Instead of opening an extra process (zcat), one can also use modules as already mentioned. Like PerlIO::gzip. For inconsistency gzip is also supported in PerlIO::via::gzip, the two other perlio compress/decompress supported algorithms in that namespace are PerlIO::via::Bzip2 and PerlIO::via::xz.

On CPAN you can find a plethora of decompressors in the IO::Uncompress namespace where IO::Uncompress::Gunzip is part of (CORE since 5.9.4)