Statolith extraction method improvements for use in microchemistry studies with laser ablation inductively coupled plasma mass spectrometry

Major hindrances for most scientific studies involve a lack of funding, sampling, or equipment. Without large, high resolution sample sets spanning significant spatial scales, long temporal scales, or both, it can be difficult to discern accurate results. This can be the case for some population studies and fisheries management efforts. One novel approach to squid population studies involves harvesting statoliths, but the power of the studies is limited by the scales at which samples are collected. Approaches that involve the characterization of trace elemental chemistry in these aragonite structures could provide a better understanding of the life cycles and behaviors of targeted fisheries species than the common practice of length-frequency studies. Often statoliths are not collected and the absence of consistently periodic or geographically distinct samples potentially limits large scale population studies. One possible reason statoliths are not always removed may be the lack of a thorough, clearly illustrated instructional method on dissection of the statoliths from the cranial cartilage. In an effort to encourage sampling of statoliths, previously published methods are improved upon in this work by including a description of the dissection of the statoliths using layman terms accompanied by detailed photographs. The methods were tested successfully with the Ommastrephid squid Dosidicus gigas and the statoliths obtained will be used to examine trace element variations determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).