Spatial Variation in the Mercury Concentration of Muscle Myomeres in Steaks of Farmed Southern Bluefin Tuna.

Kirstin Ross,John Edwards

doi:10.3390/foods4020254

Abstract

Mercury concentration in the muscular tissue of farmed southern bluefin tuna, Thunnus maccoyii (SBT) is known to vary. Data suggests that mercury concentration is negatively correlated with the lipid concentration of tissues. Those areas that accumulate higher levels of lipid are noted to have a lower mercury concentration than lean tissues. Here we further delineate variation in mercury concentration within SBT muscular tissues by determining the concentration of mercury in the muscle myomeres (those sections within whole muscles) of transverse sectional steaks of farmed SBT. Mercury concentration in myomeres is observed to significantly decrease with dorsal and ventral distance from the spine or lateral line of fish. By extension, evidence is provided for the variation of mercury concentration within tissue cuts present in SBT steaks. This paper provides the first documentation of variation in mercury concentration within muscular tissue of fish.

Highlights

Mercury has long been recognised as a toxic contaminant of fish which binds directly to proteins in the muscular tissues [1,2,3]
Results of this study indicated that mercury was uniformly distributed in the muscular tissues
Myomeres are an arbitrary indication of distance from the lateral line and add to the variability in data between SBT

Summary

Introduction

Mercury has long been recognised as a toxic contaminant of fish which binds directly to proteins in the muscular tissues [1,2,3]. Investigations into the spatial distribution of mercury in fish suggested uniform concentration of mercury throughout the muscular tissues. A pioneering study conducted by Freeman and Horne [4] examined variations in mercury concentration of muscular tissues of swordfish (Xiphias gladius) at: (1) intervals longitudinally down the length of fish; (2) intervals along the circumference of transverse sections of fish; and (3) intervals of depth (from the epidermis through to the internal cavity) in transverse sections fish. Results of this study indicated that mercury was uniformly distributed in the muscular tissues. It was concluded that a small biopsy of tissue would be representative of whole tissue mercury concentration.

Methods

Results

Conclusion