How does my bottom look?

How does my bottom look?

Scientists are changing the way we think about the effects of trawling.  A new report by the CSIRO scientists has found that 100 years of trawling in the south-east has had only minimal effects on the sea bottom (seafloor).

CSIRO integrated several data sets to produce three maps of the south-east:

  1. A map of where animals without backbones (invertebrates) that live on the seafloor like corals, sponges and sea-squirts.
  2. A map of 15 seafloor habitat types
  3. A map of where trawl fishing occurs – Skippers complete logbooks with the position of each fishing operation

Existing research about the impact that trawl fishing gear has on seafloor invertebrates, and their recovery afterwards, was also considered.

The results of the study were surprisingly positive and showed that trawling does not have the affects that many would think.

The reasons our bottom still looks good are:

  • Only 6% of the seafloor is currently trawled annually.
  • Some areas where invertebrates live are not ever trawled because they are closed by fishery closures and marine parks.  44% of the fishery is closed to trawling.  Other area are not fished because they are unproductive or too rough to trawl.
  • When trawling was at its most intensive invertebrate abundance was still high (80-93%).
  • Closures, marine parks and licence buy-backs contributed to the recovery of invertebrates by very little (1-3%)
  • Invertebrate abundance is currently very high (82-94% of their original abundance).
  • Most fishery closures and marine parks had little detectable influence on the abundance of invertebrates.

100 years of the south-east providing healthy seafood  in relation to the loss of 6-18% of the region’s invertebrate abundance contrasts favourably to the loss of 40% of Australia’s forests[1] and 50% of its wetlands[2].  The trawl fishing of 6% annually of the south-east seafloor compares very favourably with the farming of 26%[3] of the Australian landmass.

The South East Trawl Fishing Industry Association’s (SETFIA) Chairman, Mr Tom Bibby, explained,

The fishing industry has always known that there are very few trawl vessels operating in a very limited area and that our footprint would be minimal.  This research proves that.”

“Green groups must try to convince the Australian community that trawl fishing is harmful in order to drive continued donations.”

“Industry is not lobbying for the removal of marine parks but the industry operates under the constant threat of more closures; this work shows that they are not needed.  Invertebrate communities never reached low levels and are rebuilding strongly”.

For more information contact:
Mr Simon Boag, SETFIA 0428-141591

A summary report of this research can be found at:



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