Crystal Bowl GBR is aiming to examine 3 core measures across a wide range of species in the region:
- Fishing experience (how many fish per trip)
- Quality of the fish (size of fish)
- Community attitudes
- Boyne Tannum Hookup catch rate of 1.04 fish/fisher/day (reflective of limited targeting of Mangrove Jack in the BTH)
- Gladstone sports fishing club reports catch rate of 0.29 fish/fisher/day
- Qld Fisheries Boat Ramp Surveys reports catch rate of 0.12 fish/fisher/day
- Gladstone ranked 7th in the state for Mangrove Jack Rates
- Not a target species for commercial catch
Quality of the Fish
- Most of the Mangrove Jack in Estuaries are Juvenile
- 2017 Avg length in the Boyne Tannum Hookup was 424/6mm
- 2017 Avg length for Gladstone Sportfishing Club was 358.3mm
- 2017 Avg length in Qld Fisheries Boat Ramp Surveys was 430mm
- Gladstone Ranked 10th in the State on length but given the low sample size this is not a reliable measure.
- Gladstone Sportfishing caught 267 Mangrove Jack during the year as such their average length is more likely to be reliable
- Qld Fisheries Boat Ramp Surveys report that 82% of Mangrove Jack are released despite the high likelihood those fish will be legal.
- 100% of fish caught by Gladstone Sportfishing Club were tagged and released.
- 83% of fishers surveyed were locals.
Limited Take For Consumption Advised
As this species is primarily a Sports Species, and given the high release rate amongst sport fishers, recommend maximum 1 fish taken in any one session.
- Catch rates will likely be down slightly for T20 fishers - 0.2 fish/fisher/day - 0.4 fish/fisher/day
- Mangrove Jack average size will be similar to 2017.
Boyne Tannum Hookup
Boyne Tannum Hookup Annual Event
The Boyne Tannum Hookup is the biggest single fishing event in Queensland. Gladstone Sportfishing Club has run a live weigh-in as part of the event since the beginning and over that time 191 Mangrove Jack have been weighed in. All fish weighed in are of legal size or above, though trophy bream are few and far between.Boyne Tannum Hookup 2016 Report
- Catch rate at the hookup was 1.04 fish/fisher/day
- Average length of fish at the Live weigh in was 424mm
- Average weight of fish at the live weigh in was 0.43kg
Detailed Examination of Size
Over that time the condition of the Mangrove Jack has been consistent, with the fish tending to be average or above average condition. A summary of the event and condition of Mangrove Jack below.
Mangrove Jack as a Sports Species
Mangrove Jack are most commonly targetted by Sportfishers in Gladstone. They are a difficult species to target and represent a signficant challenge. Mangrove Jack are often found in similar habitat to Barramundi, though in Gladstone 2017, Barramundi were reported 3.5 times more often.
- Gladstone Sportfishing Club catch rate of 0.3 fish/fisher/day
- 2017 Gladstone Sportfishing Club average fish size was 358.2mm
A detailed snapshot of tagging by the Gladstone Sportfishing Club and Suntaggers is available:Gladstone Suntag Results
Qld FIsheries Boat Ramp Surveys - General Fishers
Monitoring of Recreational Catch by Qld Fisheries
Queensland Fisheries monitors boat ramps up and down the coast as a part of the Sustainable Fisheries Strategy. General Fishers in Gladstone rarely report catching Mangrove Jack, with a 82% of fish being released in 2017. Monitoring is ongoing in 2018.
- Only 11 Mangrove Jack were reported in Boat Ramp Surveys
- 2017 Catch Rate of 0.12 fish/fisher/day
- 2017 Average size fish 430mm
Monitoring of Mangrove Jack Recruitment
While the lifecycle of the Mangrove Jack is understood, limited research has been conducted on environmental drivers for recruitment success. Mangrove Jack recruits are detected during Bream Recruitment Surveys indicating they use similar habitat during their growth phase.
Monitoring of Mangrove Jack
Data for this assessment has been sourced from:
- Bureau of Meterology
- Boyne Tannum Hookup
- Gladstone Sportfishing Club
- Queensland Fisheries
Here are links to all the monitoring pages for Mangrove Jack:Boyne Tannum Hookup 2016 Report
- Boyne Tannum Hookup All Years Length - Weight
- Boyne Tannum Hookup All Years Condition Data
- Gladstone Sportfishing Club
- Gladstone Queensland Fisheries Boat Ramp Surveys
- Qld Fisheries Boat Ramp Surveys