GLADSTONE MUD CRAB 2018

Mud Crabs are a prized table species for recreational fishers, the general public creating great competition catches. Crabs are the most important commercial estuary species with Gladstone representing 10%+ of the state catch.

  • Overview

    Overview

    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

     

    Fishing Experience

    • Qld Fisheries Boat Ramp Surveys reports catch rate of 0.83 crabs per pot/fisher/day with a legal crab rate of 0.2 crabs per pot/fisher/day
    • Gladstone ranked 4th in the state for Mud Crab Catch Rates
    • Slight decline in Bream Commercial Catch Rates, dropping from 0.8kg/pot/day (2015) to 0.6kg/pot/day (2017 Incomplete)

     

    Quality of the Crabs

    • As Crabs are not measured at boat ramp surveys, no data exists on the quality of the Crabs in the Gladstone Fishery
    • Crab Health is monitored by the Gladstone Healthy Harbours partnership and was assessed as an A (0.86).  One area - Auckland Inlet was assessed as a C (0.63).

     

    Community Attitudes

    • Competition for Crabs is high within all sections of the Gladstone Community.
    • Crabs are the most important Commercial species in Gladstone
    • Size-Sex ratio is monitored by Gladstone Healthy Harbours Partnership and was assessed as a D (0.28) indicating high fishing pressure
    • Qld Fisheries Boat Ramp Surveys report that 78% of Crabs are released but this is likely to be due to capture of juvenile or female crabs.
    • 97% of fishers surveyed were local.

     

  • Assessment

    Limited Take For Consumption Advised

    Mud Crabs are highly prized by both local fishers and Commercial Crab fishers.  On available evidence, stocks will slowly decline until next significant recruitment occurs.  Conditions in 2017 may have been favorable indicating 2019 might be a better opportunity to harvest crabs.

    NOTE: Limited take means intermittent fishing for crabs is advised.

  • Forecast

    Forecast

    • Catch rates will likely be down slightly with catches around 1 legal crab every 5 pots.
    • Poor recruitment in recent years has limited Mud Crab numbers in the region. Until there is a larger recruitment event, conditions will remain difficult for fishing
    • Recruitment will be assessed mid year

     

  • Commercial Fishing

    Commercial Fishing Catch

    Queensland Fisheries monitors commercial catches up and down the coast. Commercial fishers are required to maintain logbooks of catch and report quarterly. The commercial catch of Mud Crabs in Gladstone (S30,S31) represents 10.5% share of the total statewide catch. Monitoring is ongoing in 2018.

    • Commercial Catch rate is down slightly from 0.8kg/pot/fisher/day in 2015 to 0.6kg/pot/fisher/day
    • Number of active licenses has fluctuated between 28 and 45 depending on fishing conditions
    • Commercial catch in 2017 is 85T (data incomplete), 133.05T in 2016.

     

    Gladstone Mud Crab Commercial Catch Dashboard

     

  • 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. Fishers in Gladstone regularly report catching Bream with most being returned to the water. Monitoring began in 2017 and continues in 2018.

    • Mud Crabs are the #1 reported species
    • No sizing data is available for Crabs
    • Fishers reported an overall catch rate of 0.83 Crabs per pot/fisher/day
    • 78% of fish reported are released (though all these will be juvenile and female crabs)
    • Peak periods of April and May.

     

    Qld Fisheries Boat Ramp Surveys monitoring dashboard

     

  • Gladstone Healthy Harbours Partnership

    Monitoring of Crab Sex Ratios and Abundance by Gladstone Healthy Harbours Partnership

    Size–sex ratio

    In some zones no female crabs of < 143mm were caught. Therefore, it was not possible to calculate asize–sex ratio comparing the ratio of male crabs of ≥ 143mm to female crabs of ≥ 143mm with theratio of male crabs of < 143mm to female crabs of < 143mm (Table 4.22). An alternative male/female ratio was used which calculates the ratio of male crabs over 143mm to female crabs over 143mm (Table 4.22). The highest value for the sex ratio, 2.2 males for every female, was recorded in the Inner Harbour and the lowest value of 0.24 males for every female was recorded in The Narrows.

    Abundance: catch per unit effort (CPUE)

    Abundance was the total number of crabs caught per pot during the 2017 mud crab monitoring for seven harbour zones. Highest catch rates were recorded in The Narrows, Boat Creek and Inner Harbour. The lowest catch rate was recorded in Rodds Bay (Table 4.23).

     

  • Crab Health

    Monitoring of Mud Crab Health

    The prevalence of rust lesions was assessed for the first 40 crabs caught in each zone. The lowest incidence of lesions was recorded in Boat Creek and The Narrows where less than 3% of the mud crabs had visual lesions. The highest incidence was recorded in Auckland Inlet (15.4%) and Rodds Bay (9.1%)


     

     

  • Recruitment

    Monitoring of Mud Crab Recruitment

    Recruitment is the success rate of juvenile fish surviving past the larval state. While the recruitment of Mud Crabs is not monitored recruitment has a strong correlation to the Southern Oscillation Index.

    • Good recruitment conditions in 2011 and 2013/14 resulted in high CPUE 2013-2016
    • Poor recruitment since has impacted stock levels
    • 2017 is a positive recruitment year based on the SOI with catches potentially to improve in 2019.



     

     

  • Monitoring

    Monitoring of Mud Crabs

    Data for this assessment has been sourced from:

    • Bureau of Meterology
    • Queensland Fisheries

     

    Here are links to all the monitoring pages for Mud Crabs:

    Gladstone Health Harbours Report Cart 2017
    Gladstone Queensland Fisheries Boat Ramp Surveys
    Gladstone Queensland Fisheries Commercial Data

  • Fishing Area

    Area Assessed

    Mud Crabs are caught throughout the Gladstone region. Commercially they are targetted in Grids S30,S31 (Gladstone) as well as T30,T31 (Rodds Bay) which are not included as that also covers Agnes Waters/1770.