From Practical Fishkeeping, about the USA:
Deepwater oil spill area has more ill fish
A government-funded survey of the entire Gulf of Mexico last summer found more ill fish in the area of the 2010 Deepwater oil spill than anywhere else.
The survey took place last summer with funding from NOAA and cooperation from the state’s marine science laboratory in St. Petersburg and caught over 4000 fish and found many exhibited unusual skin lesions.
Steve Murawski, an oceanographer who previously served as the chief fisheries scientist of the National Oceanographic and Atmospheric Administration who lead the project said that whilst the highest frequency of disease in fish was the area where the oil spill was that people shouldn’t necessarily assume that this was the cause. He pointed out that the large number of fish with skin lesions could have also been caused by oil rigs, leaky pipelines and even natural oil vents in the sea floor.
“Even if the disease is from oil,” he said. “It’s another step to show it’s from the oil spill.”
However, other scientists studying fish believe that the two are connected. James Cowan, an oceanography professor at Louisiana State University is quoted saying: “We still are seeing sick fish offshore and the USF survey confirmed our findings of 2-5% of Red snapper being affected”.
He added that lab studies show that chronic exposure to oil and dispersants can cause a wide range of effects including impacts to the genome to compromised immune systems in fish, shrimps and crabs found in the oil spill location.
Other scientists have also found fish with lesions spreading with a professor from the University of South Alabama finding affected fish in the surf off the coast.
Whilst there is unfortunately no baseline survey to compare results with, the USF scientists plan a second survey of the gulf next month. They also plan to check whether the fish they have caught also suffer from immune system and fertility problems. The results will be reported by April 20, 2012 – the second anniversary of the Deepwater Horizon explosion.
Meanwhile, there have been other signs something unusual might be going on further afield in the northern part of the gulf. More than 600 dolphins have stranded over the past two years; which in some areas is 10 times more than normal. So far 10 have tested positive for the bacterial infection Brucella, which scientists believe may be a sign that the oil spill harmed the dolphins’ immune systems.