Essential and non-essential elements in tuna and billfish around the world: Distribution patterns and influencing factors

Tuna and billfish are widely distributed in oceans worldwide. Their survival is relied on a decent share of essential and non-essential elements. We conducted a comprehensive evaluation of essential and non-essential elements in livers of tuna and billfish collected from global oceans. The individual element consistently shown similar orders of magnitude in both tuna and billfish, with essential elements generally being 1-3 orders of magnitude higher than non-essential elements. Various physicochemical properties and behaviors contributed to four distinct clusters of these elements. Also, element distribution pattern indicated the presence of four sample groups based on regions and categories. Nine elements served as characteristic indicators. Among them, fish category was the most important influencing factor. Hg, Fe, Tl, Co, and Se were influenced by body size, trophic level, and feeding habits. Ni was influenced by sampling regions, while Mg, Mn and As were influenced by body size and local primary production.

Automated summary

Tuna and billfish, widely distributed in oceans worldwide, depend on the proper balance of essential and non-essential elements for their survival. A comprehensive evaluation of the elements in the livers of these fishes was conducted, revealing similar orders of magnitude for essential and non-essential elements. Physicochemical properties and behaviors contributed to the categorization of these elements into four distinct clusters. The distribution pattern of the elements also indicated the presence of four sample groups based on regions and categories. Fish category was found to be the most influential factor, with certain elements being influenced by body size, trophic level, feeding habits, and sampling regions.