>I think it [Perl] is still quite common in the bioinformatics field though!?

That's true - many day-to-day tasks in bioinformatics are more or less plain-text parsing [1], and Perl excels in parsing text and quickly using regular expressions. "My" generation of bioinformaticians doing data cleanup and analysis (20-30) uses Python, sometimes because plotting is nicer, the language is easier to get into, it's more commonly taught in universities, or other reasons - people older than that normally use Perl.

Both BioPython and BioPerl are extremely useful.

[1] Relevant quote from Robert Edgar: "Biology = strcomp()" from https://robertedgar.wordpress.com/2010/05/04/an-unemployed-g...