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

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.