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.

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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The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single-cell, protein-based diet has a potential to promote gonad production of H. erythrogramma. KEY WORDS

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Nonspecific antibacterial activity (ABA) of lobster haemolymph was investigated as an indicator of lobster immune-system status and health condition. To determine whether ABA was localised in the plasma or in the haemocytes, we destroyed the haemocyte membrane by sonication and analysed samples containing plasma and haemocyte lysates for ABA along with sera from the same lobsters. Haemocytes were the main site of ABA in lobster haemolymph. In an experiment designed to assess typical handling conditions, lobsters were placed for 6 h under treatment conditions simulating five transport/storage approaches: submerged in flow-through water, sprayed with flow-through water, submerged in recirculating water, sprayed with recirculating water, and exposed to humid air. The lowest ABA was observed in the two submerged treatments and the highest in the two spray treatments. Lobsters that subsequently survived a simulated live-shipment procedure exhibited significantly lower ABA than did those found dead or weak during a subsequent 7 days of holding in the tank. We concluded that handling stress is associated with high ABA level in lobster haemolymph.

The contents of rock lobster cephalothorax were analyzed for lipid content and fatty acid composition. They contain a diversity of saturated (35.5 + 0.5%), monounsaturated (26.3 _+ 1.7%), and polyunsaturated fatty acids, n-3 highly unsaturated fatty acids (I 1.5 _+ 0.5%) among them. The possibility of using these products as a supplement to fish and food animals' diets is discussed. JAOCS 73,[259][260][261].KEY WORDS: Cephalothorax, fatty acid composition, fish meal, rock lobster. RESULTS AND DISCUSSIONCrustacean cephalothorax contains the organs of the respiratory, circulatory, digestive, and excretory systems. These or-

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