As a new study emerges, we learn that bluefin tuna, a long-lived migratory species, can be used efficiently as a global barometer of mercury pollution.
Researchers found intriguing new data about the fish species and how mercury pollution can affect ocean life and human health. The results are truly shocking.
Here is what you need to know.
Worrying Global Ocean Patterns of Mercury Pollution
As per a new study by Rutgers and other institutions, bluefin tuna is quite remarkable. It can be used as a global barometer of the heavy metal and the risk posed to ocean life and human health. How’s that possible?
Apparently, that fish species have high concentrations of neurotoxic methylmercury in their muscle tissue. Such a thing, researchers found, can increase with age.
What is methylmercury?
Methylmercury is a type of mercury that biomagnifies in aquatic food webs. As a result, the bluefin tuna meat can contain neurotoxic concentrations that sometimes are extremely worrying for human consumption.
However, researchers are still trying to find out how mercury accumulation varies among bluefin tuna worldwide.
How did researchers come across new data?
Researchers compared changes in muscle mercury accumulation of bluefin tuna from up to 4 different ocean sub-basins. What they found is genuinely intriguing.
FACT: there are 3 species of bluefin tuna, including Pacific, Southern, and Atlantic (one of the biggest and now most endangered).
Researchers discovered that mercury concentration rates decrease in the Indian Ocean, North Pacific Ocean, and North Atlantic Ocean, while the highest rates have been recorded in the Mediterranean. And that’s not all.
New data reveal that mercury accumulation rates grow a lot to those of methylmercury in regional zooplankton and seawater. This links methylmercury bioavailability at the base of every sub-basin’s food web to methylmercury concentration in bluefin tuna.
“[…], mercury accumulation rates provide a means to compare mercury bioavailability among geographically distinct populations of upper trophic level marine fish across oceans sub-basins, to investigate trophic dynamics of mercury in marine food webs and to improve public health risk assessments of mercury exposure from seawfood,” explained John Reinfelder, one of the study’s senor authors.