Disease agents and pests associated with freshwater crayfish fall into six main categories-viruses, bacteria, rickettsia-like organisms (RLOs), fungi, protists, and metazoans. Data and information on specific disease agents and pests from each of these categories are presented in this synopsis. Each agent or group of agents is considered under the following headings-condition, causative agent(s), life cycle/life history, epizootiology, pathology, pathogen viability. Information for the synopsis was obtained from the published literature and from personal contact with internationally recognized experts in freshwater crayfish aquaculture, biology, and disease. Data of relevance for import risk analysis are summarized.Import risk analysis is the process by which the risks associated with importation of animals and plants, and products derived from animals and plants, are assessed and managed. Hazard identification is essential and is the first component of an import risk analysis. In 1996, the Australian Quarantine and Inspection Service (AQIS) commenced a review of policy relating to the importation of nonviable freshwater crayfish products, along with a suite of other aquatic animal products. AQIS2 commissioned a synopsis of freshwater crayfish pests and pathogens for use as a resource document for hazard identification in the formal IRA process.

Total and differential haemocyte counts (THCs and DHCs) were obtained from 36 white and 36 red western rock lobsters (Panulirus cygnus) that had experienced stress during capture and transportation. The lobsters were divided into three different groups on the basis of their holding time in the factory tanks and their health status (fresh arrivals, healthy and moribund). THCs were obtained with a haemocytometer from fresh haemolymph stained with gentian violet. THCs ranged from 2.5 106 to 15.9 106 cells mL-1 in the three groups, being lowest in the moribund lobsters. DHCs were obtained from haemolymph smears stained with both Giemsa and May–GrÜnwald. Three major haemocyte groups could be identified in lobster haemolymph: hyalinocytes, semi-granulocytes and granulocytes. The proportion of hyalinocytes in the three lobster groups ranged from 29.1% to 37.0%, that of semi- granulocytes from 51.1% to 62.9%, and that of granulocytes from 5.1% to 13.1%. The proportion of granulocytes declined in lobsters after they were held for 16 h in the factory tanks and was lowest in moribund lobsters. The results show that THCs and DHCs may be useful in assessing stress or health status in the western rock lobster or other lobsters.

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This study aimed to determine the effect of post harvest operations such as air exposure on the health status of lobsters. These effects can be assessed through measurement of selected immune parameters such as total haemocyte counts, haemolymph clotting time, bacteraemia and the differential proportion of granular cells in lobster haemolymph. Lobsters were taken from factory holding tanks and exposed to air for 2, 6, 12, and 18 h through placement in foam boxes. Controls were sampled at each time point by collecting lobsters from the same tank as the experimental animals (10 animals /treatment group) with a different group of lobsters being sampled at each time point. Air exposure caused a significant increase in clotting time at 12h and 18h. Total haemocyte counts showed a decreasing trend. The proportion of granular cells tended to be lower in air-exposed animals, the difference was significant at 2h exposure. The bacteraemia levels tended to be higher in air exposed lobsters than in controls and the difference was significant at 12h exposure. Low total haemocyte counts, high clotting times, low granular cell numbers and high bacteraemia levels implied increased susceptibility to infection and lowered immunity. The results show that air exposure has a significant adverse effect on the immune system and hence on the health status of the lobsters.

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