Laser ablation mass spectrometry analyses of fish scales for the determination of Morone Saxatilis movements between fresh water and saltwater habitats

Laser ablation combined with quadrupole mass spectrometry, a new technique being developed at Oak Ridge National Laboratory, was used to analyze Sr content in striped bass (Morone saxatilis) scales to investigate movements of these fish between fresh water and saltwater habitats. It is known that saltwater has a much higher concentration of Sr as compared to fresh water. Therefore, it was hypothesized that striped bass movements could be monitored through strontium levels in fish scales due to the fact that elements such as Sr are incorporated into fish hard parts as they grow.

The system was also used to test whether elements such as Rb fed in the diet would produce marking bands in coho salmon scales.

It was found that, due to fish scale morphology and perhaps the laser/mass spectrometer system used, Ca and Sr signals obtained were extremely variable. Strong and consistent Sr peaks were not observed. It was found that Rb fed in the diet of coho salmon, produced distinct, but inconsistent marking peaks in their scales. It was concluded that further analyses of fish scale morphogenesis would be necessary to determine how the scale incorporates elements from the surrounding environment. It was also determined that more studies of the quadrupole and laser system were needed to test its suitability for the fish scale analyses.