WA marine heatwave – 3°C above average surface temperatures

An unprecedented marine ‘heatwave’ being experienced along the Western Australian coastline will come under the spotlight at a meeting of scientists this month, hosted by the Department of Fisheries in conjunction with CSIRO.

Marine experts from around the State will be joining forces to review both the physical and biological aspects of the ‘heatwave’, which appears to have some major implications for fish and invertebrate species along the continental shelf. The Department of Fisheries’ Acting Research Director, Dr Dan Gaughan said above average water temperatures had been recorded off the WA coastline since the final quarter of 2010, and an extensive patch of very warm water had moved southwards over a period of several months.

‘In February 2011, surface temperatures were more than 3°C above average for this time of year over a large area extending from Ningaloo to the Abrolhos and to over 200km offshore, while an area extending from Exmouth to the Capes and 500km offshore was more than 2°C warmer,’ said Dr Gaughan.

The southward-flowing Leeuwin Current (warmest water shown in red/orange, with red arrows) and the cool Capes Current (shown in blue, with blue arrows) represent the summer situation.

‘In some cases these are the warmest sea temperatures ever recorded for these regions and they appear to have been influenced by a stronger than usual Leeuwin Current over summer, associated with the very strong La Nina event.’

Dr Gaughan there had been a number of fish kills along the mid-west coast and in the Abrolhos, Kalbarri and Leeman areas around Geraldton . Rock lobster and abalone deaths had also been reported in areas of warmer water associated with calm conditions.

More here from the WA Dept Fisheries, and on the Capes Current here