A group of international scientists have asserted that the dolphin population could be at as low as 13% of what it used to be, after overfishing caused an “alarming” drop in numbers.
The study, which included a number of scientists from Queensland’s James Cook University, used the amount of dolphins caught in fishing nets to estimate how the overall population is functioning in the world’s oceans.
Although tens of thousands of dolphins are caught in nets every year, this number has dropped by one fifth since 2004. Scientists believe this shows an overall population decrease at an “alarming” rate.
According to the study, the dolphin population could be at just 13% of where it was at before 1980, largely because of being caught in tuna and cetacean nets.
“The declining cetacean bycatch rates shown by what we can measure suggest current mortality rates are not sustainable,” James Cook University’s Dr Putu Mustika said, according to 10 Daily.
“The estimates we have developed show that average small cetacean abundance may currently be 13 percent of the 1980 levels.”
According to Mustika, the huge decrease in population is largely believed to be a result of commercial fishing nets. In particular, the gillnets that are currently banned by the United Nations (but are still used by many fishing companies) are believed to be the cause of high numbers of dolphin deaths.
“The vast majority of the cetacean bycatch is dolphins. Estimated cetacean bycatch peaked at almost 100,000 a year during 2004−2006, but has declined to 80,000 animals a year, despite an increase in the tuna gillnet fishing effort,” Mustika said.
According to the research presented by James Cook University, there is “a need for improvements in monitoring, analysis and governance and for changes to fishing practices if dolphin numbers are to recover.”
