By Chris KingA new report from the National Fisheries Institute (NFI) has found that Sydney’s tuna and crab stocks are at “record low levels”.
It has also warned that a “potential crisis” is brewing in Sydney harbour and on the city’s waterfronts.
The report, released on Wednesday, found that the number of Atlantic cod (cod) stocks in NSW had been reduced by up to 60 per cent in the past five years.
It also noted that the Atlantic cod stocks have decreased by up 90 per cent since 2000, when the first cod stocks were released in NSW.
The NFI’s Dr Tim Moulton said that the latest report showed that the stocks were at “low or negative levels”.
“It was clear from the numbers that the stock had declined and the risk of the stock falling further was very high,” he said.
“There is no evidence that the numbers of cod were declining at the same time.”
The report said the current decline in Atlantic cod stock was due to a number of factors including the introduction of the cod cull and a reduction in commercial fisheries in NSW, which have led to “very high” mortality rates of the fish.
The NFi also said that while the population of Atlantic mackerell was stable in NSW at about 9 million tonnes in 2012, the number had dropped to around 3.5 million tonnes last year.
The new report, which examined fisheries from 1950 to 2012, found: The stock has decreased by almost 60 per-cent in the last five years with a net loss of nearly 20 million tonnes.
This represents a reduction of about 40 per cent of the total stock that existed at the time.
Although the decline in cod was driven by the introduction and removal of the Cercopithecus pacificus cull, it is also possible that other factors contributed to the decline.
According to the report, the overall stock is now estimated to be at “limited” levels.
However, Dr Moulson said that “if we can keep this stock stable we can continue to have a healthy harbour”.
“We are not yet at that point where we are at with the numbers but we are well into that phase,” he added.
“We need to continue to reduce fishing pressure in the harbour and have some fish management policies in place that are in place to help protect the population.”
The NFU report also found that there were two types of stocks in the Sydney harbour, the “new” stocks that have not been culled, and “old” stocks which were culled but still contain the same number of cod and mackes.
New stocks, including cod, had been culling for years, and they were now at the lowest levels, but the report noted that “there is a risk of an increase in this stock if the CEC cull is continued”.
The report also warned about the “potentially catastrophic” impact of the current cod cull on the mackelly stocks, and warned that the “continued high mortality rate” of mackellys was a “critical risk” for maintaining the “current stock”.
Dr Moulon said that if the cull continued, “we could see a dramatic increase in mortality and a large decline in the mackelsey stocks.”
“We would expect this would have a dramatic impact on the harbour,” he warned.
Dr Tim Moustons research into the fish stocks of Sydney was supported by the Australian Institute of Marine Science.
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