SOUTH EAST QUEENSLAND MULLOWAY 2007-2016

An assessment was made of available data for Mulloway in South East Quensland over the past 10 years from 2007-2016. This will be available from the Crystal Bowl website www.crystal-bowl.com.au.

Summary

  • There have been over 200 Mulloway tagged in each of the last 3 years
  • The highest catch rate was 2.2 fish/fisher/day in 2014
  • The average length of Mulloway has steadily increased over the past 10 years and was 690mm in 2016
  • Recruitment of Mulloway appears to correlate with flooding from Jan-Mar with strong recruitment following flooding in 2011 and high flows in 2013
  • Mulloway average growth was 164mm
  • 74% of recaptured Mulloway were in the same river system that they were tagged in while 24% were recaptured elsewhere
  • Of the fish recaptured elsewhere about 50% moved north and 50% moved south
  • The furthest distance north was to the Maroochy River (120km) and the furthest distance south was to Iluka (28-0km)
  • The annual commercial catch was less than 3 tonnes in all years except 2014 when it was 11.4t

Environmental conditions and Outlook

  • Major flooding in early 2011 and moderate to high flows in 2012 and 2013 are likely to have aided recruitment
  • BOM POAMA34 forecasts for 2017 are for neutral conditions over the recruitment period (Dec-Mar) tending towards El Niño again later in the year
  • The BOM rainfall outlook is for a 35-40% chance of exceeding median rainfall from Jan-Mar in south-east Queensland suggesting moderate recruitment however this will depend on actual river flows

Infofish Australia
July 2017

MEASURE

ACTUAL

GRAPH

SOUTH EAST QUEENSLAND MULLOWAY
Number of fish tagged

Highest  Lowest
2016    2007
244    5

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Catch rate
Fish/fisher/day

Highest  Lowest
ALL
2014    2010
2.2    1.3

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Average length mm
and size range

Highest   Lowest
2015   2008
690mm   337mm

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Percentage sizes
undersize <750mm
legal-trophy 750-999mm
trophy 1000mm+

Highest   Lowest
LEGAL-TROPHY
2014   2013
36.1%   0%

TROPHY
2015   2013
3.7%   0%
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Brisbane River flows and Mulloway lengths (mm) for SEQ

FLOODS
2011
2013
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Tracking Mulloway from 2013 recruitment

Arrows indicate fish recruited after the 2013 flood
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Mulloway growth

AVERAGE GROWTH FIRST YEAR
164mm
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Mulloway movement

74% recaptured in same river system
26% recaptured outside river system
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Mulloway moving outside of river system

Fish move roughly equally north and south
Max movement north
Maroochy River (120km)
Max movement south
Iluka (280km)
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Commercial catch
Grid W37
Mulloway (Jewfish)
Catch tonnes
Catch rate kg/day
2007-2016

Highest   Lowest
CATCH
2014   2008/2010
11.4t   N/A

Highest   Lowest
CATCH RATE
2014   2008/2010
44.6kg   N/A

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NINO34 forecast for 2017 Neutral conditions for recruitment period Dec-Mar and towards El Niño later in the year
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Rainfall outlook
Jan-Mar 2017
BOM forecast35-40% chance of exceeding median rainfall
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DATA SOURCES

Data used in the Brisbane River King Threadfin Crystal Bowl are:

BASIS FOR THE ANALYSIS

The analyses of the data were based on the following:

  • Catch and effort data for taggers were the total catch and number of days fished in the Brisbane River estuary for all species in Suntag map GC22, GC23, MB01, MB02, MB03, MB05, CAB and PPB
  • Catch rates for taggers was calculated as fish/fisher/day
  • Catch rates for taggers were only calculated for years where 20 or more fish were recorded
  • Catch rates for commercial fishers was calculated as kg/day
  • Growth was based on recaptures of tagged fish that were at liberty for 3 months or more and had positive growth
  • Movement was based on the Suntag grid locations for tag and recapture and was the shortest distance by water between the locations