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SHARK numbers across southern Australia have rocketed to unprecedented levels, with the most comprehensive marine survey ever undertaken in the nation's waters finding decades of overfishing have been curtailed.

Commercial fishermen are reaping reliable catches thanks to a quota system introduced in 2000, which has allowed stocks of gummy and school sharks to regenerate in greater numbers.

The commercial shark fishing industry primarily catches sharks to be processed for human consumption. Much of the catch ends up dipped in batter and in the deep fryer at the local fish and chippery.

According to the survey, western Bass Strait and South Australia's Eyre Peninsula recorded the largest increases of school sharks, with decreases in eastern Bass Strait.

Gummy shark numbers were up in most areas in South Australia, but lower in western Bass Strait.

The government-funded study, conducted by the Marine and Freshwater Fisheries Institute in Victoria, engaged commercial fishermen monitoring 187 sites from eastern Victoria to the South Australian and West Australian border in 2007 and last year.

Principal researcher Terry Walker told The Australian more school sharks were found around southern Tasmania than over the past 30 years, including large populations of males.

"We also found a lot of females in the Great Australian Bight," Mr Walker said. "And the gummy sharks have increased everywhere."

Survey participants counted all stock caught in nets over the two-year period.

The fishermen caught 18,983 sharks and related species, including 6010 gummies, 5655 piked spurdogs, 2814 school sharks, 1463 draughtboard and 976 Port Jackson sharks.

But Mr Walker said it had been difficult to compare the comprehensive numbers with the "opportunistic" data collected as part of tagging and smaller research projects undertaken since the 1970s.

Sharks were mainly caught with hooks until nets were introduced in the early 1980s, which led to overfishing.

Steps to end open-slather commercial shark fishing were taken to protect the fishery in the late 1980s, but it was not until 2000 that the Australian Fisheries Management Authority enforced catch quotas.

Mr Walker said quotas had limited the number of sharks taken from the water, leading to the recovery of species and the creation of a significantly more sustainable industry.

"By having the stocks rebuild, the fishermen can now experience a higher catch rate," he said. "The whole economics of the fishery have improved ... and it's a more sustainable industry."

Fisherman Kyri Toumazos, whose fleet of six boats monitored SA waters, said he had never seen such prolific numbers of sharks.

Mr Toumazos said school sharks had increased over the past decade, to the point where one of his boats recorded the largest ever catch in the southern Australian zone last year, pulling in 22 tonnes of fish near the WA border in one trip compared with the previous record of 16 tonnes.

"The vessel was full; the numbers of sharks there was enormous," Mr Toumazos said.

He said the region between Point Fowler and the WA border contained abundant numbers of female school sharks, which were big enough to breed well and not get caught in nets.

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