According to a recent UBC research, almost a quarter of Europe’s 20 most heavily fished marine species would be under acute stress by 2100 if nothing is done to concurrently address climate change, overfishing, and mercury contamination.
The combined assault of overfishing, ocean warming, and mercury contamination would decrease the resistance to climate change of seafood species that are staples of the EU market, such as great Atlantic scallop, red mullet, and common octopus, if carbon emissions continue to rise at their present pace. By the end of the century, the population of these animals will most certainly be reduced to a fraction of its current size.
According to a recent UBC research, almost a quarter of Europe’s 20 most heavily fished marine species would be under acute stress by 2100 if nothing is done to concurrently address climate change, overfishing, and mercury contamination.
“The combined onslaught of overfishing, ocean warming, and mercury pollution will weaken the resilience to climate change of seafood species that are mainstays of the EU market, such as great Atlantic scallop, red mullet, and common octopus,” said lead author Dr. Ibrahim Issifu, a postdoctoral fellow at UBC’s Institute for the Oceans and Fisheries (IOF). “By the end of the century, the population of these species will be reduced to a fraction of its current size.”
The research is one of the first to look at how increasing temperatures, overfishing, and mercury contamination affect fish in EU seas. The study team chose 20 European fish species with the largest average yearly total catch and income, and used earlier estimations of their preferred temperatures to establish the temperature tolerance range for each of these species. The scientists then compared this range to previously estimated temperature rises in EU waterways throughout the century, using both high and low carbon emission scenarios. Finally, the model included different levels of mercury contamination as well as unsustainable amounts of fishing.
The findings revealed that the effects on Europe’s fish stocks will vary greatly depending on each species’ average temperature tolerance, with seafood staples like Norway lobster, common sole, great Atlantic scallop, red mullet, and European hake expected to decrease in abundance and distribution as water temperatures reach lethal levels.
Furthermore, certain bigger, longer-lived species, such as swordfish, would likely be polluted with up to 50% more mercury than current levels, making them dangerous to consume and creating health concerns such as reproductive disorders, which would further reduce fish populations.
Dr. Vicky Lam, one of the study’s co-authors and a research associate at IOF, stated, “The combination of these elements is acting synergistically to produce an unfavorable environment for fish.” “Climate change and high mercury concentrations have a significant influence on the most overfished and exploited species. It’s a life-or-death scenario.”
According to co-author Dr. Juan Jose Alava, a research associate at the IOF and principal investigator of UBC’s Ocean Pollution Research Unit, both climate change and overfishing have the potential to increase the amount of mercury consumed by fish higher up the food web, such as bluefin tuna and sharks.
“Overfishing, mercury contamination, ocean warming, and cumulative human-caused stresses combine to debilitate fisheries’ resilience,” Dr. Alava added. “To avoid the worst effects of warming seas, a binding worldwide agreement to cut carbon dioxide and mercury emissions from coal-burning and fossil-fuel-consuming businesses and human activities is critical. To end overfishing, this worldwide effort should go hand in hand with the abolition of detrimental fisheries subsidies.”
Governments and individuals must learn to be more proactive than reactive in dealing with these various ocean stresses, according to Dr. Rashid Sumaila, co-author and professor at the IOF and the School of Public Policy and Global Affairs. “Listening to experts and community people who generally raise the alarm about impending threats is one approach to be proactive.”
