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New Report Card for Australia’s Marine Environment

By Various experts

A massive effort involving 80 Australian scientists from 34 institutions has produced a report card for Australia’s marine environment.

The Marine Climate Change in Australia Report Card 2012 looks at a range of indicators such as ocean temperatures, acidity and the strength of critical ocean currents and relates these to changes in marine biodiversity such as the southward movement of fish and other marine organisms. Several independent experts as well as several who contributed to the report respond.

Contributing author comments:
Dr Elvira Poloczanska is a senior researcher with the CSIRO Climate Adaptation Flagship and is an overall lead author of the report.

“This 2012 Report Card demonstrates that climate change is having significant impacts on Australia’s oceans and marine ecosystems. Many new changes have been documented since the 2009 Report Card. There is now striking evidence of extensive southward movements of tropical fish and plankton species in southeast Australia, declines in abundance of temperate species, and the first signs of ocean acidification impacts on marine species with shells.

The report card highlights that the Australian science community is widely engaged in research, monitoring and observing programs to increase our understanding of climate change impacts and inform management. The comprehensive information shows that adaptation planning is already underway, from seasonal forecasts for fisheries and aquaculture, to climate-proofing of breeding sites for turtles and seabirds. The up-to-date information presented will assist ocean managers and policy makers to improve and justify actions to help our marine ecosystems adapt to the threat of climate change.

Over 80 of Australia’s leading marine scientists from 34 universities and research organisations contributed to the 2012 Report Card. Each section contains information on what is already happening, what may happen in the future, and describes the actions underway to prepare and adapt to changes.”

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Fish and fisheries:
Dr Alistair Hobday is a Stream Leader with CSIRO’s Climate Adaptation Flagship and is a lead author of Pelagic fishes section of the report card.

“Off the east coast of Australia the southward flowing East Australia Current is warming and pushing further south. This region is a marine global warming hotspot, one of about 20 such ocean regions where the rate of warming is much faster than average.

Just as Nemo was carried south to Sydney, large pelagic (offshore) fish like tuna and billfish are on the move south with these warming waters. This is good news for recreational fishers in southern states, who are seeing species such as Striped Marlin, Yellowfin tuna, skipjack tuna, and dolphin fish moving into their region. Closer to shore, species like Yellowtail kingfish and cobia are also being captured further south than in the past.

Smaller coastal species such as sardines, anchovies are also responding to climate change. Their abundance may increase as stronger upwelling of cool nutrient rich water in a range of coastal locations is expected to enhance their foodchain.

On the west coast of Australia in 2011 a marine heat wave also led to many pelagic species, such as manta rays and whale sharks and coastal fishes occurring further to the south. Fishers from around Australia are playing a valuable role in reporting these changes. The overall impact on coastal systems of these moving species is as yet unknown, but both positive and negative impacts are expected for commercial fishers”.

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Professor David Booth is Director of Centre for Environmental Sustainability at the University of Technology, Sydney and is lead author of the "Temperate Fishes" section of the report card.

“Clear evidence is now emerging that tropical fish species are spreading southwards along our temperate coasts in response to climate-change sea temperature increases and this is expected to have implications for fishes and fisheries. Some State-based fish stock assessments done by Fisheries departments are still not considering climate-change in their projections, which is of concern."

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Ocean acidification:
Dr Will Howard is a visiting Fellow at the Australian National University Research School of Earth Sciences and was a contributor to the Report Card and Lead Author of the section on “Ocean Acidification”.

“The 2012 report card provides an update of what we understand about the reach, progress, and impacts of ocean acidification, perhaps the most pervasive and persistent effect of carbon dioxide emissions on the ocean. Ocean acidification impacts have only begun to be detected in nature in the last few years. The ocean acidification section provides a comprehensive view from a large and multidisciplinary community of scientists in Australia and New Zealand. A number of marine ecosystems of national and global importance, including the Great Barrier Reef and the Southern Ocean, are already feeling the effects of acidification.

This year’s update highlights the complexity of biological and ecosystem responses to ocean acidification, and the vital importance of understanding what ocean acidification means for the structure and function of ecosystems and the services they provide, and also points to the need to understand the economic and social impacts. As importantly, it provides an assessment of gaps in our understanding. Continued monitoring of emerging climate impacts and evolving science, will be vital in coming years for policymakers, the public, and the scientific community. In particular there is a critical need for a coordinated approach to ocean acidification research from a wide range of natural science and social science disciplines.”

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Plankton and climate change:
Associate Professor Anthony Richardson is an ARC Future Fellow in CSIRO Marine and Atmospheric Research and is lead author of the section on plankton in the report card.

“Plankton are microscopic plants and animals that float in the water and provide the oxygen in every 2nd breath we take, and directly and indirectly feed most fish, turtles, and seabirds. In the first Report Card in 2009, there were no published impacts of climate change on Australian plankton. From new studies in the past three years, we now have the first evidence of changes at the base of the marine foodweb.

There are dramatic changes caused by the rapid warming in southeast Australia and the strengthening of the warm East Australia Current. This has led to the expansion of subtropical plankton into Tasmanian waters and into the Southern Ocean. In particular, the red tide species Noctiluca scintillans, which can be problematic for aquaculture farms, has expanded in recent years from off the NSW coast to around Tasmania, and in 2010 into the Southern Ocean for the first time.

Over the past 40 years off Tasmania, we have also seen abundances of key cold-water zooplankton species decline and warm-water species increase, which are smaller and poorer food for fish. In tropical waters, over the past 40 years we are seeing thinning and increased porosity of shells of ‘sea butterflies’ (winged snails), important food for many fish, as ocean pH declines because of more CO2. These changes are likely to be the first of many in the future that are likely to have profound effects on many iconic fish, turtle and mammal species.”

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Independent expert comment:
Professor Ove Hoegh-Guldberg is an expert in coral reefs and marine resources and is Director of the Global Change Institute at the University of Queensland. He is also involved in the fifth assessment report for the Inter-Governmental Panel on Climate Change (regional oceans)

“It is really important that we take stock of the large number of changes taking place in Australia’s marine environment, especially given that our ocean resources are twice that of our land resources. What really strikes you about this report is the extent and diversity of changes taking place – everything from potential changes to the sex ratio of sea turtles and declining nesting success in sea birds, to mass coral bleaching and changes to important fisheries stocks. The report card brings to national attention the extent of these changes and highlights the challenges we face in the context of our national goal of sustainably managing our natural resources.

Risks to coral reefs remain extremely high and the current global trajectory means that coral reefs like those in Australia and elsewhere are likely to be removed by the middle of this century. This should have everyone’s attention.”

Source: AusSMC