GLADSTONE BARRAMUNDI FORECAST SEASON 2018

There are a total of 11 forecasts made for Barramundi in size of fish, catch rates, trends in stocks, recruitment and commercial catch. Catch details are based on the top 20% of fishers (T20) that catch 80% of the fish. Their catch rates do not reflect the catch rates of the total fishing population however their catches are more sensitive to changes in fish stocks and are comparable from year to year. Forecasts are available at www.crystal-bowl.com.au.

Season 2018 forecasts

T20 Fishers

  • There will be a reduction in the percentage of legal fish in the catch due to the size range of fish spilling from Awoonga being predominantly 500-700mm
  • Overall catch rate and catch rate for legal fish will remain steady but may increase if fish spill from Lake Awoonga again as is likely in early 2018
  • Natural recruitment is expected to be moderate with weak La Niña conditions forecast for the recruitment period from Jan-Apr
  • Stock level to remain steady with natural and fishing mortality likely to be offset by moderate natural recruitment and additional fish spilling from Awoonga

Commercial Fishers

  • Commercial Barramundi catch data for 2017 is only available for Feb-Jun and that indicates catch and catch rates are within the forecast range
  • Commercial catch and effort data will be updated as more data becomes available and will be updated when forecasts are reviewed in Jan prior to the 2018 season

Environmental conditions

  • Weak La Niña conditions are forecast for the recruitment period from Jan-Apr and neutral conditions for the remainder of the year
  • Rainfall and river flows in late Dec-early Feb will be critical to recruitment success although the rainfall outlook suggests a 45-55% chance of exceeding median rainfall
  • Actual conditions in Jan-Feb will determine recruitment and whether Awoonga will spill again (expected)

Infofish Australia
November 2017

MEASURE FORECAST

ACTUAL

GRAPH

GLADSTONE 2018

2018

Fish sizes
Undersize fish 200-579mm
Legal - trophy fish 580-999mm
Trophy fish >1m


5% (0-15%)
60% (50-70%)

35% (25-45%)

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T20 fishers
Actual catch rates
Fish/tagger/day

Overall
2.2 (2.0-2.4)
Legal fish
1.8 (1.6-2.0)

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T20 fishers
Actual catch rates
2009-2018
Fish/tagger/day
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T20 fishers
Catch rates percentage change 2018-2017
Overall
+5% (-15%-+25%)
Legal fish
+5% (-15%-+25%)
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Barramundi tags in Gladstone indicator of trends in stock
Model tagged fish
most likely and range
Tagged fish 2018 (Jan-Dec)
500 (400-600)

+20% (0-+40%)
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Recruitment
Recruits/fisher/day
Poor/Moderate
0.1 (0.05-0.15)
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Climate outlook BOM NINO34
Neutral to weak La Niña conditions Nov 2017-Jan 2018
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Rainfall Outlook
Dec 2017-Feb 2018
BOM forecast
45-55% chance of exceeding median rainfall
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DATA SOURCES

Data used in the Fitzroy Barramundi Crystal Bowl are: