Fewer sea turtles have been killed accidently by American fisheries, according to a new report, yet the lack of data being issued by shrimp trawlers has become an obstacle to finding the number of turtles killed by fish hooks and nets.

Around 4,600 sea turtles are accidently killed per year by fisheries and while this is a 90 per cent decrease since 1990, it may still not be enough to sustain turtle populations.

The study carried out by Duke University's Project Global found that if proper regulations were put into place for accidental bycatchs many more turtles would be saved per year.

Bycatch is the accidental capture and injury of marine animals in fishing gear that are not the target catch species.

It is disgraceful that U.S. fisheries are allowed to kill 4,600 endangered and threatened sea turtles each year - and that is the best case scenario. This estimate also assumes that sea turtle protection measures are being followed in all U.S. fisheries. The actual number of sea turtles killed in U.S. fisheries is likely significantly higher, said the international advocacy group Oceana.

The study complied estimates of sea turtle accidental bycatches across fisheries of the United States prior to the implementation of fisheries-specific bycatch mitigation measures. They found an annual mean of 346,500 turtle interactions was estimated to result in 71,000 annual .After the measure were put in place bycatch estimates were 60 per cent lower.

One of the problems is that we don't have that magic number that serves as a quota across all fisheries, said one of the study authors, Dr. Bryan Wallace to the Huffington Post. Coming up with that number can determine the mortality rate that populations can sustain. Then we can work out how much bycatch is happening in each fishery, and added together, that should be lower than the ceiling set for sustainable numbers.

The study was the first compilation of bycatch estimates from all fisheries in the US