A previously unrecorded shell disease syndrome in mud crabs needs to be researched because:

OBJECTIVE 1 - By developing a grading system and defining the histological process, new early lesions can be identified and the cause isolated if it is an infectious agent.

OBJECTIVE 2 - (a) Prevalence of the disease in each life stage (egg, juvenile, adults) will help to define what stages are susceptible and therefore what preventative measures can be taken in management strategies.

Prevalence in Port Curtis compared with other areas (with different water quality parameters) will help to define what secondary factors may be involved.

(b) Infection trials in juveniles and adults will determine the virulence of the (potentially) infectious agent under controlled conditions. With the 1995 total mud crab catch in Central Queensland being approximately 18% down on the previous year (Qfish database) the affect of the disease on numbers needs investigating.

(c) If adhesions caused by ulcerations prevent molting, two scenarios can occur.

(i) prevents mating (mating only occurs when a female is in the soft shell form during molting) - prevent reproduction - reduced egg number - total mud crab numbers decline.

(ii) prevents growth - death (molting is required for growth to occur).

OBJECTIVE 3 - If the condition is contagious then it has the possibility of spreading to prawns and other crustacean spp. This is important not only to commercial fisheries but environmentally ie other crabs which are keystone species in mangrove communities. If cross infection does occur then strict hygiene regulations will need to be implemented to prevent entry into commercial aquaculture farms.

OBJECTIVE 4 - A management plan is needed (based on the above data) to reduce the impact on both wild and cultured crustaceans.