Which begs the above question - is this a first for JER? The only UK airline that ever operated a CR7 was Duo - and they did not serve JER. And not a lot of non-UK airlines have served JER regularly since the CR7 was introduced.
This is, by the way, the CRJ700 Series 701 ER performance data:
FAR take-off field length (SL, ISA) at MTOW 5,500 ft
FAR landing field length (SL) at MLW 5,090 ftm