Barramundi Monitoring Project Milestone 5 Report page 20 10. BARRAMUNDI SIZES The lengths of Barramundi were recorded for tagged fish and fish were also measured by fishers and provided on their trip forms. There have been a total of 2,074 Barramundi measured. Figure 18 shows the size range of measured Barramundi. Of the 659 untagged Barramundi measured 516 (78.3%) were over the legal size of 550mm. Of the 1,415 tagged Barramundi measured 736 (52.0%) were over legal size. Figure 18: Size range of Barramundi measured and tagged Figure 19: Tagged Barramundi being measured prior to release BARRAMUNDI LENGTHS 0 50 100 150 200 250 300 350 200:249 250: 299 300: 349 350: 399 400: 449 450: 499 500: 549 550: 599 600: 649 650: 699 700: 749 750: 799 800: 849 850: 899 900: 949 950: 999 1000:1049 1050:1099 1100:1149 1150:1199 SIZE RANGE (MM) NUMBER OF FISH MEASURED NOT TAGGED TAGGED Legal size
The lengths of Barramundi were recorded for tagged fish and fish were also measured byfishers and provided on their trip forms.
There have been a total of 2,074 Barramundi measured. Figure 18 shows the size range ofmeasured Barramundi. Of the 659 untagged Barramundi measured 516 (78.3%) were over thelegal size of 550mm. Of the 1,415 tagged Barramundi measured 736 (52.0%) were over legalsize.
Figure 18: Size range of Barramundi measured and tagged
Figure 19: Tagged Barramundi being measured prior to release
Juvenile Barramundi are caught in estuaries in throw nets while chasing bait and on rod andline using small baits or lures. An electrofishing survey was undertaken by NT Fisheries toassess recruitment in the freshwater reaches of the McArthur River (see section 8). Lengths ofjuvenile fish were recorded to assess recruitment however it was not possible to get accuratelengths of many of the fish caught in throw nets.
Recruitment refers to juvenile fish that "recruit" to the fishery when they reach legal size. Goodrecruitment occurs when there is good spawning, generally from October - January, followedby above wet season flows that juvenile Barramundi use to access freshwater, which is apreferred habitat for these smaller fish4.
Barramundi are fast growing with fish generally reaching 200-350mm in their first year and400-550mm in their second year. During the third year most fish will have reached legal size5.
River flow data were obtained for the McArthur River at monitoring station G9070121 atBorroloola6 for 2005 to May 2010. Figure 20 shows river flows compared to the length of fishover time.
Figure 21 shows the juvenile Barramundi recorded to date with the lengths of fish over time.The lines are indicative of recruits from the past 3 years growing over time. This indicatesrecruitment occurred in each of the years, however there are insufficient data to draw anyconclusions on the level of recruitment each year and how that might be influenced by riverflows.
Figure 20: River flows in the McArthur River and lengths of Barramundi over time
4 "Does the quantity and timing of fresh water flowing into a dry tropical estuary affect year-class strength ofBarramundi" Jonathan Staunton-Smith et al, Marine and Freshwater Research 2004:55, 787-797 and "Effects of LocalClimate on Recreational Fisheries in Central Queensland Australia: A guide to the impacts of climate change" WSawynok and J Platten (in press)5 "Age and Growth Studies of Barramundi, Lates calcarifer (Bloch), in Northern Australia" TLO Davis and GP Kirkwood,Marine and Freshwater Research 1984:35, 673-6896 River flow data obtained from the Department of Natural Resources, Environment, the Arts and Sport
Figure 21: River flows in the McArthur River and lengths of Barramundi over time with recruits for the last 3 years(arrows indicate growth of year class recruits over time)
Figure 22: Locating small juvenile Barramundi is an important part of understanding recruitment
A small number of juvenile Barramundi of less that 200mm (figure 22) have been reportedcaught in throw nets in the estuaries however no accurate measurements of the lengths ofthese fish were available. It is important in understanding recruitment that habitats used bythese smaller fish are identified. As yet there are insufficient data.
NT Fisheries undertook an electrofishing survey from 9-11 November 2010. The survey wascarried out using their standard protocols and all Barramundi captured were tagged andreleased. The survey was carried out in the freshwater section of the McArthur River nearBorroloola, both upstream and downstream from the Carpentaria Highway bridge (figure 23).
A total of 79 Barramundi were tagged during the survey. There were also 2 recaptures of fishthat were tagged during the survey and 2 were recaptures of fish tagged as part of theMcArthur River Mine monitoring program.
Figure 24 shows the size range of fish tagged during the electrofishing survey with most fishbeing 2010 and 2009 recruits and smaller numbers of larger fish. Recruits from the past 2years comprise 77.2% of the fish electrofished.
Figure 23: Site of NT electrofishing survey on the McArthur River at Borroloola
Figure 24: Size range of fish tagged during the electrofishing survey
Infofish Australia has prepared folders that can be handed out to visiting fishers that are willingto provide details of their fishing trips. Tagging kits have also been made up for those willing toassist with the tagging. These have provided to:
King Ash Bay OfficeKing Ash Bay Service StationKing Ash Bay LodgeKing Ash Bay Mini Mart
A number of posters have also been placed at strategic locations at King Ash Bay to promoteawareness of the project.
There have now been 6 presentations and 5 workshops held by Infofish Australia. Apresentation of progress on the project and workshop was provided at King Ash Bay by WendiParsons during the July trip. A presentation on progress was provided to the King Ash BayFishing Club committee by Bill Sawynok during the November visit.
A workshop was not held during that trip due to the low number of visitors. Also many of thefishing groups had already been provided with tagging and information kits. The workshop wasreplaced with briefings and training of around 15 individual groups. This was considered moreeffective as it provided the opportunity to deal with groups on a one-on-one basis and provedvery effective in getting more fishing trip details and an improvement in the quality of the dataprovided.
A presentation on the project was made to NT Fisheries during a visit to Darwin by BillSawynok in July 2010. A briefing on project progress was also made to Chris Makepeace ofAmateur Fisherman's Association of Northern Territory (AFANT) during that visit and a furtherupdate to AFANT was provided at King Ash Bay during the November trip.
A newsletter summarising the results of the firstyear of the project was produced in September2010 (figure 25) and 500 copies were printed anddistributed at King Ash Bay. The newsletter wasalso provided to the McArthur River MineEnvironment Office. A brief summary of theresults of the October - November trip wasprovided to NT Fisheries.
Figure 25: Barramundi News 1 newsletter on the King Ash Bayproject
A significant difficulty with this project has been finding someone to undertake boat rampsurveys and managing that remotely. A number of people have been recruited however havenot been able to successfully undertake surveys.
Infofish Australia has decided to use its own staff to undertake the boat ramp surveys for theduration of the project unless a suitable person can be found. That will require that staff visitthe site more frequently than originally proposed however this will be done within the currentproject budget. Staff will be on site at least once in each season (except summer) to ensurethat we obtain sufficient fishing trip details to obtain an estimate of catch rates for that season.
Infofish Australia will be on site again in April and June 2011. This will be to undertake boatramp surveys for the autumn and winter periods, collect details of fishing trips and continuetagging of Barramundi.
Data that continues to be collected or proposed to be collected in the next milestone period:
Fishing tripsTag and recapture details of tagged fishTrailer counts and moored boat countsWeather data for Borroloola and Centre IslandRiver flow data for the McArthur River will be updatedHouseboat usageTagging details for Barramundi tagged under McArthur River Mine monitoring projectVisitations to King Ash Bay
The milestones for project are as outlined in table 6. Milestone reports have been forwarded formilestones 2-4. While some preliminary work was undertaken on the project from June -September 2009, the project did not commence until October 2009 when funding was receivedin September. Therefore the project has effectively been underway for just over a year.
Milestones dates have been revised slightly to allow milestone reporting to coincide withseasons as these have been used when assessing fishing effort and catch.
As the project was designed as a 2 year project it is proposed to extend the completion of theproject to November 2011. This will allow for just over 2 full year of data collection and providedata for 3 springs which is the most important season. The final report will be submitted by 15December 2010. No additional funding will be required to extend the project as proposed.
# Milestones Amount Required outputs for payment PaymentsReleaseDate
1 Workshop 1 -22 – 26, June2009
$50,000 Executed Agreement 16 June2009
2 Workshop 2 -November2009
$36, 460 Successful completion ofworkshop 1Report for the period: June2009 – October 2009detailing:- Expenditure of the
funds in milestone 1(providing receipts).
- Data collection andanalysis (includes thedata for NT Fisheries)on boat ramp surveys,trailer counts, taggingbarramundi, juvenilebarramundi counts,update on the settingup of the educationcentre.
December2009
3 Present anupdate reporton the projectat the MRM –CBT Boardmeeting inFebruary2010
$46, 365 Successful completion ofworkshop 2Report for the period: June2009 - January 2010detailing:- An overview of the
project includingfindings and outcomes
- Expenditure of thefunds in milestone 2(providing receipts).
- Data collection andanalysis (includes thedata for fisheries) onboat ramp surveys,
trailer counts, taggingbarramundi, juvenilebarramundi counts,update on the settingup of the educationcentre.
Payment for the second and finalyear of activities will be:
(a) subject to the satisfactoryoutcomes of the reviewundertaken in accordance withthese special conditions for thesecond year of the project;;
(b) paid in accordance with thereporting periods set out in thework plan provided by InfofishServices to the MRMCBT ProjectOfficer.
4 Workshop 3 -April 2010
$46, 365 Report for the period:November 2009 – March 2010detailing:- Expenditure of the
funds in milestone 2(providing receipts).
- Data collection(includes the data forfisheries) on boat rampsurveys, trailer counts,tagging barramundi,juvenile barramundicounts, update on thesetting up of theeducation centre.
May 2010
5 Workshop 4 -November2010
$46, 365 Successful completion ofworkshop 3Report for the period: April2010 – October (November)2010 detailing:- Expenditure of the
funds in milestone 3(providing receipts).
- Data collection(includes the data forfisheries) on boat rampsurveys, trailer counts,tagging barramundi,juvenile barramundicounts, update on thesetting up of theeducation centre.
Final Report $24, 090 – Fundsbeing for:data collection,management andanalysisprojectmanagementequipment
Successful completion ofworkshop 3Final Report - An overview ofthe Project detailing thefinding and outcomes of theproject. Included in thereport will be information onrecruitment, growth andmovement of Barramundi inthe McArthur River.Report for the period:November 2010 – April 2011detailing:- Expenditure of the
funds in milestone 4(providing receipts).
- Data collection andanalysis (includes thedata for fisheries) onboat ramp surveys,trailer counts, taggingbarramundi, juvenilebarramundi counts,update on the settingup of the educationcentre.
- An overview of theexisting barramundifishery in the McArthurRiver. Included in thereport will beinformation onrecruitment, growthand movement ofBarramundi in theMcArthur River.
- An overview of theexisting barramundifishery in the McArthurRiver. Included in thereport will beinformation onrecruitment, growthand movement ofBarramundi in theMcArthur River.
Final Report $12, 090 – Fundsbeing for:data collection,management andanalysisprojectmanagementequipment
Successful completion ofworkshop 8Final Report - An overview ofthe Project detailing thefinding and outcomes of theproject. Included in thereport will be information onrecruitment, growth andmovement of Barramundi inthe McArthur River.Report for the period: July –November 2011 detailing:- Expenditure of the
funds in milestone 4(providing receipts).
- Data collection andanalysis (includes thedata for fisheries) onboat ramp surveys,trailer counts, taggingbarramundi, juvenilebarramundi counts,update on the settingup of the educationcentre.
- An overview of theexisting barramundifishery in the McArthurRiver. Included in thereport will beinformation onrecruitment, growthand movement ofBarramundi in theMcArthur River.
