NUCLEAR MICROPROBE MAPPING OF STATOLITHS OF CHOKKA SQUID LOLIGO-VULGARIS-REYNAUDII DORBIGNY, 1845

Loliginid squid statoliths were broken in half and their elemental com position was assessed using the nuclear microprobe technique. Proton i nduced X-ray emission and proton backscattering were used simultaneous ly. True, quantitative maps of calcium and strontium distribution in t he frontal plane were obtained using a rapid-matrix-transform method c alled Dynamic Analysis. These measurements were complemented by observ ations with scanning electron microscopy and light microscopy. In juve nile and adult statoliths, Sr was concentrated in the wing and adjacen t areas, whereas the Ca concentration was highest on the edge of the l ateral dome. In contrast, Sr and Ca were uniformly distributed in the statoliths of paralarval squid. Increments showed best definition in t he areas anterior and adjacent to the wing, corresponding to areas of high Sr content. Although temperature, sex, maturity, and the administ ration of oxytetracycline may influence the quantitative distribution of Ca and Sr in the statoliths of adult squid, they do not appear to a ffect the general pattern described above. The finding that Sr is conc entrated in regions adjacent to the macula where the dearest increment s are found in loliginid statoliths supports the hypothesis linking st rontium with the regulation of statolith deposition and the definition of daily increments.