|Precision and accuracy of stable isotope signals in otoliths of pen-reared cod (Gadus morhua) when sampled with a high-resolution micromill|Hoie, H.; Andersson, C.; Folkvord, A.; Karlsen, Ø. (2004). Precision and accuracy of stable isotope signals in otoliths of pen-reared cod (Gadus morhua) when sampled with a high-resolution micromill. Mar. Biol. (Berl.) 144(6): 1039-1049. hdl.handle.net/10.1007/s00227-003-1275-5
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
|Authors|| || Top |
- Hoie, H.
- Andersson, C.
- Folkvord, A.
- Karlsen, Ø.
A high-resolution sampling technique for stable-isotope measurements in otoliths is now available, but little is known about the precision and accuracy of the results when using this technique. Otolith samples of pen-reared cod (Gadus morhua L.) with well-defined temperature history were obtained using this high-resolution sampling technique. Samples from different-aged cod otoliths were collected in two yearly increments corresponding to the calendar years 1994 and 1995, and the stable-oxygen (d 18O) and -carbon (d 13C) isotope compositions of the samples were measured. Otolith d 18O values had a clear seasonal pattern in response to the seasonal water temperature. Otolith material deposited in the same calendar years of different-aged fish showed similar d 18O values. High precision of the temperature estimate using otolith d 18O values was obtained when comparing results from different otoliths. The accuracy of the temperature estimates, relative to measured mean monthly water temperature, was also high, but reduced sampling resolution in the otoliths significantly reduced the accuracy due to attenuation of the d 18O signals. We found that the otolith d 13C values had a cyclic pattern, roughly in phase with the d 18O values. This was most likely caused by temperature-increased metabolism. Indications of age-specific otolith d 13C values are also presented.