rocky barra bounty meets crystal bowl 2015infofishaustralia.com.au/wp-content/uploads/2016/... ·...

Rocky Barra Bounty meets Crystal Bowl 2015 Background The “Crystal Bowl” is being developed as a process for predicting fish stocks. It was initially used to predict Barramundi stocks in the Fitzroy River and the first predictions were made in 2011. In 2013 it was extended to Barramundi in Gladstone. In June 2014 the first report comparing predictions with observed was produced.1 The Rocky Barra Bounty is a tag and release fishing event that has been held on the Fitzroy River since 1999. In 2015 the Crystal Bowl process was extended to making predictions for the Bounty. The predictions for the Bounty were:

! The number of Barramundi to be caught ! The proportion of Barramundi to be expected in particular size ranges ! Expected changes in catch rates

This report provides a comparison of predicted compared with observed and a summary of Bounties from 1999-‐2015 to provide context to the current status. About the event

! It is held each year in the Fitzroy River in Sep or Oct (see map for boundaries) ! It started in 1999 following the inaugural event in 1998 cancelled due to flooding ! The event was over 2 days from 1999-‐2011 and extended to 2.5 days from 2012 ! From 1999-‐2009 there were categories for bait and lures and from 2010 became lure

only ! Due to flooding in 2010 the Bounty was cancelled and a smaller limited event was held

in the lagoons adjacent to the river ! There is a cap of 70 teams (boat with 2 fishers) to minimise the impact on the river ! It has a 5 star rating under NEATfish (National Environmental Assessment of

Tournament Fishing) ! It is a tag and release at the fishing site event with photos of fish taken on a ruler to

confirm catch ! Fishers are required to phone in details following the release of a fish ! A website www.rockybarrabounty.com was established in 2010 and in 2014 and 2015

there was near real time updating of scores during the event on the website ! A Facebook page www.facebook.com/RockyBarraBounty was established in 2012 and

there is a large following during the event ! Data collected during the event provides an annual snapshot of the status of key

species in the river ! Funds raised through the Bounty go towards improving recreational fishing with funds

provided for fish stocking

1 ‘Looking into the “Crystal Bowl” June 2014 Predictions compared with observed 2104 Barramundi season Fitzroy River and Gladstone’ available from www.crystal-‐bowl.com.au

Fishing boundaries for the Rocky Barra Bounty

Some observations

! The prediction for the number of Barramundi caught in the Bounty was 300-‐400 while 408 fish were tagged and recaptured

! The catch rate for legal Barramundi in 2015 was down 45.6% on 2014 which was within the predicted range of down 30-‐50%

! The catch rate for undersized fish was up 147.6% which was slightly higher than the predicted range of 120-‐140%

! The number of Barramundi in the 580-‐799mm size range was 22.5% which was within the predicted range of 5-‐25%

! The number of Barramundi in the 800+mm size range was 4.2% which was within the predicted size range of 0-‐10%

! The number of Barramundi in the 450-‐579mm size range was 39.0% which was lower than the predicted range of 45-‐65%

! There were 516 King Threadfin tagged and for the first time this exceeded the number of Barramundi tagged

! There were almost as many King Threadfin tagged in 2015 as in the previous 16 years from 1999-‐2014 when 540 were tagged

! Hours to catch a Barramundi in the event ranged from a high of 43.1 hours per fish in 2006 to a low of 1.6 hours per fish in 2011 with 9.1 hours per fish in 2015

! The most Barramundi tagged was 1,210 in 2011 and the least was 64 in 2006 with 408 in 2015

! The average size of Barramundi tagged was highest in 2013 at 601mm and lowest in 2008 at 371mm with 509mm in 2015

! The highest percentage of legal fish tagged was 55.5% in 2013 and the lowest percentage of legal fish tagged was 3.0% in 2010 with 26.7% in 2015

Predictions for 2015 Rocky Barra Bounty The following predictions were made in Jun 2015 for the event held in Sep 2015 with some comparisons with the 2014 Bounty:

! 300-‐400 Barramundi tagged (including recaptures) ! Percentage of legal fish 15-‐35% ! Catch rates for legal sized fish to be down 30-‐50% compared with 2014 ! Catch rates for undersized fish to be up 120-‐140% compared with 2014 ! Expect 5-‐25% of fish to be in the size range 580-‐799mm ! Expect 0-‐10% of fish to be in the size range 800-‐1200mm ! Expect 45-‐65% of fish to be in the size range 450-‐579mm

Comparison of predictions for 2015 Bounty with observed The following is a comparison of predictions with actual for the event:

Barramundi caught (including recaptures) in Bounty 2015 (bars show predicted range)

MEASURE PREDICTED ACTUAL DIFFERENCE ROCKY BARRA BOUNTY JUN 2015 SEP 2015 Number of Barramundi caught

300-‐400 408 +8 fish

Percentage of legal fish 15-‐35% 26.7% In range Catch rates for legal fish Down 30-‐50% Down 45.6% In range Catch rates for undersized fish Up 120-‐140% Up 147.6% 7.6% above

range Fish in size range 0-‐449mm 15-‐35% 34.3% In range Fish in size range 450-‐579mm 45-‐65% 39.0% 6% below

range Fish in size range 580-‐799mm 5-‐25% 22.5% In range Fish in size range 800-‐1200mm 0-‐10% 4.2% In range

Bounty catch rates in 2015 compared with predicted (bars show predicted range)

Bounty Barramundi in size ranges 2015 (bars show predicted range)

Bounty Participation

! From 1999-‐2003 the maximum number of teams (boat with 2 fishers) was 60 ! From 2004-‐2015 the maximum number of teams was 70 ! The 2010 Bounty was limited to 20 teams and fishing in the lagoons due to flooding in

the river

Teams and fishers in the Bounty 1999-‐2015

Species Tagged

! Barramundi is the target species however a number of other species are also tagged ! Over all Bounties there have been 4,891 Barramundi caught (including recaptures) and

6,949 fish including other species with 408 Barramundi and 1,025 fish in total in 2015 ! In 2015 for the first time more King Threadfin than Barramundi were caught with 516 ! A total of 540 King Threadfin were tagged in the 16 years from 1999-‐2014

Number of fish of each species tagged in the Bounty 1999-‐2015

Fishing Effort

! Effort was calculated as hours to catch a fish or a Barramundi ! In 2006 it required 43.1 hours to catch a Barramundi while in 2011 it was 1.6 hours ! In 2011 the event went for 1,200 minutes and there were 1,210 fish tagged (1

fish/minute) ! In 2014 it took 8.9 hours to catch a Barramundi and 9.1 hours in 2015

Hours to catch a Barramundi and for all fish 1999-‐2015

Barramundi tagged and recaptured

! The most Barramundi tagged (including recaptures) was 1,210 in 2011 and the least was 64 in 2006

! Barramundi tagged (including recaptures) in 2014 was 433 and in 2015 was 408 ! Recapture rates are based on the first recapture only ! Recapture rates from 1999-‐2001 were 17.9% to 23.6% ! Recapture rates from 2005-‐2007 were lower than actual due to under reporting by

commercial fishers ! Recapture rates from 2011-‐2014 were lower than actual due to under reporting by

commercial fishers ! In 2015 there was virtually no reporting of commercial recaptures due to the Net Free

Area proposal for the Fitzroy River ! Recapture rates from 2010-‐2015 will continue to increase over the next few years as

more recaptures are made

Barramundi tagged and recapture rate for fish tagged in each Bounty 1999-‐2015

Barramundi recaptured

! Of the 4,744 Barramundi tagged in all Bounties 512 (10.8%) have been recaptured once with 22 recaptured twice

! Recaptures kept by commercial fishers from fish tagged in each Bounty ranged from 80.0% for 2003 to 17.6% in 2012 however in that year there was under reporting of recaptures

! Recaptures kept by recreational fishers ranged from 34.7% for 2013 to 0% for 2006 ! Recaptures released by recreational fishers ranged from 82.4% for 2010 to 5.6% for

2002

Recaptured Barramundi kept and released for fish tagged from 1999-‐2015

Barramundi sizes 2015

! 26.7% of Barramundi tagged in 2015 were above legal size with 2 over 1m and the largest fish 1,050mm

! 76.4% of Barramundi tagged were from 300-‐600mm

Size range of Barramundi tagged in Bounty 2015

! The average size of Barramundi tagged was highest in 2013 at 601mm and 2014 at

603mm ! The average size of Barramundi was lowest in 2008 at 371mm and 2010 at 391mm ! The highest percentage of legal fish tagged was 55.5% in 2013 and in 2014 was 53.3% ! The lowest percentage of legal fish tagged was 3.0% in 2010 ! The average size in 2015 was 509mm and the percentage of legal fish was 26.7%

Average size of Barramundi tagged and percentage of legal fish in each Bounty 1999-‐2015

King Threadfin tagged

! King Threadfin tagged (and recaptured) ranged from a low of 3 in 2001 to a high of 516 in 2015

! The 516 King Threadfin tagged in 2015 exceeded the 408 Barramundi tagged and was almost as many as the 540 tagged in the 16 years from 1999-‐2014

! Hours to catch a Threadfin ranged from a high of 518.3 hours per fish to a low of 7.3 hours per fish in 2015

! No King Threadfin were caught in 2010 as the event was confined to lagoons

King Threadfin tagged in each Bounty from 1999-‐2015

Hours to catch a King Threadfin in each Bounty from 1999-‐2015

King Threadfin sizes 2015

! 75.2% of King Threadfin tagged in 2015 were over the legal size limit of 600mm ! 14 King Threadfin were tagged over 1m with the longest fish 1,310mm ! Most King Threadfin tagged were between 600-‐750mm

Size ranges King Threadfin tagged in 2015

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