Modelling studies by the international team of scientists found that although there has been a decrease in levels of mercury pollution due to various environmental regulations, the amounts of mercury found in fish have been different in different species – some types of fish have less mercury than before, and some, alarmingly more. The research was led from India by Dr. Asif Qureshi, Associate Professor, Department of Civil Engineering, IIT Hyderabad, and co-authored by Dr. Amina Schartup, Dr. Colin Thackray, Dr. Clifton Dassuncao, Dr. Kyle Gillespie, Dr. Alex Hanke and Dr. Elsie Sunderland.
A joint research of Indian Institute of Technology Hyderabad, Harvard University, and Fisheries and Oceans Canada, a Canadian government agency, has been researching how climate change impacts mercury accumulation in fish. This seminal work has been published in the August 2019 issue of the prestigious international peer-review journal Nature.
The researchers focused on whether the environmental measures already established alleviated the problem of elevated mercury levels in fish or made it worse in some way. Explaining the complexity of the problem, Dr. Asif Qureshi, who wrote the first versions of the model code, said, “There are three factors that affect mercury accumulation in fish- overfishing, which leads to dietary changes among marine animals, variations in the temperature of the sea water, which leads to changes in fish metabolism that gears towards survival rather than growth, and changes in the amounts of mercury found in sea water as a result of pollution.”
The researchers included all three factors in their modelling studies. They modelled the changes in mercury levels in tissues of the Atlantic cod and spiny dogfish that would result from the three factors – overfishing, increase in sea temperature and reductions in mercury emissions. Modelling showed a 10 percent decrease in tissue mercury concentrations for this type of fish.