|Sigl, R; Imhof, HK; Settles, M; Laforsch, C: A novel, non-invasive and in vivo approach to determine morphometric data in starfish, Journal of Experimental Marine Biology and Ecology, 449, 1-9 (2013), doi:10.1016/j.jembe.2013.08.002|
|Stichworte: Acanthaster planci (Linnaeus 1758); Echinodermata; Gonad index; Magnetic resonance imaging; Non-invasive; Pyloric cecum index|
Starfish (Echinodermata: Asteroidea) are present in most benthic ocean habitats and play an important ecolog- ical role as keystone species or by dominating through sheer individual numbers. In order to assess nutritional and reproductive states in ecological studies on asteroids, invasive techniques to calculate organ indices are con- ventionally used.Wepresent a non-invasive method that enables imaging andmorphometricmeasurements in starfish in vivo.We used a clinical 1.5 T magnetic resonance imaging (MRI) scanner to produce sectional images of three starfish species and employed these image stacks to generate 3D models of the pyloric ceca, gonads and the endoskeleton. In comparison to pre-clinicalMRI scanners, that provide higher resolutions, clinicalMRI is not limited to small objects, but allows the investigation of larger samples such as the starfish used in the present study. Volume data from MRI-based 3D reconstructions were compared to conventional invasive measurement techniques as well as high resolution MRI scans and were tested for inter-observer effects. Here we show that MRI is a suitablemethod for precise imaging and volumetricmeasurements infixed and livingmarinespecimens. Compared to othermethods, it allows not only the production of time series data on single individuals aswell as populations, but also non-destructive analyses of valuable specimens, such as museummaterial.