Measurements of bodily parts were taken throughout life from captive male and female eastern grey kangaroos of known birth date. For each body measurement a growth curve was fitted, and confidence intervals calculated for determining the age of any new animal. A change of phase in the growth curve was apparent at the time when the young vacate the pouch. A join point in the curve was empirically estimated to occur at approximately 310 days, and the growth curve was represented by a 4-parameter non-linear model consisting of two hyperbolas constrained to pass through this common point. Tables presented permit determination of age from body measurements with corresponding confidence intervals for both males and females at 30-day intervals in the first year and less frequent intervals for the age of 15-36 months. Head and leg lengths proved to be the most reliable criteria for age determination; arm and foot length were reasonably accurate; ear length, tail length and weight were unreliable criteria.

The recruitment of postlarval Penaeus plebejus Hess to nursery areas in Moreton Bay, Qld, was examined in detail. The distribution and annual recruitment of postlarval immigrants of this species and that of P. esculentus Haswell and Metapenaeus bennettae Racek & Dall in Moreton Bay were also studied. Pelagic postlarval P. plebejus entering the Nerang River mouth showed no regular significant difference in vertical or horizontal stratification. Entry occurred substantially at night, was completed within the first 3 h of the flood tide, and the number decreased as the water velocity reached a maximum. Epibenthic P. plebejus immigrants settled upon the substrate in inverse proportion to their distance from the river mouth, their numbers decreased as the salinity decreased, and more settled in shallow than in deep areas. Water temperature showed no significant effect on their distribution, and similar numbers settled on seagrasses as on bare substrate. The annual recruitment pattern showed a seasonal cycle for P. esculentus and M. bennettae with maxima in January-February and March-May respectively. P. plebejus showed at least two peaks in the annual cycle with a maximum usually from July to September, suggesting that when the three species coexist in a habitat a temporal partitioning may occur. Generally, differences in the form of recruitment were seen between geographic areas, but not on different habitats within the areas. P. plebejus recruits were no more abundant on seagrassed than on bare substrates, but there were fewer at stations with a freshwater influence. In contrast, consistently greater numbers of P. esculentus recruits were obtained from seagrass meadows and most occurred adjacent to river mouths near the ocean. M. bennettae occurred over the whole study area but more were present at stations with a greater freshwater influence. When present in large numbers more were found on seagrassed areas. These differences in recruitment were considered to be a result of the reproductive biology of the species concerned, tidal currents, and distance between the spawning areas and each study site.

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Seven body measurements were taken at regular intervals throughout life from both male and female western grey kangaroos of known birth date. For each sex of three subspecies and for each body measurement a growth curve was fitted, and confidence intervals calculated for determining the age of new animals. As with eastern grey kangaroos, a phase change in the growth curve was apparent at the time when the young vacate the pouch. Join points in the curve for each subspecies of western grey kangaroos were estimated empirically, as three-quarters through the interval between first emergence and final vacation of the pouch by a young animal. The growth curves were represented by a four-parameter non-linear model consisting of two hyperbolas constrained to pass through the common point. Tables presented contrast the ages at which percentile growth values are attained for each subspecies, and also provide examples of the determination of age from body measurements for both males and females, at monthly intervals during their first year. As found for the eastern grey kangaroo, head length proved to be the most reliable criterion, and all measurements of animals older than 2 years were unreliable for age determination.

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