The occurrence of chemical and oil spills in Upper Spencer Gulf in 1992
December 1, 1992|Posted in: Oil Spills
The waters of upper Spencer Gulf were subjected to two major spills during 1992. Marine life in the area was threatened as a result of both spills. The first spill occurred on the 7th of July 1992 when about 350 kilograms of chlorine leaked from a pipe at the Thomas Playford power station. This chemical spill killed fish in the area. Thousands of fish were reported to have been killed but an ETSA report only acknowledged the death of “at least 100 fish thinly scattered in the area.”
The ETSA report was the result of an internal inquiry into the spill. The report said that the inquiry found no long-term environmental impact on marine life. The report went on to say that “the extent of the fish kill could not be ascertained because of the tidal action and poor visibility, but approximately 100 (dead fish) were spotted from the sea wall at 11am on July 8th. ETSA scientists said that underwater checks at a series of locations revealed “no obvious impacts on the marine flora and fauna both directly under the spillage point and further away.”
Copies of the ETSA report were sent to the Department of Fisheries and the Marine Environment Protection Committee.
The second spill in the area occurred less than eight weeks later. On 30th August, 296 tonnes of heavy engine fuel oil from the tanker Era was spilled at Port Bonython (pictured above). This incident became our state’s worst oil spill. Reports about the spill dominated the newspapers for months. Heavy seas at the time helped to break up the slick with the help of chemical dispersants which were sprayed the same day.
The next morning, the slick was about 2 kilometres long and 500 metres wide. Dispersant was sprayed from the air all that day. On the third day, floating booms were used to try and stop the slick from reaching shore. By the fourth day, 20 tonnes of oil had reached shore! The slick had drifted eastwards into the Port Pirie mangroves- sensitive fish breeding grounds.
Below is a map showing the journey of the oil slick from Port Bonython (near Point Lowly) eastwards to the mangroves south of Port Pirie.
Mangroves are critical to the health and productivity of the gulf. Each half hectare of mangroves generates about 100 tonnes of nutrients into the water. The samphire flats behind the mangroves also generate about 50 tonnes of nutrients per hectare to the mangroves.
King tides pushed the slick into tidal creeks just south of Port Pirie. The 25 kilometre long coastline was home to thousands of seabirds. Hundreds of these birds died. Of 256 birds rescued and treated, only seven survived. Society member Jean Cannon felt that when the people who captured all of the birds trampled through the mangroves, they possibly did as much damage to the mangroves as the oil did. The oil spill possibly caused long-term damage to prawn breeding grounds. Fauna Rescue spokesman Doug Reilly said that the spill occurred near one of SA’s largest breeding areas for Western King Prawns. He also said that chemical dispersants could add to the dangers for fish and bird life.
Three weeks after the spill occurred, a team of Fisheries department officers went to Port Pirie to set up a long term monitoring program. Senior officer Vic Neverauskus who has spent several years studying mangroves and intertidal areas in Port Pirie and Adelaide said that Sixth Creek bore the brunt of the oil. He said that essentially it was a scattered effect. He also siad he was confident that the residual oil in creeks would break up with minimal impact on fishing grounds.
Port Pirie fisherman David Wilks said that when the tide went out in Sixth Creek it uncovered a distinctive 30cm wide black band on each of the mangrove stems. National Parks and Wildlife Service Senior Officer Ian May said that the oil had concentrated in among the mangroves in a band about 30 metres wide and 14 to 15 kilometres long. The oil stuck to the stems and lower branches of the mangrove trees. It didn’t stick over their roots, so he didn’t expect the impact on them to be too severe.
Senior Environment and Planning Department officer Brian Wagstaff said that the spill posed no long or medium-term ecological damage. He said “Basically, there won’t be a die back of mangroves, although there will be some loss of branches and leaves.” He said that smaller spills near Port Adelaide had shown that mangroves usually recovered within six months. Both the Fisheries and the Environment departments are establishing monitoring programs to ascertain the rate of dissipation of the remaining oil and any impact on mangroves, intertidal areas and seagrasses.
Vic Neverauskas said that the Fisheries team would assess the condition of mangroves, prawn and fish larvae. Scientists have been sampling seabed sediments. The Fisheries research would be part of a larger monitoring program being set up by the Marine Environment Protection Committee. Dr. Karen Edyvane and Research Officer Deborah Nias from the Department of Fisheries both went to Port Pirie in October. I asked Karen about her impressions during her October visit to the area. She told me that the mangrove trees looked good despite being covered in oil. None of the trees were dying, but it would take some two months before any effects could be seen.
She also told me that they had taken water samples in the area but the Department could not afford to have them tested. Karen and Deborah were both going to be guest speakers at our November general meeting but had to cancel the arrangement when they were scheduled to return to Port Pirie in November. They were going to be collecting fish, prawn larvae and other samples of marine life from the area. Karen arranged for Vic Neverauskas to speak at our November meeting in her place. Vic is the Scientific and Development Coordinator for the Department of Fisheries. His topic was the impact and monitoring of the Spencer Gulf oil spill. Karen and Deborah will now be our guest speakers early in 1993.
Three weeks after the oil spill, commercial fishermen from Port Pirie were concerned about its effect. They closed their fishing grounds down until they were assured that fish had not been contaminated either by oil or by chemical dispersant. They said that whiting were returning to the fishing grounds, but surface feeders like garfish were not. Almost two months after the spill, the fishermen remained concerned about the condition of their fishing grounds. They presented a 1 kilogram snapper, about 45 cm long to the Department of Fisheries for analysis. It was severely undernourished and oil-affected. Karen Edyvane told me that unfortunately it had been gutted and could not be analysed.
Prawn fishermen were also still concerned about prawn nursery grounds being affected. In mid-November they were still concerned about the effects of the oil spill on the prawns in Spencer Gulf. In early November, The Advertiser reported that Port Pirie fishermen had found dozens of crabs with disfigured shells. Fifteen Blue Swimmer crabs with gaping holes in their backs were sent to the Fisheries Department for analysis by its scientists. An adult female crab had eggs which were black and shriveled. All of the crabs had holes burned through their shells. They had been caught 3.6 kilometres east of Port Bonython in Spencer Gulf.
On 18th November, Vic Neverauskas was the guest speaker at our general meeting. A report about his talk follows later on in this Journal.
On 20th November, The Advertiser had an article about Karen Edyvane and Deborah Nias’ return to Port Pirie. The headline read:- “A miracle in the mangroves – Life returns to area devastated by oil spill.” The article said that life in the Spencer Gulf was starting to get back to normal three months after the oil spill. The only explanation that the article gave for these headlines though was that the mangrove trees were still surviving and that fishermen had started returning to the area.
The fishermen said that there was “a dramatic reduction in the number of fish in the area” and that it was “the first time in 40 years that crabs have not been readily available.” The fishermen were still waiting to hear the results of tests on the crabs found with holes burnt in their shells. The article went on to describe the work being carried out by Karen, Deborah and Dr Janice Warren. It said that the spill was the first ttime an oil slick had hit the coastline of Australia and that this is the reason that scientists are monitoring the ecosystem and marine life. They are endeavouring to measure how bad the spill was and to determine what “damage control” can be implemented in case of other spills.
The Fisheries team is visiting the area monthly. Karen Edyvane felt that the data they were collecting was breaking new ground.
“What we find in port Pirie is going to be really important in the long run, both here and overseas, because we are using many of these techniques for the first time. Because there has never been anything like this, we are basically producing a guideline for management if it ever happens again in this country,” Karen said.
They have been tagging mangroves, testing for stress levels and checking fish numbers. They have also been testing for pollution in fish by taking their livers and freezing them in liquid nitrogen. Researchers from Adelaide University will then study the livers for a particular enzyme which is considered to be an early warning sign of pollution in the body. This method was developed in the U.K. and it is the first time that it has been used in Australia. The article concluded by saying that Karen felt that it was still too early to tell how bad the damage was and only sensible marine management would prevent another spill.
On November 28th, The Advertiser featured an article about the lack of contributions from the organisations involved in the spill towards the costs of monitoring its impact. The studies are expected to last 3 or 4 years. The Government is looking at ways of being able to force companies involved in pollution to pay for such studies. There has been increasing frustration at the lack of contributions from companies and the lack of provisions for their accountability. The ship’s insurers are obliged to pay for long-term environmental monitoring.
Steve Reynolds is the current President of MLSSA and is a long-standing member of the Society. Steve is a keen diver, underwater explorer, photographer and is chief author of the Society’s extensive back catalogue of newsletters and journals.