Trace elements in the statoliths of jumbo flying squid off the Costa Rica waters

Jumbo flying squid,Dosidicus gigas,is the most important commercial fishery in east Pacific Ocean,and the statolith in statocyst is widely applied in the field of population identification,life history analysis and habitat environment.In this paper,we studied the trace element composition of statolith in Dosidicus gigas and its relationship with the corresponding sea surface temperature(SST)by laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),then deduced the habitat in different life stages.The results showed that 54 kinds of elements were found in statolith of Dosidicus gigas,calcium(Ca),sodium(Na)and strontium(Sr)are the major elements.Sr/Ca ratio in total statolith is higher than that in Todarodes pacificus,Loligo gahiand Gonatus fabricii.Sr/Ca ratio is the highest in embryonic phase and declined by the age,and its relationship with SST shows a reciprocal ratio.There is no significant difference of Sr/Ca ratio between different hatching months in every life stage.Ba/Ca ratio shows a “U”form from larva to adult,this could be seen as the indicator of vertical movement with larva living in the surface and deep layer for adult.Nucleus is higher than peripheral zone in Mg/Ca ratio which presents positive correlation with SST,and this might be possible with the gradua decrease of growth rate in statolith.Meanwhile,this study also shows that Dosidicus gigasin embryonic phase used its own vitellicle as the nutrient substance,so the trace elements in this phase are related with genetic factor in parent rather than the water environment.