MANAGEMENT, CONCLUSIONS, REFERENCES

MANAGEMENT

Amongst all the countries where mud crabs are commercially fished, the fishery is most highly regulated is Australia. All states and territories where mud crabs are fished have detailed management plans, which are backed up by legislation and enforcement by specialised fisheries enforcement agencies. The number of commercial fishers and the number of crab pots used is strictly limited.

All commercial mud crab fishers in Australia must complete logbooks recording the date, the number of crabs caught and the location of their catches. Information from these logs are collected on a monthly basis, entered into databases and analysed routinely. For recreational fishers, the number of crab pots that can be used, the number of mud crabs in possession and where and when they can fish is legislated. Considerable research and monitoring is also targeted on the mud crab fisheries in Australia to ensure management arrangements are working (Hay et al., 2005). No crabs under a specified minimum size limit can be collected, so utilization of mud crab seed-stock in Australia is not an issue as none is allowed. In Queensland, all female crabs are protected, so only males can be legally harvested by commercial or recreational fishermen, making Queensland the most regulated mud crab fishery in Australia.

Many countries have regulations or plans, which seek to control mud crab fisheries. However economic necessity and the lack of resources to enforce such legislation appear to result in a low level of compliance in most countries. In many countries strings of immature, under legal size crabs are routinely sold for human consumption, in addition to the collection of seed-stock for farming, putting enormous pressure on the reproductive population.
Whilst there have been some efforts to examine the potential for stock enhancement of mud crab fisheries from a research perspective, there appears to have been little long term efforts to do this on a commercial scale, apart from Japan.

CONCLUSIONS

Mud crabs can be the focus of commercial fishing activities throughout their life cycle in many countries, which can put intense fishing pressure on stocks. Juveniles (crablets) of varying sizes can be collected to stock farms for grow-out for either hard or soft shell crab production, whilst larger crabs are harvested for direct sale, or for fattening if the crabs are “empty” when collected, as is the case in the first few weeks post-moult.
The development of hatchery technology for mud crabs to support industrial scale development of crab farming is beginning to impact on the ecological, socio-economic and livelihoods traditionally linked to mud crab fishing in some countries.
The growth of mud crab aquaculture will increase demands on the collection of wild stock for grow-out and for limited trash fish and molluscan resources to feed crabs. To cope with increasing pressure on mud crab fisheries innovative management regimes need to be developed where fisheries management and enforcement resources are limited. The need to develop economically viable feeds for mud crabs to minimize the use of trash fish, is one shared with many types of aquaculture, as is the replacement of fishmeal and fish oils generally in stock feed formulation.

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