Overfishing, pollution, and climate change have contributed to a devastating decline in marine life.
Image: Leatherback Turtles Credit: Alamy/Dailymail
According to a recent comprehensive study, overall populations of marine mammals, birds, reptiles and fish have decreased by half in the past four decades. Worryingly, the report also highlighted that many species of fish commonly eaten by humans were seeing some of the greatest declines.
By compiling data from 2,337 individual sources, including population estimates from scientific studies and databases, the researchers were able to estimate the changes in species populations from 1970 and 2012.
Image: Yellowtail and albacore tuna are becoming increasingly rare, as well as bluefin. Credit: Brian Skerry/WWF
The scientists attributed the marine population crash to overfishing, habitat destruction, and climate change. In other words, the blame lies with us.
The report, which looked at 1,234 species of mammal, bird, reptile, and fish, found that between 1970 and 2012, populations declined by 49 percent, with some species hit much harder than others. Commercially valuable species like tuna and mackerel declined by 74 percent, and sea cucumbers (seen as a delicacy in some parts of the world) saw their populations reduced by over 90 percent in specific areas like the Galapagos and the Red Sea.
Wildlife biologists have been warning for some time now that many marine populations were not recovering for a variety of reasons related to human activity, and this new study offers yet more support for this conclusion.
Image: Sea cucumbers Credit: Cat Holloway/WWF
Robin Freeman, the head of indicators and assessments at ZSL, noted: "This is a wake-up call, but it’s also an opportunity. These are populations that are smaller than they would be, and should be. They aren’t recovering."