Artemia, in all stages of its life cycle, is suitable food for most diversi¢ed groups of aquatic animals. Although its size at di¡erent stages restricts its use as a food for some groups of ¢sh, this problem can be overcome using selective breeding techniques. The formulation of any selective breeding programme calls for a proper understanding of the genetic architecture of the economically important traits of the population under study. Thus, heritability for certain important life history and reproductive traits was estimated in Artemia franciscana from the Great Salt Lake, Utah. In the present study, the sexwise heritability values for growth and reproduction traits were estimated using parent^o¡spring regression. The phenotypic parameters for the same traits are also recorded. The naupliar length was 487.072.0 and 490.671.8 mm for males and females, respectively, whereas the heritability values for naupliar length were 0.585170.2153 and 0.376670.1899 respectively. The length at 3 and 6 days of age were 1.8770.03 and 4.1070.08 mm, respectively, for males whereas1.8770.03 and 4.3070.08 mm, respectively, for females. The heritability values for length at 3 and 6 days of age for males were 0.327270.3651 and 0.496570.2466, respectively, whereas the respective values for the females were 0.116770.3841 and 0.022270.2971. The estimates of length at ¢rst brood, pre-reproductive period and number of o¡-spring in ¢rst brood were 10.0970.23 mm, 16.007 0.23 days and 53.5771.37 days, respectively, whereas the heritability values for respective traits were 0.040370. 1078, 0.323470.2874 and 0.340470.2202.

Bidirectional mass selection for naupliar length was practised in Artemia franciscana from Great Salt Lake, UT, USA, with the aim of developing two divergent lines, namely small naupliar size (SNS) and bigger naupliar size (BNS). A random-bred control line was also maintained to quantify the environmental e¡ects. The mean naupliar length in the base population was 486.9972.11 mm in males and 490.5871.82 mm in females. Six generations of selection for smaller naupliar size in the SNS line resulted in a phenotypic response of^45.32 mm and^37.52 mm decreases in naupliar size in males and females respectively. In the BNS line, responses (increase in size) from ¢ve generations of selection for bigger size were 8.59 mm and 35.80 mm respectively. The cumulative genetic gain in males and females of the SNS were^41.72 mm and^38.76 mm compared with 12.64 mm and 39.48 mm, respectively, in the BNS line.

The freshwater mussel Lamellidens corrianus (Lea 1834) is widely distributed in ponds and large bodies of perennial waters in the Indian subcontinent. It is one of the important species for producing freshwater pearls in India. As the freshwater pearl aquaculture activity may expand on wide scale in future, it may require collecting L. corrianus from the distant places and transport to pearl producing centres. Hence, in order to develop suitable method for transportation of L. corrianus to obtain high survival with minimum physiological stress, the present study was conducted. L. corrianus were transported by two different methods i.e. in air (in wet gunny bags) and in water (in plastic polyethylene bags containing water) to find out the best method for transportation. Glucose was chosen as the stress factor as the heightened circulating glucose levels may reflect the bivalve's ability to respond to weather extremes, handling stress or any recent environmental stress perceived to require extra energy. Experiments were conducted both under field as well as laboratory conditions, during the start of winter season, where regional temperature falls to 4-5°C below the average. Under the field experiment, L. corrianus (total length = 8.26 ± 0.34 cm; wet weight = 52.62 ± 3.18 g) were transported by road from Khopoli (Dist. Raigad, Maharashtra State) to Ratnagiri (Dist. Ratnagiri, Maharashtra State) for 12 h in air and water (reservoir water temperature = 26.4°C). Under laboratory conditions, simulating air transportation was done in wet gunny bags (42.5 cm 9 62.5 cm), each bag containing 50 mussels (total length = 8.34 ± 0.46 cm; wet weight = 53.2 ± 3.24 g). Simulating water transportation was carried out using plastic polyethylene bags (45 cm 9 60 cm), with 50 mussels in five litres of water (water temperature = 26.5°C). At periodical intervals, glucose concentrations from mantle, gill and posterior adductor muscle were estimated. Under both field and laboratory conditions, glucose levels were significantly higher in mantle, gill and posterior adductor muscle tissue of L. corrianus transported in air when compared to that of water-transported mussels. Results showed that air transportation was comparatively more stressful than water transportation. However, cent per cent survival was obtained in the both methods just after transportation and after 7 days of transportation. Considering the absence of mortality in both methods, it can be concluded that the choice of the mussel transportation method is more economical dependent than biological dependent.

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