NMR relaxometry as a potential non-invasive routine sensor for characterization of phenotype in Crassostrea gigas

12 MR imaging is the most appropriate non-invasive technique for quantifying the growth of 13 somatic and gonad tissues and to determine sex in the Pacific oyster, Crassostrea gigas. 14 However, this technique is too costly for field studies where oysters are used as bioindicators of 15 environmental quality or to be applied routinely in hatcheries. We have tested the ability of low 16 Nuclear Magnetic Resonance relaxometry, a much less expensive technique, to obtain phenotype 17 parameters that can be used to monitor the physiological state of oysters. NMR measurements 18 were carried out at three different periods using a low field spectrometer equipped with a 50 mm 19 diameter probe to investigate 60 oysters in their first year of maturity, which were then dissected 20 to measure internal shell cavity volume and dry flesh weight and to determine sex and gonad 21 development. The NMR results showed that it was possible to determine both internal shell 22 cavity volume and dry flesh weight in less than one minute with very high determination R 23 coefficients (0.95 and 0.94, respectively). The results showed also that it was possible to identify 24 sex and gonad development, with success rates of 93% and 83%, respectively. For oysters with 25 dry weight above 0.7g, the success rate in identifying sex was 100%. Further studies are required 26 Manuscript Author-produced version of the article published in Aquaculture, 291 (1-2, 3), 74-77. Original publication available at www.elsevier.com doi:10.1016/j.aquaculture.2009.03.008