Influence of temperature and salinity on the trace element incorporation into statoliths of the common cuttlefish (Sepia officinalis)

The use of statolith chemistry to trace migration pathways and distinguish populations of cephalopods is based on the assumption that the elemental composition of statoliths is influenced by physicochemical properties of the ambient environment. However, such influences have not been investigated experimentally up until now. This study presents the first microchemical analyses of cephalopod statoliths obtained from laboratory experiments under different controlled temperature and salinity conditions. Our results show that statolith chemical composition is strongly related to both salinity and temperature in ambient waters. The Ba/Ca ratio is negatively related to temperature and shows no relation to salinity. The I/Ca ratio is positively related to temperature and negatively to salinity. No Sr/Ca relation was found to either salinity or temperature, suggesting that the well-established proxy strontium is not as useful in cephalopod statoliths as in other biomineralized aragonites. Microanalysis of trace elements, however, shows an enormous potential for field studies on distribution, migration and stock separation of cephalopods. Furthermore, Synchrotron X-ray Fluorescence Analysis is introduced as a promising novel method for statolith analysis, providing a spatial resolution of typically 10–15 μm combined with detection limits down to 0.5 ppm

Temperature and salinity effects on strontium incorporation in otoliths of larval spot (Leiostomus xanthurus)

Author Posting. © National Research Council Canada, 2004. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 61 (2004): 34-42, doi:10.1139/F03-143.Temperature dependence of strontium/calcium (Sr/Ca) ratios in foraminiferal calcite and coral aragonite is well established; however, factors controlling Sr/Ca ratios in fish otoliths remain obscure. To assess temperature dependence of Sr/Ca in marine fish otoliths, we reared spot (Leiostomus xanthurus) larvae under controlled temperature (17–26 °C) and salinity (15‰ and 25‰). We found a significant linear relationship between temperature and Sr/Ca ratios, with a sensitivity of approximately 5%·°C–1. Otolith Sr/Ca values were also significantly higher at a salinity of 25‰ vs. 15‰, after accounting for differences in dissolved Sr/Ca ratios in the ambient water, with a sensitivity of approximately 1%/salinity (‰). These observations complicate the use of Sr/Ca ratios to determine temperature histories of spot larvae, because accurate temperature reconstructions are possible only with a priori knowledge of both ambient salinity and dissolved Sr/Ca ratios. Fully marine species residing in oceanic waters will not experience significant salinity variations; therefore, otolith Sr/Ca ratios may be useful recorders of temperature exposure. Otolith Sr/Ca thermometry in coastal fish species that make regular excursions into estuarine waters will be more problematic. Multiple geochemical tracers, including oxygen stable isotopes and other trace elements, may be necessary to accurately reconstruct temperature and salinity histories in these species.This research was supported by grants from the National Science Foundation to S.R.T. (OCE-0134998) and to S.R.T. and C.M.J. (OCE-9876565), a grant in aid to G.B.M. from the International Women’s Fishing Association, and a PEO International Women’s Organization Scholar Award to G.B.M