Application of image analysis software to the morphometrics of Posidonia oceanica (L.) Delile and Cymodocea nodosa (Ucria) Ascherson

Abstract

Leaf biometrics are important parameters of seagrasses measured in coastal marine environment-monitoring programs. This study tested the application of several image analysis software packages to the biometry of Posidonia oceanica and Cymodocea nodosa leaves as an alternative to the commonly used manual technique. The biometrics of leaves and epiphytes measured using Image-Pro Plus image analysis software were significantly different from measures made with the manual technique; this was a reflection of the precision of the digital measurements related to the application of "best fit" measures to the shape of the leaves. Among the advantages of the digital method, we found enhanced precision and, presumably, higher accuracy in measurement, faster time of execution, availability of a wide range of free software for image analysis, the permanence of a photographic record, the ability to create data bases to compare new samples with older ones, and the possibility of analysing different morphometric variables on the same sample after a long period of time.