publishing to one of these. They crop up as often as they get knocked down.